zones and containers faq
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Zones and Containers FAQ
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Last Updated: April 2010
Maintained by Jeff Victor, Penny Cotten, et al.
Dozens of contributors
This page is a list of Questions, some Frequently Asked, some Not So. It also includes Frequently
Requested Web Links. It is intended for use by anyone interested in learning more about Oracle Solaris
Zones and Oracle Solaris Containers.
If you would like to provide feedback on this FAQ, please send it to zones-discuss AT opensolaris DOT
org.
A date appearing after an answer provides the most recent date the answer has been updated.
Answers with old dates, or no date at all, might not provide the most recent information. All answers
without dates were current on June 14, 2005.
Topics in this FAQ
o Section 1: Basics
o Section 2: Configuration (non-I/O)
o Section 2B: I/O Configuration
o Section 2C: What Services can a Zone Provide?
o Section 3: Resource Management, Performance
o Section 4: System Administration
o Section 5: Security
o Section 6: Application-specific Information
o Section 7: Other Server Virtualization Solutions
o Section 8: Zones in OpenSolaris
o Section 9: Common but Non-Obvious Problems
Questions:
Edit
o Section 1: Basics
o Q: What is a zone?
o Q: What is a container?
o Q: What types of zones are available?
o Q: What is a global zone? Sparse-root zone? Whole-root
zone? Local zone?
o Q: Can I create a zone which shares ("inherits") some,
but not all of /usr, /lib, /platform, /sbin?
o Q: How do I get zones or containers?
o Q: What hardware can utilize zones or containers?
o Q: Will my software run in a zone or container?
o Q: How can I test my software for use in a container?
o Q: What applications are certified to run in zones or
containers?
o Q: How can I use the Solaris Explorer program to collect
information on my zone(s)?
o Q: What changes have happened to zones since it was
first released?
o Q: What features are new in Oracle Solaris 10 10/09?
o Section 2: Configuration (non-I/O)
o Q: How "big" is a zone?
o Q: How many containers can one copy of Solaris have?
o Q: Can each zone run a different Solaris version?
o Q: What types of re-configurations require a non-global
zone re-boot?
A:
o Q: What types of re-configurations require a complete
system re-boot?
o Q: Can containers be clustered?
o Q: Can I use SysV shared memory between containers?
o Q: Can a zone include multiple zones (aka "is the
containment model hierarchical")?
o Q: Can I automate the process of entering system
information, e.g. with sysidcfg?
o Q: Can some local zones be in different time zones?
o Q: Can some non-global zones have different date
and/or time settings (i.e. different clocks)?
o Q: Can I label my terminal windows with the name of the
zone I’m logged into?
o Section 2B: I/O Configuration
o Q: How can I learn more about using zones with IPMP or
iSCS?
o Q: How can I add a file system to an existing zone?
o Q: How can I make a writable /usr/local in a sparse-root
zone?
o Q: Can I assign a ZFS volume (zvol), an SVM meta-
device, or a Veritas Volume, to a non-global zone?
o Q: Can I, and should I, import raw devices into a non-
global zone?
o Q: Can I share an I/O resource (e.g. NIC, HBA) between
containers?
o Q: Can zones in one computer communicate via the
network?
o Q: How do I modify the network configuration of a
running zone?
o Q: Can IP Multipathing (IPMP) be used with zones?
o Q: Can IP Filter be used with zones?
o Q: Can I prevent a zone from using the network?
o Q: Are VLANs supported in zones?
o Q: How do I configure a default route in a container?
o Q: How can I restrict a zone (or a few zones) to one NIC
(network connector)?
o Q: When I tried to mount a file system into a non-global
zone, an error message displayed stating that the mount
point was busy. Why?
o Q: How can I mount a file system into two or more
different zones safely?
o Q: How can I create a zone with its own /usr or root file
system (a ’whole root file system’)?
o Q: How can I restrict a zone (or a few zones) to one HBA
(storage connector)?
o Q: Can a non-global zone NFS-mount a file system that
has been shared from its own global zone?
o Q: Can a zone’s root directory be on a ZFS file system?
o Section 2C: What Services can a Zone Provide?
o Q: Can a zone be an NFS server?
o Q: Can a zone be a DHCP server?
o Q: Can a zone be a DNS server?
o Q: Can a zone be an NTP client or server?
o Q: Can a zone be a NIS (aka yp), NIS+, or LDAP server?
o Q: Can a zone provide network login via telnet, rlogin,
rsh or ssh?
o Q: Can a zone be an ftp server?
o Q: Can a zone run sendmail?
o Q: Can I use X windows in a zone?
o Section 3: Resource Management, Performance
o Q: How can I prevent one container from consuming all
of the CPU capacity, preventing other workloads from
running properly?
o Q: What is the resource granularity for CPU assignment
to a container?
o Q: How can I limit the memory used by a container?
o Q: Can I dynamically change the quantity of a resource
(CPU, memory, network bandwidth) assigned to a
container?
A: To change the number of CPU shares associated with
a container without re-booting it, use the prctl
command, e.g.
o Q: Can swap space usage be managed?
o Q: Can I limit the network bandwidth used by a zone?
o Q: Do Containers use up a lot of CPU power?
o Q: Can the share value for a running project or zone be
changed?
o Q: Can I bind a zone to a pool?
o Q: Can projects/zones be reassigned to a different
resource pool while they are running?
o Q: Can you move processors between processor sets
while the system is running?
o Q: How can I prevent one zone from using all the swap
space by filling up /tmp?
o Q: Do I need to set a locked memory cap for a zone? If
so, what value should I set?
o Section 4: System Administration
o Q: What software can manage zones?
o Q: How do I create a zone?
o Q: How do I remove a zone?
o Q: Is the maximum number of exclusive-IP zones limited
to the number of physical ethernet ports?
o Q: Is it still necessary to set the NFSv4 domain
parameter?
o Q: How do I patch zones?
o Q: Can each container be a different Solaris patch level,
so I can test patches in a "test" container before
applying them to a "production" container?
o Q: Can I move a zone from one computer/domain to
another?
o Q: Is there a way to correlate audit records from multiple
containers?
o Q: Can I add packages to just the global zone (for
example, SRS netConnect)?
o Q: Can I add a package to one non-global zone without
adding it to the global zone?
o Q: What commands don’t work, or behave differently,
inside a zone?
o Q: Do zones boot automatically, or must I boot each one
manually every time the system (re)boots?
o Q: Should I halt a system’s zones before applying
patches?
o Q: Where does a zone’s syslog output go?
o Q: I removed a device from a zone, but it’s still there.
Why, and how do I get rid of it?
o Q: How do I upgrade a system with zones installed?
Does Live Upgrade work?
o Q: Are there any special guidelines for using Live
Upgrade with zones?
o Q: Are Solaris 10 zones configured on ZFS prior to the
Solaris 10 10/08 release upgradeable using Live
Upgrade?
o Q: What is the default networking service configuration
of a non-global zone when it is installed?
o Q: Can the patch levels between a zone migrated to the
target machine using update on attach and a zone
created on the target machine be different?
o Q: I tried to halt my zone but it is stuck in the 'shutting
down' or 'down' state and won't halt. What should I do?
o Section 5: Security
o Q: Can I access one zone from another zone?
o Q: Can I ’su’ from one zone to another?
o Q: Can I prevent the root account in one zone from
affecting other zones?
o Q: Can programs running in one zone change the
operation of programs running in another container?
o Q: How do I prevent a ’fork bomb’ from affecting all of
the zones?
o Section 6: Application-specific Information
o Q: Can Oracle use shared memory in a Container?
o Q: Can I use the Solaris 10 FSS (Fair Share Scheduler)
with Oracle in a Solaris Container?
o Q: Can I use Oracle RAC in a Container?
o Q: Are there any third-party documents that address
using applications with zones?
o Section 7: Other Server Virtualization Solutions
o Q: What are zone’s strengths compared to other server
virtualization solutions?
o Q: Are containers like VMware?
o Q: Are containers like HP vPars or nPars?
o Q: Are containers like IBM Micro-Partitions?
o Q: Are containers like Linux vServers?
o Section 8: Zones in OpenSolaris
o Q: How are zones different on OpenSolaris 2009.06?
o Q: Why are zones so different on OpenSolaris?
o Q: Why can’t I use sparse root zones?
o Q: Are zones on OpenSolaris done? Will zones continue
to look like they do on 2009.06?
o Q: How do I control what software is installed in the
zone?
o Q: Why is zone root its own dataset?
o Q: Why isn’t the zone root available when the zone is
halted? How do I set up the zone’s sysidcfg file?
o Q: I created a zone in OpenSolaris 2009.06, and tried to
add an /etc/sysidcfg file - but <zonepath>/root/etc
doesn't exist! Where did it go?
o Q: Can I continue to use zones created on OpenSolaris
2008.05?
o Section 9: Common but Non-Obvious Problems
o Q: I created a zone and booted it, but it doesn’t work.
What should I do?
o Q: I added some privileges to a user in a zone, and now
the user can’t login. What should I do?
o Q: I tried to upgrade to Solaris 10 11/06 and it told me
the upgrade failed and I need to restore from backup.
Now what?
Answers:
Edit
Section 1: Basics
Q: What is a zone?
A: A zone is a virtual operating system abstraction that provides a protected environment in which
applications run. The applications are protected from each other to provide software fault isolation. To
ease the labor of managing multiple applications and their environments, they co-exist within one
operating system instance, and are usually managed as one entity.
The original operating environment, before any zones are created, is also called the "global zone" to
distinguish it from non-global zones, The global zone is the operating system instance.
Q: What is a container?
A: A native, default zone on the Oracle Solaris 10 OS is called a container. The other containers that
run on Oracle Solaris 10 include Oracle Solaris 8 Containers and Oracle Solaris 9 Containers. Many
people use the terms "zone" and "container" interchangeably.
Q: What types of zones are available?
A: It is possible to create non-global zones that run the same OS as the global zone, which is the OS
running on the system. It is also possible to create a non-global zone that runs a different operating
environment from the global zone. The branded zone (BrandZ) framework extends the zones
infrastructure to include the creation of brands that contain alternative sets of runtime behaviors. The
following types of non-global zones are available:
o native:
A default Oracle Solaris Container non-global zone is called a
native zone. It has the same characteristics as the Oracle
Solaris 10 Operating System release that is running in the
global zone.
If you have configured your system with Oracle Solaris
Trusted Extensions, each non-global zone is associated with a
level of security, or label. Labeled zones can be configured
starting with the Oracle Solaris 10 11/06 release. For more
information, see Solaris Trusted Extensions Installation and
Configuration.
o ipkg:
The ipkg non-global zone is the default non-global zone on
the OpenSolaris release. It has the same characteristics as
the release that is running in the global zone. Each ipkg zone
manages its own software packages.
o Branded zones that run an environment different that
the OS release on the system
o The lx branded zone introduced in the Solaris 10 8/07
release provides a Linux environment for your
applications and runs on x86 and x64 machines on the
Oracle Solaris 10 OS. For more information, visit the
OpenSolaris Community: BrandZ.
o The solaris8 and solaris9 branded zones enable you to
migrate an Oracle Solaris 8 or Oracle Solaris 9 system to
an Oracle Solaris 8 or Oracle Solaris 9 Container on a
host running the Oracle Solaris 10 8/07 Operating
System or later Oracle Solaris 10 release. A solaris8
branded zone is an environment for Oracle Solaris 8
applications on SPARC machines. A solaris9 branded
zone is an environment for Oracle Solaris 9 applications
on SPARC machines. Now named Oracle Solaris 8
Containers and Oracle Solaris 9 Containers, these
products were introduced through a product called the
Solaris 8 Migration Assistant 1.0, on October 22, 2007.
For more information, see System Administration Guide:
Solaris 8 Containers and System Administration Guide:
Solaris 9 Containers. To download, go to Solaris
Containers. [May 2008]
o The Oracle Solaris 10 Container brand is available in
OpenSolaris build 127. These branded zones host Oracle
Solaris 10 user environments. [August 2010]
Q: What is a global zone? Sparse-root zone? Whole-root zone? Local zone?
A: After installing Oracle Solaris 10 on a system, but before creating any zones, all processes run in
the global zone. After you create a zone, it has processes that are associated with that zone and no
other zone. Any process created by a process in a non-global zone is also associated with that non-
global zone.
Any zone which is not the global zone is called a non-global zone. Most people call non-global zones
simply "zones." Some people call them "local zones" but this is discouraged.
The default native zone file system model on Oracle Solaris 10 is called "sparse-root." This model
emphasizes efficiency and security at the cost of some configuration flexibility. Sparse-root zones
optimize physical memory and disk space usage by sharing some directories, like /usr and /lib. Sparse-
root zones have their own private file areas for directories like /etc and /var. Whole-root zones increase
configuration flexibility but increase resource usage. They do not use shared file systems for /usr, /lib,
and a few others.
There is no supported way to convert an existing sparse-root zone to a whole-root zone. Creating a
new zone is required. [August 2010]
Q: Can I create a zone which shares ("inherits") some, but not all of /usr, /lib, /platform, /sbin?
A: The original design of Solaris Containers assumes that those four directories are either all shared
("inherited") or all not shared. Sharing some and not others will lead to undefined and/or unpredictable
behavior. [August 2010]
Q: How do I get zones or containers?
A: Oracle Solaris 10 includes all of the programs and files needed to use zones (and Containers).
Operating systems based on the OpenSolaris code base, including OpenSolaris 2009.06, may elect to
include support for zones. [August 2010]
Q: What hardware can utilize zones or containers?
A: Zones and resource management are all software features of Oracle Solaris and other operating
systems based on the OpenSolaris code base. As software features, they do not depend upon any
specific hardware platform. Any hardware that runs a Solaris distro (Oracle Solaris 10, OpenSolaris, or
another) will be able to have these features.
Q: Will my software run in a zone or container?
A: Most Oracle Solaris software will run unmodified in a zone, without needing to re-compile.
Unprivileged software (programs that do not run as root nor with specific non-default privileges)
typically run unmodified in a zone once they can be successfully installed. Installation software must
not assume that it can write into shared, read-only file systems, e.g. /usr. This can be circumvented by
adding a writable file system to the zone (e.g. at /usr/local) or using a whole-root zone.
However, there are a few applications which need non-default privileges to run - privileges not
normally available in a zone, such as the ability to set the system?s time-of-day clock. For these
situations, the feature named "configurable privileges" has been added. This feature allows the global
zone administrator - the person who manages zones on a system - to assign additional, non-default
privileges to a zone. The zone?s administrator can then allow individual users to use those non-default
privileges.
An application that requires privileges that cannot be added to a zone might need modification to run
properly in a zone.
Here are some guidelines:
o An application that accesses the network and files, and
performs no other I/O, should work correctly.
o Applications that require direct access to certain devices,
e.g., a disk partition, will usually work if the zone is configured
correctly. However, in some cases this may increase security
risks.
o Applications which require direct access to these devices
must run in the global zone, or must be modified to work
correctly:
o /dev/kmem
o a network device
1. Starting with OpenSolaris build 37 and Oracle
Solaris 10 8/07, a default zone can be configured
as an "exclusive-IP zone" which gives it exclusive
access to the NIC(s) that the zone has been
assigned. Applications in such a zone can
communicate directly with the NIC(s) available to
the zone.
2. Applications running in shared-IP zones should
instead use one of the many IP services.
For more details, read the white paper "Bringing Your Application Into the Zone". Note that changes
have been made to privileges, IP types, and other areas used with zones since this paper was
published. For current information, also see the administration guide. [November 2007]
Q: How can I test my software for use in a container?
A: See the document Qualification Best Practices for Application Support in Non-Global Zones." [March
2006]
Q: What applications are certified to run in zones or containers?
A: Supportability of an application running in a container is evaluated by the ISV. Some software
vendors treat zones as just another feature set of Oracle Solaris, and do not feel a need to specifically
certify their software to use zones. Others have specifically certified their software to use zones.
Applications that have been reported to be officially supported include those in the following list. For
more details see the section "Application-specific Information"
o BEA WebLogic Server 8.1 SP4
o Veritas Storage Foundation 5.0 (MP3)
o Oracle's pricing policy regarding containers
o Veritas NetBackup 5.0 (MP4) and 5.1 (MP2)
o Sun N1 Grid Engine 6 (Update 4)
o CA Ingres
o IBM DB2 8.2
o IBM Websphere
o Oracle TimesTen
o Oracle Ebusiness Suite 11
o SAP R/3
o Veritas VCS - see " Implementing Solaris? Zones with Veritas?
Cluster Server by Symantec"
Q: How can I use the Solaris Explorer program to collect information on my zone(s)?
A: Explorer 5.0 can be run on Oracle Solaris 10 in a global zone. It can be used to collect information
on containers (non-global zones) with the -w option.
Q: What changes have happened to zones since it was first released?
A: See the OpenSolaris project page for changes made since the initial release. [September 2006]
Q: What features are new in Oracle Solaris 10 10/09?
A: New features include the following:
o Support has been added for zones parallel patching to reduce
patching time, a fast
patching solution that utilizes the patchadd utility. For
releases prior to Oracle Solaris 10 10/09, the patch is
delivered in the patch utilities patch, 119254-66 or later
revision (SPARC) and 119255-66 or later revision (x86).
o For a zone that cannot be halted, as of the Oracle Solaris 10
10/09 release, you can migrate a zone that has not been
detached by using the zoneadm attach -F option to force the
attach without a validation. The target system must be
properly configured to host the zone. An incorrect
configuration could result in undefined behavior. Moreover,
there is no way to know the state of the files within the zone.
[Oct 2008]
Back to Top
Section 2: Configuration (non-I/O)
Q: How "big" is a zone?
A: If configured with default parameters, a zone requires about 100MB of free disk space per zone
when the global zone has been installed with the "All" metacluster of Oracle Solaris 10 packages.
Additional packages installed in the global zone will require additional space in the non-global zones.
ZFS quotas or SVM soft partitions can be used to enforce per-zone disk space constraints. When
performing capacity planning, 100MB of additional RAM per zone is suggested (in addition to the needs
of its workload). An application does not use any "extra" RAM because it is running in a zone.
A zone installed using the "full-root model" will take up as much space as the initial Oracle Solaris 10
installation, which will be more than 500MB in most cases. [August 2010]
Q: How many containers can one copy of Solaris have?
A: While the theoretical limit is over 8,000, the practical limit depends on:
o The amount of hardware resources used by the applications
versus the amount available in the system. This includes the
number and processing power of CPUs, memory size, NICs,
HBAs, etc.
o What portion of the installed zones are actually in use. For
example, you can create 100 zones, each ready to offer a
web service, but only boot the 10 that you need this month.
The unbooted zones take up disk space, but do not cause the
use of any extra CPU power, RAM, or I/O. [August 2010]
Consider these examples which worked:
o 40 zones, each running five copies of the Apache web service,
on an E250 with two 300MHz CPUs, 512MB RAM, and three
hard disk drives totalling 40GB. With all zones running and a
load consisting of multiple simultaneous HTTP requests to
each zone, the overhead of using zones was so small it wasn’t
measurable (<5%).
Q: Can each zone run a different Solaris version?
A: All of the zones use a single underlying kernel. The version of the kernel determines the version of
every container in that domain. However, the Oracle Solaris 8 Containers and Oracle Solaris 9
Containers products provide the appropriate system calls so that binaries compiled for Oracle Solaris 8
or Oracle Solaris 9 work correctly. [August 2010]
Q: What types of re-configurations require a non-global zone re-boot? A:
o Adding a device to a non-global zone.
o Binding a zone to a pool.
o Modifying a zone's privilege set.
[August 2010]
Q: What types of re-configurations require a complete system re-boot?
A: We are not aware of any. [August 2010]
Q: Can containers be clustered?
A: Yes, but not without adding additional cluster management software. As of this writing, Sun is
developing extensions to its Sun Cluster software, so that Resource Groups can be placed within non-
global zones. <Veritas/Symantec> has also announced support for Zones in the Veritas Cluster
product.
Q: Can I use SysV shared memory between containers?
A: No, this is prohibited. This would violate several security principles. [August 2010]
Q: Can a zone include multiple zones (aka "is the containment model hierarchical")?
A: No, the model is strictly two-level: one global zone and zero or more non-global zones. Only the
global zone can create non-global zones, and each non-global zone must be contained within the
global zone. [August 2010]
Q: Can I automate the process of entering system information, e.g. with sysidcfg?
A: Yes, after a zone has been installed, copy a sysidcfg(4) file to the zone’s /etc/sysidcfg before the
first boot of that zone.
[August 2010]
Q: Can some local zones be in different time zones?
A: Yes. Each non-global zone has its own copy of /etc/default/init, which contains the timezone setting.
You can change the line starting with "TZ=". The recognized names of timezones are in
/usr/share/lib/zoneinfo. For example, Eastern Standard Time in the USA is defined in the file
/usr/share/lib/zoneinfo/US/Eastern. To set a non-global zone’s timezone to that timezone, the line in
/etc/default/init would look like this:
TZ=US/Eastern
[August 2010]
Q: Can some non-global zones have different date and/or time settings (i.e. different clocks)?
A: Although different zones can ’be’ in different time zones, each zone gets its date and time clock
from the same source. This means that the time zone setting gets applied after the current time data
is obtained from the kernel.
If you would like the ability to have different clock sources per zone, please add a call record to RFE
5033497. [August 2010]
Q: Can I label my terminal windows with the name of the zone I’m logged into?
A: Yes. After logging into the zone, enter this command:
zone% /bin/echo "\033]0;Zone `/bin/zonename`\007\c"
[August 2010]
Back to Top
Section 2B: I/O Configuration
Q: How can I learn more about using zones with IPMP or iSCS?
A:See Jeff’s Blog for step-by-step instructions. [May 2008]
Q: How can I add a file system to an existing zone?
A: There are four methods. The following list uses UFS examples, but other types of file systems, such
as ZFS, HSFS and VxFS, can be used in the zonecfg "fs" resource type property or attached by
mount(1M).
1. Create and mount the file system in the global zone and use
LOFS to mount it into the non-global zone (very safe)
2. Create the file system in the global zone and use zonecfg to
mount the file system into the zone as a UFS file system (very
safe)
3. Export the device associated with the disk partition to the
non-global zone, create the file system in the non-global zone
and mount it. Security consideration: If a _block_ device is
present in the zone, a malicious user could create a corrupt
file system image on that device, and mount a file system.
This might cause the system to panic. The problem is less
acute with raw (character) devices. Disk devices should only
be placed into a zone that is part of a relatively trusted
infrastructure.
4. Mount a UFS file system directly into the non-global zone’s
directory structure (allows dynamic modifications to the
mount without rebooting the non-global zone)
See the administration guide for instructions to use these methods. [September 2006]
Q: How can I make a writable /usr/local in a sparse-root zone?
A: Use one of the methods above, for example:
global# mkdir -p /path/to/some/storage/local/twilight
global# zonecfg -z twilight
zonecfg:twilight> add fs
zonecfg:twilight:fs> set dir=/usr/local
zonecfg:twilight:fs> set special=/path/to/some/storage/local/twilight
zonecfg:twilight:fs> set type=lofs
zonecfg:twilight:fs> end
zonecfg:twilight> commit
zonecfg:twilight> exit
global#
[August 2010]
Q: Can I assign a ZFS volume (zvol), an SVM meta-device, or a Veritas Volume, to a non-global zone?
A: With Solaris 10 1/06, you can directly assign an SVM meta-device into a non-global zone, using the
same method you would with most other devices. However, see the answer to the next question.
Symantec supports the assignment of a Veritas Volume into a non-global zone. For more information,
see this guide. [June 2009]
Q: Can I, and should I, import raw devices into a non-global zone?
A: The Solaris Zones feature set provides the global zone administrator with the ability to allow a non-
global zone to access a raw device. There are many situations where this will be the best approach to
solve a problem. There are even situations which require such use.
First, however, it is important to stress that there are usually other solutions that do not require direct
device access. Let’s discuss this first.
With regard to importing VxVM devices into a zone: this is possible with VxVM 5.0MP3 and up. For
earlier versions, your options depend on the goal. If the goal is to make a file system available in the
zone, the solution is to create the file system in the global zone, and LOFS or direct mount the file
system in the zone. On the other hand, if the goal is to make a mirrored block device available in the
zone, the only solution is to upgrade to VxVM 5.0MP3 or higher.
If you want to make a file system available in the zone, create the file system in the global zone, and
use LOFS to make the file system available in the zone. On the other hand, if the goal is to make a
mirrored block device available in the zone, another solution must be found.
In any situation, if direct device access is required within a zone, you must perform careful failure
analysis and evaluation of the possible outcomes of "catastrophic application failure. If the non-global
zone will use COTS software, and will be managed by trustworthy people, then the risks will be small.
Fortunately, in most cases there are also other solutions which do not use direct device access from a
zone.
Here are two extreme examples:
1. A zone will be created for the purpose of training students on
basic Unix commands. The root account will only be used by
the global zone administrator. The system will be attached to
a LAN which is not connected to any other networks. The
instructor needs access to the sound device. There are very
few risks associated with such access - it would be very
difficult for the sound device to suffer a failure, and even if it
did it would be unlikely to affect other zones.
The zone can be given access to this via the zonecfg sub-
commands:
global# zonecfg -z zonename
zonecfg:zonename> add device
zonecfg:zonename:device> set match=/dev/sound/*
zonecfg:zonename:device> end
zonecfg:zonename> exit
The zone will have access to sound devices, but will not have access to any other devices.
2. A zone will be created for the purpose of teaching students about a database program that requires
access to raw disk partitions. The instructor knows how to use Unix, but does not have a background in
Unix system administration. Further, the instructor will require use of the root account to assist
students. It is possible that the instructor could make a mistake, or a malicious student could abuse
the raw disk access, leading to a crash of the kernel. This would also stop all of the other non-global
zones, as well as the global zone. If the other zones are running production software, this request for
raw disk access in a zone should not be fulfilled. Other solutions should be pursued, such as creating
an RBAC role for the instructor which only gives the necessary privileges to the isntructor’s Unix
account.
Other examples must be judged by their particulars, e.g. a production database program which needs
raw access. Factors to consider include:
o Who will login to the zone? How trustworthy are they?
o Is this system protected from unauthorized access by a
firewall?
o What level of availability is required by applications running in
this zone and in other zones?
For more information on this topic, see the section "SECURITY AND DATA INTEGRITY" of the man page
for sgen(7d).
[August 2010]
Q: Can I share an I/O resource (e.g. NIC, HBA) between containers?
A: Yes, in fact, that is the default model. Each container is assigned its own IP address, but usually
multiple containers will share one NIC. Further, multiple zones may be assigned separate file systems
accessed through one HBA. [August 2010]
Q: Can zones in one computer communicate via the network?
A: Both shared-IP and exclusive-IP zones can communicate via the network. In general, a zone is
assigned to use one or more network ports (aka NICs), and network traffic to or from other computers
uses the assigned NIC(s), following standard IP rules.
Network traffic between two zones on the same system may require extra planning. If a zone is an
"exclusive-IP" zone, its network packets will always leave the computer, and inbound packets will
always come from outside the computer. Further, an exclusive-IP zone performs all of its own network
configuration, including routing and IP filtering.
Before Solaris 10 10/08, network traffic between two shared-IP zones always stayed in the computer,
i.e. it didn’t traverse the physical network. This provided very high bandwidth, low latency
transmission. However, starting with Solaris 10 10/08, traffic between two shared-IP zones stays in the
computer unless a default router is used for one or both zones. Traffic from a zone with a default
router will go out to the router before coming back to the destination zone. For more information on
default routers for zones, see the documentation and Steffen’s blog.
Full IP-level functionality is available in an exclusive-IP zone. Exclusive-IP zones always communicate
with each other over the physical network. That communication can be restriced using IP Filter from
within such zones, just as it can for a separate system.
For shared-IP zones in one computer that communicate using IP networking,the following applies:
o Inter-zone network latency is extremely small, and bandwidth
is extremely large
o Solaris IP Filter can be enabled in non-global zones by turning
on loopback filtering as described in System Administration
Guide: IP Services. Filter rules are still configured in the global
zone.
It is possible to configure routing to block traffic between specific zones completely.
For more information on IP types, see the System Administration Guide: Solaris Containers-Resource
Management and Solaris Zones.
Further, OpenSolaris 2009.06 added the features "virtual NICs" and "virtual switches" - part of "Project
Crossbow." They allow you to configure an entire internetwork in a system, using VNICs, vSwitches,
and zones that are configured as routers. [August 2010]
Q: How do I modify the network configuration of a running zone?
A: For shared-IP zones, the ifconfig(1M) command can be used in the global zone to modify that zone’s
existing network configuration or to add new logical interfaces to a zone. Here are some examples that
add, and then delete a logical interface assigned to a zone:
global# ifconfig bge0 addif 192.168.200.202 zone myzone
global# ifconfig bge0 removeif 192.168.200.202
[August 2010]
Q: Can IP Multipathing (IPMP) be used with zones?
A: Yes.
Exclusive-IP zones can use IPMP. IPMP is configured the same way in an exclusive-IP zone as it is on a
system not using zones.
For shared-IP zones, IPMP can be configured in the global zone. Failover of a network link (e.g. hme0)
that is protected by IPMP will bring the associated logical interfaces (e.g. hme0:3) for the zones over to
the secondary link (e.g. bge0).
For more information, see the section "Using IP Network Multipathing on a Solaris System With Zones
Installed" in System Administration Guide: Solaris Containers-Resource Management and Solaris
Zones.
Take extra care with IPMP and the defrouter setting. See this blog entry. [August 2010]
Q: Can IP Filter be used with zones?
A: Yes. The global zone can configure IP Filter rules for shared-IP zones. An exclusive-IP zone can
configure IP Filter rules for itself.
For shared-IP zones, the IPFilter features in Solaris 10 can be used to filter traffic passing between one
non-global zone and other computers on the network. This includes the ability to use NAT features, i.e.,
redirect traffic destined for the global zone to non-global zones.
[August 2010]
Q: Can I prevent a zone from using the network?
A: Yes. A zone does not need a network interface in order to operate. If you don’t specify a network
interface when you create the zone, it will still boot correctly. If an existing zone has been given access
to a network interface, you can use zonecfg(1M) to remove that access, but if the zone is running you
must also either re-boot the zone or use ifconfig(1M) to remove access until the next re-boot.
It is also possible to allow a shared-IP zone to access the network, but not communicate with other
zones on the same system. One method is to set up a pair of routes using the "-reject" argument to
the route(1) command. For example, if one zone has an IP address of <Addr1> and the second zone
has an address of <Addr2>, then the following commands will prevent network traffic from passing
between the two zones. [August 2010]
global# route add <Addr1> <Addr2> -interface -reject
global# route add <Addr2> <Addr1> -interface -reject
Q: Are VLANs supported in zones?
A: Yes. For a shared-IP zone, the VLAN interface must be plumbed in the global zone. LAN and VLAN
separation are available in an exclusive-IP non-global zone.
Q: How do I configure a default route in a container?
A: For a shared-IP configuration: All routes, including default routes, must be configured by the global
zone administrator. By default, such zones use the global zone’s default router. Starting with Solaris 10
10/08, each shared-IP zone can be assigned its own default router with the "defrouter" setting in
zonecfg. For more information on default routers for zones, see the documentation and Steffen’s blog.
For an exclusive-IP configuration: The zone administrator can configure IP on those data-links with the
same flexibility and options as in the global zone.
[August 2010]
Q: How can I restrict a zone (or a few zones) to one NIC (network connector)?
A: The global zone administrator configures each zone’s access to zero or more NICs. A shared-IP zone
can be the only zone using a NIC.
Exclusive-IP zones have more separation which reaches down to the data-link layer. One or more
data-link names, which can be a NIC or a VLAN on a NIC, are assigned to an exclusive-IP zone by the
global administrator. The zone administrator can configure IP on those data-links with the same
options as in the global zone. [August 2010]
Q: When I tried to mount a file system into a non-global zone, an error message displayed stating that the mount point was busy. Why?
A: All accesses to entries in lofs mounted file systems map to their underlying file system. Therefore, if
a mount point is made available in multiple locations via lofs and it is in use in any of those locations
(as a mount point, a current working directory, etc.), an attempt to mount a file system at that mount
point will fail unless the overlay flag has been specified. [November 2007]
Q: How can I mount a file system into two or more different zones safely?
A: Create a directory in the global zone, and remount it into each non-global zone using lofs. This will
allow reading and writing from both zones without corrupting. It’s the same mechanism used by the
automounter in certain cases.
Q: How can I create a zone with its own /usr or root file system (a ’whole root file system’)?
A: By default a zone shares /usr and a few other directories with the global zone. If a zone needs its
own separate copy of /usr, et al., you must tell zonecfg to not use the default configuration. To do this,
use the "-b" option on the "create" sub-command of the zonecfg(2) command.
If you do this, you must specify each existing file system that you do want to share with this new
zone. [August 2010]
Q: How can I restrict a zone (or a few zones) to one HBA (storage connector)?
Each zone uses space in at least one disk partition - its root directory and several others (e.g. /etc) live
there. All of these files are part of Solaris. In addition, each zone can be given access to one or more
file systems and/or one or more raw disks. By planning carefully, you can configure one zone so that all
of its files and devices are accessible through one HBA, and all of the storage of another zone is
accessible through a different HBA. [August 2010]
Q: Can a non-global zone NFS-mount a file system that has been shared from its own global zone?
A: No. This may be addressed in the future. However, the shared file system can also be LOFS-
mounted into the local zone, and, if necessary, the global zone can export the same file system via
NFS so that other computers can also access those files. [August 2010]
Q: Can a zone’s root directory be on a ZFS file system?
A: Solaris 10 release:
Placing a zone’s root directory (i.e. its PATHNAME) on ZFS is supported starting with Solaris 10 10/08,
and you can then upgrade with Live Upgrade going forward. There are still issues with placing a zone
on ZFS on a release prior to Solaris 10 10/08 and then trying to upgrade.
[August 2010]
Back to Top
Section 2C: What Services can a Zone Provide?
Q: Can a zone be an NFS server?
A: A global zone can be an NFS server. A non-global zone cannot use the Solaris NFS server features.
However, non-Solaris NFS server software (i.e. "userland" NFS server software) has been shown to
work correctly in a non-global zone. Such software works because it does not run in the kernel, unlike
the Solaris NFS server software which runs in the Solaris kernel in order to maximize performance.
[August 2010]
Q: Can a zone be a DHCP server?
A: A global zone can be a DHCP server.
Starting with Solaris 10 11/06, a non-global zone can be a DHCP server. This ability became more
flexible with Solaris 10 8/07, which added a feature called IP Instances. [August 2010]
Q: Can a zone be a DNS server?
A: Yes.
Q: Can a zone be an NTP client or server?
A1: A zone can be an NTP server.
A2: The NTP client software sets the system time clock shared by all zones, including the global zone.
By default, non-global zones cannot do this. However, the global zone administrator can give a zone
the ability to change the system time clock with the "sys_time" privilege. Be aware that this changes
the time clock for all zones.
See http://blogs.sun.com/JeffV/entry/shrink_wrap_security1 for an example. (August 2010)
Q: Can a zone be a NIS (aka yp), NIS+, or LDAP server?
A: Yes, yes, and yes.
Q: Can a zone provide network login via telnet, rlogin, rsh or ssh?
A: Yes, yes, and yes.
Q: Can a zone be an ftp server?
A: A zone can be an ftp server, but it is not possible to use ftpconfig(1M) to set up a zone to be an
anonymous ftp server. This is because ftpconfig attempts to set up certain device special files, and a
zone does not have the necessary privileges. [December 2005]
Q: Can a zone run sendmail?
A: Yes.
Q: Can I use X windows in a zone?
A: There are a few different methods to use X windows with zones:
1. On the system console: at the login screen, you can choose
"Remote Host" and enter the hostname of the zone. The X
windows login screen should be replaced with an X windows
remote login screen.
2. At the console, logged into the global zone: you can tell X
to allow remote connections from the non-global zone, telnet
to that zone, and set the appropriate environment variable so
that X sessions go to the global zone’s X windows session,
e.g. "setenv DISPLAY my-global-zone".
3. At another system, you can login directly to the non-global
zone, and perform steps similar to the previous method.
Back to Top
Section 3: Resource Management, Performance
Q: How can I prevent one container from consuming all of the CPU capacity, preventing other workloads from running properly?
A: Use the resource management features of Solaris. This requires using some combination of the Fair
Share Scheduler, CPU caps, assigned (’dedicated’) CPUs, and/or [Dynamic] Resource Pools features.
Fair Share Scheduler: FSS guarantees a minimum amount of CPU utilization, so it doesn’t waste CPU
cycles. Excessive CPU use is only prevented if there is contention for CPU resources. Minima are
specified by "shares" and enforced by the Fair Share Scheduler. You can assign 100 shares to each of
two workloads, 200 shares to a third workload, and 400 shares to the global zone. The first two
workloads will get at least 1/8 of the CPUs' capacity, if they need it, and the global zone will get at
least 1/2 of the CPUs' capacity, if it needs it. If only one Container wants to use the CPUs, it will be able
to use all of the processing capacity of the system.
You should give the global zone a quantity of shares similar to the largest quantity given to any
Container, to ensure that you can manage the Containers.
Starting with Solaris 10 5/08, you can use the capped-cpu resource type. Starting with Solaris 10
8/07, you can use the dedicated-cpu resource type to automatically create a temporary pool when
the zone boots. See Non-Global Zone Configuration (Overview).
Alternatively, you can create a processor set with one or more CPUs and bind it to a resource pool.
Then create a zone and bind it to the same resource pool. Run the application in that zone. The
application will only "see" that set of processors. For more information, see Resource Pools (Overview)
and Resource Pools (Tasks).
Web Links:
Non-Global Zone Configuration (Overview)
Fair Share Scheduler (Overview)
CPU Caps
Dynamic Resource Pools (Overview)
[January 2010]
Q: What is the resource granularity for CPU assignment to a container?
A: Fair Share Scheduler: Arbitrary, i.e. one-thousandth of a CPU or smaller. For example, CPU share
assignments could be 1, 1000, 999, resulting in utilization minima of 0.05%, 50%, and (practically
speaking) 50%.
CPU Cap: number of CPUs, in hundredths of a CPU. One zone can be capped at 4.01 CPUs, and
another can be capped at 4.02 CPUs. Dedicated CPU: CPU range, in integer number of CPUs. For
systems with multiple hardware threads per CPU core, Solaris considers each core to be a "CPU." For
systems with multiple threads per CPU core (including Nehalem, SPARC CMT and SPARC64-VII) Solaris
considers each hardware thread to be a "CPU." August 2010
Q: How can I limit the memory used by a container?
A: You can use the Resource Capping Daemon (rcapd) for all Solaris 10 releases. Starting with Solaris
10 8/07, you can use the capped-memory resource to set limits for physical, swap, and locked
memory. Determine values for this resource if you plan to cap memory for the zone by using rcapd
from the global zone. The physical property of the capped-memory resource is used by rcapd as the
max-rss value for the zone.
Web Links:
Non-Global Zone Configuration (Overview)
Administering the Resource Capping Daemon
[January 2009]
Q: Can I dynamically change the quantity of a resource (CPU, memory, network bandwidth) assigned to a container?
A: To change the number of CPU shares associated with a container without re-booting it, use the prctl command, e.g.
prctl -n zone.cpu-shares -r -v $SHARES `pgrep -z $ZONENAME init`
where $SHARES is the new number of shares and $ZONENAME is the name of the zone.
In Solaris 10, starting with 5/08, similar methods can be used to change the CPU cap, RAM cap, VM
cap and shared memory cap.
Web Links:
Resource Controls
Using the prctl Command
Fair Share Scheduler (Overview)
prctl(1)
[August 2010]
Q: Can swap space usage be managed?
A: The entire swap partition is treated as a single global resource to processes running in both global
and non-global zones. Before Solaris 10 8/07, you couldn’t limit the amount of swap used by a zone on
a per-zone basis. You can globally limit the size of the swap-based file systems (e.g. /tmp) by using the
"size" mount option in the container’s /etc/vfstab file, e.g. "size=200m". This allows you to decrease
the effect of many and/or large files created in /tmp.
Starting with Solaris 10 8/07, you can use the 'swap' property of the capped-memory resource to cap
the amount of virtual memory (VM) that a zone uses. This can also be set dynamically with the
resource control zone.max-swap.
[August 2010]
Q: Can I limit the network bandwidth used by a zone?
A: Yes, use the IPQoS features in Solaris 10. You must manage this from the global zone for the
containers.
Q: Do Containers use up a lot of CPU power?
A: CPU overhead of containers is hardly measurable (i.e. <1%) for a few zones or even dozens of
zones, depending somewhat on the applications.
Q: Can the share value for a running project or zone be changed?
A: Yes. Here is an example:
prctl -n project.cpu-shares -v 10 -r -i project group.staff
The prctl utility allows the examination and modification of the resource controls associated with an
active process, task or project on the system. It allows access to the basic and privileged limits on the
specified entity.
-n specifies the name of the resource to get or set
-r specifies a replace operation
-v specifies the new value for the resource
-i specifies the owning process, task or project of the resource.
Q: Can I bind a zone to a pool?
A: Yes, but in Solaris 10 8/07 and later, it’s much easier to use the ’dedicated-cpus’ feature.
To bind a zone’s processes to a pool, first create the pool, then use zonecfg(1M) to bind a zone to it.
1. Enable resource pools on your system using either svcadm or
pooladm -e.
2. Use pooladm -s to create the pool configuration.
3. Use pooladm -c to commit the configuration at
/etc/pooladm.conf.
4. Use poolcfg -c to modify the configuration.
poolcfg -c ’create pset pset_zone (uint pset.min = 3; uint pset.max = 3)’
poolcfg -c ’create pool pool_zone (string pool.scheduler="FSS")’
poolcfg -c ’associate pool pool_zone (pset pset_zone)’
5. Use pooladm -c to commit the configuration at /etc/pooladm.conf.
See the administration guide.
The command to perform the binding, from the global zone, would be:
zonecfg -z zone1 set pool=pool_zone
If the zone was running, you must re-boot it for the binding to take effect, unless you also dynamically
assign the zone to the pool, as described in the question "Can projects/zones be reassigned to a
different resource pool while they are running?". [August 2010]
Q: Can projects/zones be reassigned to a different resource pool while they are running?
A: Yes. Here is an example:
poolbind -p web_app -i zoneid myzone
The poolbind command binds zones, projects, tasks and processes to a pool.
-p is the name of the pool to bind
-i specifies the process id, zone id, task id or project id to be bound to the pool.
Q: Can you move processors between processor sets while the system is running?
A: Yes, you can. Here is the command(s) you would use:
o If you don’t care which CPUs you move from a processor set
the command would be:
poolcfg -dc "transfer 2 from pset pset1 to pset2"
which will move any two processors from pset1 to pset2
-d operate directly on the kernel state
-c this signifies the command
If you want to move a specific CPU(s) here is the command:
poolcfg -dc "transfer to pset pset2 (CPU 0, CPU 1)"
which will move CPUs 0 and 1 to pset2.
Q: How can I prevent one zone from using all the swap space by filling up /tmp?
A: For manual mounts, use the option "-o size=sz" where sz is the size limit you want. Ending the size
in ’k’ means kilobytes, ending it in ’m’ means megabytes. Example: "-o size=500m". This option can
also be added into /etc/vfstab. For more details, view the man pages for mount_tmpfs(1M) and
vfstab(4).
With Solaris 10 8/07, you can use the resource control, zone.max-swap. (The swap property of the
capped-memory resource is the preferred way to set this control.)
Q: Do I need to set a locked memory cap for a zone? If so, what value should I set?
A: A locked memory cap in a zone can be set using the 'locked' property of the zonecfg capped-
memory resource. Applications generally do not lock significant amounts of memory, but you might
decide to set locked memory if the zone’s applications are known to lock memory.
If a Container locks down enough memory, it can cause other Containers to page excessively. For that
reason, setting the 'locked' property is recommended, because each Container can use locked
memory.
If the zone administrator is less than trusted or if DOS exploits are of concern, you can also consider
setting the locked memory cap to 10% of the system’s physical memory or to the zone’s physical
memory cap.
[August 2010]
Back to Top
Section 4: System Administration
Q: What software can manage zones?
A: Here are just a few of the software tools - some free, some not free - which will help you manage
Solaris Zones:
o Oracle Enterprise Manager Ops Center (Sun Management
Center) can create and manage Solaris Containers
o WebMin GUI has a Solaris Zones module
o Xone Control GUI
o The Zone Manager Command
o Zonestat command reports on resource usage and caps
[August 2010]
Q: How do I create a zone?
A: First gather some information, then use the Solaris Container Manager GUI or the commands shown
below. This is the simplest possible creation of a zone that has network access. You will need this
information (example values in parentheses):
1. Name that you choose for the zone (my-zone)
2. Hostname that choose for the zone (my-zone)
3. Name of the directory in the global zone where all of the
zone’s operating system files will be (/zones/zone_roots/my-
zone)
4. IP address of the zone (10.1.1.1)
5. Name of the network device that the zone should use
(hme0)
Using the sample information in the appropriate commands, which will take about 10 minutes on a
small system with a new installation of OpenSolaris or Solaris 10:
global# zonecfg -z my-zone
zonecfg:my-zone> create
zonecfg:my-zone> set zonepath=/zones/zone_roots/my-zone
zonecfg:my-zone> add net
zonecfg:my-zone:net> set address=10.1.1.1
zonecfg:my-zone:net> set physical=hm0
zonecfg:my-zone:net> end
zonecfg:my-zone> commit
zonecfg:my-zone> exit
global# zoneadm -z my-zone install
global# zoneadm -z my-zone boot
Also, see the two chapters on installing and uninstalling zones at docs.sun.com. [August 2010]
Q: How do I remove a zone?
A: Use these commands, substituting the correct names for <bracketed> text.
global# zoneadm -z <zonename> uninstall
global# zonecfg -z <zonename> delete
Also, see the two chapters on installing and uninstalling zones at docs.sun.com. [August 2010]
Q: Is the maximum number of exclusive-IP zones limited to the number of physical ethernet ports?
A: No, if you use VLANs you can have one per VLAN per port. To use the same base ’bge0’ for multiple
dhcp zones, in the case of VLANs you would assign bge1000 to zoneA, bge2000 to zoneB, etc. The
VNIC component of Crossbow allows multiple virtual NICs on a port without any VLANs. You can try this
out at Crossbow project. [August 2010]
Q: Is it still necessary to set the NFSv4 domain parameter?
A: The new keyword nfs4_domain was added to the sysidcfg file to allow "no-hands" reboot in SX CE
and Solaris 10 8/07.
Q: How do I patch zones?
A: See the Patching and Packaging sections in the guide at docs.sun.com. Note that a recent (2009)
zones parallel patching enhancement to the standard Solaris 10 patch utilities increases the patching
tools performance on systems with multiple zones by allowing parallel patching of the non-global
zones. See "Zones Parallel Patching" on the Solaris Containers (Zones) page on OTN:
http://www.oracle.com/technetwork/systems/containers/index.html
Q: Can each container be a different Solaris patch level, so I can test patches in a "test" container before applying them to a "production" container?
A: There are two parts to the answer: 1) There is only one kernel running on the system, so all zones
must be at the same patch level with respect to the kernel and other Solaris system components. Such
patches can only be applied from the global zone, and they affect the global and all local zones
equally. The KU is an example of such a patch.
2) Software which is not part of Solaris can be patched on a per-zone basis. If the software can be
installed in the non-global zone then it must be patchable from the local zone as well, regardless of the
zone type, whole-root or sparse-root.
Q: Can I move a zone from one computer/domain to another?
A: Yes. See Migrating a Non-Global Zone to a Different Machine. For information on migrating a Solaris
8 or Solaris 9 container, see System Administration Guide: Solaris 8 Containers and System
Administration Guide: Solaris 9 Containers.
[August 2010]
Q: Is there a way to correlate audit records from multiple containers?
A: Yes, the global zone sees all audit records. Each non-global zone only sees its own audit records.
Q: Can I add packages to just the global zone (for example, SRS netConnect)?
A: Yes, use pgkadd -G. Note that if the SUNW_PKG_THISZONE package parameter is set to true, you
do not have to use the -G option. See packaging and patching chapters
[September 2010]
Q: Can I add a package to one non-global zone without adding it to the global zone?
A: That depends on the settings used when the package was created. See the Packaging sections at
docs.sun.com.
Q: What commands don’t work, or behave differently, inside a zone?
A: Most Unix commands and programs work correctly, without alteration or re-compilation.
However, the implementation of the security isolation boundary limits the functionality of several
system calls and libraries. That, in turn, limits the functionality of several system commands. In other
words, some Solaris commands behave differently when run inside a zone, or do not work at all inside
a zone.
See the sections 6.1 System Calls, 6.2 Library Functions, 6.3 Commands, and 6.4 Device and Interface
Special Files in http://www.sun.com/bigadmin/features/articles/zones_partition.html#limitations.
For information on the status of privileges in zones, see Table 26-1 Status of Privileges in Zones
[November 2006]
Q: Do zones boot automatically, or must I boot each one manually every time the system (re)boots?
A: The zones autoboot property determines whether the zone is booted when the system boots. The
global zone adminstrator can set the autoboot property to "true" or "false." The zones service
svc:/system/zones:default must also be enabled. [August 2010]
Q: Should I halt a system’s zones before applying patches?
A: There is no need to do this. In fact, the package and patch tools will perform their operations on all
zones that are running, as well as all zones that are not currently running but are capable of being
booted (e.g. they are at least in the "installed" state). The running zones are operated on first, and
then for each zone that is not running but can be booted, the zone is booted, the operation is
performed, and the zone is then halted.
Q: Where does a zone’s syslog output go?
A: By default the syslog output from a zone goes only into the zone’s syslog file. If you would like the
output to also appear in the global zone’s log files, configure the non-global zone’s loghost to be the
global zone.
Q: I removed a device from a zone, but it’s still there. Why, and how do I get rid of it?
A: This bug (4963368) was corrected in Solaris 10 8/07. For release before that, the workaround is:
after using zonecfg to remove the device, manually remove the corresponding entry in
{ZONEPATH}/dev.
Q: How do I upgrade a system with zones installed? Does Live Upgrade work?
A: Information about how to upgrade your Solaris 10 system to a later release if you are running zones
is available in the System Administration Guide: Solaris Containers--Resource Management and Solaris
Zones, Chapter 27 Upgrading a Solaris 10 System That Has Installed Non-Global Zones.
Full upgrade for a Solaris 10 system that has zones installed began in Solaris 10 8/07. You can use
Solaris Live Upgrade, the standard Solaris interactive installation program, or the custom JumpStart
installation program to upgrade your Solaris system with zones installed. See the installation
documentation. Limited upgrade via standard upgrade with limitations and limited JumpStart keywords
was available in Solaris 10 11/06.
Solaris ReleaseTraditional Upgrade w/
Zones
Live Upgrade w/
Zones
Solaris 10 3/05 N/A N/A
Solaris 10 1/06 Yes No
Solaris 10 6/06 Yes No
Solaris 10 11/06 Yes* No
Solaris 10 8/07
onwardYes* Yes
o Note, however, that there are two limitations regarding the
process of upgrading Solaris 10 if there are zones that use
ZFS or LOFS. Note that the LOFS problem has been fixed in
Solaris 10 8/07.
1. Solaris 10 6/06 supports the use of ZFS file systems. It is
possible to install a zone into a ZFS fs, but the
installer/upgrader program does not yet understand ZFS well
enough to upgrade zones that ’live’ on a ZFS file system.
Because of this, upgrading a system that has a zone installed
on a ZFS file system is not yet supported.
2. If all non-global zones that are configured with "lofs" fs
resources are mounting directories that exist in the miniroot,
the system can be upgraded from a previous release of
Solaris 10 to the Solaris 10 11/06 release using standard
upgrade. For example, a lofs mounted /opt directory presents
no issues for upgrade.
However, if any of your non-global zones are configured with
a non-standard lofs mount, such as a lofs mounted /usr/local
directory, the following error message is displayed:
The zones upgrade failed and the system needs to be restored
from backup. More details can be found in the file
/var/sadm/install_data/upgrade_log on the upgrade root file
system.
The error message is incorrect: although this error message states that the system must be restored
from backup, the system is actually fine, and it can be upgraded successfully using the workaround.
Workaround:
1. Reboot your system with the installed OS.
2. Reconfigure the zones, removing the "fs" resources defined with a
type of "lofs."
3. After removing these resources, upgrade the system to Solaris 10 11/06.
4. Following the upgrade, you can again reconfigure your zones to
restore the additional "fs" resources that you removed.
This problem is being tracked as CR 6454140: "Zones With an "fs" Resource Defined With a Type of
"lofs" Cannot Be Upgraded to Solaris 10 11/06" and is also described in the Solaris 10 11/06 Release
Notes.
[November 2006]
Q: Are there any special guidelines for using Live Upgrade with zones?
A: There are a number of considerations when using Live Upgrade (LU) on a system with zones
installed. It is critical to avoid zone state transitions during lucreate and lumount operations.
o When you lucreate an alternate boot environment (ABE), if a
zone is not running, then it cannot be booted until the
lucreate has completed.
o When you lucreate an ABE, if a zone is running, it should not
be halted or rebooted until the lucreate has completed.
o When an ABE is lumounted, you cannot boot zones or reboot
them, although zones that were running before the lumount
can continue to run.
Because a non-global zone can be controlled by a non-global zone administrator as well as the global
zone administrator, it is best to have all zones halted during lucreate or lumount.
It is important to note that when LU operations are underway, non-global zone administrator
involvement is critical. The upgrade affects their work as administrators, and they will be dealing with
the changes that occur as a result of the upgrade. They should make sure that any local packages are
stable throughout the sequence, handle any post-upgrade tasks (such as configuration file tweaking),
and generally schedule around the system outage.
Here is an example of a problem that could occur if these guidelines are not followed. If this sequence
of actions takes place:
1. In global zone: lucreate -n new
2. In non-global zone: pkgadd FooBar
3. In global zone: luupgrade -n new, luactivate -n new, init 6
When the system comes back up, the non-global zone users will notice that they no longer have the
FooBar feature added by the package.
[January 2008]
Q: Are Solaris 10 zones configured on ZFS prior to the Solaris 10 10/08 release upgradeable using Live Upgrade?
A: Not yet, but it is being investigated. Live Upgrade can be used on Solaris 10 10/08 systems that
have zones configured with the zonepath on ZFS.
[November 2008]
Q: What is the default networking service configuration of a non-global zone when it is installed?
A: On Solaris 10 systems, the traditional open configuration is installed.
You can switch the zone to either networking configuration by using the netservices command, or
enable and disable specific services by using SMF commands. [September 2006]
Q: Can the patch levels between a zone migrated to the target machine using update on attach and a zone created on the target machine be different?
A: Yes. It is normal and expected that a migrated zone and a newly installed zone would have different
patches. The update on attach feature looks at the zone you are migrating and determines which
packages need to be updated to match the new host. Only those packages are updated. By definition,
the rest of the packages (with their patches) are allowed to vary from zone to zone. You can think of
this as setting up a number of zones and then, over time, the zone administrators for those zones
install and remove packages and apply different patch streams to the packages that they are allowed
to change in their zones.
The update on attach feature for zone migration was added in the Solaris 10 10/08 release.
[August 2010]
Q: I tried to halt my zone but it is stuck in the 'shutting down' or 'down' state and won't halt. What should I do?
A: Collect a system dump and submit it to Oracle for analysis. You can reboot the global zone.
[August 2010]
Back to Top
Section 5: Security
Q: Can I access one zone from another zone?
A: Only through IP connections, e.g. telnet, rlogin.
Q: Can I ’su’ from one zone to another?
A: No, this would violate the security implementation of zones. In this context, think of zones as
separate computers - you can’t ’su’ from one Unix computer to another.
You can use the zlogin(1) command to login to a non-global zone from the global zone. You must have
all privileges(5) to use zlogin.
Q: Can I prevent the root account in one zone from affecting other zones?
A: Because each container has its own namespace, each container has its own root account. Each
zone’s root account is unable to access other containers in any way.
Q: Can programs running in one zone change the operation of programs running in another container?
A: A great deal of design work was done to prevent containers from affecting each other. By default it
is very difficult for one local zone to affect another zone, but it is possible. It is also easy for the global
zone administer to configure containers unsafely. Consider these factors:
o First, there are no known methods for one user (even root) in
one zone to ’break into’ another zone (global or non-global).
However, a modern computer has many resources, some of
them real, some virtual. Denial of Service attacks often
attempt to use all of the instances of a virtual resource. One
early attack on Unix systems was creating so many processes
that all of the PIDs were in use, preventing the creation of
new processes. There are now methods to prevent those
attacks, and those methods automatically apply, or have
been applied to, zones. In some cases the method of
prevention includes the manual use of Solaris features, e.g.
projects.
o By default it is difficult to disrupt operation of zones.
However, the global zone administrator can make it easier for
a non-global zone user to impact operation of one or more
other zones, even the global zone. Try to avoid assigning disk
devices directly to non-global zones: the root user of that
zone might be able to take advantage of this to cause a SCSI
bus reset or even panic the kernel. Also, avoid assigning the
same device or file system to multiple zones unless needed to
achieve a specific goal. If that is necessary, ensure that all of
the software in those two zones will obey a synchronization
mechanism when using the device or file system.
Q: How do I prevent a ’fork bomb’ from affecting all of the zones?
A: A ’fork bomb’ is a process which creates (forks) as many child processes as possible, attempting to
use up all of the virtual memory or PIDs in a system, resulting in a Denial of Service to other users. If
you would like to prevent someone from doing this in a non-global zone, add this to a zone’s
configuration, using zonecfg(1M):
set max-lwps=1000
That will prevent a zone’s processes from having a total of more than 1000 LWPs simultaneously.
[August 2010]
Back to Top
Section 6: Application-specific Information
Q: Can Oracle use shared memory in a Container?
A: In Solaris, Oracle uses ISM (Intimate Shared Memory) or DISM (Dynamic ISM). DISM is preferred
because it provides more flexibility.
ISM can be used in a Solaris Container, for any release of Solaris 10.
Because we keep improving Containers, there are slightly different answers to the question "can DISM
be used," depending on the particular release of Solaris 10.
1. Solaris 10 8/07 and newer: Yes, Oracle can use DISM in a
Container. Because the Solaris privilege ’proc_lock_memory’
is in a zone’s default set of privileges, you should limit the
amount of RAM that a particular zone can lock. If you don’t do
this, that zone could lock down enough memory that the
global zone - including platform management tools - cannot
function properly.
In Solaris 10 5/08 and later, you should set that limit with the
following command:
global# zonecfg -z myzone
add capped-memory
set locked=4g
end
exit
Note that common memory-size suffixes can be used: k or K (kilobytes), m or M (MB), g or G (GB), etc.
See zonecfg(1M) for more details.
In Solaris 10 8/07 you should set that limit with the following command:
global# zonecfg -z myzone
set max-locked-memory=4g
exit
2. Solaris 10 11/06: Yes, Oracle can use DISM in a Container. To enable the use of DISM, the global
zone administrator must add the privilege "proc_lock_memory" to the Container. To do this, use
zonecfg(1M) to add the line
set limitpriv=default,proc_lock_memory
to the Container’s configuration.
3. Solaris 10, Releases 3/05, 1/06, 6/06: A Container can only use ISM. It cannot use DISM. This is a
side-effect of the implementation of the security boundary which protects zones from each other.
[September 2008]
Q: Can I use the Solaris 10 FSS (Fair Share Scheduler) with Oracle in a Solaris Container?
A: There are currently (June 2006) two distinct concerns regarding the use of FSS in a Container when
running Oracle databases:
1. In testing - Oracle processes use internal methods to prioritize
themselves to improve inefficiency. It is possible that these
methods might not work well in conjunction with the Solaris
FSS. Although there are no known problems with non-RAC
configurations, Sun and Oracle are testing this type of
configuration to discover any negative interactions. This
testing should be completed soon.
2. It is not possible to use the Solaris FSS with Oracle RAC in a
Container. A Solaris patch is being tested that fixes this
problem.
Q: Can I use Oracle RAC in a Container?
A: This is really three questions: (1) does it work (2) in what configurations does Sun support the
Solaris components (3) in what configurations does Oracle support this? The short answers are:
1. Oracle RAC has been demonstrated consistently using the
Solaris OS, the Solaris Zones Cluster feature of Solaris Cluster
software and Oracle RAC
2. Sun supports ’Solaris Zone Clusters" using Solaris Cluster
3. only Oracle can determine the level of support available for
Oracle RAC in Solaris Zones Clusters.
The Sun BluePrint "Deploying Oracle Real Application Clusters (RAC) on Solaris Zone Clusters"
describes the installation and use of Oracle RAC in Solaris Zone Clusters. [May 2009]
Q: Are there any third-party documents that address using applications with zones?
A: Yes. To use Veritas Volume Manager Volumes from non-global zones, see this document.
Sun is not responsible for the availability of third-party web sites mentioned in this FAQ. Sun does not
endorse and is not responsible or liable for any content, advertising, products, or other materials that
are available on or through such sites or resources.
Back to Top
Section 7: Other Server Virtualization Solutions
Q: What are zone’s strengths compared to other server virtualization solutions?
A: Solaris Zones have many strengths relative to other server virtualization solutions, including:
o Cost: zones are a feature of the operating system. There is no
extra charge for using them.
o Integration: Zones are integrated into the operating system,
providing seamless functionality and a smooth upgrade path.
o Portability: Zones are not tied to any one hardware platform.
As a device-independent feature set of OpenSolaris, their
functionality is exactly the same on all hardware to which
OpenSolaris has been ported.
o Observability: The Global Zone has visibility into all activity in
all zones, including viewing process and network activity,
system-wide accounting and auditing, etc. This makes it
possible to find performance problems and resolve inter-zone
conflicts, both of which are extremely difficult problems on
most other SV solutions. It is even possible to re-host
applications typically found on different systems (e.g. web
server and app server) on different zones in the same system,
and then use DTrace to analyze their interactions.
o Manageability: You can manage all of the zones on one
system as one collection, rather than as separate servers.
This includes adding packages and patches once per system,
not once per zone.
o Sun Dynamic System Domains
Q: Are containers like VMware?
A: They are only vaguely similar. Both technologies are very useful for consolidating servers. However,
the basic model is different: Containers form isolated application environments that share one OS
instance, while VMware hosts multiple OS instances. The differences also include:
o Containers are only available for Solaris 10 and SX Nevada.
VMware supports Solaris, Microsoft Windows and Linux
clients, simultaneously.
o VMware uses a great deal of CPU capacity managing the
multiple environments. CPU overhead of containers is hardly
measurable (typically <1%) for a few zones or even dozens of
zones, depending somewhat on the applications.
o Containers do not have any financial cost beyond Solaris
license and/or support costs. VMware for production
environments costs thousands of dollars, and a license is
necessary for each Windows or RH instance hosted on top of
VMware.
Q: Are containers like HP vPars or nPars?
A: Containers are not similar to either except in purpose: server consolidation. However, the
differences include:
o HP nPars and Sun’s Dynamic System Domains are similar in
that both provide complete isolation of data, applications, and
programs. A complete comparison of Domains and nPars is
outside the scope of this document.
o vPars are HP’s "soft" partitioning technology. vPars and
Containers each enable multiple applications to co-exist in a
set of hardware resources with some degree of isolation.
o Each vPar is its own instance of an operating system, and
must be managed separately. Each container is a virtual
instance of Solaris, but there is only one copy of Solaris to
maintain.
o Containers are only available for Solaris 10. vPars only
support HP-UX (versions ??).
o All vPars share the same root password. Someone who gains
root access in one vPar can do anything to any vPar.
Conversely, each Solaris Container has its own namespace,
including its own root account. Someone who gains root
access in one container can damage that container (unless
privileges have been removed) but cannot cause any damage
to any other container, including the global container.
However, keep in mind that if a vPar or Container is
configured poorly, the potential for inter-partition damage is
increased.
Q: Are containers like IBM Micro-Partitions?
A: They are only vaguely similar. Both technologies are very useful for consolidating servers. However,
the differences include:
o Containers are only available for Solaris 10. MicroPars only
support AIX 5.3, RH.
o Each MicroPartition requires a separate license to run an
operating system. There is a cost associated with each AIX
license.
o Containers have almost no overhead, i.e. running 10
applications in 10 Containers is only slightly less efficient than
running those 10 applications in a non-zoned system. The
difference is typically <1%. MicroPartitions are inefficient and
have high overhead. According to IBM documentation, 10
MicroPartitions can have a compute overhead of 35%, in
addition to the application workload.
o Containers and MicroPartitions can share I/O resources, but
the implementation is different. MicroPars that want to share
an I/O connector must use an LPAR dedicated to the
multiplexing of I/O. This LPAR has extra costs associated with
it: one or more additional Power processors, another AIX
license, etc. [Updated July 2005]
Q: Are containers like Linux vServers?
A: The basic model used to implement the Solaris 10 Containers feature set and the Linux vServers
project are fairly similar. However, the implementation is different. (More coming soon!) [Updated
August 2005]
Back to Top
Section 8: Zones in OpenSolaris
Q: How are zones different on OpenSolaris 2009.06?
A:
o The ipkg brand is the default instead of the native brand
o Are whole-root type only; inherit-pkg-dir should not be used
o Have different software management related functionality
o IPS vs SVr4 packaging
o install, detach/attach, p2v
For attach, you currently have to manually set up the
correct dataset hierarchy, which might cause problems if
Not done correctly. Also, dry-run doesn’t work yet.
Engineering is currently fixing these problems.
o Have different global zone software operations: employ
manual syncing, not patching. Currently, the zones don’t
automatically update when you pkg image-update the
system. You must manually update the zones after rebooting
to keep them in sync with the global zone.
o Use boot environments instead of LU
o Integrated with beadm
o Zone root is a dataset
o Host identifiers (hostids) can be emulated on a per-zone
basis; see zonecfg(1M)). (Also available in the community
release beginning with snv_108.)
o Zone software is minimized to start; any additional packages
the zone needs must be added
o Must be on net to install zone; install is from the OpenSolaris
Packaging Repository
Note that pkg_image-update is not fully supported. You can use detach and attach -u as a
workaround. Detach the zone before running pkg_image-update, and use attach -u after running
pkg_image-update. [Added June 2009]
Q: Why are zones so different on OpenSolaris?
A: IPS is a new model for software management, and zones have to change to utilize this model.
[Added June 2009]
Q: Why can’t I use sparse root zones?
A: The sparse root type of zone describes a fundamental interaction between zones and the package
management system, and IPS doesn’t support this concept. BUT, we’re working on providing the
positive attributes of sparse root zones in different ways:
o reduced memory footprint
o reduced disk footprint
o centralized control of zone’s software
o security due to read-only mounts
o faster install/upgrade times
o fewer bits to migrate across systems
[Added June 2009]
Q: Are zones on OpenSolaris done? Will zones continue to look like they do on 2009.06?
A: No, zones are a work in progress and things will continue to evolve as development continues.
[Added June 2009]
Q: How do I control what software is installed in the zone?
A: Use the -e option to zoneadm install. [Added June 2009]
Q: Why is zone root its own dataset?
A: Eventually, we want to support beadm inside zones for pkg_image-update, just as you can do in the
global zone. To accomplish this, the zone’s root dataset must be controlled inside the zone. [Added
June 2009]
Q: Why isn’t the zone root available when the zone is halted? How do I set up the zone’s sysidcfg file?
A: Ready the zone, which will mount the correct zone root dataset. [Added June 2009]
Q: I created a zone in OpenSolaris 2009.06, and tried to add an /etc/sysidcfg file - but <zonepath>/root/etc doesn't exist! Where did it go?
A: OpenSolaris zones are a little different from Solaris 10 zones. When a zone is in the 'installed' state,
its ZFS file system is not mounted. To mount the zone's root file system before booting the zone, use
this command:
global# zoneadm -z <zonename> ready
Then edit <zonepath>/root/etc/sysidcfg. After that, you can finish booting the zone. If the sysidcfg file
was correct, configuration questions will not be sent to the zone's console, and it will complete the
boot process.
Q: Can I continue to use zones created on OpenSolaris 2008.05?
A: No, existing zones from this release cannot be used. [Added June 2009]
Back to Top
Section 9: Common but Non-Obvious Problems
Q: I created a zone and booted it, but it doesn’t work. What should I do?
A: The most common problem is that the zone doesn’t have its system identification information yet.
You can determine if this is the problem by running "ps -fz " in the global zone. If the output only
shows zsched, init, and a (3-6) processes related to SMF (/lib/svc/..., /usr/sbin/svccfg) then system
identification is not complete. To complete this, attach to the zone’s console by running "zlogin -C " in
the global zone, pressing once, and following the instructions. [March 2006]
Q: I added some privileges to a user in a zone, and now the user can’t login. What should I do?
A: This resulted from a bug that was fixed in Solaris Express 4/06. It will be corrected in Solaris 10
11/06 as well.
Updated information on privileges and zones has been added to the System Administration Guide:
Solaris Containers--Resource Management and Solaris Zones. See documentation for a list of the
Solaris privileges and the status of each privilege with respect to zones. To alter privileges in zones,
use the limitpriv property in zonecfg. [September 2006]
Q: I tried to upgrade to Solaris 10 11/06 and it told me the upgrade failed and I need to restore from backup. Now what?
A: Although this error message states that the system must be restored from backup, the system is
actually fine, and it can be upgraded successfully. See "How do I upgrade a system with zones
installed? Does Live Upgrade work?" for more information and a workaround you can use to upgrade
your system.
Back to Top
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Created by admin on 2009/10/26 12:11