Performance Comparison Between Linux Containers and Virtual

Machines

Venue: 2015 International Conference on Advances in Computer Engineering

and Applications

Agenda

• What is virtualization?

• Virtualization technologies

• Comparing the technologies

• Conclusion

What is virtualization?

• virtual machine (VM) is an emulation of a particular computer system.

• VM is a common way to run different services in the cloud.

• Main benefits of virtualizations are:– Portable deployment (fast application delivery)– Scale and deploy with ease– Hardware independence– Isolation– Secure user environment– ….

Virtualization technologies

• Hypervisor-based virtualization

– Kernel-based VM (KVM), VMWare

• Container-based virtualization

– Docker, LXC

• Hybrid virtualization

– ZeroVM, OSv

Hypervisor-based virtualization

• Operates at the hardware level• Isolates VM from the underlying host system.• Benefits

– Abstracts hardware – Support running VMs independently and

isolated from the hardware (windows VM can run on Linux host)

Problems• A full OS runs on the VM=>

emulation of VM has huge overhead.(big images and long start-up time)

Container-based virtualization• Implemented in Linux kernel via

– control groups(resource management) – namespaces(restricted access to resources)

• Benefits – A light weight alternative to hypervisor-based– implement isolation of processes at the OS level– Disk images are smaller– A higher density of virtualized instances

Problems• Window container cannot run on a Linux host• Resource isolation is not as accurate as

hypervisors (issues for multi-tenant security)

Comparing the technologies-performance comparison

• In this paper, Docker is used for running containers.

• The set up: – Two physical servers (OS: Ubuntu14.04, RAM: 2GB) for hosting

docker and VM.

– front-end= application server hosting Joomla

– Back-end= database server hosting Postgres

– Jmeter is used for stress testing Joomla by sending simultaneous requests to Joomla.

Application performance comparison

Comparing the technologies-Scalability comparison

• For container scalability test, use Kebernetes cluster manager to scale the the Docker host on the 2 physical servers.

• For VM scalability test, The application is deployed in an AWS EC2 with auto scaling enabled.

• The set up: – AWS EC2 for cloud and a physical server to host docker.

– Application = a load balanced WordPress application

– Jmeter is used for stressing and trigger the scaling

Scalability comparison

The time to scale for deploying another container (~8 sec.) is much less than the time to scale for deploying another virtual machine (~3 mins).=> 22x times faster scalability

Conclusion

• Containers out performed virtual machines both in terms of scalability and performance.

• Containers are better for application deployment.

• However, using containers for applications with business critical data may reveal security breaches.