openstack swift as a backend for git - object-storage-ca ... · chmouel boudjnah - @chmouel -...
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Chmouel Boudjnah!OpenStack Summit 2014 Atlanta
OpenStack Swift as a Backend for Git
Chmouel Boudjnah - @chmouel - eNovance
Chmouel Boudjnah - @chmouel - eNovance
The mandatory about me
Chmouel Boudjnah - @chmouel - eNovance
About me
I am not the author, Fabien Boucher aka: @bzho
Chmouel Boudjnah - @chmouel - eNovance
Chmouel Boudjnah - @chmouel - eNovance
About me
We both work for eNovance
Chmouel Boudjnah - @chmouel - eNovance
About me
OpenStacker for quite some time now
Chmouel Boudjnah - @chmouel - eNovance
So what is Swift?
Chmouel Boudjnah - @chmouel - eNovance
• Object Storage • Not a file system • Eventually Consistent • HTTP REST API • Very Scalable • Software defined Storage
What is Swift
Chmouel Boudjnah - @chmouel - eNovance
Why would you want to use GIT with Swift?
Chmouel Boudjnah - @chmouel - eNovance
Why Swift with GIT
Why not?
Chmouel Boudjnah - @chmouel - eNovance
Why Swift with GIT
When you use a file system you have to :
Perform backups of your repositories regularly
Perform complex and risky operations to extend the storage capabilities for you repositories.
You have mostly have to manage it yourself
It’s an another piece in your infrastructure
You have to manage the downtime
Not fun
Chmouel Boudjnah - @chmouel - eNovance
So what are the benefits?
Chmouel Boudjnah - @chmouel - eNovance
Why Swift with GIT
The advantages of using Swift
Safety: The inherent replication of a data store.
Capability: easily extend storage capacity.
High Availability: no single point of failure.
Maintainability: allow operations teams to maintain the cluster without any downtime.
In an OpenStack environment it’s usually already there.
Chmouel Boudjnah - @chmouel - eNovance
Let’s see how git internal works
Chmouel Boudjnah - @chmouel - eNovance
Chmouel Boudjnah - @chmouel - eNovance
Chmouel Boudjnah - @chmouel - eNovance
So how did we plug that to Swift?
Chmouel Boudjnah - @chmouel - eNovance
We did not want to modify the GIT client binaries.
Chmouel Boudjnah - @chmouel - eNovance
We used a pure python GIT library called Dulwich
Chmouel Boudjnah - @chmouel - eNovance
• Create, read, manage loose objects (blob, tree, commit, tag).
• Create, read, manage pack files, pack indexes. • Implement the Git smart protocol through git-
upload-pack and git-receive-pack. • Implement the Git, HTTP, SSH listeners to start
Dulwich as a Git server. • Provide a well designed interface to the storage
backend. (Repo, MemoryRepo).
Dulwich
Chmouel Boudjnah - @chmouel - eNovance
How do we use Dulwhich
We implemented a custom repo called SwiftRepo as a backend to the git listener of Dulwich which communicate to OpenStack Swift
Chmouel Boudjnah - @chmouel - eNovance
So about that SwiftRepo backend how does it work?
Chmouel Boudjnah - @chmouel - eNovance
SwiftRepos backend to Dulwich
It doesn’t use the standard way to store Git references (one file by reference).
It doesn’t store loose objects but instead uses the pack format.
In addition to the .index that relate to each pack file we added .info object
It makes the Request to Swift concurrently.
Chmouel Boudjnah - @chmouel - eNovance
How’s the benchmark then?
Chmouel Boudjnah - @chmouel - eNovance
Benchmark Setup
Benchmark performed on two architectures : Github : ● Git client from eNovance network <-> GitHub ! Dulwich/Swift : ●· Git client from eNovance network <-> Dulwich (Rax compute) <-> Rax Cloudfiles !Three different repos : ! ●· Swiftsync (873 objects with 293 commits) ●· Edeploy (2246 objects with 618 commits) ●· Swift (23480 objects with 3212 commit)
Chmouel Boudjnah - @chmouel - eNovance
Full repository push
Chmouel Boudjnah - @chmouel - eNovance
Clone
Chmouel Boudjnah - @chmouel - eNovance
That’s it, hope you enjoyed.
Chmouel Boudjnah - @chmouel - eNovance
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