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Docker 0.7 runs on all Linux distributions

blog.docker.io

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Re: Docker 0.7 runs on all Linux distributions

#21

Post by mateuszf »

shykes wrote: post #2

A few details on the "standard linux support" part. To remove the hard dependency on the AUFS patches, we moved it to an optional storage driver, and shipped a second driver which uses thin LVM snapshots (via libdevmapper) for copy-on-write. The big advantage of devicemapper/lvm, of course, is that it's part of the mainline kernel. If your system supports AUFS, Docker will continue to use the AUFS driver. Otherwise i…

Does the LVM part mean that the partition/disk used to store/run Docker images has to use LVM?

Re: Docker 0.7 runs on all Linux distributions

#23

Post by DannoHung »

shykes wrote: post #2

A few details on the "standard linux support" part. To remove the hard dependency on the AUFS patches, we moved it to an optional storage driver, and shipped a second driver which uses thin LVM snapshots (via libdevmapper) for copy-on-write. The big advantage of devicemapper/lvm, of course, is that it's part of the mainline kernel. If your system supports AUFS, Docker will continue to use the AUFS driver. Otherwise i…

Is there a document on the relative costs and benefits of the two drivers?

Re: Docker 0.7 runs on all Linux distributions

#24

Post by knitatoms »

shykes wrote: post #2

A few details on the "standard linux support" part. To remove the hard dependency on the AUFS patches, we moved it to an optional storage driver, and shipped a second driver which uses thin LVM snapshots (via libdevmapper) for copy-on-write. The big advantage of devicemapper/lvm, of course, is that it's part of the mainline kernel. If your system supports AUFS, Docker will continue to use the AUFS driver. Otherwise i…

Any drawbacks to using lvm comapared to AUFS? I'd like to switch to Debian from Ubuntu - will I notice any performance differences or other restrictions?

Re: Docker 0.7 runs on all Linux distributions

#25

Post by m_mueller »

shykes wrote: post #15
gexla wrote: post #12

So, I assume that if you aren't using AUFS then you don't have to deal with potentially bumping up against the 42 layer limit? Or does this update also address the issue with AUFS?

The 42 layer limit is still there... But not for long! There is a fix underway to remove the limitation from all drivers, including aufs. Instead of lifting the limit for some drivers first (which would mean some images on the index could only be used by certain drivers - something we really want to avoid), we're artificially enforcing the limit on all drivers until it can be lifted altogether. If you want to follow…

One thing I've been wondering is whether the 42 limit was related to performance considerations. If yes, I actually somewhat like it - I'm a proponent to making systems behave in a way that they won't come around and bite you. Will a container based on, say, 200 layers still load and run with reasonable performance?

Re: Docker 0.7 runs on all Linux distributions

#26

Post by mateuszf »

neals wrote: post #9

I see docker come around every now and then here. I'm a smalltime developer shop, small team, small webspps. What can docker do for me? Can this reduce the time it takes me to put up and Ubuntu installation on Digital Ocean? Is this more for larger companies ?

You will be able to have multiple Ubuntu servers running on one Ubuntu VPS on Digital Ocean. Each of them may have some initial state (installed some software, configuration) that you will be able to spawn as separate virtual machine. The "inside" machine will consume mnimal amount of memory (for running applications) and not for whole OS as in case of "real virtual machine". Also, you will be able to spawn and destroy new VMS very fast (under 1s).

Re: Docker 0.7 runs on all Linux distributions

#27

Post by shykes »

apphrase wrote: post #16

Can anyone please tell about the overhead of Docker, compared to no-container scenario (not against a fat vm scenario)? I am a "dev" not "ops", but we might make use of Docker in our rapidly growing service oriented backend... Thanks

For process isolation, the overhead is approximately zero. It adds a few milliseconds to initial execution time, then CPU and memory consumption of your process should be undistinguishable from a no-container scenario.

For disk IO, as long as you use data volumes [1] for performance-critical directories (typically the database files), then overhead is also zero. For other directories, you incur the overhead of the underlying copy-on-write driver. That overhead varies from negligible (aufs) to very small (devicemapper). Either way that overhead ends up not mattering in production because those files are typically read/written very unfrequently (otherwise they would be in volumes).

[1] http://docs.docker.io/en/master/use/working_with_volumes/

Re: Docker 0.7 runs on all Linux distributions

#28

Post by T-zex »

julien421 wrote: post #20
T-zex wrote: post #17

Is it possible to have multiple instances of the same app running in Docker containers and having readonly access to a "global" memory linked file? What I'm trying to achieve is having sand-boxed consumers having access to some shared resource.

Have you try to use the mount option/instruction to do so?

Haven't tried anything yet. Just wondering if this is an idiomatic use case to grant container access to global resources.

Re: Docker 0.7 runs on all Linux distributions

#29

Post by julien421 »

jfchevrette wrote: post #22

Unfortunately it looks like the documentation has not been updated yet... So much for feature #7. Documentation should be part of the development/release process

The doc has been updated, but there was a problem while pushing it this morning. We are working on it.

Re: Docker 0.7 runs on all Linux distributions

#30

Post by shykes »

neals wrote: post #9

I see docker come around every now and then here. I'm a smalltime developer shop, small team, small webspps. What can docker do for me? Can this reduce the time it takes me to put up and Ubuntu installation on Digital Ocean? Is this more for larger companies ?

Yes, Docker should be able to help you. It is definitely not just for large companies.

Docker can help you streamline your development and deployment process across all the machines, from the development laptop to the production server. The result should be that your development environment is easier to setup and replicate, more similar to production, and easier to customize as you evaluate new tools, hosting providers and software components.

I recommend checking out the "Getting started" page, it has a great online tutorial: http://www.docker.io/gettingstarted/

You should also browse through this list of real-world use cases. http://www.docker.io/community/#What-people-have-already-bui...

I hope this helps!

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