Add support for setting storage size on ZFS containers

[kenXengineering]

- What I did
Added support for for the --storage-opt CLI flag to ZFS. Users can specify a container's block device size by passing size (--storage-opt size=2G). Built off of pull request #19367

- How I did it
When creating or cloning a ZFS volume, check storage options for the key size. If it is provided, set the ZFS property quota to the given value on the new ZFS filesystem. If size is not specified, do not set quota.

- How to verify it
Have docker engine setup with ZFS as the storage driver. Pull an image and run it with the --storage-opts size=<size> flag. Run df -h to view attached volumes sizes. The Avail space on the root device should be the size specified.

root@dockerzfs:~# docker run -it --rm --storage-opt size=2G ubuntu bash
root@217c5a71c117:/# df -h
Filesystem                                                                            Size  Used Avail Use% Mounted on
zpool-docker/docker/a9897bab72a60873898191704eb0dfff96aa4efdb0a2676d9e8a74ad20b265a7  2.2G  198M  2.0G   9% /
tmpfs                                                                                1001M     0 1001M   0% /dev
tmpfs                                                                                1001M     0 1001M   0% /sys/fs/cgroup
zpool-docker/docker                                                                    48G  3.2M   48G   1% /etc/hosts
shm                                                                                    64M     0   64M   0% /dev/shm

Note: Due to the way docker utilizes ZFS, the newly created ZFS volume will be from a read-only snapshot of the docker image. Therefore setting the quota on the new volume will make the available space the size of the quota as it is applied to the new volume and not parent volumes.

- A picture of a cute animal

This is my first pull request to Docker, and I welcome all comments and suggestions!

Signed-off-by: Ken Herner [email protected]

[calavera]

Nice! This was in my list of improvements for ZFS.

[thaJeztah]

experimental is green; https://jenkins.dockerproject.org/job/Docker-PRs-experimental/17500/console

22:17:40 Archiving artifacts
22:17:41 Notifying endpoint 'HTTP:https://leeroy.dockerproject.org/notification/jenkins'
22:17:41 Finished: SUCCESS

[calavera]

This would be easier to implement after merging #21139.

[calavera]

we should have global quota(at the daemon level) and local quota(what this PR implements).

[kenXengineering]

@calavera @thaJeztah Hello. I haven't seen any movement on the pull request. Do you have any questions or comments?

[calavera]

Design LGTM. I moved it to code-review so others can give feedback.

[thaJeztah]

Should err be checked here?

[thaJeztah]

Perhaps return early on error (also below), because there's now a lot of nested if's (but that's just a suggestion)

[cpuguy83]

Looks ok to me, but I don't use zfs... apart from @thaJeztah's comment.

[thaJeztah]

ping @chosenken could you address my comment? Also don't forget to update the relevant documentation and man-pages, but let me know if you need hints for which ones need an update

[Mic92]

For reference: I also made a pull request for quotas for zfs in the past: #12520

I introduced a global flag for that, which can be run per container not global for the daemon. Maybe you can copy&paste the tests I made.

[kenXengineering]

@thaJeztah I've updated that section to return on error, thanks for the review! As for documentation, I think the details added in this commit b16decf#diff-505c72218d90da970c16fdbf0b4f613c should cover it. I'm using the same option from #19367. I'm also going to add tests for this, so I will update when I get them added.

[kenXengineering]

I've added a test case based off of @Mic92 pull request #12520.

[calavera]

LGTM.

It looks like there is a flaky test:

19:26:02 FAIL: docker_cli_run_unix_test.go:947: DockerSuite.TestRunSeccompDefaultProfile
19:26:02 
19:26:02 docker_cli_run_unix_test.go:1045:
19:26:02     c.Assert(err, checker.IsNil)
19:26:02 ... value *errors.errorString = &errors.errorString{s:"expected No such file or directory, got: /go/src/github.com/docker/docker/bundles/1.12.0-dev/test-integration-cli/../binary-client/docker: Error response from daemon: rpc error: code = 2 desc = \"containerd: container did not start before the specified timeout\".\n"} ("expected No such file or directory, got: /go/src/github.com/docker/docker/bundles/1.12.0-dev/test-integration-cli/../binary-client/docker: Error response from daemon: rpc error: code = 2 desc = \"containerd: container did not start before the specified timeout\".\n")

[cpuguy83]

LGTM

[barrachri]

Hello, does this work only with containers?

Because if I follow the docs from here: https://docs.docker.com/engine/userguide/storagedriver/zfs-driver/#configure-docker-with-the-zfs-storage-driver

I just get this error #33847