Rename docker volume

I miss a command which I can use to rename a volume.

Once I have created a lot of modules and forget to name the volumes at the start, it gets really difficult to identify which volume contains what.

A command like
docker volume mv 27722c3065e2f074bc7f29963fe62f73669cb369617482596e222f9991daee57 my-nice-volume-name
would be nice.
If that is not possible (because the id is used in a definition), it would be nice to have the ability to add a short comment:
docker volume set-comment 27722c3065e2f074bc7f29963fe62f73669cb369617482596e222f9991daee57 "This is the volume /var/logs/ for my creat app"
This comment should be visible in the list docker volume ls.

[FranklinYu]

It's useful to rename a volume when using Docker-Compose, for example I can rename my proj_data to proj_data_backup, so that subsequent docker-compose up creates new proj_data volume, while I can still access the old proj_data_backup. Currently I have to edit my docker-compose.yaml.

[shishir-a412ed]

@thaJeztah I can open a PR for this. #dibs

Shishir

[thaJeztah]

@shishir-a412ed I'm not sure this one is easy to implement; it would require the path (on disk) of the container to be renamed, and given that multiple containers can use the same volume, those containers will have to be updated.

Possibly the solution would be to give volumes an id, and use that id for the path (and store the volume name as metadata of the volume)

@cpuguy83 any thoughts?

[FranklinYu]

@thaJeztah Is it possible to check whether a volume is not linked to any (running or stopped) containers? It suffices to be able to rename stand-alone volumes.

[shishir-a412ed]

What I am implementing right now will allow you to rename a volume only if it is not used by running containers. I am guessing this API should give me that information:
https://github.com/moby/moby/blob/master/volume/store/errors.go#L52
I see your point, that stopped containers will have volume information/name in their metadata too which might needs to be updated.

Right now I was just implementing this change for local volumes. I was planning to extend that later to support volume plugins .e.g. If someone did docker volume create foobar.

docker would create a local directory under /var/lib/docker/volumes/foobar which will be bind mounted at docker run time. If the container is not running this is just a directory.

docker volume rename foobar newFoobar would rename the directory to /var/lib/docker/volumes/newFoobar and update the volumeStore with this info.

This is what I am thinking. Let me know your thoughts:

1. docker volume NAME NEW_NAME
2. If the volume is in use by running containers, error out saying stop the containers first before renaming the volume.
3. If the volume is not used by running containers, we change the name of the volume directory (path on the host for either volume plugins or local volumes) and update the in memory stores which are doing the book keeping. We need to think about metadata on disk for stopped containers, that have old volume information.

This would require changes at:

1. docker/cli which would need daemon changes to be vendored in. So daemon PR should be merged first. (I already have this, I can open a PR if you like)
2. docker engine changes for handling volume rename
3. Volume plugin API changes for handling rename

@thaJeztah @cpuguy83 thoughts ?

Shishir

[cpuguy83]

This is hard. If we internally use an alias but still refer to the volume by the original name with the driver this could work, but I see this as a little strange.

[FranklinYu]

@johanbrandhorst From #33966:

I think @thaJeztah wanted to support the use case for downgrading to an earlier version of docker. This design does not support that use case.

I don't see an easy solution to this. so ideas are welcome.
Also, feel free to take this over, if someone from the community wants to take this forward.

[bugdanov]

I ended up with creating a new volume and moving manually the content of /var/lib/docker/volumes/old-volume/_data/

[Hyruu]

For those who don't run Docker on Linux, and as such can't easily access /var/lib/docker on the root VM, you can still just create the new volume and create a temporary container to copy your data:

docker volume create --name <new_volume>
docker run --rm -it -v <old_volume>:/from -v <new_volume>:/to alpine ash -c "cd /from ; cp -av . /to"
docker volume rm <old_volume>

[FranklinYu]

@Hyruu I’m tempted to write a bash function with completion…

[honoref]

That's work fine.
I only add a test about the run command. I hope if the copy is wrong, errorlevel is greater than 0

#/bin/bash
docker volume create --name $2
docker run --rm -it -v $1:/from -v $2:/to alpine ash -c "cd /from ; cp -av . /to"
[ $? -eq 0 ] && docker volume rm $1