Hi all

I’m running several docker containers with local persistent volumes that I would like to backup. I haven’t found an easy method to do so.

What do you use / recommend to do that? AFAIK you can’t just rsync the volume directory while the container is running.

  • outcide@kbin.social
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    1 year ago

    Use bind mounts instead of docker volumes. Then you just have normal directories to back up, the same as you would anything else.

    • MaggiWuerze@feddit.de
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      1 year ago

      This is your answer. It also has the benefit of allowing you to have a nice folder structure for your Docker setup, where you have a folder for each service holding the corresponding compose yaml and data folder(s)

    • mirisbowring@lemmy.primboard.de
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      1 year ago

      Exactly the reason why i always exchange the volumes in any compose file with bind mounts.

      Also you don‘t have the provlem of many dangling volumes

  • Ruud@lemmy.worldM
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    1 year ago

    Rsync works fine for most data. (I use borgbackup) For any database data, create a dump using pg_dump or mysqldump or whatever. Then backup the dump and all other volumes but exclude the db volume.

  • Michael717@lemmy.world
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    1 year ago

    In general there is no problem in rsync’ing the volume bind directory. But that depends on the application, which is running in the container. I. e. you should not copy the files of a running database. It may corrupt the data while it’s being written.

  • irreducible12302@lemmy.world
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    1 year ago

    I personally use a script which stops all containers, rsyncs the bind mounts (normal folders on the filesystem) and then restarts them. It runs every night so it isn’t a problem that services are down for a few minutes.

    Ideally, you would also make a database dump instead of just backing up the bind mounts.

  • easeKItMAn@lemmy.world
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    1 year ago

    Bind mounts are easy to maintain and backup. However if you share data amongst multiple container docker volumes are recommend especially for managing state.

    Backup volumes:

    docker run --rm --volumes-from dbstore -v $(pwd):/backup containername tar cvf /backup/backup.tar /dbdata

    • Launch a new container and mount the volume from the dbstore container
    • Mount a local host directory as /backup
    • Pass a command that tars the contents of the dbdata volume to a backup.tar file inside /backup directory.

    docker docs - volumes

    Database volume backup without stopping the service: bash into the container, dump it, and copy it out with docker cp. Run it periodically via crontab