CODEWITHSUNDEEP
dockerzfs
Pascal
Pascal

Reputation: 6030

Access hosts zfs from docker container

Is there a way to access the hosts zfs snapshots from within the docker?

I'm trying to get some custom backup, using zfs snapshots with send/receive, running on a cluster of docker based servers. To stick to the current setup, I'd like the backup service to run in a docker container as well. I'm having a hard time figuring out if there's any way to access the hosts file system, on an administrative level, from within a docker container.

I basically need a way to run zfs list, zfs snap and zfs send from within the container. My gut tells me "no", but maybe there's a clever way by some mount options and privilege wizardry

Upvotes: 3

Views: 2324

Answers (4)

stuckj
stuckj

Reputation: 996

Znapzend (a backup utility using ZFS snapshots) covers this in their github page: https://github.com/oetiker/znapzend#running-in-container. I'm using this to automate backups on my NAS to a separate offsite backup NAS.

Here's the relevant info from the link:

---SNIP---
znapzend is also available as docker container image. It needs to be a privileged container depending on permissions.

docker run -d --name znapzend --device /dev/zfs --privileged \
    oetiker/znapzend:master

To configure znapzend, run in interactive mode:

docker exec -it znapzend /bin/sh
$ znapzendzetup create ...
# After exiting, restart znapzend container or send the HUP signal to
# reload config

By default, znapzend in container runs with --logto /dev/stdout. If you wish to add different arguments, overwrite them at the end of the command:

docker run --name znapzend --device /dev/zfs --privileged \
    oetiker/znapzend:master znapzend --logto /dev/stdout --runonce --debug

Be sure not to daemonize znapzend in the container, as that exits the container immediately.
---SNIP---

Upvotes: 1

Meckie
Meckie

Reputation: 11

for me it worked with:

  • docker container in privileged mode
  • zfs device mapped into the container (--device /dev/zfs)
  • zfsutils-linux installed in the container

Upvotes: 1

Negash
Negash

Reputation: 156

I use rancherOS 1.3.0 with zfs on /mnt i start container with:

    privileged: true
    pid: host
    volumes:
    - /mnt:/mnt:shared

with this confis i can clone snaphots

Upvotes: 1

Dan
Dan

Reputation: 7737

Unfortunately, there is no way to do that. We've had the same problem ourselves, and the way we worked around it was by creating a container-less service which the containers can issue commands to, and the container-less service could then issue ZFS commands on their behalf and return the results. It's not a perfect solution, but (at least for us) it was better than nothing.

Upvotes: 0

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