Offtopic: Rootless docker storage driver for Debian 11/12 VM?

Dunuin

Distinguished Member
Jun 30, 2020
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Hi,

A bit offtopic but I've read several threads here discussing storage drivers when using LXCs and a lot of people here know more about docker than I do, so maybe some can answer me a question.

At first I was running a few Debian 10 LXCs with portainer and root docker with fuse-overlayfs.
Then I was annoyed by problems with running docker in unprivileged LXCs and I switched to a few Debian 11 VMs with Portainer EE, rootless docker and fuse-overlayfs.
Now I am at a point where I want a dedicated Debian 11(or better 12 next week or whenever possible) VM without portainer but rootless docker for each single docker container stack. So that it is easier to migrate my services between different PVE nodes.
But when reading about the recommended storage drivers I'm wondering what the docker documentation is actually recommending.

One the one hand I read this:
DriverDescription
overlay2overlay2 is the preferred storage driver for all currently supported Linux distributions, and requires no extra configuration.
fuse-overlayfsfuse-overlayfsis preferred only for running Rootless Docker on a host that does not provide support for rootless overlay2. On Ubuntu and Debian 10, the fuse-overlayfs driver does not need to be used, and overlay2 works even in rootless mode. Refer to the rootless mode documentation for details.
I understand that in a way that overlay2 should be used unless you use rootless docker. But rootless docker with Debian 10 overlay2 would still be recommended.
But on the other hand I read this:
Only the following storage drivers are supported:
  • overlay2 (only if running with kernel 5.11 or later, or Ubuntu-flavored kernel)
  • fuse-overlayfs (only if running with kernel 4.18 or later, and fuse-overlayfs is installed)
...
Installing fuse-overlayfs is recommended. Run sudo apt-get install -y fuse-overlayfs. Using overlay2 storage driver with Debian-specific modprobe option sudo modprobe overlay permit_mounts_in_userns=1 is also possible, however, highly discouraged due to instability.
So overlay2 requires the 5.11 kernel and Debian 11 is still using 5.10 so I would need to wait for Debian 12. But then it sounds like you should still prefer fuse-overlayfs with rootless Debian, because overlay2 isn't as stable...

For me this is conflicting.
Should I choose overlay2 or fuse-overlayfs for my rootless docker Debian 12 VMs?
And if I now install a rootless docker Debian 11 VM with fuse-overlayfs, would it later be hard to switch from fuse-overlayfs to overlay2 when upgrading from Debian 11 to 12 in case overlay2 would be recommended there?

Right now my storage looks like this:
ZFS 4 disk striped mirror (ashift=12, LZ4) -> zvol (encrypted, 8K volblocksize) -> virtio SCSI single -> ext4 -> fuse-overlayfs

Would be great If someone got a recommendation what storage driver I should use for best stability.
 
Last edited:
Debian 10 is old, so documentation is probably little outdated in that section.
 
Allow me to highjack this thread as I have a similar problem.

I have been using rootless docker in a dedicated Debian 11 VM for a while now. And I would like to switch from fuse-overlayfs to overlay2 but I can't find the place where to change the configuration. Everything I find only talks about (rootful) docker.

So, does anyone know how to switch the storage driver on rootless docker?

Thanks!
 
You are not using the default 5.10.X kernel with the Debian 11 VM but 5.11.X or higher like required by overlay2 according to "overlay2 (only if running with kernel 5.11 or later, or Ubuntu-flavored kernel)"?

By the way, still did not find n answer for the initial post.
 
You are not using the default 5.10.X kernel with the Debian 11 VM but 5.11.X or higher like required by overlay2 according to "overlay2 (only if running with kernel 5.11 or later, or Ubuntu-flavored kernel)"?

By the way, still did not find n answer for the initial post.
No, I will probably update to Debian 12, if I find a way to replace the storage-driver. If not, I will create a new Deb12 VM and install Rootless Docker from scratch.
 

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