[Wolves] Kubernetes

James Courtier-Dutton james.dutton at gmail.com
Sun Mar 14 11:15:35 UTC 2021


After further investigations.
microk8s version 1.20.2  is not compatible with btrfs.
My problem is btrfs specific:
30>1 2021-03-14T10:03:03.965578+00:00 thread microk8s.daemon-kubelet
33517 - -  F0314 10:03:03.965459   33517 kubelet.go:1350] Failed to
start ContainerManager failed to get rootfs info: failed to get device
for dir "/var/snap/microk8s/common/var/lib/kubelet": could not find
device with major: 0, minor: 29 in cached partitions map

Essentially, btrfs reports fs device major/minor number differently
from say ext4, and thus is not appearing in /proc/X/mountinfo
So, kubelet cannot find the mount point for a btrfs mount.

So, my advice to people is don't use btrfs with kubernetes for now.

Kind Regards


On Sat, 13 Mar 2021 at 17:46, James Courtier-Dutton
<james.dutton at gmail.com> wrote:
> Hi,
> I thought I would have a play with microk8s on a home pc.
> Suffice to say I have got nowhere fast.
> The initial install looked ok, but it failed to start the process that
> listens on port 16443. I fixed that with the command:
> microk8s disable ha-cluster
> Now it is complaining of disk problems. I.e. overlayfs not working.
> I have so far narrowed this down to overlayfs not being compatible with btrfs.
> Does anyone have any clues with regards to making microk8s play nicely
> with btrfs?
> It looks like containerd supports btrfs as it has a btrfs folder, but
> I cannot find any documentation that explains how to get it working.
> I am pleased that kubernetes is using just containerd now, instead of
> all of docker. So, at least kubernetes is getting a little less
> complex over time.
> Any help would be welcome.
> Kind Regards
> James

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