[Wolves] Kubernetes

[Stephen Welch]

HI all.

Done a bit with Kubernetes on a training course but not used it into in any
anger.  If you want to have a play with it this microservices pattern

https://microservices-demo.github.io/docs/quickstart.html

is an excellent thing to learn from for Kubernetes.  A few commands and you
can have an operational cluster running for debugging and exploring.

At some point I had the docker containers running running on AWS Kubernetes
and AKS (Azure) did not get round to migrating the message services.

HTH



On Mon, 15 Mar 2021 at 00:15, John Alexander via Wolves <
wolves at mailman.lug.org.uk> wrote:

> Fortunately that bug didnt last that long ;-)
>
>
> On Sunday, 14 March 2021, 18:14:26 GMT, James Courtier-Dutton via Wolves <
> wolves at mailman.lug.org.uk> wrote:
>
>
> Kubernetes problems solved.
> Kubernetes 1.20.2 has bugs related to btrfs and will not work with btrfs.
> Kubernates 1.20.4 has fixed those bugs and it works fine with btrfs
>
> On Sun, 14 Mar 2021 at 11:14, James Courtier-Dutton
> <james.dutton at gmail.com> wrote:
> >
> > Hi.
> >
> > 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
> >
> > James
> >
> >
> >
> > 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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