Install of PowerScale fails: docker changes break cluster

Question

Performing the step from the install doc for docker setup: [Service] ... MountFlags=shared And restarting docker causes our cluster to fail. Running k8s v1.20.6. After adding that line to the docker config and restarting causes the K8 docker processes to no longer startup. After digging I found this, where it looks like they recommend not adding that to the docker config at all. https://docs.docker.com/engine/release-notes/18.09/#18091 Running docker-ce-20.10.6-3 on RHEL 8.4. Once I removed all the MountFlags=shared entries and restarted docker, everything is fine again. Is this flag required, or will PowerScale work without it now?

Thar_J · Answer

Hi @powderbuck

As we could observe from the docker documentation that :

In Docker versions prior to 18.09, containerd was managed by the Docker engine daemon.
In Docker Engine 18.09, containerd is managed by systemd. Since containerd is managed by systemd, any custom configuration to the docker.service systemd configuration which changes mount settings (for example, MountFlags=slave) breaks interactions between the Docker Engine daemon and containerd, and you will not be able to start containers.

And these configurations are specific to Docker and we have verified that PowerScale works perfectly fine without these flags in the docker.service.

Regards

Thar_J

Containers

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