document fan config conflict

[kwmonroe]

Summary

Fan networking is enabled by default on some substrates. This conflicts with some CNIs (especially those with vxlan encapsulation). CNI pods will not become ready when this conflict exists.

What Should Happen Instead?

Documentation noting the potential for conflict when fan networking is enabled.

Reproduction Steps

1. juju bootstrap aws
2. juju deploy canonical-kubernetes --channel edge
3. juju exec --unit k8s/0 -- sudo k8s kubectl get po -A

System information

n/a

Can you suggest a fix?

Document this todo prior to deployment:

juju model-config $model container-networking-method=local fan-config=

Are you interested in contributing with a fix?

No response

[evilnick]

Trying to think of a way this could be surfaced in docs which is not

• overly intrusive (we don't want people sidetracked down rabbit holes when they are just getting started)
• sufficiently prominent that users get the remedial steps before they run into the issue.

Two options spring to mind -

1. include a step of model configuration in the charm install docs
2. include it as a step when enabling a different CNI

opinions?