CABPK: Support disk_setup and mounts in cloud-init

[CecileRobertMichon]

This is to support mounting etcd on a data disk.

CAEP: https://docs.google.com/document/d/12eYcQrlZdkojHY3atUCCIS9YGPQ1LSQvT4gdg6JWroc/edit?usp=sharing

(shared edit permissions with the kubernetes-sig-cluster-lifecycle google group).

/kind feature

[vincepri]

/milestone v0.3.x

[vincepri]

+1 from me, have some thoughts about extra validation bits, overall having looked at the POC + the proposal, the implementation looks pretty straightforward.

[CecileRobertMichon]

/assign

[voor]

I really like this proposal, as it's going to open up the option of putting /var/lib/containerd and /var/log onto separate partitions as well (I need /home on another partition, but that's more for legacy compliance reasons than anything).

[CecileRobertMichon]

For anyone who is interested, I have a working prototype of this with these changes:

• https://github.com/kubernetes-sigs/cluster-api/compare/master...CecileRobertMichon:etcd-mount
• https://github.com/kubernetes-sigs/cluster-api-provider-azure/compare/master...CecileRobertMichon:etcd-disk

[randomvariable]

+1 on this

[dhawal55]

+1 This enables me to have separate volume mounts for /var/lib/docker, /var/lib/kubelet and etcd data dir

I would like to see this change in other infrastructure providers (vpshere, aws) as well