Documentation: 3 or more Masters into Regions with only 2 AZ

[nilocbb]

Heres my problem:
I only have a Region with 2 AZ. When I created a cluster with 3 masters split into 2 AZ I ran into connection lost every now and then.

kubectl get nodes sometimes gets the nodes sometimes not.

I used it in a Private subnet.

I resolve this using 3 masters in only one AZ and nodes split between the other two.

Maybe we should Doc this to alert when creating a cluster (best practice).

[jatan28]

I can work on this, also would it make sense to support having 3 masters balanced across 2 AZs in the regions that has only 2AZs.

[slongstreet]

I would categorize this is a "known issue", not a best practice. Putting all 3 masters in a single AZ means it isn't highly available -- this is just a workaround until kops supports specifying only two AZs for the master zones.

[chrislovecnm]

Related: #3503

[chrislovecnm]

We just want to make sure that we have (N-1)/2 spread across two AZ to have HA. Creating an instancegroup type for just etcd, may be best, but I am open to other options.