rolling restart example doesn't wait for "serving" status

[tarzanek]

nor does it wait for cqlsh port so this rolling restart isn't that friendly to cql clients

• above is for seed hosts - resp when switching from seeds to non-seeds

[tarzanek]

https://github.com/scylladb/scylla-ansible-roles/blob/master/example-playbooks/rolling_ops/rolling_restart.yml#L71 checks for nodetool status to become UN which however isn't the state of "serving"

[dyasny]

What is the state of "serving? Check for open port 9042?

[r4fek]

nodetool statusbinary tells that.