Does rolling upgrade require Kerberos turned off on Ambari 2.2.2.0 and does it stop both namenodes at any given point in time?

[#1]

I reviewed the documentation for Ambari 2.2.2.0 and do not see requirement to turn off Kerberos during rolling upgrade. It also does not say whether both namenodes are down at any point in time. Can someone confirm with 100% surety that there is no point in time where both namenodes are down and hdfs is unaccessible? I also need confirmation that in the latest Ambari it is no longer necessary to turn off Kerberos to perform rolling upgrade.

[#2]

@Artem Ervits

That's correct! There is no need to turn off Kerberos while rolling upgrade using Ambari 2.2.2.0

I believe it stops both the Namenode and then perform upgrade and that's what minimal downtime is. For slaves it will do upgrade in batches to avoid complete downtime.

[#3 · Accepted solution]

It upgrades one namenode at a time not both. Kerberos can stay on.