Ambari experimental functionality

[#1]

I noticed that using Ambari experimental functionality we can do lot of interesting stuff.

For e.g. rolling/express upgrade is in progress and some service checked failed, to recover from failure we need to update some configuration parameters and restart that particular service, during upgrade Ambari will not allow us to modify any configuration property, so either we can use configs.sh script or another option is to use ambari experimental functionality and enable "opsDuringRollingUpgrade" option 🙂

Please feel free add more information about Ambari experimental functionality here!

[#2]

I believe that in either Ambari 2.1.2 or 2.2.0 we introduced a button to "Pause" the upgrade. This essentially aborts all of the pending tasks from the upgrade so that you can perform operations on your own, such as restarting services.

In this "paused" state, we only recommended to start/stop/restart services and change configs; anything that involves changing the topology (adding hosts, adding services, HA, etc.) is likely to result in problems.

Because the RU/EU is still technically active (although in an ABORTED state), there will be a button to "Resume" it.

[#3]

Can you please elaborate how to set the flags on the experimental page, either via command line or REST API?

Thanks.

[#4]

Thanks @Alejandro Fernandez

[#5]

@Julius Lerm - Not sure if there is any.

Tagging one of our Ambari Engineer. @Alejandro Fernandez

[#6]

We use HDFS on Isilon OneFS and the upgrade would normally get stuck on upgrade check on the Isilon node. In order to allow the upgrade to proceed, we have to disable the preUpgradeCheck. Hoping Ambari will eventually have a better documented upgrade guide for those who use Isilon HDFS.