Ambari experimental functionality
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!

