@saeil lilla 

With the release of A360.28, Automation Anywhere have has moved to Opensearch (OS) from Elasticsearch  (ES). All on-premise installations who started using Automation 360 from A360.15 or older must check for any ES indices created by ES v6.x.

The upgrade to A360.28 will fail if any ES index created by ES 6.x is present. Any ES index created by ES v6.x cannot be migrated to OS 2.x. ES indices created by ES v7.x can be migrated. AA recommends all impacted customers to check, re-index & verify the upgrade of all ES indices created by ES 6.x to ES 7.x before planning an upgrade to A360.28.

Kindly check the follow  KB article to identify if you are using old ES indices.

https://apeople.automationanywhere.com/s/article/Automation-360-On-Premise-Edition-A360-28-Upgrade-Considerations

HTH

Regards.

 @Raul Jaimes I am about to perform an update from v27 to v29 in a 3-node cluster environment. As far as I know I have to follow the instructions from this link (from what I know this customer started using AA (this customer started working with A360 v23 so no 6.x version indices)

Have you experienced any issue or should I consider anything apart from what that article states? (I’m asking this as AA software is a “box of surprises”...)

@saeil lilla , maybe is a bit late but here you have a powershell script that return all the info from the indices and stores them in a csv file (sorry, the forum does not allow me to include it, ping me if you want it. This forum has a lot to improve)

@saeil lilla make sure your elastic search on all nodes are up and running while performing the upgrade 

Have a look here, it is a bit messy but overall procedure for a 3-node deployment is there