How beats behave during agent upgradation and installation failed?

[Nehal_Mahida]

Hi all,

I am new to elastic agents and beats. I wish to know how beats support rollback or do it support?
Here are my questions.

1. What happens when agent installation failed in between (suppose filebeat is installed and metric beat is remaining)? do I need to start it again?
2. What happens during the up-gradation of the agent? Do beats stop onboarding data from integrations or Will store it in buffer?

In nutshell, I want to know how beats handle any type of failure.

I hope you guys understood my questions. I appreciate your quick response

[blaker (Blake Rouse)]

Elastic Agent manages and starts the beats on your behalf, you do not need to manage them or control them.

On upgrade the Elastic Agent will upgrade the beats, if it hits an issue with upgrading it will automatically rollback to the previous version of the Elastic Agent and beats. The beats and Elastic Agent are in alignment with versions. So updating Elastic Agent updates the underlying beats, same with rollback (beats rollback).

On upgrade the beats are stopped for a moment in time to perform the upgrade. That does mean there is a chance of data lost during that time. When it comes to logs the last read log line is stores so on start of upgrade version it picks up where it left off. In the case of metrics there is a possibility of a hole in the data while it performed the upgrade.

[Nehal_Mahida]

Thanks for your quick response @blaker,

So basically you mean to say there is a chance of data loss while we are upgrading the elastic agent as beats are going to stop for some time.

Could you please confirm my understanding?

[blaker (Blake Rouse)]

Yes there is a chance, for metrics and synthetics. But not for logs.

[Nehal_Mahida]

Got it Thanks.