[Self-managed]: Unable to upgrade self-managed Elasticsearch from 8.19.0 to 9.1.0

[harshitgupta-qasource]

Kibana Build details:

VERSION: 9.1.0 BC6
BUILD: 88250
COMMIT: 9f30374092edd41719399f7ef81cb7ae78d8a3ab

VERSION: 8.19.0 BC6
BUILD: 85490
COMMIT: ffd7cbf34ac1234c78354f2a22ef5f1703c04eaf

Host OS and Browser version: Windows, All

Preconditions:

1. Kibana 8.19.0 (self-managed) should be set up and available.

Steps to reproduce:

1. Navigate to the Endpoint.
2. Stop both Elasticsearch and Kibana.
3. Download and place Elasticsearch and Kibana version 9.1.0 in the elk2 directory.
4. Copy the data and config folders from both Elasticsearch and Kibana version 8.19.0 into the respective 9.1.0
5. Start Elasticsearch and Kibana (v9.1.0).
6. Observe that error :

[0.006s][error][logging] Error opening log file 'logs/gc.log': No such file or directory
[0.006s][error][logging] Initialization of output 'file=logs/gc.log' using options 'filecount=32,filesize=64m' failed.
error:
Invalid -Xlog option '-Xlog:gc*,gc+age=trace,safepoint:file=logs/gc.log:utctime,level,pid,tags:filecount=32,filesize=64m

Expected Result:
Elasticsearch should start successfully, completing the upgrade from version 8.19.0 to 9.1.0 in a self-managed setup.

Screen-shot:

Logs
logs.zip

[elasticmachine]

Pinging @elastic/fleet (Team:Fleet)

[harshitgupta-qasource]

@amolnater-qasource Kindly review

[amolnater-qasource]

Secondary Review for this ticket is Done.
JFI @kpollich @pierrehilbert
Could you please tag the related team.

[pierrehilbert]

@arpadkiraly sorry if you are not the right person but we would need someone to take a look here