Hi!
We are observing 1.5-2x increase in CPU usage after upgrade of our ES cluster from version 8.8.2 to 8.15.3.
Our cluster is hosted on AWS EC2 instances, it consists of 6 nodes: 3 master nodes (c6i.large) and 3 data nodes (c7i.8xlarge).
Load on the cluster is mostly "search" requests from our search & recommendations APIs (no significant indexing is going on).
This is how CPU consumption on data nodes looks before/after upgrade:
On a " stack monitoring" tab, some weird things I see is a spike on "cgroup" graph:
and increase in "request time" for our most used index:
Please advise what is the most convenient way to debug this.
Thanks in advance, Alex.