Overview
Sometimes you can observe that the CPU and load on one of your cluster_manager is higher than on others.
This is absolutely normal behavior assuming that the loaded cluster manager is the elected master. Although you need more than one cluster manager (and ideally an odd number), only one of these nodes will be active at any one time. If CPU is very high and the node appears to be overloaded, then this may be cause for concern, since an overloaded cluster manager may cause instability in the cluster.
How to resolve it
How to fix loaded cluster_manager in OpenSearch
- Check for split brain
Make sure you are not suffering from the split brain problem described.
- Check other processes
Ensure that there are no other processes running on the cluster manager which could cause it to become unstable.
- Check the cluster manager logs
Check the loaded cluster manager logs. If the elected cluster manager is loaded, the log can reveal the potential causes, such as: high rate of mapping exceptions, too many doc types (for ES versions older than v6), or large metadata – too many fields/indices/shards.