For a MongoDB replica set it is useful to define less resources (memory, cpu) for the arbiter in opposite to other replica set members which should have identical values.
Also moving different hidden secondaries and the arbiter on other worker nodes by using nodeSelector, affinity and tolerations can help to make the cluster more robust. These settings should be available independently from the primary and secondary members for arbiter and hidden secondaries.
For a MongoDB replica set it is useful to define less resources (memory, cpu) for the arbiter in opposite to other replica set members which should have identical values. Also moving different hidden secondaries and the arbiter on other worker nodes by using nodeSelector, affinity and tolerations can help to make the cluster more robust. These settings should be available independently from the primary and secondary members for arbiter and hidden secondaries.