We were having very long restart times. Set hadoop.user.group.static.mapping.overrides for the hadoop accounts as described in https://community.hortonworks.com/articles/38591/hadoop-and-ldap-usage-load-patterns-and-tuning.html
This didn't seem to help a lot until we also set fetch_nonlocal_groups=false, using the following command:
/var/lib/ambari-server/resources/scripts/configs.sh set sandbox.hortonworks.com Sandbox cluster-env fetch_nonlocal_groups false
My question is this safe/recommended to set this option on in production? Will it disable group lookups for all users including "real" (users and applications) as well as the system accounts?