Ambari - configure email notification using sendmail (HDP)

1. start sendmail on the host where ambari server runs
   1. service sendmail start
2. ambari web -> alerts -> actions -> manage notifications -> "+"
3. name
   1. test
4. groups
   1. all
5. use default value for others
6. save
7. test
   1. select one service/component and stop/start it