There were active commands running before upgrade. This includes commands a user might have run and also for commands Cloudera Manager automatically triggers, either in response to a state change, or something configured to run on a schedule, such as Backup and Disaster Recovery replication or snapshot jobs.

• Stop any running commands from the Cloudera Manager Admin Console or wait for them to complete. See Aborting a Pending Command.
• Ensure that you have disabled any scheduled replication or snapshot jobs from the Cloudera Manager admin console to complete before proceeding with the upgrade. See Enabling, Disabling, or Deleting A Replication Schedule.

Hostname mapping or permissions are not set up correctly.

• For hostname configuration, see Configuring Network Names.
• For permissions, make sure the values you enter into the wizard match those you used when you configured the databases. The value you enter into the wizard as the database hostname must match the value you entered for the hostname (if any) when you configured the database.

  For example, if you had entered the following when you created the database

  grant all on activity_monitor.* TO 'amon_user'@'myhost1.myco.com' IDENTIFIED BY 'amon_password';

  the value you enter here for the database hostname must be myhost1.myco.com. If you did not specify a host, or used a wildcard to allow access from any host, you can enter either the fully qualified domain name (FQDN), or localhost. For example, if you entered

  grant all on activity_monitor.* TO 'amon_user'@'%' IDENTIFIED BY 'amon_password';

  the value you enter for the database hostname can be either the FQDN or localhost.

You may have network connectivity problems.

You might have mismatched versions of the Cloudera Manager Server and Agents.

Java might not be installed or might be installed at a custom location.

Make sure you have upgraded the Cloudera Manager Agents on all hosts. (The previous version of the Agents will heartbeat with the new version of the Server, but you cannot start HDFS and MapReduce with this combination.)

See Configuring a Custom Java Home Location for more information on resolving Java issues.

HDFS caching, which is enabled by default in CDH 5 and higher, requires new memlock functionality from Cloudera Manager Agents.

Do the following:

1. Stop all CDH and managed services.
2. On all hosts with Cloudera Manager Agents, hard-restart the Agents. Before performing this step, ensure you understand the semantics of the hard_restart command by reading Hard Stopping and Restarting Agents.
   • RHEL-compatible 7 and higher:

     $ sudo service cloudera-scm-agent next_stop_hard
     $ sudo service cloudera-scm-agent restart

   • All other Linux distributions:

     sudo service cloudera-scm-agent hard_restart

3. Start all services.