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Host Down

Description

At time T, the Monitoring on host X had not detected a mongod process running on host Y port Z for A minutes.

Common Triggers

  • The mongod process could not be reached because of a network issue.
  • The mongod process is not running.
  • The host is powered off.

Possible Solutions

  • Verify network communication between the host running the Monitoring and the host that is listed as down. One way to do this is through the mongo shell:

    mongo <hostname:port>
    

    If connecting from the mongo shell fails, try a basic ping test:

    ping <hostname>
    
  • Verify the mongod process is running:

    If the process was installed from deb or rpm package, query the service manager for the status:

    sudo service mongod status
    

    Alternatively, you can use ps:

    ps aux | grep mongo
    

Notes

The Host Down alert should not be used to detect all occurrences of a host rebooting. The alert is triggered only if the host is seen as down at the instant that the Monitoring runs the check. The interval between checks can vary from 1 to 3 minutes.

Documentation

  • Host is down alert condition