[SOLVED] Ambari There are no DataNodes to do rolling restarts when there are DataNodes that do need a restart

When maintaining a Hadoop cluster, you will need to restart various service from time-to-time when/if you update Hadoop configurations.

I ran into a problem today with Ambari where I wanted to do a rollling restart of all of my DataNodes, but when I clicked on the “Restart DataNodes” entry in the “Restart” drop down the dialog indicated “There are no DataNodes to do rolling restarts”.

This was clearly incorrect.

It did not take me too long to figure out that → Continue reading “[SOLVED] Ambari There are no DataNodes to do rolling restarts when there are DataNodes that do need a restart”

[SOLVED] Unable to Connect to ambari-metrics-collector Issues

I was having some issues with the ambari-metrics family of services on a ‘pseudo-distributed’ cluster that I have installed on my workstation.

The symptoms were:

1.  Ambari indicated the following CRITICAL errors in the Ambari Dashboard under the Ambari Metrics section

Connection failed: [Errno 111] Connection refused to rchapin-wrkstn:6188

2.  After attempting to restart the ambari-metrics-collector via either the Ambari Dashboard or through the commandline (# ambari-metrics-collector [stop|start]) you see the following (similar) messages in the ambari-metrics-collector.log

2016-09-02 12:15:37,505 INFO 
Continue reading “[SOLVED] Unable to Connect to ambari-metrics-collector Issues”