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Posted to user@ambari.apache.org by "Ray Chaudhuri, Shirsha (Nokia - IN/Bangalore)" <sh...@nokia.com> on 2017/03/25 12:58:44 UTC

How does Ambari resolve hosts for NN1, NN2 when both belong to same Host Group?

Hi,

I am trying to use Apache Ambari’s Blueprints to setup a cluster having HDFS configured to work with Name Node in HA mode. The blueprint will consist of references only to the host group that represents the Name Nodes. If we have exactly similar set of services and components on the 2 hosts which will have to contain the Name Node service, then how does the Blueprint Processor map the different hosts to the nn1, nn2 options in the hdfs-site.xml? This is a case when both hosts belong to the same Host Group for the NN service.

We have seen that the Ambari server makes both nn1 and nn2 point to the same host, leading to a bad cluster.
Is this a limitation of the Blueprint Processor in Ambari or are we missing a way to specify things in the Blueprint in such circumstances?

Regards
Shirsha

Re: How does Ambari resolve hosts for NN1, NN2 when both belong to same Host Group?

Posted by Sumit Mohanty <sm...@hortonworks.com>.
It is possible. I have not seen an usage like that yet. Within a group there is no way to identify which one is host1 and host2 - perhaps thats why.


What is the motivation behind both hosts belonging to the same group?

________________________________
From: Ray Chaudhuri, Shirsha (Nokia - IN/Bangalore) <sh...@nokia.com>
Sent: Saturday, March 25, 2017 10:35 PM
To: user
Subject: Re: How does Ambari resolve hosts for NN1, NN2 when both belong to same Host Group?

Hi Sumit,
We have used these steps and they work great when the 2 name nodes belong to different host groups but not when they are in same host group. Is this a known limitation?
Regards
Shirsha





Sent from OPPO Mail
On Mar 25, 2017 9:27 PM, Sumit Mohanty <sm...@hortonworks.com> wrote:

Shirsha, the following two wikis should provide you the details. Blueprints do support deployment of HA clusters including NN-HA.


https://cwiki.apache.org/confluence/display/AMBARI/Blueprints

https://cwiki.apache.org/confluence/display/AMBARI/Blueprint+Support+for+HA+Clusters?


thanks

-Sumit

________________________________
From: Ray Chaudhuri, Shirsha (Nokia - IN/Bangalore) <sh...@nokia.com>
Sent: Saturday, March 25, 2017 5:58 AM
To: user@ambari.apache.org
Subject: How does Ambari resolve hosts for NN1, NN2 when both belong to same Host Group?

Hi,

I am trying to use Apache Ambari's Blueprints to setup a cluster having HDFS configured to work with Name Node in HA mode. The blueprint will consist of references only to the host group that represents the Name Nodes. If we have exactly similar set of services and components on the 2 hosts which will have to contain the Name Node service, then how does the Blueprint Processor map the different hosts to the nn1, nn2 options in the hdfs-site.xml? This is a case when both hosts belong to the same Host Group for the NN service.

We have seen that the Ambari server makes both nn1 and nn2 point to the same host, leading to a bad cluster.
Is this a limitation of the Blueprint Processor in Ambari or are we missing a way to specify things in the Blueprint in such circumstances?

Regards
Shirsha

Re: How does Ambari resolve hosts for NN1, NN2 when both belong to same Host Group?

Posted by "Ray Chaudhuri, Shirsha (Nokia - IN/Bangalore)" <sh...@nokia.com>.
Hi Sumit,
We have used these steps and they work great when the 2 name nodes belong to different host groups but not when they are in same host group. Is this a known limitation?
Regards
Shirsha





Sent from OPPO Mail
On Mar 25, 2017 9:27 PM, Sumit Mohanty <sm...@hortonworks.com> wrote:

Shirsha, the following two wikis should provide you the details. Blueprints do support deployment of HA clusters including NN-HA.


https://cwiki.apache.org/confluence/display/AMBARI/Blueprints

https://cwiki.apache.org/confluence/display/AMBARI/Blueprint+Support+for+HA+Clusters​


thanks

-Sumit

________________________________
From: Ray Chaudhuri, Shirsha (Nokia - IN/Bangalore) <sh...@nokia.com>
Sent: Saturday, March 25, 2017 5:58 AM
To: user@ambari.apache.org
Subject: How does Ambari resolve hosts for NN1, NN2 when both belong to same Host Group?

Hi,

I am trying to use Apache Ambari’s Blueprints to setup a cluster having HDFS configured to work with Name Node in HA mode. The blueprint will consist of references only to the host group that represents the Name Nodes. If we have exactly similar set of services and components on the 2 hosts which will have to contain the Name Node service, then how does the Blueprint Processor map the different hosts to the nn1, nn2 options in the hdfs-site.xml? This is a case when both hosts belong to the same Host Group for the NN service.

We have seen that the Ambari server makes both nn1 and nn2 point to the same host, leading to a bad cluster.
Is this a limitation of the Blueprint Processor in Ambari or are we missing a way to specify things in the Blueprint in such circumstances?

Regards
Shirsha

Re: How does Ambari resolve hosts for NN1, NN2 when both belong to same Host Group?

Posted by Sumit Mohanty <sm...@hortonworks.com>.
Shirsha, the following two wikis should provide you the details. Blueprints do support deployment of HA clusters including NN-HA.


https://cwiki.apache.org/confluence/display/AMBARI/Blueprints

https://cwiki.apache.org/confluence/display/AMBARI/Blueprint+Support+for+HA+Clusters?


thanks

-Sumit

________________________________
From: Ray Chaudhuri, Shirsha (Nokia - IN/Bangalore) <sh...@nokia.com>
Sent: Saturday, March 25, 2017 5:58 AM
To: user@ambari.apache.org
Subject: How does Ambari resolve hosts for NN1, NN2 when both belong to same Host Group?

Hi,

I am trying to use Apache Ambari's Blueprints to setup a cluster having HDFS configured to work with Name Node in HA mode. The blueprint will consist of references only to the host group that represents the Name Nodes. If we have exactly similar set of services and components on the 2 hosts which will have to contain the Name Node service, then how does the Blueprint Processor map the different hosts to the nn1, nn2 options in the hdfs-site.xml? This is a case when both hosts belong to the same Host Group for the NN service.

We have seen that the Ambari server makes both nn1 and nn2 point to the same host, leading to a bad cluster.
Is this a limitation of the Blueprint Processor in Ambari or are we missing a way to specify things in the Blueprint in such circumstances?

Regards
Shirsha