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HA blueprint specific queries


HA blueprint specific queries

Hello all,

My questions are related to HA blueprints. Suppose I have a 2 master/1 worker setup on AWS/Azure. Now one of my master is down/faulty and I want to add a new master(master3) to existing cluster.

Also, I want to remove the faulty/unhealthy master(master1) from the cluster.

While instantiating the cluster, I had used the HA blueprint with 2 hostgroups (master1 and master2) with their set of components/services.

Now if I say spawn master3 node on cloud platform which has all the required accesses to the existing cluster. Will the following approach work for getting a HA enabled healthy cluster with new master3?

  1. I get the cluster name using Ambari APIs.
  2. Create a host_mapping.json with host-group as master1(since master1 is faulty) and use blueprint API to register new master3.

Will Ambari take care of the installing and starting the components/services and also rebalance the cluster with HA settings?

Is there anything other approach using which I can achieve the HA again? OR

Will the re-configuration of all the components in HA be handled outside the ambari's scope?

Please let me know your views. I have limited exposure to ambari at this time so feel free to correct me or atleast give some pointers.


Re: HA blueprint specific queries

As the blueprints focus heavily on the host_groups concept which usually means some highly specialized master setups and then a more generic worker model, I feel that using blueprints beyond the initial cluster layout really works best for when you are adding more workers. My INITIAL recommendation (I'm arm-chair QBing this w/o all the details) would be to simple go to Ambari's UI and add a new host via the wizard process and then assign whatever master and worker processes you need.


Re: HA blueprint specific queries

Thanks for the reply @Lester Martin. Will the blueprint take care of setting up/re-configure component level HA with this new node?

In my scenario, I am setting up cluster using the HDP's ansible repo. I plan to add new node using the same mechanism where I can get the VMs in the existing cluster with active master (as user's input) and make sure this new node is added to the cluster via Ansible

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