Remove instance from ECE cluster on ECE 2.4

Hi,

I want to remove definively an instance from one of my cluster on ECE 2.4

please let know how to complete this

thanks in advance

Kamal

Hi,

When you say you want to remove an 'instance' are you meaning that your want to remove ECE off an allocator completely ?

Or are you wanting to remove an 'instance' from a particular deployment ?

Hi Kamal,
ECE does not allow removing a particular instance. In ECE we use plans (the desired state of the cluster) to manage clusters: change topology, configuration, etc. Therefore, to remove an instance from a cluster you have to change the cluster's topology and to do that you have to apply a plan.

For example, we have 3 dedicated masters and 3 data nodes and you need to remove a data node, we have to submit a plan that changes topology to 3 masters and 2 data nodes. ECE will choose a node according to the internal logic and remove the instance.

However, the plan lets you provide some hints about what instances (or allocators) should have priority during calculating instances that should be removed (or moved from one allocator to another). We use them to specify what instances need to be moved to other allocators (eg when the allocator gets unhealthy). Therefore, if your hint won't match topology change, the constructor will just replace the instance with exactly the same instance (ie moves the instance to another allocator).

To give those hints you have to use "Advanced Plan Configuration" or API. The plan specification (JSON) has a fields "move_instances" and "move_allocators", which are the part of the section "transient.plan_configuration"

For example, in the cluster above you need to get rid of an instance instance-0000000121, which is one of data nodes (instance-0000000120, instance-0000000121,instance-0000000122).

  1. You need to change topology, ie decrease the number of instances in the cluster (eg zone_count)
  2. Add instance to move_instances.
    "move_instances" : [{ "from" : "instance-0000000121" }]
    

In this case, constructor will remove instance 121 instead of 120.

The technique I described is not trivial and requires you to really know what you want to achieve. I would recommend you contacting support and they will help you.

If you want to move an instance from one allocator to another, please follow this guide https://www.elastic.co/guide/en/cloud-enterprise/2.4/ece-move-nodes.html.

Hi,

I mean remove an instance from deployment

Kamal

Hi Yuri,

Thank you so much for your clarification ,now i have an clair idea about that

Thanks again for your time.

Kamal