You might need to move nodes between allocators from time to time for a number of reasons:
- To prepare for removing the allocator role from the first host on which you installed Elastic Cloud Enterprise, as part of setting up your deployment.
- To avoid downtime during maintenance: You can create a new allocator, move all nodes from an existing allocator to the new one, and then deal with the allocator that needs maintenance.
- To make room on an allocator: You can move some smaller nodes to another allocator if you need additional room for a larger node on an allocator.
- To move nodes after a failure: When host failures happen, you can move all nodes from the affected allocator to a healthy allocator quickly before spending any time on fixing the failure.
Note that moving nodes does not actually move the same node onto a different allocator. Under the covers, Elastic Cloud Enterprise creates a new node and then migrates the data for you.
When you move all nodes from an existing allocator to the new one, ECE migrates the data to new nodes. The migration can take some time, especially when clusters contain large amounts of data and have a heavy workload. Is your cluster under a heavy workload? You might need to stop routing requests first.
To move nodes from one allocator to another one, in this case from a failed allocator:
- Log into the Cloud UI.
- Click Platform and then select an installation.
- Click Allocators to see a list of all allocators that are part of this installation and look for allocators that are unhealthy.
- Recommended: Put the allocator into maintenance mode before continuing.
- Click the name of an unhealthy allocator and then click Vacate Allocator.
Let the user interface guide you through the steps and the options available to move the nodes. You can move only one type of node at a time.
If you did not enable maintenance mode, set a target allocator under the advanced options when moving nodes to make sure the nodes do not end up on the same allocator again. By default, moving a node moves it to any allocator that has enough capacity.
- Repeat step 5 for each of the node types until no nodes remain on the allocator.