Replace a node in the cluster

Introduction

In some cases it might be necessary to replace an existing node in the cluster with a new node. In this article we'll go through our recommended procedure for accomplishing this task.

Note: When using the below procedure the existing license will not be carried over to the new node automatically so it's necessary to contact us if you want to do this (at no extra cost).

1. Write down what host-specific settings the existing node has such as IP-addresses, routes and DNS resolvers (which you can find under the Hosts tab in the web interface) as well as any cluster overrides that the node might have
2. Pause all the active SMTP listeners on the the existing node. This can be done either by adding cluster overrides for each mail_server__ key and changing the active parameter from yes to no or by simple removing the node from the external load balancer (when one is used)
3. Wait for the existing node's mail queue to empty. You can also bounce any emails that looks like they will never be able to be delivered
4. Remove the existing node from the cluster under Hosts -> Cluster on one of the other nodes in the cluster (that you're going to keep)
5. Shut down the existing node that your going to replace with the new node
6. Bring up the new node that you're going to replace the existing node with (using the correct network settings). Don't run the First run guide from it's web interface since that would configure some default SMTP listeners which you do not want enabled at this time
7. Add the new node to the existing cluster

Note: All history, logs and graphs from the existing node will not be carried over to the new node.