Clustering WSO2 EI ESB and WSO2 EI MB profiles, WKA vs Multicast? Are my assumptions correct?

Question

I have to create and configure a two node WSO2 EI cluster. In particular I have to cluster an ESB profile and MB profile.

I have some architectural doubts about this:

CLUSTERING ESB PROFILE DOUBTS:

I based my assumptions on this documentation: https://docs.wso2.com/display/EI640/Clustering+the+ESB+Profile

I found this section:

Note that some production environments do not support multicast. However, if your environment supports multicast, there are no issues in using this as your membership scheme

What could be the reason for not supporting multicast? (so I can inform about possible issues with it). Looking into the table (inside the previous link) it seems to me that possible problem could be related to the following points:

• All nodes should be in the same subnet
• All nodes should be in the same multicast domain
• Multicasting should not be blocked

Is obtaining this information from system\network engineers enough to decide whether to proceed with the multicast option?

Using multicast instead of WKA, would I need to do the same configuration steps listed in the first deployment scenario (the WKA based one) related to the "mounting registry" and "creating\connecting to databases" (as shown in the first documentation link)?

Does using Multicast instead of WKA allow me to not stop the service when I add a new node to the cluster?

CLUSTERING MB PROFILE:

From what I understand, MB profile cluster can use only WKA as membership scheme. Does using WKA mean that I have to stop the service when I add a new node to the cluster?

So at the end can we consider the ESB cluster and the MB cluster two different clusters? Does the ESB cluster (if it is configured using multicast) need the service to be stopped when a new node is added while the MB cluster is stopped to add a new one?

Answer 1

Many virtual private cloud networks, including Google Cloud Platform, Microsoft Azure, Amazon Web Services, and the public Internet do not support multicast. Because such a platform does not support multicast.

If you configure wso2 products with multicast as the membership shceam it will not work as expected. That is the main reason for the warning in the official documentation.

You can consider the platform capability and chose any of the following membership schemes when configuring Hazalcast clustering in WSO2 Products.

• WKA
• Multicast
• AWS
• Kubernetes

Other than WKA the rest of the options for membership schema does not require you to include all the IPs of the member's in the configuration. So newly introduced nodes can join the cluster with ease.

Even in the WKA membership scheme if you have at least one known member active you can join a new member to the cluster then follow the configuration change and restart the other services without any service interruption.

Please note with all the above membership scheme usages the rest of the configurations related to each product are needed to successfully complete the cluster.

Regarding your concern about Clustering the MB Profile, You can use any of the above-mentioned membership schemas which matches your deployment environment.

Regarding the adding new members to WKA, You can maintain service availability and apply the changes to servers one by one. You only need at least one WKA member running to introduce a new member to the cluster.

WSO2 MB Profile introduces cluster coordination through an RDBMS. With this new feature by default, cluster coordination is not handled by hazelcast engine. When the cluster coordination through an RDBMS is dissabled is allow the hazelcast engine to manage cluster coordination

Please note when the RDMS coordination is used there are no server restarts required.

I hope this was helpfull.