Cannot ping a secondary address apart from the server which it is assigned to

Question

Hello,
I am trying to setup up a High Availability Cluster in Azure using CentOS 8, Pacemaker and Corosync. Everything is deployed using terraform.

For our application, we need to migrate a floating IP address, a shared storage and our daemon between nodes. These resources are grouped into a service and these are successfully migrating between nodes as required. We are also using a private DNS zone and there is no firewall on either server. There is a DNS entry for the floating IP and that is resolvable by both servers and client.

The problem is that floating IP address is only pingable on the server which has the floating IP address assigned as a secondary address. All other nodes in the same subnet will get the error Destination Host Unreachable, but pings to the primary address will succeed. All the IP addresses are in the same subnet (172.16.31.0/24). Auto-registration is enabled for the servers and client which makes up the test environment. The floating address was a somewhat arbitrary choice, but remains in that same subnet and would not be otherwise allocated. I mentioned the auto registration because the floating IP is not auto-registered.

If I migrate the service to the other server node, the roles are reversed, the server which could not ping the address can now do so and the server which could, cannot.

Any insight would be welcome.

Thanks
-paul

Answer 1

@Paul Warwicker ,

There is no service in Azure that can be used to automate this behavior. You need to have a logic running in the form of scripts which switches the IP when the roles are changed.

Regards,
Karthik Srinivas