session replication across server does not work in wildfly10 + mod_cluster 1.2.6

[skyoutflygod]

Hi Guys,

I set up two hosts in domain mode using wildfly10 and mod_cluster. Each host has two servers in it. All of these four servers belong to the same server group and I assigned one application to that server group. In mode cluster manager, 4 nodes showed up successfully.

The problem is I can get session replication work within the two nodes in the same host but cannot get session replicated with the two nodes in different hosts. Any idea what I might have missed here?

[rhusar]

The problem is I can get session replication work within the two nodes in the same host but cannot get session replicated with the two nodes in different hosts. Any idea what I might have missed here?

Mostly likely the nodes across physical hosts are not discovering each other. By default, they are discovered by UDP multicast (see jgroups subsystem configuration). This is often due to network or firewall blocking multicast.

You can switch to TCP but you need to subsitute the multicast discovery with something else (e.g. static configuration via TCPPING).  See Chapter 7. List of Protocols