My bad, just tried to set this up using Azure Container Instance, but not successful since they don't support setting shm yet. Similarly, we can use docker environment variable on the docker create step when creating the broker on your CentOS VMs to setup HA.

For example, on the primary node, use this docker create command instead.
sudo docker run \
--network=host \
--uts=host \
--shm-size=2g \
--ulimit core=-1 \
--ulimit memlock=-1 \
--ulimit nofile=2448:42192 \
--restart=always \
--detach=true \
--memory-swap=-1 \
--memory-reservation=0 \
--env 'username_admin_globalaccesslevel=admin' \
--env 'username_admin_password=admin' \
--env 'nodetype=message_routing' \
--env 'routername=primary' \
--env 'redundancy_matelink_connectvia=[backup node IP/hostname]' \
--env 'redundancy_activestandbyrole=primary' \
--env 'redundancy_group_password=password' \
--env 'redundancy_enable=yes' \
--env 'redundancy_group_node_primary_nodetype=message_routing' \
--env 'redundancy_group_node_primary_connectvia=[primary node IP/hostname]' \
--env 'redundancy_group_node_backup_nodetype=message_routing' \
--env 'redundancy_group_node_backup_connectvia=[backup node IP/hostname]' \
--env 'redundancy_group_node_monitor_nodetype=monitoring' \
--env 'redundancy_group_node_monitor_connectvia=[monitor node IP/hostname]' \
--env 'configsync_enable=yes' \
-v /opt/vmr/internalSpool:/usr/sw/internalSpool \
-v /opt/vmr/diags:/var/lib/solace/diags \
-v /opt/vmr/jail:/usr/sw/jail \
-v /opt/vmr/softAdb:/usr/sw/internalSpool/softAdb \
-v /opt/vmr/var:/usr/sw/var \
-v /opt/vmr/adb:/usr/sw/adb \
--name=solacePrimary solace-pubsub-standard

for all the *connect_via variables, you can use hostname, public IP, or internal IP. The important thing is the nodes must be able to resolve the other nodes via that hostname/IP.

Now, for the backup node, similarly use the following command:
sudo docker run \
--network=host \
--uts=host \
--shm-size=2g \
--ulimit core=-1 \
--ulimit memlock=-1 \
--ulimit nofile=2448:42192 \
--restart=always \
--detach=true \
--memory-swap=-1 \
--memory-reservation=0 \
--env 'username_admin_globalaccesslevel=admin' \
--env 'username_admin_password=admin' \
--env 'nodetype=message_routing' \
--env 'routername=backup' \
--env 'redundancy_matelink_connectvia=[primary node IP/hostname]' \
--env 'redundancy_activestandbyrole=backup' \
--env 'redundancy_group_password=password' \
--env 'redundancy_enable=yes' \
--env 'redundancy_group_node_primary_nodetype=message_routing' \
--env 'redundancy_group_node_primary_connectvia=[primary node IP/hostname]' \
--env 'redundancy_group_node_backup_nodetype=message_routing' \
--env 'redundancy_group_node_backup_connectvia=[backup node IP/hostname]' \
--env 'redundancy_group_node_monitor_nodetype=monitoring' \
--env 'redundancy_group_node_monitor_connectvia=[monitor node IP/hostname]' \
--env 'configsync_enable=yes' \
-v /opt/vmr/internalSpool:/usr/sw/internalSpool \
-v /opt/vmr/diags:/var/lib/solace/diags \
-v /opt/vmr/jail:/usr/sw/jail \
-v /opt/vmr/softAdb:/usr/sw/internalSpool/softAdb \
-v /opt/vmr/var:/usr/sw/var \
-v /opt/vmr/adb:/usr/sw/adb \
--name= solaceBackup solace-pubsub-standard

And, lastly for the monitor node, use this command:

sudo docker run \
--network=host \
--uts=host \
--shm-size=2g \
--ulimit core=-1 \
--ulimit memlock=-1 \
--ulimit nofile=2448:42192 \
--restart=always \
--detach=true \
--memory-swap=-1 \
--memory-reservation=0 \
--env 'username_admin_globalaccesslevel=admin' \
--env 'username_admin_password=admin' \
--env 'nodetype= monitoring' \
--env 'routername= monitor' \
--env 'redundancy_activestandbyrole= monitor' \
--env 'redundancy_group_password=password' \
--env 'redundancy_enable=yes' \
--env 'redundancy_group_node_primary_nodetype=message_routing' \
--env 'redundancy_group_node_primary_connectvia=[primary node IP/hostname]' \
--env 'redundancy_group_node_backup_nodetype=message_routing' \
--env 'redundancy_group_node_backup_connectvia=[backup node IP/hostname]' \
--env 'redundancy_group_node_monitor_nodetype=monitoring' \
--env 'redundancy_group_node_monitor_connectvia=[monitor node IP/hostname]' \
--env 'configsync_enable=yes' \
-v /opt/vmr/internalSpool:/usr/sw/internalSpool \
-v /opt/vmr/diags:/var/lib/solace/diags \
-v /opt/vmr/jail:/usr/sw/jail \
-v /opt/vmr/softAdb:/usr/sw/internalSpool/softAdb \
-v /opt/vmr/var:/usr/sw/var \
-v /opt/vmr/adb:/usr/sw/adb \
--name= solaceMonitor solace-pubsub-standard

For your case, if you want to debug your current setup, please share the commands you have used when setting up the HA. Otherwise, if you want to try the commands I shared, then just make sure the docker container names are not the same as your current ones.

Hi Susi,
For the LB setup, you can refer to this page for the default ports that Solace PubSub+ use. For encrypted SMF port, the default is 55443. To enable that, you basically need to setup the server certificate and then enable secured port for the service that you want. You can start from this page for that.
A bit more detailed on this is about the load balancer health-check, please refer to this page for that. Note that this is HTTP-based checks and you should refer to the Redundancy Configured column.

Hi Susi,
Monitoring node is mandatory. And for a quick answer, I'd try to create a new node and run the same command.

Hi Susi,
You can check the docker container logs, but for the complete logs you can go inside the container and have access the complete set of the broker's log files.
$ docker exec -it /bin/bash
$ cd logs

Or, you can stream the broker's log to you existing syslog server. More on that in here.

Hi Susi,
For your monitoring node, it looks like the storage of that node was gone or corrupted. Since this is a new node, would be easier just to recreate a new node and rerun the monitor node setup cli commands

You can run "show redundancy" from the CLI, can be either on the primary or backup node. The result will tell you the redundancy status is up or down.