Scenario 1 : opHA-MB failover and failback commands.
State: It is possible to get the state of the Peers on the Main Primary using the cli
sudo /usr/local/omk/bin/ophad cmd consumer state
Failover: If Poller were to go down, the Mirror would take over automatically. But, once the Poller comes back online, the switchover from Mirror to Poller is not automatic.
Failback: There is a cli command to accomplish the same which needs to be run the Main Primary (and Primary)
sudo /usr/local/omk/bin/ophad cmd consumer failback <Poller Cluster ID>
There is also a way to force a Failover which again needs to be run on Main Primary (and Primary)
sudo /usr/local/omk/bin/ophad cmd consumer failover <Poller Cluster ID>
Scenario 2 : (Replication mode) If the main-primary were to go down in replication mode.
Switching Main and Secondary Primary Servers
In the unforeseen event where the main-primary server goes down the second-primary will take over and become the primary server and ensure that the system still runs. Once we recover the main-primary server we can then restart all the services on the main-primary server, to do that run the following command.
Run as root user
systemctl restart nmis9d opchartsd opeventsd omkd ophad
To switch from the Secondary Primary back to the Main-Primary so the main-primary is the master again follow these steps:
Connect to MongoDB on the master server in this case the (second-primary):
mongosh --username opUserRW --password op42flow42 admin
Update member priorities:
cfg = rs.conf() cfg.members[0].priority = 0.6 cfg.members[1].priority = 0.5 rs.reconfig(cfg)