In the last post we upgraded EDB EFM from version 2.0 to 2.1. In this post we’ll look at the new features. Actually we’ll look only at two of the new features in this post:
- Failover Manager now simplifies cluster startup with the auto.allow.hosts property
- efm promote now includes a -switchover option; the -switchover option instructs Failover Manager to perform a failover, promoting a Standby to Master, and then, return the Master node to the cluster as a Standby node. For more information
Lets go …
My failover cluster status is still fine:
[root@edbbart efm-2.1]$ /usr/edb-efm/bin/efm cluster-status efm Cluster Status: efm VIP: 192.168.22.250 Automatic failover is disabled. Agent Type Address Agent DB Info -------------------------------------------------------------- Witness 192.168.22.244 UP N/A Standby 192.168.22.243 UP UP Master 192.168.22.245 UP UP Allowed node host list: 192.168.22.244 192.168.22.243 192.168.22.245 Membership coordinator: 192.168.22.244 Standby priority host list: 192.168.22.243 Promote Status: DB Type Address XLog Loc Info -------------------------------------------------------------- Master 192.168.22.245 0/3C000220 Standby 192.168.22.243 0/3C000220 Standby database(s) in sync with master. It is safe to promote.
The first bit we’re going to change is the auto.allow.hosts on the database servers. According to the documentation this should eliminate the need to allow the hosts to join the cluster and registration should happen automatically. So, lets change it from “false” to “true” on all nodes:
[root@ppasstandby efm-2.1]$ grep allow.hosts efm.properties auto.allow.hosts=true
… and then lets add all nodes to the efm.nodes files on the witness:
[root@edbbart efm-2.1]$ cat efm.nodes # List of node address:port combinations separated by whitespace. # The list should include at least the membership coordinator's address. 192.168.22.244:9998 192.168.22.243:9998 192.168.22.245:9998
When we now shutdown the EFM service on all hosts and bring it up again on the witness what is the result?
[root@edbbart efm-2.1]$ systemctl stop efm-2.1.service # do this on all hosts
Lets start on the witness again:
[root@edbbart efm-2.1]$ systemctl start efm-2.1.service [root@edbbart efm-2.1]$ /usr/edb-efm/bin/efm cluster-status efm Cluster Status: efm VIP: 192.168.22.250 Automatic failover is disabled. Agent Type Address Agent DB Info -------------------------------------------------------------- Witness 192.168.22.244 UP N/A Allowed node host list: 192.168.22.244 192.168.22.243 192.168.22.245 Membership coordinator: 192.168.22.244 Standby priority host list: (List is empty.) Promote Status: Did not find XLog location for any nodes.
So far so good, all nodes are in the “Allowed” list. What happens when we start EFM on the current primary node:
[root@ppasstandby efm-2.1]$ systemctl start efm-2.1.service [root@ppasstandby efm-2.1]$
We should see the node as a member now without explicitly allowing it to join:
[root@edbbart efm-2.1]$ /usr/edb-efm/bin/efm cluster-status efm Cluster Status: efm VIP: 192.168.22.250 Automatic failover is disabled. Agent Type Address Agent DB Info -------------------------------------------------------------- Witness 192.168.22.244 UP N/A Master 192.168.22.245 UP UP Allowed node host list: 192.168.22.244 192.168.22.243 192.168.22.245 Membership coordinator: 192.168.22.244 Standby priority host list: (List is empty.) Promote Status: DB Type Address XLog Loc Info -------------------------------------------------------------- Master 192.168.22.245 0/3D000060 No standby databases were found.
Cool, same on the standby node:
[root@edbppas edb-efm]$ cat efm.nodes # List of node address:port combinations separated by whitespace. # The list should include at least the membership coordinator's address. 192.168.22.244:9998 [root@edbppas edb-efm]$ systemctl start efm-2.1.servic
What is the status:
[root@edbbart efm-2.1]$ /usr/edb-efm/bin/efm cluster-status efm Cluster Status: efm VIP: 192.168.22.250 Automatic failover is disabled. Agent Type Address Agent DB Info -------------------------------------------------------------- Witness 192.168.22.244 UP N/A Master 192.168.22.245 UP UP Standby 192.168.22.243 UP UP Allowed node host list: 192.168.22.244 192.168.22.243 192.168.22.245 Membership coordinator: 192.168.22.244 Standby priority host list: 192.168.22.243 Promote Status: DB Type Address XLog Loc Info -------------------------------------------------------------- Master 192.168.22.245 0/3D000060 Standby 192.168.22.243 0/3D000060 Standby database(s) in sync with master. It is safe to promote.
Perfect. Makes it a bit easier and fewer things to remember to bring up a failover cluster.
Coming to the “big” new feature (at least in my opinion): Switching to the standby and making the old master automatically a new standby which follows the new master. According to the docs all we need to do is this:
[root@edbbart efm-2.1]$ /usr/edb-efm/bin/efm promote efm -switchover
Does it really work?
[root@edbbart efm-2.1]$ /usr/edb-efm/bin/efm promote efm -switchover Promote/switchover command accepted by local agent. Proceeding with promotion and will reconfigure original master. Run the 'cluster-status' command for information about the new cluster state.
Hm, lets check the status:
[root@edbbart efm-2.1]$ /usr/edb-efm/bin/efm cluster-status efm Cluster Status: efm VIP: 192.168.22.250 Automatic failover is disabled. Agent Type Address Agent DB Info -------------------------------------------------------------- Witness 192.168.22.244 UP N/A Master 192.168.22.243 UP UP Standby 192.168.22.245 UP UP Allowed node host list: 192.168.22.244 192.168.22.245 192.168.22.243 Membership coordinator: 192.168.22.244 Standby priority host list: 192.168.22.245 Promote Status: DB Type Address XLog Loc Info -------------------------------------------------------------- Master 192.168.22.243 0/410000D0 Standby 192.168.22.245 0/410000D0 Standby database(s) in sync with master. It is safe to promote.
It really worked! And backwards:
[root@edbbart ~]$ /usr/edb-efm/bin/efm promote efm -switchover
Promote/switchover command accepted by local agent. Proceeding with promotion and will reconfigure original master. Run the 'cluster-status' command for information about the new cluster state.
[root@edbbart ~]$ /usr/edb-efm/bin/efm cluster-status efm
Cluster Status: efm
VIP: 192.168.22.250
Automatic failover is disabled.
Agent Type Address Agent DB Info
--------------------------------------------------------------
Witness 192.168.22.244 UP N/A
Standby 192.168.22.243 UP UP
Master 192.168.22.245 UP UP
Allowed node host list:
192.168.22.244 192.168.22.245 192.168.22.243
Membership coordinator: 192.168.22.244
Standby priority host list:
192.168.22.243
Promote Status:
DB Type Address XLog Loc Info
--------------------------------------------------------------
Master 192.168.22.245 0/480001A8
Standby 192.168.22.243 0/480001A8
Standby database(s) in sync with master. It is safe to promote.
Cool, that is really a great new feature.
![Thumbnail [60x60]](https://www.dbi-services.com/blog/wp-content/uploads/2022/08/DWE_web-min-scaled.jpg)