Verifying the Configuration of HA Cluster Managing SAP Resources

Outcomes

After completing this section, you should be able to verify the status of a basic high availability cluster for managing SAP HANA or SAP NetWeaver.

All nodes in a Pacemaker cluster must use the same major version of Red Hat Enterprise Linux. Red Hat Enterprise Linux 8 clusters use Corosync 3.x for communication. Red Hat Enterprise Linux 7 Pacemaker clusters use Corosync 2.x.

Run the pcs status command to verify the current state of the cluster:
```
[root@node ~]# pcs status
```
To verify the detailed status of the cluster, including the configuration, use the pcs config command:
```
[root@nodea ~]# pcs config
```
When performing any maintenance activity, you might want to monitor the real-time status of the cluster in a separate terminal. Run the following command to start the real-time monitoring:
```
[root@nodea ~]# crm_mon
```
This process occupies the terminal; to return to the prompt, press Ctrl+c.
To verify resource constraints, run the pcs constraint command:
```
[root@nodea ~]# pcs constraint
```
To review the constraints in more detail, run the pcs constraint --full command:
```
[root@nodea ~]# pcs constraint --full
```

Move the resource and verify the status:

[root@nodea ~]# pcs resource move <sap-resource> <Node-Name>

For SAP HANA resources, use the following command for the move:

[root@nodea ~]# crm_resource --move --resource <sap-hana-resource> \
> <Node-Name>

To prevent the myresource resource group from running on node2, execute the following command:
```
[root@nodea ~]# pcs resource ban <sap-resource> node2.example.com
```
Both pcs resource move and pcs resource ban create a constraint rule on the cluster. Constraints are used, among other reasons, to influence which resources can run where. How to list and delete constraints is described later in this chapter.

To clear the ban restriction for the sapresource resource group, execute the following command:
```
[root@nodea ~]# pcs resource clear <sapresource>
```
To view current resource defaults, run this command:
```
[root@nodea ~]# pcs resource defaults
```

Finish

You have verified the configuration of a RHEL HA cluster for managing SAP resources.