Cluster configuration - SAP HANA on AWS
Update user hacluster passwordStart and enable the pcs servicesAuthenticate pcs with user haclusterReview instance settingsSet up the clusterEnable and start the clusterIncrease corosync totem token timeout

Cluster configuration

Update user hacluster password

Change the password of the user haclustser on both the nodes, as shown in the following example: 

[root@prihana ~]# passwd hacluster
[root@sechana ~]# passwd hacluster

Start and enable the pcs services

The following commands start and enable the pcs service on both the nodes: 

[root@prihana ~]# systemctl start pcsd.service
[root@prihana ~]# systemctl enable pcsd.service

Authenticate pcs with user hacluster

The following command authenticates pcs to the pcs daemon on the nodes in the cluster. The user name for the pcs administration must be hacluster on both the nodes with the same password.

RHEL 7.x

[root@prihana ~]# pcs cluster auth prihana sechana
Username: hacluster
Password:
sechana: Authorized
prihana: Authorized
[root@prihana ~]#

RHEL 8.x

[root@<host1> ~]# pcs host auth prihana sechana
Username: hacluster
Password:
sechana: Authorized
prihana: Authorized
[root@<host1> ~]#

Review instance settings that conflict with cluster actions

To ensure that restarts are predictable, we recommend disabling simplified automatic recovery and not configuring Amazon CloudWatch action based recovery for instances that are part of a pacemaker cluster. Use the following command to disable simplified automatic recovery.

aws ec2 modify-instance-maintenance-options --instance-id i-0abcdef1234567890 --auto-recovery disabled

You must ensure that stop protection is disabled for Amazon EC2 instances that are part of a pacemaker cluster. Use the following command to disable stop protection.

aws ec2 modify-instance-attribute --instance-id i-1234567890abcdef0 --no-disable-api-stop

Set up the cluster

The following command configures the cluster configuration file and syncs the configuration on both the nodes. 

pcs cluster setup –name rhelhanaha prihana sechana

[rooteprihana~]pcs cluster setup --name rhelhanaha prihana sechana 
Destroying cluster on nodes: prihana, sechana... 
sechana: Stopping Cluster (pacemaker)... 
prihana: Stopping Cluster (pacemaker)... 
sechana: Successfully destroyed cluster 
prihana: Successfully destroyed cluster 
Sending 'pacemaker_remote authkey' to iprihana', 'sechana' prihana: 
successful distribution of the file 'pacemaker remote authkey' 
sechana: successful distribution of the file 'pacemaker_remote authkey' 
Sending cluster config files to the nodes... 
prihana: Succeeded 
sechana: Succeeded 
Synchronizing pcsd certificates on nodes prihana, sechana... saphdbdbe2: Success 
prihana: Success 
Restarting pcsd on the nodes in order to reload the certificates... sechana: Success 
prihana: Success

Enable and start the cluster

The following commands enable and start the cluster: 

pcs cluster enable –all

root@prihana etc]# pcs cluster enable --all 
prihana: Cluster Enabled 
sechana: Cluster Enabled
pcs cluster start –all

[root@prihana etc]# pcs cluster start --all 
prihana: Starting Cluster (corosync)... 
sechana: Starting Cluster (corosync)... 
sechana: Starting Cluster (pacemaker)... 
prihana: Starting Cluster (pacemaker)... 
[rooteprihana etc]# I

Increase corosync totem token timeout

RHEL 7.x

  1. Edit the /etc/corosync/corosync.conf file in all the cluster nodes and increase or add the value for token, as shown in the following example.

    
totem {
    version: 2
    secauth: off
    cluster_name: my-rhel-sap-cluster
    transport: udpu
    rrp_mode: passive
    token: 30000  <------ Value to be set
}

  2. Reload corosync by running the following command in only one cluster node to reload. This will not require any downtime.

    # pcs cluster reload corosync

  3. Run the following command to confirm that your changes are active.

    
# corosync-cmapctl | grep totem.token
Runtime.config.totem.token (u32) = 30000

RHEL 8.x

Run the following command to increase the corosync token timeout.

# pcs cluster config update totem token=29000