Guided Exercise: Deploying and Configuring the Pacemaker Cluster

Outcomes

After completing this section, you should be able to install and start a basic high availability cluster for managing SAP HANA.

As the student user on the workstation machine, use the lab command to prepare your system for this exercise.

This command ensures that the environment is configured correctly for creating your Ansible Playbooks in the future.

[student@workstation ~]$ lab start ansible-pacemaker

You now configure a High Availability cluster to manage previously created HANA resources by using the latest cluster HA roles.

Red Hat Enterprise Linux 8 and Red Hat Enterprise Linux 7 cluster nodes are not compatible in a single cluster. 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, although Red Hat Enterprise Linux 7 Pacemaker clusters use Corosync 2.x.

Ensure all aliases for the cluster are distributed to all nodes

For running SAP HANA in a cluster we need to define virtual ip adresses for these services in /etc/hosts.

Verify that the ansible collection community.sap_install is installed in version 1.4.0

[student@workstation ~]$ ansible-galaxy collection list
Collection               Version
------------------------ -------
ansible.posix            1.4.0
community.general        5.5.0
redhat.rhel_system_roles 1.22.0
redhat.sap_install       1.1.0

# /home/student/.ansible/collections/ansible_collections
Collection                Version
------------------------- -------
community.sap_install     1.4.0
community.sap_launchpad   1.0.0
community.sap_libs        1.1.0
community.sap_operations  0.9.0

Change to the ansible-files directory in your home directory:
```
[student@workstation ~]$ cd ~/ansible-files
```

Create the file group_vars/all with the following content

# Virtual IP addresses
sap_service_vips:
  - node_ip: 172.25.250.80
    node_name: hana
    state: present
    alias_mode: overwrite
  - node_ip: 172.25.250.81
    node_name: s4ascs
    state: present
    alias_mode: overwrite
  - node_ip: 172.25.250.82
    node_name: s4ers
    state: present
    alias_mode: overwrite

Create a playbook update_host_aliases.yml with the following content:

- name: Update host aliases
  hosts: localhost,all
  become: true

  tasks:
    - name: Update Hostaliases
      ansible.builtin.include_role:
        name: community.sap_install.sap_maintain_etc_hosts
      vars:
        sap_maintain_etc_hosts_list: "{{ sap_service_vips }}"

NOTE: you may need to install ansible.utils collection

Execute the playbook:

[student@workstation ansible-files]$ ansible-playbook update_host_aliases.yml -v -K
BECOME password: student

Install the pacemaker cluster on the HANA servers

Change to the ansible-files directory:

[student@workstation ~]$ cd ~/ansible-files

Update the group_vars/hanas file with the following variables:

## BEGIN pacemaker parameters
sap_ha_pacemaker_cluster_system_roles_collection: "redhat.rhel_system_roles"
ha_cluster_cluster_name: cluster1
ha_cluster_hacluster_password: "my_hacluster"

sap_ha_pacemaker_cluster_vip_hana_primary_ip_address: "172.25.250.80"

sap_ha_pacemaker_cluster_stonith_custom:
  - name: "fence_hana1"
    agent: "stonith:fence_ipmilan"
    options:
      ip: bmc-hana1
      pcmk_host_list: hana1
      power_timeout: 180
      username: admin
      password: password
      lanplus: 1
  - name: "fence_hana2"
    agent: "stonith:fence_ipmilan"
    options:
      ip: bmc-hana2
      pcmk_host_list: hana2
      power_timeout: 180
      username: admin
      password: password
      lanplus: 1
## END pacemaker parameters

Create the playbook setup-pacemaker.yml:

[student@workstation roles]$ cd ~/ansible-files
[student@workstation ansible-files]$ vim setup-pacemaker.yml

Add this content

---
- name: "03-D HA Cluster deployment on a 2-node cluster"
  hosts: hanas
  become: true

  tasks:
    - name: Execute Cluster Setup Role
      ansible.builtin.include_role:
        name: community.sap_install.sap_ha_pacemaker_cluster
      vars:
        sap_ha_pacemaker_cluster_system_roles_collection: redhat.rhel_system_roles
        sap_ha_pacemaker_cluster_vip_client_interface: eth0
        ha_cluster_enable_repos: false

Execute the playbook:

[student@workstation ansible-files]$ ansible-playbook setup-pacemaker.yml -v -K
BECOME password: student

After the successful completion of the playbook, verify the cluster state.

Log in to the hana1 node as the root user with redhat as the password:
```
[student@workstation ~]$ ssh root@hana1
```

Verify the cluster status with the following command:

[root@hana1 ~]# pcs status --full
Cluster name: cluster1
Cluster Summary:
  * Stack: corosync
  * Current DC: hana2.lab.example.com (2) (version 2.0.5-9.el8-ba59be7122) - partition with quorum
  * Last updated: Thu May 11 05:35:35 2023
  * Last change:  Thu May 11 05:35:06 2023 by root via crm_attribute on hana1.lab.example.com
  * 2 nodes configured
  * 7 resource instances configured

Node List:
  * Online: [ hana1.lab.example.com (1) hana2.lab.example.com (2) ]

Full List of Resources:
  * res_fence_hana1 (stonith:fence_ipmilan):     Started hana1.lab.example.com
  * res_fence_hana2 (stonith:fence_ipmilan):     Started hana2.lab.example.com
  * vip_RHE_00_primary  (ocf::heartbeat:IPaddr2):    Started hana1.lab.example.com
  * Clone Set: SAPHanaTopology_RHE_00-clone [SAPHanaTopology_RHE_00] (promotable):
    * SAPHanaTopology_RHE_00    (ocf::heartbeat:SAPHanaTopology):    Slave hana2.lab.example.com
    * SAPHanaTopology_RHE_00    (ocf::heartbeat:SAPHanaTopology):    Slave hana1.lab.example.com
  * Clone Set: SAPHana_RHE_00-clone [SAPHana_RHE_00] (promotable):
    * SAPHana_RHE_00    (ocf::heartbeat:SAPHana):    Slave hana2.lab.example.com
    * SAPHana_RHE_00    (ocf::heartbeat:SAPHana):    Master hana1.lab.example.com

Node Attributes:
  * Node: hana1.lab.example.com (1):
    * hana_rhe_clone_state              : PROMOTED
    * hana_rhe_op_mode                  : logreplay
    * hana_rhe_remoteHost               : hana2
    * hana_rhe_roles                    : 4:P:master1:master:worker:master
    * hana_rhe_site                     : DC01
    * hana_rhe_srmode                   : sync
    * hana_rhe_sync_state               : PRIM
    * hana_rhe_version                  : 2.00.067.01.1682405377
    * hana_rhe_vhost                    : hana1
    * lpa_rhe_lpt                       : 1683797706
    * master-SAPHana_RHE_00             : 150
  * Node: hana2.lab.example.com (2):
    * hana_rhe_clone_state              : DEMOTED
    * hana_rhe_op_mode                  : logreplay
    * hana_rhe_remoteHost               : hana1
    * hana_rhe_roles                    : 4:S:master1:master:worker:master
    * hana_rhe_site                     : DC02
    * hana_rhe_srmode                   : sync
    * hana_rhe_sync_state               : SOK
    * hana_rhe_version                  : 2.00.067.01.1682405377
    * hana_rhe_vhost                    : hana2
    * lpa_rhe_lpt                       : 30
    * master-SAPHana_RHE_00             : 100

Migration Summary:

Tickets:

PCSD Status:
  hana1.lab.example.com: Online
  hana2.lab.example.com: Online

Daemon Status:
  corosync: active/enabled
  pacemaker: active/enabled
  pcsd: active/enabled

Finish

You have configured a basic High Availability cluster for SAP HANA.