Automate your SAP HANA System Replication Deployment using Ansible and RHEL System Roles for SAP

Setting up Ansible Cloud Modules for Azure

You’ll first need to set up your RHEL subscription and Ansible Engine.

# subscription-manager clean
# mv /etc/yum.repos.d/rh-cloud.repo /etc/yum.repos.d/rh-cloud.repo.bk
# subscription-manager register --auto-attach
# subscription-manager repos --enable=ansible-2.8-for-rhel-8-$(uname -m)-rpms
# yum install -y ansible

Once the Ansible Engine is installed, set up and install Azure CLI.

# rpm --import https://packages.microsoft.com/keys/microsoft.asc
# sh -c 'echo -e "[azure-cli]\nname=Azure CLI\nbaseurl=https://packages.microsoft.com/yumrepos/azure-cli\nenabled=1\ngpgcheck=1\ngpgkey=https://packages.microsoft.com/keys/microsoft.asc" > /etc/yum.repos.d/azure-cli.repo'
# yum install -y azure-cli

Now, let’s install the required packages for the Azure Python SDK modules.

# yum install -y gcc libffi-devel platform-python-devel openssl-devel
# yum install -y python3-pip python3-wheel
# curl https://bootstrap.pypa.io/get-pip.py -o get-pip.py
# python3 get-pip.py
# pip3 install 'ansible[azure]' --use-feature=2020-resolver

It is worth mentioning that these Ansible Cloud modules for Azure will be installed in path /usr/lib/python3.6/site-packages/ansible/modules/cloud/azure.

Ansible includes a suite of modules for interacting with Azure Resource Manager, giving you the tools to easily create and orchestrate infrastructure on the Microsoft Azure Cloud. Using the Azure Resource Manager modules requires authenticating with the Azure API. Let’s configure Azure authentication with Azure service principal. 

You’ll first need to enter “az login” to authenticate your Azure administration server and log in.

# az cloud set --name AzureCloud
# az login

And then, create an Azure service principal with Azure CLI.

# az ad sp create-for-rbac --name hanaSP

# az account show

Lastly, Insert the following lines into the credentials file.

# mkdir $HOME/.azure
# vi $HOME/.azure/credentials
[default]
subscription_id=<id from command "az account show">
client_id=<"appId"> 
secret=<"password">
tenant=<"tenant">

Now, Azure authentication is configured, you need to create an ssh key pair on the bootstrap server, and record the public key. You will use it while creating Azure VMs.

# ssh-keygen -t rsa

Setting up NFS server for SAP media

To store the installation media, you will need to install and set up NFS server, and unzip the SAP HANA installation binary to the NFS share (e.g. /ssd_vms/SAP_HANA_BINARY/HANA2SPS04/)

Setting up System Roles for SAP HANA

Now, let’s install the following system roles for SAP.

- redhat_sap.sap_rhsm
- redhat_sap.sap_hana_mediacheck
- linux-system-roles.timesync
- linux-system-roles.storage
- redhat_sap.sap_hana_deployment
- redhat_sap.sap_hostagent
- redhat_sap.sap_hana_hsr

Make sure to install the RHEL System Roles for SAP.

# yum -y install rhel-system-roles-sap

Once the roles are installed, you will need to set the RHEL release and enable required repositories for the bootstrap server by running the following playbook: 

setup_subscription.yaml

---
- name: test variables of rhsm
 hosts: localhost
 connection: local
 become_user: root

 vars:
   # sap_rhsm role variables
   sap_rhsm_username: '<your Red Hat login>'
   sap_rhsm_password: '<your Red Hat login password>'
   sap_rhsm_pool_ids:
               - "<pool id>"
  roles:
     - { role: redhat_sap.sap_rhsm }

If you have questions about which repositories have been enabled currently, you can check the handy tool - RHEL for SAP Configurator. 

And then, it is an important step to set up variables for SAP HANA servers, you can refer to the following configurations:

You survived! Congratulations! There are only a few steps left, I promise.

Deploying 2 Azure VMs for SAP HANA

Once you’ve got all of the proper prerequisites, it’s time to deploy the Azure VMs. To get the VMs deployed, you would need to do some preparatory steps on Azure. You’ll first need to create Resource Group (i.e. ResourceGroupHana) and Virtual Network (i.e. VirtualNetworkHana). And then, check your Azure subscription’s quotas to make sure that you have a sufficient number of vCPU in your quotas. Otherwise, your playbook will fail.

./deploy_azure_vms.yaml

---
- hosts: localhost
  connection: local
  vars:
    resource_group: ResourceGroupHana
    virtual_network: ResourceGroupHana-vnet
    virtual_subnet: default
    virtual_machine1: saphana01
    virtual_machine2: saphana02
    nic1: NicHana01
    nic2: NicHana02
    security_group: SecurityGroupHana

  tasks:
    - name: Ensure a security group that allows SSH
      azure_rm_securitygroup:
        resource_group: "{{ resource_group }}"
        name: "{{ security_group }}"
        rules:
          - name: 'AllowSSH'
            protocol: Tcp
            destination_port_range: 22
            access: Allow
            priority: 101
            direction: Inbound

    - name: Ensure a network interface for VM saphana01 
      azure_rm_networkinterface:
        resource_group: "{{ resource_group }}"
        name: "{{ nic1 }}"
        virtual_network: "{{ virtual_network }}"
        subnet_name: "{{ virtual_subnet }}"
        security_group: "{{ security_group }}"
        ip_configurations:
          - name: ipconfig1
            primary: True
    - name: Ensure a VM saphana01 to run SAP HANA
      azure_rm_virtualmachine:
        resource_group: "{{ resource_group }}"
        name: "{{ virtual_machine1 }}"
        vm_size: Standard_E8s_v3
        admin_username: adminUser
        admin_password: "adminUser#1"
        ssh_public_keys:
          - path: /home/adminUser/.ssh/authorized_keys
            key_data: <Insert the public key of the bootstrap server here>
        network_interfaces: "{{ nic1 }}"
        image:
          offer: "RHEL"
          publisher: "RedHat"
          sku: '8.1'
          version: latest
        managed_disk_type: Standard_LRS
        data_disks:
            - lun: 0
              disk_size_gb: 128
              managed_disk_type: Premium_LRS

    - name: Ensure a network interface for VM saphana02
      azure_rm_networkinterface:
        resource_group: "{{ resource_group }}"
        name: "{{ nic2 }}"
        virtual_network: "{{ virtual_network }}"
        subnet_name: "{{ virtual_subnet }}"
        security_group: "{{ security_group }}"
        ip_configurations:
          - name: ipconfig2
            primary: True
    - name: Ensure a VM saphana02 to run SAP HANA
      azure_rm_virtualmachine:
        resource_group: "{{ resource_group }}"
        name: "{{ virtual_machine2 }}"
        vm_size: Standard_E8s_v3
        admin_username: adminUser
        admin_password: "adminUser#1"
        ssh_public_keys:
          - path: /home/adminUser/.ssh/authorized_keys
            key_data: <Insert the public key of the bootstrap server here>
        network_interfaces: "{{ nic2 }}"
        image:
          offer: "RHEL"
          publisher: "RedHat"
          sku: '8.1'
          version: latest
        managed_disk_type: Standard_LRS
        data_disks:
            - lun: 0
              disk_size_gb: 128
              managed_disk_type: Premium_LRS
...

The following picture is the screen dump while running the above playbook:

Once the VMs are deployed successfully, remember to add the entries of the VMs to /etc/hosts on the bootstrap. The following playbook helps you get the IP address for your HANA servers:

---
- hosts: localhost
 connection: local

 tasks:
 - name: Get facts for saphana01's network interface
   azure_rm_networkinterface_facts:
     resource_group: ResourceGroupHana
     name: NicHana01
   register: result

 - name: Print Private IP address for saphana01
   debug:
     msg:
     - "saphana01 Private IP address: {{ result.networkinterfaces[0].ip_configurations[0].private_ip_address }}"

 - name: Get facts for saphana02's network interface
   azure_rm_networkinterface_facts:
     resource_group: ResourceGroupHana
     name: NicHana02
   register: result

 - name: Print Private IP address for saphana02
   debug:
     msg:
     - "saphana02 Private IP address: {{ result.networkinterfaces[0].ip_configurations[0].private_ip_address }}"
...

Once you’ve got the IP addresses, edit the /etc/hosts.

10.0.0.5 saphana01 saphana01.<domain_name>
10.0.0.6 saphana02 saphana02.<domain_name>

Installing SAP HANA with System Replication

Now that you’ve deployed the Azure VMs, it’s time to install SAP HANA with System Replication. Before getting to the last step, let’s run the below playbook to fix a few existing issues: 

./fix_vms_issues.yaml

---
- hosts: hana
 tasks:
 - name: Copy a new "/etc/hosts" file into place, backing up the original if it differs from the copied version
   copy:
     src: /etc/hosts
     dest: /etc/hosts
     owner: root
     group: root
     mode: '0644'
     backup: yes

 - name: Disable RHUI repos by renaming repo file /etc/yum.repos.d/rh-cloud.repo
   command: mv /etc/yum.repos.d/rh-cloud.repo /etc/yum.repos.d/rh-cloud.repo.bk

 - name: Extend root filesystem “/” of VMs to 10GB, the default to 2GB
   lvol:
     vg: rootvg
     lv: rootlv
     size: 10240
 
 - name: Extend the filesystem
   filesystem:
     fstype: xfs
     dev: "/dev/mapper/rootvg-rootlv"
     resizefs: yes
...

Now, you are free to go and run the following playbook to deploy SAP HANA SR: 

./deploy-sap-hana-hsr.yaml

---
- hosts: hana
 roles:
         - { role: redhat_sap.sap_rhsm }
         - { role: redhat_sap.sap_hana_mediacheck }
         - { role: redhat_sap.sap_hostagent }
         - { role: linux-system-roles.timesync }
         - { role: linux-system-roles.storage }
         - { role: sap-preconfigure }
         - { role: sap-hana-preconfigure }
         - { role: redhat_sap.sap_hana_deployment }
         - { role: redhat_sap.sap_hana_hsr }
...

Here is the screen dump while running the playbook. It takes approximately 20 minutes to install the SAP HANA instances and configure  System Replication.

Once the installation is complete, you can check the status of SAP HANA System Replication.

Summary

As SAP HANA takes on a central function as the primary database platform for SAP landscapes, requirements for stability, and reliability increase dramatically. With RHEL for SAP Solutions and system roles, you can deploy your SAP HANA in about 20 minutes! 

To further simplify the settings, you can convert the bootstrap server to an Azure VM image, so you can quickly start up a bootstrap to deploy your SAP applications when you need it. Besides, Red Hat Enterprise Linux (RHEL) for SAP Solutions meets those requirements by enhancing native SAP HANA replication and failover technology to automate the takeover process, in order to reduce system administrators’ efforts and increase the stability and availability of your SAP applications.