Kunal Kumar

July 18, 2018 8 minute read

SAP B4HANA High Availabilty on AWS

B4HANA HA

ARCHITECTURE

ASCS HA Auto Failover – Clustering

ASCS ERS

ascsserver – 10.0.1.106 ersserver – 10.0.1.229

VIP – 10.2.0.1 VIP – 10.2.0.1

Virtual hostname – haascs Virtual hostname – haers

HANA HA Auto Failover – Clustering

HANA NODE1 HANA NODE2

Hanaha1 – 10.0.1.78 Hanaha2 – 10.0.1.225

VIP – 10.2.0.3

Virtual hostname – hanaha

Amazon EC2 – Amazon Elastic Compute Cloud (Amazon EC2) provides scalable computing capacity in the Amazon Web Services (AWS) cloud. Using Amazon EC2 eliminates your need to invest in hardware up front, so you can develop and deploy applications faster. You can use Amazon EC2 to launch as many or as few virtual servers as you need, configure security and networking, and manage storage. Amazon EC2 enables you to scale up or down to handle changes in requirements or spikes in popularity, reducing your need to forecast traffic.

SUSE LINUX Community AMI, Launch 5 instances – PAS, ASCS and ERS and 2 HANA instances.

suse-sles-sap-12-sp3-byos-v20180706-hvm-ssd-x86_64 – ami-2c693f54

SUSE Linux Enterprise Server for SAP Applications 12 SP3 for BYOS (HVM, 64-bit, SSD-Backed)

Creation of EC2 instances

Amazon EFS – Amazon Elastic File System (Amazon EFS) provides simple, scalable file storage for use with Amazon EC2 instances in the AWS Cloud. Amazon EFS is easy to use and offers a simple interface that allows you to create and configure file systems quickly and easily. With Amazon EFS, storage capacity is elastic, growing and shrinking automatically as we add and remove files, so our applications have the storage they need, when they need it. As EFS is a file storage it can be mounted across several EC2 instances.

Creation of Elastic file system

Amazon Elastic File System (Amazon EFS) provides simple, scalable file storage for use with Amazon EC2 instances in the AWS Cloud. Amazon EFS is easy to use and offers a simple interface that allows you to create and configure file systems quickly and easily. With Amazon EFS, storage capacity is elastic, growing and shrinking automatically as we add and remove files, so our applications have the storage they need, when they need it. As EFS is a file storage it can be mounted across several EC2 instances.

Mounting EFS to EC2 Instances

Create Directory on the EC2 instances

Create /etc/fstab entry

ASCS/ERS filesystem

PAS filesystem

HANAHA1 filesystem

HANAHA2

Change the hostname of the EC2 Instances

ASCS

sudo hostnamectl set-hostname ascsserver

ERS

Sudo hostnamectl set-hostname ersserver

HANAHA1

Sudo hostnamectl set-hostname hanaha1

HANAHA2

Sudo hostnamectl set-hostname hanaha2

PAS

Sudo hostnamectl set-hostname passerver

Tagging the EC2 instances

Amazon Web Services (AWS) allows customers to assign metadata to their AWS resources in the form of tags. Each tag is a simple label consisting of a customer-defined key and an optional value that can make it easier to manage, search for, and filter resources.

The EC2 instances will have host names which are automatically generated.

The SLES agents will have to be able to identify the EC2 instances in the correct way.

ASCS

In the same way do it for ERS,PAS,HANAHA1 and HANAHA2

Creating an AWS CLI Profile on EC2 Instances

The SLES agents use the AWS Command Line Interface (CLI). They will use an AWS CLI profile which needs to be created for the root account root on both instances. The SUSE resources require a profile which creates output in the text format. The name of the profile is arbitrary.

ASCS

In the same way do it for ERS,PAS,HANAHA1 and HANAHA2

Disable the Source/Destination Check for the Cluster Instances

** Do this on all the server**

The following command needs to be executed one time for both EC2 instances, which are supposed to receive traffic from the Overlay IP address.

Overlay IP Addresses

Add VIP on Route table

add the virtual ip to the network interface of ASCS, ERS and HANAHA1

Add the Service IP Address for your ASCS Service

add the overlay ip to ascs, ers and hanaha1

Configure http Proxies

** Do this on all the server**

export http_proxy=10.*.*.*:80

export https_proxy=10.*.*.*:443

export NO_PROXY=169.254.169.254

Permit Root Login in SSH and Change Root Password

SAP Installation

ASCS INSTALLATION

./sapinst SAPINST_USE_HOSTNAME=haascsIS_HOST_LOCAL_USING_STRING_COMPARE=true

ASCS installation got Completed.

ERS INSTALLATION

./sapinst SAPINST_USE_HOSTNAME=haers IS_HOST_LOCAL_USING_STRING_COMPARE=true

ERS Installation got completed

Post steps for ASCS and ERS

Stopping ASCS and ERS

Maintaining sapservices

Ensure that the file /usr/sap/sapservices holds both entries (ASCS+ERS) on both cluster nodes.

Integrating the Cluster Framework using the sap_suse_cluster_connector Package

For the ERS and ASCS instance edit the instance profile files B4H_ASCS10_haascs and B4H_ERS20_haers in the profile directory /usr/sap/B4H/SYS/profile/

ASCS profile

ERS profile

Start ASCS and ERS

Add the user b4hadm to the Unix user group haclient

DB INSTANCE INSTALLATION

INSTALL DB INSTANCE ON HANAHA1

./sapinst SAPINST_USE_HOSTNAME=hanaha

IS_HOST_LOCAL_USING_STRING_COMPARE=true

DB Instance Installation Completed.

PAS INSTALLATION

./sapinst

PAS installation completed.

ASCS/ERS CLUSTER CREATION

ASCS

ERS

ssh ersserver from ascsserver

ssh ascsserver from ersserver

ASCS

ha-cluster-init

ERS

Preparing the Cluster for adding the Resources

Put cluster on maintenance

As user root

crm configure property maintenance-mode=”true”

**NOTE**

Stop all SAP instances

Remove the (manual added) IP addresses on the cluster nodes

Unmount the file systems which will be controlled by the cluster

Configure AWS specific Settings

Configuration of AWS specific Stonith Resource

The EC2 tag pacemaker entry needs to match the tag chosen for the EC2 instances. The value for this tag will contain the host name.

Configure the Resources for the ASCS

Filesystem Primitives

VIP Primitives

SAP instance

The name of the AWS CLI profile will have to match the previously configured AWS profile.

Group the resources for ASCS

Configure the Resources for the ERS

Filesystem Primitives

VIP Primitives

SAP Instance

The name of the AWS CLI profile will have to match the previously configured AWS profile.

Group the resources for ERS

Configure the Colocation Constraints between ASCS and ERS

The constraints between the ASCS and ERS instance are needed to define that the ASCS instance should start-up exactly on the cluster node running the ERS instance after a failure.