Google Cloud – Create the SAP HANA Primary Database Load Balancer

In Google Cloud, a TCP Internal Load Balancer is used to facilitate failover of the SAP HANA virtual IP. The frontend of the load balancer is assigned an ephemeral IP from the subnet that it operates in. In this example, we will be using the following IP address for load balancer corresponding to the sps-hana virtual hostname:

Following the steps provided in Google Cloud – Using an Internal Load Balancer and Responding to Load Balancer Health Checks, create and configure the following Google Cloud and LifeKeeper resources.

1. Create two unmanaged instance groups: ig-sps-hana-zone1, containing node-a, and ig-sps-hana-zone2, containing node-b.

2. Create a TCP Internal Load Balancer, ilb-sps-hana, with the following properties. The icon indicates that the default option is chosen.

Name	ilb-sps-hana
Backend configuration
Region	<Deployment region> (e.g., us-east1)
Network	lk-vpc
Backends	ig-sps-hana-zone1 ig-sps-hana-zone2
Health Check
Name	hc-sps-hana
Protocol	TCP
Port	50098 (This must agree with the corresponding LifeKeeper GenLB resource created later)
Proxy protocol	NONE
Request	Leave empty
Response	Leave empty
Check interval	5 seconds
Timeout	5 seconds
Healthy threshold	2 consecutive successes
Unhealthy threshold	2 consecutive failures
Connection draining timeout	10 seconds
Frontend configuration
Name	fe-sps-hana
Subnetwork	lk-subnet
Purpose	Non-shared
IP address	Ephemeral (Custom)
Custom ephemeral IP address	10.20.0.5
Ports	All
Global access	Disable
Service label	Leave empty

Once created, the Network services → Load balancing page in the Google Cloud Console will show the load balancer.

3. Follow the steps described in the Disable IP Forwarding section of Google Cloud – Using an Internal Load Balancer to allow node-a and node-b to communicate through the frontend IP addresses of the load balancer. Reboot node-a and node-b for the changes to take effect.

Note that this step is not strictly required in order to connect to the primary database through the load balancer frontend IP address, but it will make it possible to test the database connection from within the cluster, as described in the Test Switchover and Failover section.

4. Following the steps described in Creating an IP Resource, use the following parameters to create and extend a LifeKeeper IP resources (ip-sps-hana), with net mask 255.255.255.255, to protect the SAP HANA virtual IP address on node-a and node-b. Notice that ip-sps-hana is created on node-a and extended to node-b. Also note that this IP resource should not be extended to node-c, the witness node. The icon indicates that the default option is chosen.

!The use of 255.255.255.255 as the value of the Netmask parameter (both during create and extend) is important. Be careful not to select “Accept Defaults” during the extend process as this will typically cause 255.255.255.0 to be incorrectly used as the network mask on the standby node, which may lead to unexpected networking issues.

Field	Value
Create Resource Wizard
Switchback Type	intelligent
Server	node-a
IP Resource	10.20.0.5
Netmask	255.255.255.255
Network Interface	eth0
IP Resource Tag	ip-sps-hana
Pre-Extend Wizard
Target Server	node-b
Switchback Type	intelligent
Template Priority	1
Target Priority	10
Extend comm/ip Resource Hierarchy Wizard
IP Resource	10.20.0.5
Netmask	255.255.255.255
Network Interface	eth0
IP Resource Tag	ip-sps-hana

Once the IP resource has been created successfully, the LifeKeeper GUI should resemble the following image.

5. Following the steps in Responding to Load Balancer Health Checks, install the LifeKeeper Generic Application Recovery Kit for Load Balancer Health Checks (“GenLB Recovery Kit”) and create a LifeKeeper GenLB resource, ilb-sps-hana, with the following properties. The icon indicates that the default option is chosen.

Field	Value
Create Resource Wizard
Switchback Type	intelligent
Server	node-a
Restore Script	/opt/LifeKeeper/SIOS_Hotfixes/Gen-LB-PL-7172/restore.pl
Remove Script	/opt/LifeKeeper/SIOS_Hotfixes/Gen-LB-PL-7172/remove.pl
QuickCheck Script	/opt/LifeKeeper/SIOS_Hotfixes/Gen-LB-PL-7172/quickCheck (Note: Although the quickCheck script may be optional for some ‘Generic Application’ resource types, it is required for GenLB resources.)
Local Recovery Script	None (Empty)
Application Info	50098
Bring Resource In Service	Yes
Resource Tag	ilb-sps-hana
Pre-Extend Wizard
Target Server	node-b
Switchback Type	intelligent
Template Priority	1
Target Priority	10
Extend gen/app Resource Hierarchy Wizard
Resource Tag	ilb-sps-hana
Application Info	50098

The resource will appear in the LifeKeeper GUI resource pane once it has been created and extended successfully.

6. Right-click the ilb-sps-hana resource on node-a and click “Create Dependency…” Specify ip-sps-hana as the Child Resource Tag and click Create Dependency.

Once the dependency has been created, the LifeKeeper GUI should resemble the following image.

7. Add the following entry to /etc/hosts on node-a and node-b to allow resolution of the virtual hostname to the frontend IP address of the corresponding load balancer:

10.20.0.5 sps-hana

8. Test switchover and failover of the GenLB resources as described in the Test GenLB Resource Switchover and Failover section of Responding to Load Balancer Health Checks. Correct any issues found or tune the parameters of the load balancer health checks as required to achieve successful operation.