In Microsoft Azure, a TCP Internal Load Balancer is used to facilitate failover of the ASCS and ERS virtual IP’s. The load balancer consists of two frontends, each assigned an IP address from the subnet that it operates in. In this example, we will be using the following IP addresses for the load balancer frontends corresponding to each virtual host:

Instance
Virtual Host Name
Internal TCP Load Balancer
Frontend IP Address
ASCS10 sps-ascs ilb-sps-ascs-ers 10.20.0.10
ERS20 sps-ers ilb-sps-ascs-ers 10.20.0.20

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

  1. Create a single Load Balancer in Azure, ilb-sps-ascs-ers, with the following properties.
Name
ilb-sps-ascs-ers
Create Load Balancer
Resource Group LK-QSG
Name ilb-sps-ascs-ers
Region (same as the Virtual Machines)
Type Internal
SKU Standard (select Standard as the workload is distributed across Availability Zones)
Tier Regional
Frontend IP 1 Configuration
Name SPSASCSFrontEnd
Virtual Network LK-VNET
Subnet LK-subnet (10.20.0.0/22)
Assignment Static
IP address 10.20.0.10
Availability zone Zone-redundant
Frontend IP 2 Configuration
Name SPSERSFrontEnd
Virtual Network LK-VNET
Subnet LK-subnet (10.20.0.0/22)
Assignment Static
IP address 10.20.0.20
Availability zone Zone-redundant
Backend Pool
Name backend-sps-ascs-ers
Backend Pool Configuration NIC
IP Version IPv4
Virtual machines node-a, node-b
Health Probe #1
Name probe-sps-ascs
Protocol TCP
Port 51098 (This must agree with the corresponding LifeKeeper LB Health Check resource created later)
Interval 5 seconds
Unhealthy threshold 2 consecutive failures
Health Probe #2
Name probe-sps-ers
Protocol TCP
Port 52098 (This must agree with the corresponding LifeKeeper LB Health Check resource created later)
Interval 5 seconds
Unhealthy threshold 2 consecutive failures
Load Balancing Rule #1
Name ilb-rule-sps-ascs
IP Version IPv4
Frontend IP address SPSASCSFrontEnd (10.20.0.10)
HA Ports Click (allow forwarding to all ports for simplicity of evaluation deployment)
Backend pool backend-sps-ascs-ers
Health probe probe-sps-ascs (TCP:51098)
Session persistence None
Idle timeout 4 minutes
TCP reset Disabled
Floating IP Enabled
Load Balancing Rule #2
Name ilb-rule-sps-ers
IP Version IPv4
Frontend IP address SPSERSFrontEnd (10.20.0.20)
HA Ports Click (allow forwarding to all ports for simplicity of evaluation deployment)
Backend pool backend-sps-ascs-ers
Health probe probe-sps-ers (TCP:52098)
Session persistence None
Idle timeout 4 minutes
TCP reset Disabled
Floating IP Enabled

Once created, the Load Balancing Services → Load Balancer page in the Microsoft Azure Console will show the newly created load balancer.

  1. Following the steps in Responding to Load Balancer Health Checks, create two LifeKeeper LB Health Check resources, ilb-sps-ascs and ilb-sps-ers, with the following properties. Notice that ilb-sps-ascs is created on node-a and extended to node-b, while ilb-sps-ers is created on node-b and extended to node-a. The icon indicates that the default option is chosen.
Field
Value
Create Resource Wizard
Switchback Type intelligent
Server node-a
Reply daemon Port 51098
Reply daemon message None (Empty)
LB Health Check Resource Tag ilb-sps-ascs
Pre-Extend Wizard
Target Server node-b
Switchback Type intelligent
Template Priority 1
Target Priority 10
Extend LB Health Check Resource Hierarchy Wizard
LB Health Check Resource Tag ilb-sps-ascs
Field
Value
Create Resource Wizard
Switchback Type intelligent
Server node-b
Reply daemon Port 52098
Reply daemon message None (Empty)
LB Health Check Resource Tag ilb-sps-ers
Pre-Extend Wizard
Target Server node-a
Switchback Type intelligent
Template Priority 1
Target Priority 10
Extend LB Health Check Resource Hierarchy Wizard
LB Health Check Resource Tag ilb-sps-ers

The resources will appear in the LifeKeeper GUI resource pane once they have been created and extended successfully.

  1. Following the steps described in Creating an IP Resource, use the following parameters to create and extend a LifeKeeper IP resource (ip-sps-ascs) to protect the ASCS virtual IP address on node-a and node-b. Notice that the IP resource is being created on node-a and extended to node-b. Also note that the resulting resource should not be extended to node-c, the witness node. The icon indicates that the default option is chosen.
Field
Value
Create Resource Wizard
Switchback Type intelligent
Server node-a
IP Resource 10.20.0.10
Netmask 255.255.252.0
Network Interface eth0
IP Resource Tag ip-sps-ascs
Pre-Extend Wizard
Target Server node-b
Switchback Type intelligent
Template Priority 1
Target Priority 10
Extend comm/ip Resource Hierarchy Wizard
IP Resource 10.20.0.10
Netmask 255.255.252.0
Network Interface eth0
IP Resource Tag ip-sps-ascs
  1. Following the steps described in Creating an IP Resource, use the following parameters to create and extend a LifeKeeper IP resource (ip-sps-ers) to protect the ERS virtual IP address on node-a and node-b. Notice that the IP resource is being created on node-b and extended to node-a. Also note that the resulting resource should not be extended to node-c, the witness node. The icon indicates that the default option is chosen.
Field
Value
Create Resource Wizard
Switchback Type intelligent
Server node-b
IP Resource 10.20.0.20
Netmask 255.255.252.0
Network Interface eth0
IP Resource Tag ip-sps-ers
Pre-Extend Wizard
Target Server node-a
Switchback Type intelligent
Template Priority 1
Target Priority 10
Extend comm/ip Resource Hierarchy Wizard
IP Resource 10.20.0.20
Netmask 255.255.252.0
Network Interface eth0
IP Resource Tag ip-sps-ers

Once the IP resources have been created successfully, the LifeKeeper GUI should resemble the following image.

  1. Right-click the ip-sps-ascs resource on node-a and click “Create Dependency…” Specify ilb-sps-ascs as the Child Resource Tag and click Create Dependency.
  1. Right-click the ip-sps-ers resource on node-b and click “Create Dependency…” Specify ilb-sps-ers as the Child Resource Tag and click Create Dependency.

Once the dependencies have been created successfully, the LifeKeeper GUI should resemble the following image.

  1. Add the following entries to /etc/hosts on node-a and node-b to allow resolution of each virtual host name to the frontend IP address of the corresponding load balancer. The entry for sps-ascs must also be added on node-d and node-e (the PAS and AAS hosts), as this virtual host name will be used to access the /export/sapmnt/SPS and /export/usr/sap/trans shared file systems.

10.20.0.10 sps-ascs
10.20.0.20 sps-ers

  1. Test switchover and failover of the LB Health Check resource hierarchies as described in the Test LB Health Check 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.

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