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Configure a high-availability setup with multiple IP addresses and NICs

June 25, 2020
Contributed by:  S S

You can deploy a pair of NetScaler virtual appliances with multiple NICs in an active-passive high availability (HA) setup on Azure. Each NIC can contain multiple IP addresses.

An active-passive deployment requires:

  • An HA Independent Network Configuration (INC) configuration

  • The Azure Load Balancer (ALB) in Direct Server Return (DSR) mode All traffic goes through the primary node. The secondary node remains in standby mode until the primary node fails.

Note

For a Citrix VPX high availability deployment on Azure cloud to work, you need a floating public IP (PIP) that can be moved between the two VPX nodes. The Azure Load Balancer (ALB) provides that floating PIP, which is moved to the second node automatically in the event of a failover.

Diagram: Example of a high availability deployment architecture, using Azure Availability Set

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In an active-passive deployment, the ALB floating public IP (PIP) addresses are added as the VIP addresses in each VPX node. In HA-INC configuration, the VIP addresses are floating and SNIP addresses are instance specific.

ALB monitors each VPX instances by sending health probe at every 5 seconds and redirects traffic to that instance only that sends health probes response on regular interval. So in an HA setup, the primary node responds to health probes and secondary does not. If the primary instance misses two consecutive health probes, ALB does not redirect traffic to that instance. On failover, the new primary starts responding to health probes and the ALB redirects traffic to it. The standard VPX high availability failover time is three seconds. The total failover time that might take for traffic switching can be maximum of 13 seconds.

You can deploy a VPX pair in active-passive high availability mode in two ways by using:

  • NetScaler VPX standard high availability template: use this option to configure an HA pair with the default option of three subnets and six NICs.
  • Windows PowerShell commands: use this option to configure an HA pair according to your subnet and NIC requirements.

This topic describes how to deploy a VPX pair in active-passive HA setup by using the Citrix template. If you want to use PowerShell commands, see Configuring an HA Setup with Multiple IP Addresses and NICs by Using PowerShell Commands.

Configure HA-INC nodes by using the Citrix high availability template

You can quickly and efficiently deploy a pair of VPX instances in HA-INC mode by using the standard template. The template creates two nodes, with three subnets and six NICs.  The subnets are for management, client, and server-side traffic, and each subnet has two NICs for both the VPX instances.

You can get the NetScaler 12.0 HA Pair template at the Azure Marketplace.

Complete the following steps to launch the template and deploy a high availability VPX pair, by using Azure Availability Sets.

1. From Azure Marketplace, select and initiate the Citrix solution template. The template appears.

2. Ensure deployment type is Resource Manager and select Create.

3. The Basics page appears. Create a Resource Group and select OK.

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4. The General Settings page appears. Type the details and select OK.

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5. The Network Setting page appears. Check the vnet and subnet configurations, edit the required settings, and select OK.

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6. The Summary page appears. Review the configuration and edit accordingly. Select OK to confirm.

7. The Buy page appears. Select Purchase to complete the deployment.

It might take a moment for the Azure Resource Group to be created with the required configurations. After completion, select the Resource Group in the Azure portal to see the configuration details, such as LB rules, back-end pools, health probes, and so on. The high availability pair appears as ns-vpx0 and ns-vpx1.

If further modifications are required for your HA setup, such as creating more security rules and ports, you can do that from the Azure portal.

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Next, you need to configure the load-balancing vserver with the ALB public IP (PIP) address, on each node. To find the ALB PIP, select ALB > Frontend IP configuration.

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See the Resources section for more information about how to configure the load-balancing vserver.

Resources:

The following links provide additional information related to HA deployment and virtual server (vserver) configuration:

Related resources:

Configure a high-availability setup with multiple IP addresses and NICs

June 25, 2020
Contributed by:  S S

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