Points to consider for a high availability setup


The following requirements for configuring systems in an HA setup:

  • In an HA configuration, the primary and secondary Citrix ADC appliances should be of the same model. Different Citrix ADC models are not supported in an HA pair.

  • In an HA setup, both nodes must run the same version of Citrix ADC, for example, nCore/nCore or classic/classic. If the nodes are running Citrix ADC classic and you want to migrate to Citrix ADCs nCore of the same Citrix ADC release, prop and sync are not supported during the migration process. Once migration is complete, prop and sync are auto-enabled. The same applies if you migrate from Citrix ADC nCore to Citrix ADC classic.

  • Entries in the configuration file (ns.conf) on both the primary and the secondary system must match, with the following exceptions:

    • The primary and the secondary systems must each be configured with their own unique IP addresses (NSIPs.)
    • In an HA pair, the node ID and associated IP address of one node must point to the other node. For example, if you have nodes NS1 and NS2, you must configure NS1 with a unique node ID and the IP address of NS2, and you must configure NS2 with a unique node ID and the IP address of NS1.
  • If you create a configuration file on either node by using a method that does not go directly through the GUI or the CLI (for example, importing SSL certificates, or changing to startup scripts), you must copy the configuration file to the other node or create an identical file on that node.

  • Initially, all Citrix ADC appliances are configured with the same RPC node password. RPC nodes are internal system entities used for system-to-system communication of configuration and session information. For security, you should change the default RPC node passwords.

    One RPC node exists on each Citrix ADC. This node stores the password, which is checked against the password provided by the contacting system. To communicate with other systems, each Citrix ADC requires knowledge of those systems, including how to authenticate on those systems. RPC nodes maintain this information, which includes the IP addresses of the other systems, and the passwords they require for authentication.

    RPC nodes are implicitly created when adding a node or adding a Global Server Load Balancing (GSLB) site. You cannot create or delete RPC nodes manually.


    If the Citrix ADC appliances in a high availability setup are configured in one-arm mode, you must disable all system interfaces except the one connected to the switch or hub.

    For an IPv6 HA configuration, the following considerations apply:

    • You must install the IPv6PT license on both Citrix ADC appliances.
    • After installing the IPv6PT license, enable the IPv6 feature by using the GUI or the command line interface.
    • Both Citrix ADC appliances require a global NSIP IPv6 address. In addition, network entities (for example, switches and routers) between the two nodes must support IPv6.
Points to consider for a high availability setup