When you configure App Controller for high availability, the two
virtual machines (VMs) communicate by using TCP port 9736. Each VM in an App
Controller high availability pair generates a heartbeat message at one second
intervals. You can view the status of the VMs by using the App Controller
command line. The heartbeat service running on the two VMs monitors the health
of each App Controller system and the health of the high availability pair.
If the primary App Controller VM fails for any reason, the secondary
VM immediately takes over as the primary VM. If the active VM does not respond
or reports a failure, the passive VM acquires the virtual IP address and
When the failed VM comes back online, it joins with the current
active VM and becomes the passive VM. The passive VM then synchronizes with the
data from the active VM.
Before you configure an high availability pair, do the following:
- Install the same build
version for each App Controller virtual machine (VM).
- Install both VMs in the
same network subnet.
- Assign IP addresses from
the same subnet to each VM in the pair.
The basic steps for configuring high availability are as follows:
- Identify which VM is the
primary role and which VM is the secondary role.
- Configure the virtual IP
address, the peer IP address, and shared key on the primary VM.
- When you finish
configuring high availability on the primary VM, configure the peer IP address
and shared key on the secondary VM.
To prepare each VM for high availability in App Controller, you use
the command-line console to configure the settings. You can log on to the
command-line console by using the
Console tab in XenCenter or vSphere. You can
also log on to App Controller by using a command-line tool, such as PuTTY. You
must enable SSH in App Controller to use PuTTY.