Prerequisites for High Availability

Ensure that these requirements are met:

• Controller installation pre-requisites for both servers are met. See Platform Requirements.
• Two dedicated machines running Linux. The Linux operating systems can be Fedora-based Linux distributions (such as Red Hat or CentOS) or Debian-based Linux distributions (such as Ubuntu).
• In a Controller HA pair, a load balancer should route traffic from the Controller clients (Controller UI users and App Agents) to the active Controller. Before starting, make sure that a load balancer is available in your environment and that the virtual IP address for the Controller pair is known as presented by the load balancer.
• Open port number 3388 between the machines in an HA pair.
• The login shell must be bash (/bin/bash).

• A network link connecting the HA hosts can support a high volume of data. The primary and replica must be in the same data center, and there must be a dedicated network link between the hosts.

  Warning: IO Latency must be under 3 ms.
• Passwordless ssh has been set up between two Controller hosts. See Set Up the SSH Key.
• SSH keys on each host allow ssh and rsync operations by the Splunk AppDynamics user.
• The hosts file (/etc/hosts) on both Controller machines should contain entries to support reverse lookups for the other node in the HA pair.
• Because Controller licenses are bound to the network MAC address of the host machine, the HA replica Controller requires an additional HA license. You should request a secondary license for HA purposes in advance.
• While adding high availability hosts as part of the add host operation, you determine and provide the remote user, of which the Controller needs to be installed as. The platform path you specify (while creating the platform) must be writable on the two HA hosts for the remote user specified during add host operation.

• The following packages are installed on both Controller hosts, and the relevant installation commands are provided:

  Command	Yum based installer (RH, Centos, Amazon Linux)	Apt based installer (Ubuntu)
  lsof	yum install lsof	apt-get install lsof
  ssh	yum install openssh-server	apt-get install openssh-server
  awk	yum install gawk	apt-get install gawk
  scp	yum install openssh-clients	apt-get install openssh-client
  rsync	yum install rsync	apt-get install rsync
  curl	yum install curl	apt-get install curl
  sed (GNU)	yum install sed	apt-get install sed
  openssl	yum install openssl	apt-get install openssl
  ps	yum install procps	apt-get install procps
  xmllint	yum install libxml2-utils	apt-get install libxml2-utils
  timeout/base64/tr	yum install coreutils	apt-get install coreutils