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Failover support for High Availability

Overview

Failover is an application High Availability (HA) mode that facilitates automatic switching to a secondary/ backup server when the primary system breaks down, or is unavailable due to maintenance. Configuring failover support for Applications Manager not only helps achieve uninterrupted availability, but also ensure hassle-free monitoring of mission-critical servers that may be important to your business.

Applications Manager HA / Failover is available by default for Professional and Enterprise Editions.

Working

Applications Manager's failover is a dual server, single database system. There are two servers - a primary server and a secondary server along with a common database. Every time the primary server interacts with the database, the secondary server listens. If for some reason, there have been no interactions between the primary server and the database (and if an entry has not been added in the failover table in the last 60 seconds), the secondary server understands that there might be a problem and hence automatically starts acting as the primary server. Once the primary server has been restarted, it then starts acting as the secondary server.

When failover happens and the secondary server becomes active, the IP of the primary server might have changed and you will have to access the IP of the secondary server which will now act as the primary server.

Note: It is recommended that you enable replication for the backend database to avoid sudden database unavailability and minimize downtime as much as possible.

Prerequisites

Following are the prerequisites that need to be implemented before configuring failover:

  • It is recommended that the backend database for your Applications Manager installation is setup in a separate server and not the same server in which the primary or secondary Applications Manager instance is installed. (Microsoft DB setup is preferred)
  • The same version of Applications Manager should be installed on both the servers.
  • Both primary and secondary servers should have the same protocol (http/https).
  • Both primary and secondary servers should have a static IP address.
  • The primary server and secondary server should be able to access each other's host name and IP address.
  • Both the servers should have high connectivity and bandwidth.

Failover configuration

Browse through the following links to learn more about configuring failover in various environments:

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