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High availability (HA) is a redundancy operation that automatically switches to a standby server if the primary server fails or is temporarily shut down for maintenance. HA enables BMC TrueSight Operations Management to continuously function so that monitoring of your mission-critical systems is continuously available. Operations Management supports out-of-the box HA that eliminates the need for third-party software and reduces the manual steps required to deploy. HA utilizes a load balancer software component as an HA proxy to switch operations between the primary and standby server.

Operations Management in HA mode

Operations Management in HA mode consists of two servers with identical configurations. The first server is referred to as the primary server, and the standby server is referred to as the secondary server.  The primary server always takes on an active role and all the Operations Management processes that are running during this time. When the primary server is down or in case of a failover, the secondary server takes on an active role. Only one Presentation Server can be active at a time. In case of a failover due to an event that triggers a server shutdown, the secondary server takes over the active role, and all of the processes change from standby mode to operation mode on the secondary server.

The detection and management of a failover is built in to the Presentation Server.  However, it does not manage the failback transfer back to the primary server. You must issue CLI commands to restart the primary server and re-establish its role as the active server.

HA architecture

An Operations Management HA deployment comprises the following systems:

  • Primary server
  • Secondary server
  • Load balancer (HAProxy)

 

A load balancer is a software component that routes the client requests to the active server. In the context of the Operations Management system, the load balancer is more of a proxy server that accepts client requests and directs these requests to the active server. The load balancer resides on a separate computer and redirects requests to the active server.

Why is a load balancer required?

In a successful HA deployment, the secondary server must take over when the primary server is not working, or the primary server is ready to take over a load balancer is required to direct the client requests to the active server.

A load balancer:

  • Gives a unified contact point to access the Presentation Server
  • Enables to detect the active node, primary or secondary server, automatically in an HA deployment.

HAProxy

BMC recommends using HAProxy as the load balancer. HAProxy is a free, fast, and reliable solution offering HA, load balancing, and proxy capabilities. It is particularly suited for web sites that encounter very high loads or heavy traffic. For information about installing and deploying HAProxy, see  http://haproxy.1wt.eu/ .

HAProxy can be installed only on UNIX systems. However, you can install HAProxy on UNIX systems and use it to deploy Presentation Servers on Microsoft Windows systems. You can use a single instance of HAProxy to deploy multiple pairs of Presentation Servers.

Advantages of HAProxy

  • HAProxy can serve as a load balancer for multiple sets of primary and secondary servers.
  • HAProxy is a free software although some companies offer paid support.

  • The HAProxy performance is very fast, with micro optimizations resulting in very low CPU usage on moderate loads. Even at very high loads, when the CPU is saturated, it is common to note figures such as 5% user and 95% system, which means that the HAProxy process consumes about 20 times less than its system counterpart. A hit rate above 10,000 per second is sustained for objects smaller than 6 KB, and the gigabits are sustained for objects larger than 40 KB.

  • To use HAProxy, the servers do not require static IP addresses.

HA deployment options

There are two ways to deploy Operations Management in HA mode:

  • Deploying in HA mode during the installation process
  • Deploying in HA mode post-installation

Deploying in HA mode during installation

You can choose to deploy Operations Management in HA mode during installation by selecting the Enabled option, If you choose to enable HA, you are required to specify which system is the primary server and which system is the secondary server. For information about deploying in HA mode during installation, see Performing the Presentation Server installation.

Deploying in HA mode post installation

You can choose to deploy Operations Management in HA Primary mode or HA Secondary mode post installation.

Note

On Linux computers, add & at the end of the tssh server start and tssh server stop commands so that the process runs in the background and you can continue to use the shell.

You can choose to deploy the TrueSight Presentation Server in HA Primary mode or HA Secondary mode post installation.

Navigate to the <Presentation Server installation directory>\truesightpserver\bin directory, open a CLI command prompt, and run the following commands:

  1. Run the tssh server stop command on the primary and the secondary server.
  2. Run the tssh process start database command on the primary server. 
  3. Run the tssh ha configure master command on the primary server.
    Provide the primary and the secondary server details in the CLI which will be used to generate the configuration information in the ha-shared.conf file. Copy the ha-shared.conf file to the secondary server.
  4. Run the tssh process stop database on the primary server.
  5. Run the tssh server start command on the primary server.
  6. Run the tssh ha configure standby command on the secondary server. 
    Type the path to the ha-shared.conf file.
  7. Run the command tssh ha copysnapshot on the secondary server.
  8. Run the tssh server start command on the secondary server.

Transferring the service between the secondary server and primary server

In Operations Management HA mode, the secondary server becomes the active server if the primary server stops operating, due to an event that triggers a server shutdown. Once the primary server is up and running, it does not become the active server by default. The primary server is still in a standby mode. The service can be transferred back to the primary server, or the primary server can remain in standby mode.

To transfer service to the primary server

Open a CLI command prompt, and from the <Presentation Server installation directory>\truesightpserver\bin directory, perform the following steps to transfer control from the secondary server to the primary server:

  1. tssh server stop
  2. tssh ha copysnapshot
  3. tssh server start
  4. After the primary server is running, stop the secondary server
    tssh server stop
  5. Verify that the user can login to the primary server.
  6. Start the secondary server:
    tssh ha copysnapshot
    tssh server start

To set the primary server in standby mode

Open a CLI command prompt, and from the <Presentation Server installation directory>\truesightpserver\bin directory, perform the following steps to operate the primary server in standby mode:

  1. tssh server stop
  2. tssh ha copysnapshot
  3. tssh server start

To set the secondary server in standby mode

Open a CLI command prompt, and from the <Presentation Server installation directory>\truesightpserver\bin directory, perform the following steps to operate the secondary server in standby mode:

  1. tssh server stop
  2. tssh ha copysnapshot
  3. tssh server start

Limitations of HA in Operations Management

  • If the host name of the Presentation Server is mapped to the loopback address in the etc/hosts file, HA will not work. Ensure that the hosts file is not updated with the loopback address.
  • If the primary and secondary servers are both disconnected from the network, you must restart both servers, and set one server to the active mode and the other server to standby mode.
  • During a Tomcat session, you must login on failover.
  • The primary and secondary server should be located on the same platform and use the same operating system.

Related topics

Performing the Presentation Server installation

Infrastructure Management high availability deployment and best practices