Foglight 7.3.0 - High Availability Field Guide

Redirecting secondary Management Servers to the correct URL

When Foglight® Management Servers are configured as an HA cluster, the browser interface for each of the secondary Management Servers redirects to the primary Management Server. By default, the URL for the browser interface to which the secondary Management Servers are redirected is generated automatically by Foglight based on the primary Management Server machine’s host name.

You can override this URL and point Foglight to a different URL by starting the secondary Management Servers from the command-line with the following option:

Use this option in cases where a single machine hosts multiple applications (including Foglight) and is configured with multiple host names and IP addresses. In such cases:

You can base the URL on the alias using the -D option.

You have two machines, whose host names are server1 and server2. You have an HA cluster running on these machines. The primary Management Server runs on server1 and the secondary Management Server runs on server2.

Both machines have two IP addresses: one internal and one external. The external IP addresses are bound to the DNS (Domain Name System) names foglight1.example.com and foglight2.example.com. Foglight has been bound to the external IP addresses and is not listening on the internal IP addresses. In this case, the Foglight browser interface is available at
http://foglight1.example.com:8080.

However, the secondary server redirects to the default URL http://server1:8080. In this case, the Foglight browser interface is not available at this URL. To resolve this issue, override the URL with: -Dquest.host.name=foglight1.example.com.

Remote Monitor

The Remote Monitor is a JavaTM program that regularly communicates with a set of High Availability (HA) servers. If there is no reply after it attempts to contact the server, then it logs the event and (optionally) sends e-mail notifications to an administrator.

The Remote Monitor takes a list of host names or host name and port pairs as parameters. When invoked without parameters, Remote Monitor takes the list of host names or host name and port pairs from the file <foglight_home>/config/remote_monitor.config under the entry server.urls.

Each parameter in the entry server.urls points to a specific HA server. If a port is not specified as part of this entry, the default port 51231 is used. The default port can be configured in <foglight_home>/config/remote_monitor.config, under the entry health.monitor.port. This entry should match the health.monitor.port entry in the file <foglight_home>/config/restart_monitor.config on your servers.

NOTE: To use the Remote Monitor, JRE 1.5 or later must be installed on the machine hosting the Remote Monitor and the JAVA_HOME environment variable must be set to point to the installation directory.

NOTE: The Foglight Management Server must be running before you can start the Remote Monitor.

On UNIX®, enter the command:

On Windows®, do one of the following:

Do one of the following:

Enabling email notification for High Availability

Servers running in High Availability (HA) mode can send out email notifications in various situations, such as when servers stop responding or on failure to restart a server. The files <foglight_home>/config/restart_monitor.config and <foglight_home>/config/remote_monitor.config control how email notification functions, such as email protocols, email server information, and the message and recipients for each situation. Email can be sent out from the HA server or from the Remote Monitor. See the comments in these configuration files for more information about email notification.

Starting and stopping the HA server from the command line

The fmsha command provides a command-line interface to the Management Server process running in High Availability (HA) mode. Running Foglight® in HA mode allows you to manage multiple instances of the Management Server in a JGroup partition that supports the HA feature.

This command offers a set of options that you can use to perform any of the following operations as required:

NOTE: If you do not specify any options, fmsha uses the default option, s, and starts an instance of the Management Server in HA mode.