Use the Service Monitor to check the health of your services and servers on an ongoing basis. A visual indicator appears next to the service or server if it is not available. You can enable notifications on a per-service basis to have an email sent to the system alerts email address(es) recorded in the BASIC > Administration page if the number of operating real servers for a service falls below a preset threshold. Also, you can configure SNMP traps to be generated on certain conditions using the ADVANCED > SNMP Configuration page.
Service Status
Following is the list of Service status indicators:
- The Service is up and all Real Servers are responding to requests.
- The Service is up, but at least one Real Server is not responding.
- The Service is down. No Real Servers are responding.
A Real Server may not respond because it was removed from the Service by an administrator or because of a system failure.
Real Server Status
Following is the list of Real Server status indicators:
- The Real Server is up and responding to requests.
- The Real Server is not enabled; click the Edit icon to change its status.
- The Real Server is not responding but its state is enabled.
Service Monitor
The Service Monitor checks the health of each Service and Real Server on an ongoing basis. Specify which test to perform and how frequently to do the test by editing the Service or Real Server on the BASIC > Services page. The BASIC > Services and BASIC > Server Health pages display the health of all load-balanced Services and associated Real Servers.
There are many different methods available to establish the availability of a Service or Real Server. These include TCP port check, HTTP GET request, DNS query and RADIUS test. The various tests are fully documented in the online help.
The tests always use the configured Real Server port for the Service unless the Real Server port is set to ALL. In that case, the tests use the default port for the test type (e.g. SMTP = 25, HTTP = 80, DNS = 53, HTTPS = 443, IMAP = 143, POP = 110 and SNMP = 161).
If a Real Server is associated with more than one Service, but with the same test and test interval for each Service, it will be tested once per test interval. Otherwise, it may be checked more frequently. Unless the tests are identical, the Service Monitor performs its health checks for each Service’s set of Real Servers independently.
Monitor Groups
Monitor groups are sets of tests that are conducted on Real Servers. Use them when one test does not give a complete picture of the health of a Real Server. You can specify a monitoring group with two or more tests and the Service Monitor will perform all the tests in the group. The failure of any one test means the Real Server is considered to be unavailable and it will be removed from the load-balancing pool.
Create monitor groups that contain one or more tests on the TRAFFIC > Monitor Groups page. Then edit the Real Server or Service. The monitor groups appear in the Testing Methods for the Service or Server Configuration page.