MACROMEDIA COLDFUSION MX-CLUSTERCATS, Руководство пользователя

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Using ColdFusion probes 77
Using ColdFusion probes
ClusterCATS provides load-balancing and failover support for your web applications in
two ways. First, it automatically interprets and reacts to the load metric that the
ColdFusion server generates. Second, ClusterCATS lets you create web application
monitors. These monitors can have multiple probes that periodically test the health and
operation of the websites that the servers process.
Note: Multiple probes are allowed per web server, and web applications can be restarted
individually. However, each web application should have only one probe that restarts on a
failure.
The probe is a high-availability feature that verifies that ColdFusion servers are running
properly on clustered servers. It periodically tests specific URLs at specified intervals and
verifies their validity against user-defined strings contained in the returned pages.
If the validation test succeeds, inbound HTTP requests continue to be sent to the server
for which the probe exists. However, if a test fails (the URL fails, times out, or does not
return the user-specified string in the page accessed), ClusterCATS restricts that server
and redirects requests to other available servers in the cluster. ClusterCATS continues to
test the restricted server; when the probe returns a valid value, the server is considered
available.
If a ColdFusion server hangs or fails, ClusterCATS attempts to recover the failed service.
When the service is recovered, the probe can restart the server and begin sending HTTP
traffic to it again.
This section describes the following:
•
“Configuring ColdFusion probes in Windows” on page 77
•
“Configuring ColdFusion probes in UNIX” on page 81
Configuring ColdFusion probes in Windows
This section describes the following:
•
“Adding ColdFusion probes” on page 77
•
“Removing ColdFusion probes” on page 81
Adding ColdFusion probes
ClusterCATS lets you set up one probe monitor for each server in the cluster. Each
monitor can have multiple probes associated with it. As a result, clusters will typically
have multiple probe monitors (one for each server), and each monitor can have one or
more probes.
The procedure for adding a new monitor and probe is different from adding a probe to a
server that already has a probe monitor. This section describes how to perform both
activities.
Note: The ColdFusion service must be running on your server to add a probe.