Coyote Point Systems Equalizer GX Series, Administration Manual

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Simple Health Check Probes
Simple health checks allow you to configure Equalizer to probe a specified target and retrieve a
"load" value from the target which describes its current level of load.
A user-supplied "server agent" must be running at the target, which supplies a load value in
response to a simple health check query from the Equalizer with a load value. This information is
obtained by the server agent by any means available at the target server. For example, if
supported by the target, the server agent program could check current CPU or memory allocation
to determine a load value.The only requirement from Equalizer's perspective is that the server
agent's response must be in the form of a single integer or floating point value. The server agent
may either return the load value immediately upon accepting a connection on the configured port,
or it may require a stimulus string before returning the value. After returning the value, the
server agent closes the connection and waits for another connection.
Configuring Simple Health Check Probe Parameters
Simple Health check probe parameters are configured on server pools and then must be applied
to the server instances (and thus the servers) within a server pool.
The following is a table of Simple Health Check Parameters.
GUI Parameter (CLI Parameter) Description
Health Check Relative Weight (weight)
Set the relative weight (default: 100 ) of the health check
load value returned by the application compared to other
health check values returned by other health checks. The
weight must be between 1 and 100.
Lightest Load Value (healthy)
A floating point value that is the ‘healthiest’ (or least busy)
load value that can be returned by the health check server
application. For example: if the application returns a value
of -1 to indicate that it is very lightly loaded, then set
healthy to -1. The default healthy value is 0.000000 .
Heaviest Load Value (loaded)
A floating point value that is the busiest (or most highly
loaded) load value that can be returned by the health
check server application for the health check. For
example: if the application returns a value of 10 to indicate
that it is very lightly loaded, then set
healthy to 10. The
default loaded value is 100.000000 .
Health Check Port (probe_port)
The port number for probing the health check server
application. The default port is
1510 .
Probe Interval (probe_interval)
The number of seconds (default: 15 ) Equalizer will wait
for a health check attempt to succeed before marking a
server down.
Max Tries Per Interval (probe_maxtries)
The maximum number of health check connection
attempts per probe interval before marking a server down.
Simple Health Check Parameters
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Equalizer Administration Guide