Coyote Point Systems E350GX, Installation And Administration Manual

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Chapter 6: Administering Virtual Clusters
152 Equalizer Installation and Administration Guide
Automatic Cluster Responders
A Responder is a server-like object that can be associated with a Match Rule. If an incoming request matches a
Match Rule expression and all of the servers specified in the Match Rule are down, a Responder definition in the
Match Rule (if present) tells Equalizer to send one of two automatic responses to the client:
•
A customized HTML “sorry page”
that can, for example, ask the client to retry later or go to another URL.
•
A standard HTTP Redirect response
that specifies a return code and redirect URL. When the client
receives this page, it is automatically redirected to the redirect URL. Redirect pages can be configured to
use parts of the request URL in the HTTP Redirect response (using a regular expression).
Managing Responders
To display a list of all currently defined Responders,
click
Responders
in the left frame to open the
Responders
tab. The table lists all the existing Responders and their configuration:
Figure 30 The Responders tab
To add a Responder
, you can either click the
Add
icon at the bottom of the
Actions
column, or click the Responder
name in the left frame (click the plus sign next to
Responders
to display a list of Responder names).
To edit a Responder’s configuration
, you can either click the
Edit
icon in one of the rows in the table above, or
click the Responder name in the left frame (click the plus sign next to
Responders
to display a list of Responder
names).
To delete a Responder
, you can either click the
Delete
icon in one of the rows in the table above, or right-click the
Responder name in the left frame and select
Delete Responder
from the menu (click the plus sign next to
Responders
to display a list of Responder names). A Responder cannot be deleted if it is currently used in a match
rule definition.
Adding a Responder
Responders are a “global” resource: once created, they can be individually assigned to one or more match rules in
one or more clusters. Up to 8192 Responders can be created.
Note – In previous releases, HTTP Redirects and “sorry pages” for clusters were configured by defining a
separate server as a hot spare -- this server would return a customized page to the client when no other servers
are available. Responders allow you to do this without configuring a separate server, and avoid the problem of the
hot spare itself becoming unavailable. Please see “Responders and Hot Spares” on page 160 for a discussion of
when each is appropriate to use in your configuration.
Note – Responder definitions are not automatically transferred between Failover pairs or amongst Envoy sites.
This means that Responders need to be created and maintained separately on each Equalizer in a Failover or
Envoy configuration.
Responders
are not
supported
on E250
GX
model
Equalizers