fallback

Function

The fallback command creates a fallback host for a virtual server.

The undo fallback command deletes a backup host for a virtual server.

Format

fallback fallback-host

undo fallback

Parameters

Parameter	Description	Value
fallback-host	IP address of domain name of the fallback host	Specifies an IP address or fully qualified domain name (FQDN). The value is a string of 1 to 255 characters, which can contain period (.), asterisk (*), hyphen (-), colon (:), underscore (_), question mark (?), equal sign (=), at sign (@), comma (,), ampersand (&), slash mark (/), and space. If a question mark or space is contained, the character string must be enclosed with quotation marks and can contain only 1 to 253 characters, for example, "http://host.domain.com/redirect.html?title=abc".

Views

Virtual server view

Default Level

2: Configuration level

Usage Guidelines

If no fallback host is specified, the virtual server will be disconnected when no real server is available in the real server group associated with the virtual server. When the function is enabled, the FW redirects the client-side access requests to the fallback host. The real servers in the real server group are unavailable in the following states:

The server is in Inactive or Admin-Invalid state.
The number of connections to the real servers reaches the upper limit, and the policy for busy real servers is re-scheduling.

The fallback host function can be configured only when the virtual server protocol is HTTP or HTTPS (SSL offloading is required for HTTPS).

Example

# Set the fallback host to http://192.168.0.1:80.

<sysname> system-view
[sysname] slb
[sysname-slb] vserver test
[sysname-slb-vserver-0] protocol http
[sysname-slb-vserver-0] fallback http://192.168.0.1:80