Cluster General
Table of Contents
Session Extraction | Session ID String | Session Timeout | Insert Tracking Cookie | Tracking Cookie Name | Show Backend In Header | Forward IP Header | Forwarded By Header
Name⇑
Description
A unique name for a cluster.
Type⇑
Description
Specifies the type of cluster.
"Layer7" HTTP load balancing, also known as application-level load balancing, parses HTTP requests and distributes requests to servers based on different types of request contents.
"Layer4" load balancing is transport layer load balancing, such as TCP and UDP transport protocols. It does not look at the content when selecting a backend server. In theory, Layer 4 load balancing supports every application type.
Syntax
Select from drop down list
Mode⇑
Description
Specifies which mode the load balancer operates in, "Stateless" or "Stateful".
"Stateful" mode track sessions associated with each back-end server. It also called "Session Affinity".
"Stateless" mode does not care about sessions.
For the Layer 4 Load Balancer, if the Mode is “Stateful”, it will track the IP address of the client to extract previous sessions.
Syntax
Select from drop down list
Strategy⇑
Description
Select load balancing strategy from the list.
- The round-robin algorithm cycles through a list of backend Server instances in order.
- The least-load algorithm improves on the round-robin algorithm by also taking into account the current work load of each server.
- The least-session algorithm choose the server with fewest session associated.
- The Fastest Response algorithm chooses the Worker Group node that responds the fastest to a backend worker ping.
- The Failover algorithm chooses the Worker Group node that is configured with the highest priority. When that node becomes unhealthy, the next highest priority node is selected. If multiple nodes are configured with the same priority, then the first node configured will be selected. When an unhealthy node with a higher priority recovers, it will return as the highest priority node choice.
Syntax
Select from drop down list
Session Extraction⇑
Description
Specify how to extract session ID from request.
IP Address: Uses Client IP as session ID.
Basic Authentication: Uses username in the basic authentication as session ID.
Query String: Uses a Parameter in request query string as session ID.
Cookies: Uses a Parameter in cookie as session ID.
SSL Session: Uses SSL Session ID as session ID.
JVM Route: JVM Route is an extra section appended to a Servlet session ID, which used to identify servlet backend. Example: JSESSIONID=344BA8002DE6FBE2QDF25.tomcat1
URL Path Parameter: Uses a URL Path Parameter as session ID.
Syntax
Select from checkbox
Tips
For Layer 4 Load Balancers, only the IP Address extraction method will work. For Layer 7 Load Balancers, any of the above methods will work.
Session ID String⇑
Description
Specifies the Session ID string. The string is used to extract the session id value from cookie, query string and URL path parameter.
Session Timeout⇑
Description
Specify for how long a session will be valid, in seconds.
Syntax
Integer number
Insert Tracking Cookie⇑
Description
Specify whether to insert a tracking cookie. The tracking cookie can be used to reconstruct session cache in case load balancer lost it.
Syntax
Select from radio box
Tracking Cookie Name⇑
Description
Specify the tracking cookie name.
Syntax
string
Show Backend In Header⇑
Description
Add response header 'x-lsadc-backend' which indicates that backend server that served the request. The header's value is a concatenation of the cluster name and the backend IP and port.
Default value: No
Syntax
Select from radio box
Example
Forward IP Header⇑
Description
An additional header to be added to all proxy requests made to the backend server. This header will use either the visiting IP or the value set in the 'X-Forwarded-For' header as it's value, depending on the value set for Use Client IP in Header.
Default value: Not Set
Syntax
String with allowed characters a-z, A-Z, 0-9, underscore(_), and hyphen(-)
Example
Forwarded By Header⇑
Description
An additional header to be added to all proxy requests made to the backend server. This header's value will be set to the serverName value.
Default value: Not Set
Syntax
String with allowed characters a-z, A-Z, 0-9, underscore(_), and hyphen(-)
Example
Custom Error Messages⇑
Description
Specify a custom error message in case error occured during distributing request to backend servers. Custom error messages configured at virtual host level will override this configuration.