Application Server property settings for a Web server plug-in


To set appserver settings for a Web server plug-in.

To view this admin console page ...

Servers > Server Types > WebSphere application servers > server_name, and then, in the Additional Properties section, click Web server plug-in properties.

Server Role

Role this appserver is assigned.

Select Primary to add this appserver to the list of primary appservers. The plug-in initially attempts to route requests to the appservers on this list.

Select Backup to add this appserver to the list of backup appservers. The plug-in does not load balance across the backup application servers. A backup server is only used if a primary server is not available. When the plug-in determines that a backup appserver is required, it goes through the list of backup servers, in order, until no servers are left in the list or until a request is successfully sent and a response received from one of the servers on this list.

Default setting Primary

Connection timeout

Connection timeout settings.

This setting specifies whether or not there is a limited amount of time the appserver will maintain a connection with the Web server. Check the Use connection timeout checkbox to set a connection timeout. If no timeout is selected, the plug-in performs nonblocking connections with the appserver. If the checkbox is checked, specify a value in the seconds field. Specify a value of 0, if we want the plug-in to perform a blocking connection. Specify a value greater than 0, if we want the plug-in to wait the specified number for seconds to perform a successful connection. If a connection does not occur after that time interval, the plug-in marks the server unavailable and sends the request to another application server defined in the cluster.

This property enables the plug-in to perform non-blocking connections with the appserver. Non-blocking connections are beneficial when the plug-in is unable to contact the destination to determine whether or not the port is available. If no value is specified for this property, the plug-in performs a blocking connect in which the plug-in sits until an operating system times out (which could be as long as 2 minutes depending on the platform) and allows the plug-in to mark the server unavailable.

A value of 0 causes the plug-in to perform a blocking connect. A value greater than 0 specifies the number of seconds you want the plug-in to wait for a successful connection. If a connection does not occur after that time interval, the plug-in marks the server unavailable and fails over to another appserver defined for the requested application.

Data type Integer
Default 5

Read/Write timeout

Whether there is a time limit for how long the plug-in waits to send a request to or receive a response from the appserver.

Check the Use read/write timeout checkbox to set a read/write timeout. If the checkbox is checked, specify the length of time, in seconds that the plug-in waits to send a request or to receive a response. When selecting a value to specify for this field, remember that it might take a couple of minutes for an appserver to process a request. Setting the value too low might cause the plug-in to send a false server error response to the client. If the checkbox is not checked, the plug-in uses blocked I/O to write requests to and read responses from the appserver until the TCP connection times out.

This field is ignored for a plug-in running on a Solaris platform.

Data type Integer
Default 60 seconds

Maximum number of connections that can be handled by the appserver

Maximum number of pending connections to an appserver that can be flowing through a Web server process at any point in time.

This field corresponds to the ServerMaxConnections element in plugin-cfg.xml.

Check the Use maximum number of connections checkbox to set a maximum number of connections. If the checkbox is checked you, must specify the maximum number of connections that can exist between the Web server and the appserver at any given point in time.

For example, assuming that:

  • The appserver is fronted by 5 nodes that are running an IHS Web server.

  • Each node starts 2 processes.

  • Is set to 50.

In this example, the application server could potentially get up to 500 connections. (You take the number of nodes, 5, multiply it by the number of processes, 2, and then multiply that number by the number specified for this property, 50, for a total of 500 connections.)

If this attribute is set to either zero or -1, there is no limit to the number of pending connections to the appservers.

Data type Integer
Default 0

Use extended handshake to check whether appserver is running

When selected, the Web server plug-in will use an extended handshake to check whether or not the appserver is running.

This field corresponds to the ServerExtendedHandshake element in plugin-cfg.xml.

Select this property if a proxy firewall is between the plug-in and the appserver.

The plug-in marks a server as down when the connect() fails. However, when a proxy firewall is in between the plug-in and the appserver, the connect() will succeed, even though the back end appserver is down. This causes the plug-in to not failover correctly to other appservers.

If the plug-in performs some handshaking with the appserver to ensure that it is started before it sends a request it can failover to another appserver if it detects that the appserver with which it is attempting to perform a handshake is down.

By default, this field is not checked. Select this field to use extended handshake to check whether an appserver is running.

Send the header "100 Continue" before sending the request content

This field corresponds to the WaitForContinue element in plugin-cfg.xml.

When selected, the Web server plug-in will send the header "100 Continue" to the appserver before it sends the request content.

By default, this field is not checked. Select this field to enable this function.





 

Related tasks


Communicating with Web servers

 

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