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Operating Systems: AIX, HP-UX, Linux, Solaris, Windows, z/OS

 

Controlling the generation of the plugin-cfg.xml file


You can override the default attribute values of the plugin-cfg.xml file that is automatically generated by the on demand router (ODR).

The following elements are formatted as com.ibm.ws.odr.plugincfg.<element>.<attributeName>, where <element> is the name of the configuration file keyword that denotes the element that contains an attribute, and <attributeName> is the name of the attribute that is located within that element. Configure the elements as JVM system properties. To set a JVM system property on the ODR in the administrative console, click Servers > On Demand Routers > on_demand_router > Java and Process Management > Process Definition > Java Virtual Machine > Custom Properties > New.

 

Config

This element starts the plug-in configuration file. It can include one or more of the following elements and attributes.

com.ibm.ws.odr.plugincfg.config.ASDisableNagle
Specifies whether the user wants to disable Nagle's algorithm for the connection between the plug-in and the server.

The default value is false.

com.ibm.ws.odr.plugincfg.config.AcceptAllContent
Specifies whether or not you can include content in POST, PUT, GET, and HEAD requests when a Content-Length or Transfer-encoding header is contained in the request header. You can specify one of the following values for this attribute:

  • True if content is to be expected and read for all requests

  • False if content only is only to be expected and read for POST and PUT requests.

The default value is false.

com.ibm.ws.odr.plugincfg.config.AppServerPortPreference
Specifies which port number is used to build URI's for a sendRedirect.

The default value is HostHeader.

com.ibm.ws.odr.plugincfg.config.ChunkedResponse
Specifies whether the plug-in groups the response to the client when a Transfer-Encoding : Chunked response header is present in the response.

You can specify one of the following values for this attribute:

  • True if the plug-in is to chunk the response to the client when a Transfer-Encoding : Chunked response header is present in the response.

  • False if the response is not to be chunked.

The default value is false.

com.ibm.ws.odr.plugincfg.configIISDisableNagle
Specifies if you want to disable nagle algorithm.

The default value is false.

com.ibm.ws.odr.plugincfg.configIISPluginPriority
Specifies the priority in which the Web server loads the plug-in. You can specify one of the following values for this attribute:

  • High

  • Medium

  • Low

The default value is High.

com.ibm.ws.odr.plugincfg.configIgnoreDNSFailures
Specifies if the plug-in ignores DNS failures within a configuration when started. When set to true, the plug-in ignores DNS failures within a configuration and starts successfully if at least one server in each ServerCluster resolves the host name. Any server for which the host name is not resolved is marked unavailable for the life of the configuration. The host name is not resolved later during the routing of requests. If a DNS failure occurs, a log message is written to the plug-in log file and the plug-in continues initializing instead of the Web server not starting.

The default value is false.

com.ibm.ws.odr.plugincfg.configRefreshInterval
The time interval, in seconds, at which the plug-in should check the configuration file for updates or changes. The plug-in checks the file for any modifications that occur since the plug-in configuration was loaded.

The default value is 60. In a development environment in which changes are frequent, set the time interval to less than 60 seconds. In production, set a higher value than the default, because updates to the configuration do not occur as often. If the plug-in reload is not successful, the plug-in log file contains a message, and the previous configuration is used until the plug-in configuration file successfully reloads. Refer to the plug-in log file for more information if an error occurs.

com.ibm.ws.odr.plugincfg.configResponseChunkSize
The plug-in file reads the response body in 64k chunks until all of the response data is read, which causes a performance problem for requests whose response body contains large amounts of data.

Use this attribute to specify the maximum chunk size to use when reading the response body. For example, Config ResponseChunkSize="N">, where N equals the chunk size in kilobytes.

If the content length of the response body is unknown, a buffer size of N kilobytes is allocated and the body is read in N kilobyte size chunks, until the entire body is read. If the content length is known, then a buffer size of either content length or N is used to read the response body.

The default chunk size is 64k.

com.ibm.ws.odr.plugincfg.configVHostMatchingCompat
Specifies to use the port number for virtual host matching. The following values can be specified:

  • True for physically matching by using the port number for which the request is received.

  • False for logically matching by using the port number contained in the host header.

The default is false.

 

Log

The log describes the location and level of log messages that are written by the plug-in. If a log is not specified within the configuration file, the log messages might be written to the error log.

com.ibm.ws.odr.plugincfg.log.Name
The fully qualified path to the log file to which the plug-in writes error messages.

The default value is profileRoot/logs/http_plugin.log.

com.ibm.ws.odr.plugincfg.log.LogLevel
The level of detail of the log messages that the plug-in writes to the log. You can specify one of the following values for this attribute:

  • Trace. All of the steps in the request process are logged in detail.

  • Stats. The server selected for each request and other load balancing information relating to request handling is logged.

  • Warn. All warning and error messages resulting from abnormal request processing are logged.

  • Error. Only error messages resulting from abnormal request processing are logged.

  • Debug. All of the critical steps performed in processing requests are logged.

  • Detail. All of the information about requests and responses are logged.
The default value is Error. CAUTION:A lot of messages are logged at the trace level, which can cause the file system to fill up very quickly. Never use a trace setting in a normally functioning environment as it adversely affects performance.

 

ServerCluster

This element is a group of servers that are generally configured to service the same type of requests.

In the simplest case, the cluster contains only one server definition. When you define more than one server, the plug-in completes a load balance across the defined servers by using either a Round Robin or a Random algorithm. The default is Round Robin.

com.ibm.ws.odr.plugincfg.cluster.CloneSeparatorChange
Some pervasive devices cannot handle the colon character (:) that is used to separate clone IDs in conjunction with session affinity. This attribute tells the plug-in to expect the plus character (+) as the clone separator. You must change the server configurations so that the server separates clone IDs with the plus character as well.

The default value is false.

com.ibm.ws.odr.plugincfg.cluster.LoadBalance
The Round Robin implementation has a random starting point. The first server is selected randomly, and the Round Robin value is used to select servers from that point forward. This implementation ensures that in multiple process-based Web servers, all of the processes do not start by sending the first request to the same server.

The default load balancing type is Round Robin.

com.ibm.ws.odr.plugincfg.cluster.PostSizeLimit
The maximum number of bytes of request content allowed for the plug-in to attempt to send the request to a server. If a request is received that is greater than this size, the plug-in ends the request.

The default value is -1 bytes, which indicates that there is no limit for the post size.

com.ibm.ws.odr.plugincfg.cluster.RemoveSpecialHeaders
The plug-in adds special headers to the request before it is forwarded to the server. These headers store information about the request that the application then uses. By default, the plug-in removes these headers from incoming requests before adding the required headers.

The default value is true. If you set the attribute to false, you introduce a potential security exposure by not removing headers from incoming requests.

com.ibm.ws.odr.plugincfg.cluster.RetryInterval
An integer that specifies the length of time that elapses from the time a server is marked down to the time that the plug-in reattempts to make a connection.

The default value is 60 seconds.

 

Server

This element is a server instance that is configured to handle requests routed to it based on the routing rules of the plug-in configuration. The server element corresponds to an application server running on either the local workstation or a remote workstation.

com.ibm.ws.odr.plugincfg.server.ConnectTimeout
Enables the plug-in to perform non-blocking connections with the application server, which are beneficial when the plug-in is unable to contact the destination to determine if the port is available or unavailable.

If no value is specified, the plug-in performs a blocking connect in which the plug-in waits until an operating system times out and allows the plug-in to mark the server unavailable. A value greater than 0 specifies the number of seconds the plug-in waits for a successful connection. If a connection does not occur after that time interval, the plug-in marks the server unavailable, and proceeds with one of the other servers defined in the cluster.

The default value is 0.

com.ibm.ws.odr.plugincfg.server.ExtendedHandShake
Used when a proxy firewall is between the plug-in and the application server. In such a case, the plug-in is not failing over, as expected.

The plug-in marks a server as stopped when the connect() ends. However, when a proxy firewall is in between the plug-in and the application server, the connect() succeeds, even though the back-end application server is stopped. This causes the plug-in to not failover correctly to other application servers.

The plug-in contains this attribute to ensure that it is started before sending the request.

The default value is false.

com.ibm.ws.odr.plugincfg.server.MaxConnections
Specifies the maximum number of pending connections to a server that flows through a Web server process at any point in time.

The default value is set to -1.

com.ibm.ws.odr.plugincfg.cluster.WaitForContinue
Specifies whether to use the HTTP 1.1 100 Continue support before sending the request content to the application server. The default value is false. The plug-in does not wait for the 100 Continue response from the application server before sending the request content.

This property is ignored for POST requests to prevent a failure from occurring if the application server closes a connection because of a time-out.

Enable this function when configuring the plug-in to work with certain types of proxy firewalls.

 

Property

com.ibm.ws.odr.plugincfg.property.ESIEnable
Used to enable or disable the Edge Side Include (ESI) processor. If the ESI processor is disabled, the other ESI elements in the file are ignored.

The default value is true.

com.ibm.ws.odr.plugincfg.property.ESIMaxCacheSize
An integer specifying, in 1K byte units, the maximum size of the cache. The default maximum size of the cache is 1024K bytes (1 megabyte). If the cache is full, the first entry to be evicted from the cache is the entry that is closest to its expiration time.
com.ibm.ws.odr.plugincfg.property.ESIInvalidationMonitor
Indicates whether or not the ESI processor receives invalidations from the application server.

The default value is false.

com.ibm.ws.odr.plugincfg.property.https.keyring
Use this element to specify the initialization parameters when the protocol of the transport is set to HTTPS.

This attribute is a supported name that is recognized by the transport. The default value for the keyring element is profileRoot/etc/plugin-key.kdb.

com.ibm.ws.odr.plugincfg.property.https.stashfile
The default value for the stash file is profileRoot/node/etc/plugin-key.sth



 

Related concepts


Overview of request flow prioritization

 

Related tasks


Creating and configuring ODRs Configure an on demand router to dynamically update the Web server plug-in configuration