Limiting the growth of JVM log files using scripting

You can use scripting to configure the size of Java™ virtual machine (JVM) log files. JVM logs record events or information from a running JVM.

Before you begin

There are two ways to perform this task. This topic demonstrates how to use the AdminConfig object to modify your server configuration. Alternatively, you can use the configureJavaProcessLogs Jython script in the AdminServerManagement script library to configure the JVM log settings. The wsadmin tool automatically loads the script when the tool starts. Use the following syntax to configure JVM log settings using the configureJavaProcessLogs script:

AdminServerManagement.configureJavaProcessLogs(nodeName, serverName, processLogRoot, otherAttributeList)

For additional information and argument definitions, see the documentation for the AdminServerMananagment script library.

Procedure

Start the wsadmin scripting tool.

Identify the application server of interest.

Determine the configuration ID of the application server of interest and assign it to the server1 variable, as the following example demonstrates:

Using Jacl:

set s1 [$AdminConfig getid /Cell:mycell/Node:mynode/Server:server1/]

Using Jython:

s1 = AdminConfig.getid('/Cell:mycell/Node:mynode/Server:server1/')
print s1

where:

Table 1. Syntax explanation . The following table describes the elements of the getid command.
Element	Description
`set`	is a Jacl command
`s1`	is a variable name
`$`	is a Jacl operator for substituting a variable name with its value
`AdminConfig`	is an object representing the WebSphere® Application Server configuration
`getid`	is an AdminConfig command
`Cell`	is the object type
`mycell`	is the name of the object that will be modified
`Node`	is the object type
`mynode`	is the name of the object that will be modified
`Server`	is the object type
`server1`	is the name of the object that will be modified
`print`	a Jython command

Example output:

server1(cells/mycell/nodes/mynode/servers/server1|server.xml#Server_1)

Identify the stream log of interest.

Determine the stream log of interest and assign it to the log variable. The following example identifies the output stream log:

Using Jacl:

set log [$AdminConfig showAttribute $s1 outputStreamRedirect]

Using Jython:

log = AdminConfig.showAttribute(s1, 'outputStreamRedirect')

The following example identifies the error stream log:

Using Jacl:

set log [$AdminConfig showAttribute $s1 errorStreamRedirect]

Using Jython:

log = AdminConfig.showAttribute(s1, 'errorStreamRedirect')

Example output:

(cells/mycell/nodes/mynode/servers/server1|server.xml#StreamRedirect_2)

List the current values of the stream log.

Use the following example to display the current values of the stream log of interest:

Using Jacl:
```
$AdminConfig show $log
```
Using Jython:
```
AdminConfig.show(log)
```

Example output:

{baseHour 24}
{fileName ${SERVER_LOG_ROOT}/SystemOut.log}
{formatWrites true}
{maxNumberOfBackupFiles 1}
{messageFormatKind BASIC}
{rolloverPeriod 24}
{rolloverSize 1}
{rolloverType SIZE}
{suppressStackTrace false}
{suppressWrites false}

Modify the rotation policy for the stream log.

The following example sets the rotation log file size to two megabytes:

Using Jacl:

$AdminConfig modify $log {{rolloverSize 2}}

Using Jython:

AdminConfig.modify(log, [['rolloverSize', 2]])

The following example sets the rotation policy to manage itself. It is based on the age of the file with the rollover algorithm loaded at midnight, and the log file rolling over every 12 hours:

Using Jacl:

$AdminConfig modify $log {{rolloverType TIME} 
{rolloverPeriod 12} {baseHour 24}}

Using Jython:

AdminConfig.modify(log, [['rolloverType', 'TIME'], 
['rolloverPeriod', 12], ['baseHour', 24]])

The following example sets the log file to roll over based on both time and size:

Using Jacl:

$AdminConfig modify $log {{rolloverType BOTH} {rolloverSize 2} 
{rolloverPeriod 12} {baseHour 24}}

Using Jython:

AdminConfig.modify(log, [['rolloverType', 'BOTH'], ['rolloverSize', 2], 
['rolloverPeriod', 12], ['baseHour', 24]])

Save the configuration changes.
Use the following command example to save your configuration changes:
```
AdminConfig.save()
```
In a network deployment environment only, synchronize the node.
Use the syncActiveNode or syncNode scripts in the AdminNodeManagement script library to propagate the configuration changes to node or nodes.
- Use the syncActiveNodes script to propagate the changes to each node in the cell, as the following example demonstrates:
```
AdminNodeManagement.syncActiveNodes()
```
- Use the syncNode script to propagate the changes to a specific node, as the following example demonstrates:
```
AdminNodeManagement.syncNode("myNode")
```