Friday Apr 19, 2013

WLST Offline Script to Create Summary of WebLogic Domain

Introduction

I have always believed it is important to find out the bigger picture early on in a problem investigation. For example, if a managed server is exhibiting problematic behaviour, as well as I looking at the logs, I like to know the context - for example:

  • Is the server part of a cluster?
  • How many servers / clusters are in the Weblogic Domain?
  • Is the domain spread across multiple machines?
  • Are System Resources such JDBC and JMS in play?

Weblogic Server scripting ( WLST ) has been around for many years. Consequently there are a large number of examples to be found in blogs, websites and forums. The vast majority assume you can run the script in online mode. What if, however, a WLST online connection cannot be established? Ok, sure we can manually peruse the DOMAIN_HOME/config/config.xml. It is not a friendly a solution partly because some of the configuration is held in other xml files referenced by the config.xml. There has to be another way, I thought, after all WebLogic Server holds domain configuration in MBeans. This got me thinking about WLST.


WLST's readDomain Function

We can use WLST's readDomain function, in offline mode, to load the domain MBean configuration hierarchy / tree. It is as simple this:

Example: Unix Machine:

WL_HOME=/oracle/middleware/wlserver_10.3
DOMAIN_HOME=/oracle/middleware/user_projects/domains/MyDomain
$WL_HOME/common/bin/wlst.sh
wls:/offline/readDomain('/oracle/middleware/user_projects/domains/MyDomain')

Now you are ready to navigate the "tree" using "cd" and "ls" style syntax

wls:/offline/MyDomain/ls()

drw-   AnyMachine
drw-   AppDeployment
drw-   Cluster
drw-   EmbeddedLDAP
drw-   FileStore
drw-   JDBCSystemResource
drw-   JMSServer
drw-   JMSSystemResource
drw-   Library
drw-   MigratableTarget
drw-   Security
drw-   SecurityConfiguration
drw-   Server
drw-   ShutdownClass
drw-   StartupClass
drw-   WLDFSystemResource
-rw-   Active                                        false
-rw-   AdminServerName                               AdminServer
-rw-   AdministrationMBeanAuditingEnabled            false
-rw-   AdministrationPort                            9002
.... etc
wls:/offline/MyDomain/cd ('Server')
wls:/offline/MyDomain/Server/ls()
drw-   AdminServer
drw-   MyManagedServer
drw-   MyManagedServer01
wls:/offline/MyDomain/Server/cd ('MyManagedServer')
wls:/offline/MyDomain/Server/MyManagedServer/ls()
drw-   DataSource
drw-   NetworkAccessPoint
drw-   SSL
drw-   ServerDiagnosticConfig

-rw-   AcceptBacklog                                 300
-rw-   AdminReconnectIntervalSeconds                 10
-rw-   AdministrationPort                            0
-rw-   AdministrationPortEnabled                     false
-rw-   AdministrationProtocol                        null
...
-rw-   JavaCompilerPostClassPath                     null
-rw-   JavaCompilerPreClassPath                      null
-rw-   JavaStandardTrustKeyStorePassPhraseEncrypted  null
-rw-   JdbcLoginTimeoutSeconds                       0
-rw-   KeyStores                                     null
-rw-   ListenAddress                                 127.0.0.1
-rw-   ListenDelaySecs                               0
-rw-   ListenPort                                    7021
-rw-   ListenPortEnabled                             true

... etc
wls:/offline/MyDomain/Server/MyManagedServer/foo = get('ListenPort')
wls:/offline/MyDomain/Server/MyManagedServer/print foo

7021

 

Sample Script and Output

To write a script, which automates the capture and print out of attributes useful to a summary, is challenging because the functions to traverse and search the MBean tree are limited compared to online mode. You are pretty much stuck with the cd(), ls() and get(). However, with a bit of coding creativity with IF and FOR loop syntax you can programmatically explore the tree and return output in a nice format - in my sample I have chosen HTML tables.

Sample Output

To view sample output, go here

Screenshot below shows snipper of sample output.


Download Sample Script

You can grab the sample script by clicking here.

Instructions to Run:

1. Edit the environment variables in the start wrapper script startWLSofflineCollection.sh (Unix) or startWLSofflineCollection.cmd (MS Windows) to suit your system

Example - startWLSofflineCollection.sh

WL_HOME=/oracle/middleware/wlserver_10.3
DOMAIN_HOME=/oracle/middleware/user_projects/domains/MyDomain; export DOMAIN_HOME
WLST_OUTPUT_PATH=/temp/wlst/; export WLST_OUTPUT_PATH
WLST_OUTPUT_FILE=WLST_MBean_Config_Summary.html; export WLST_OUTPUT_FILE
${WL_HOME}/common/bin/wlst.sh CollectWLSConfigOffline.py

Note: The WLST_OUTPUT_PATH directory value must have a trailing slash. If there is no trailing slash script will error and not continue.

2. Then run the wrapper script. It should launch WLST and run the script. The script will collect MBean values and render them in a HTML file.
(Once the script has invoked the WLST shell, the execution of the python script should not take longer than 5 to 10 seconds.)

Disclaimer

This is a sample script. I have tested it against WebLogic Server 10.3.6 domains on MS Windows and Unix.  I cannot guarantee that the script will run error free or produce the expected output on your system. That said, a number of colleagues have also run the script and with their feedback I have ironed out a few problems. If you have any feedback add a comment to the blog. I will endeavour to fix any problems with my WLST code. 

Credits

I found the following blogs particularly useful.

Java / Oracle SOA blog
[http://biemond.blogspot.co.uk/2010/02/invoking-fmw-application-mbeans-in.html]

WLST By Examples
[http://wlstbyexamples.blogspot.co.uk/]


Some Pitfalls (which required coding around)

Checking whether Configuration MBean Hierarchy Exists

If a service or functionality, such as Clusters, JDBC, JMS, Filestore are not configured, the related MBean hierarchy will not be visible when listing at domain level. Example: If Cluster, JDBC, JMS and Filestore have not been configured, the ls() will show:

wls:/offline/MyDomain/ls()

drw-   AnyMachine
drw-   AppDeployment
drw-   EmbeddedLDAP
drw-   Library
drw-   MigratableTarget
drw-   Security
drw-   SecurityConfiguration
drw-   Server
drw-   ShutdownClass
drw-   StartupClass
drw-   WLDFSystemResource

A programmatic attempt to cd to a directory not listed will return an error e.g.

Error: cd() failed. Do dumpStack() to see details.

To work-around, the script contains a custom findMBean function. The function places the contents of the ls() in an array using the returnmap parameter. We can then loop through the array and check whether a given string - the MBean directory name exists e.g.

def findMBean(v_pattern):
        # get a listing of everything in the current directory
    mydirs = ls(returnMap='true');

        v_compile_pattern = java.util.regex.Pattern.compile(v_pattern);

    found = 'Nope not here';

    for mydir in mydirs:
        x = java.lang.String(mydir);
        v_matched = v_compile_pattern.matcher(x);
        if v_matched.find():
            found = 'true';

        return found;

AnyMachine v Machines

In WebLogic Server 10.3, if a domain has one or more machines configured (i.e nodemanager related machines) the ls() at domain level will show

wls:/offline/MyDomain/ls()

drw-   AnyMachine

A cd ('AnyMachine'), however, will fail. The correct cd syntax is

wls:/offline/MyDomain/cd ('Machines')

Identifying Target Information

Features such as JDBC System Resources, Clusters may or may not have targets. An attempt to cd to an MBean directory or get an MBean attribute which does not exist will throw an error and prevent the script from continuing. To work-around we can use TRY / EXCEPT syntax. Example - snippet from sample script which deals with the capture of JDBC System Resource targets.

try:
            v_any_targets = '';
            v_jdbc_target = get('Target');

            # Even if the get fails, the variable is assigned a value of none, set the flag variable accordingly
            if v_jdbc_target == 'None':
                v_any_targets = 'None';
                v_no_of_targets = 1;
            else:   
                # If the get has succeeded then set flag accordingly and obtain length of array returned by the get
                # The array length will be used to determine the HTML rowspan value

                v_any_targets ='Use v_jdbc_target';
                v_no_of_targets = len(v_jdbc_target);

        except:

            # Setting flag and rowspan variable here as well .. belt and braces
            v_any_targets = 'None';
            v_no_of_targets = 1;

            # The exception will still display to standard out, which may cause alarm
            # So adding this message telling the user the exception is expected and can be ignored
            print "IGNORE this exception";   

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