Antony Reynolds

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Free WebLogic Administration Cookbook

Fri, 2013-06-28 10:16
Free WebLogic Admin Cookbook

Packt Publishing are offering free copies of Oracle WebLogic Server 12c Advanced Administration Cookbook : http://www.packtpub.com/oracle-weblogic-server-12c-advanced-administration-cookbook/book  in exchange for a review either on your blog or on the title’s Amazon page.

Here’s the blurb:

  • Install, create and configure WebLogic Server
  • Configure an Administration Server with high availability
  • Create and configure JDBC data sources, multi data sources and gridlink data sources
  • Tune the multi data source to survive database failures
  • Setup JMS distributed queues
  • Use WLDF to send threshold notifications
  • Configure WebLogic Server for stability and resilience

If you’re a datacenter operator, system administrator or even a Java developer this book could be exactly what you are looking for to take you one step further with Oracle WebLogic Server, this is a good way to bag yourself a free cookbook (current retail price $25.49).

Free review copies are available until Tuesday 2nd July 2013, so if you are interested, email Harleen Kaur Bagga at: harleenb@packtpub.com.

I will be posting my own review shortly!

Target Verification

Tue, 2013-05-21 13:02
Verifying the Target

I just built a combined OSB, SOA/BPM, BAM clustered domain.  The biggest hassle is validating that the resource targeting is correct.  There is a great appendix in the documentation that lists all the modules and resources with their associated targets.  The only problem is that the appendix is six pages of small print.  I manually went through the first page, verifying my targeting, until I thought ‘there must be a better way of doing this’.  So this blog post is the better way Smile

WLST to the Rescue

WebLogic Scripting Tool allows us to query the MBeans and discover what resources are deployed and where they are targeted.  So I built a script that iterates over each of the following resource types and verifies that they are correctly targeted:

  • Applications
  • Libraries
  • Startup Classes
  • Shutdown Classes
  • JMS System Resources
  • WLDF System Resources
Source Data

To get the data to verify my domain against, I copied the tables from the documentation into a text file.  The copy ended up putting the resource on the first line and the targets on the second line.  Rather than reformat the data I just read the lines in pairs, storing the resource as a string and splitting apart the targets into a list of strings.  I then stored the data in a dictionary with the resource string as the key and the target list as the value.  The code to do this is shown below:

# Load resource and target data from file created from documentation
# File format is a one line with resource name followed by
# one line with comma separated list of targets
# fileIn - Resource & Target File
# accum - Dictionary containing mappings of expected Resource to Target
# returns - Dictionary mapping expected Resource to expected Target
def parseFile(fileIn, accum) :
  # Load resource name
  line1 = fileIn.readline().strip('\n')
  if line1 == '':
    # Done if no more resources
    return accum
  else:
    # Load list of targets
    line2 = fileIn.readline().strip('\n')
    # Convert string to list of targets
    targetList = map(fixTargetName, line2.split(','))
    # Associate resource with list of targets in dictionary
    accum[line1] = targetList
    # Parse remainder of file
    return parseFile(fileIn, accum)

This makes it very easy to update the lists by just copying and pasting from the documentation.

Each table in the documentation has a corresponding file that is used by the script.

The data read from the file has the target names mapped to the actual domain target names which are provided in a properties file.

Listing & Verifying the Resources & Targets

Within the script I move to the domain configuration MBean and then iterate over the resources deployed and for each resource iterate over the targets, validating them against the corresponding targets read from the file as shown below:

# Validate that resources are correctly targeted
# name - Name of Resource Type
# filename - Filename to validate against
# items - List of Resources to be validated
def validateDeployments(name, filename, items) :
  print name+' Check'
  print "====================================================="
  fList = loadFile(filename)
  # Iterate over resources
  for item in items:
    try:
      # Get expected targets for resource
      itemCheckList = fList[item.getName()]
      # Iterate over actual targets
      for target in item.getTargets() :
        try:
          # Remove actual target from expected targets
          itemCheckList.remove(target.getName())
        except ValueError:
          # Target not found in expected targets
          print 'Extra target: '+item.getName()+': '+target.getName()
      # Iterate over remaining expected targets, if any
      for refTarget in itemCheckList:
        print 'Missing target: '+item.getName()+': '+refTarget
    except KeyError:
      # Resource not found in expected resource dictionary
      print 'Extra '+name+' Deployed: '+item.getName()
  print

Obtaining the Script
I have uploaded the script here.  It is a zip file containing all the required files together with a PDF explaining how to use the script.

To install just unzip VerifyTargets.zip. It will create the following files

  • verifyTargets.sh
  • verifyTargets.properties
  • VerifyTargetsScriptInstructions.pdf
  • scripts/verifyTargets.py
  • scripts/verifyApps.txt
  • scripts/verifyLibs.txt
  • scripts/verifyStartup.txt
  • scripts/verifyShutdown.txt
  • scripts/verifyJMS.txt
  • scripts/verifyWLDF.txt
Sample Output

The following is sample output from running the script:

Application Check
=====================================================
Extra Application Deployed: frevvo
Missing target: usermessagingdriver-xmpp: optional
Missing target: usermessagingdriver-smpp: optional
Missing target: usermessagingdriver-voicexml: optional
Missing target: usermessagingdriver-extension: optional
Extra target: Healthcare UI: soa_cluster
Missing target: Healthcare UI: SOA_Cluster ??
Extra Application Deployed: OWSM Policy Support in OSB Initializer Aplication

Library Check
=====================================================
Extra Library Deployed: oracle.bi.adf.model.slib#1.0-AT-11.1-DOT-1.2-DOT-0
Extra target: oracle.bpm.mgmt#11.1-DOT-1-AT-11.1-DOT-1: AdminServer
Missing target: oracle.bpm.mgmt#11.1.1-AT-11.1.1: soa_cluster
Extra target: oracle.sdp.messaging#11.1.1-AT-11.1.1: bam_cluster

StartupClass Check
=====================================================

ShutdownClass Check
=====================================================

JMS Resource Check
=====================================================
Missing target: configwiz-jms: bam_cluster

WLDF Resource Check
=====================================================

IMPORTANT UPDATE

Since posting this I have discovered a number of issues.  I have updated the configuration files to correct these problems.  The changes made are as follows:

  • Added WLS_OSB1 server mapping to the script properties file (verifyTargets.properties) to accommodate OSB singletons and modified script (verifyTargets.py) to use the new property.
  • Changes to verifyApplications.txt
    • Changed target from OSB_Cluster to WLS_OSB1 for the following applications:
      • ALSB Cluster Singleton Marker Application
      • ALSB Domain Singleton Marker Application
      • Message Reporting Purger
    • Added following application and targeted at SOA_Cluster
      • frevvo
    • Adding following application and targeted at OSB_Cluster & Admin Server
      • OWSM Policy Support in OSB Initializer Aplication
  • Changes to verifyLibraries.txt
    • Adding following library and targeted at OSB_Cluster, SOA_Cluster, BAM_Cluster & Admin Server
      • oracle.bi.adf.model.slib#1.0-AT-11.1.1.2-DOT-0
    • Modified targeting of following library to include BAM_Cluster
      • oracle.sdp.messaging#11.1.1-AT-11.1.1

Make sure that you download the latest version.  It is at the same location but now includes a version file (version.txt).  The contents of the version file should be:

FMW_VERSION=11.1.1.7

SCRIPT_VERSION=1.1

Event Processed

Wed, 2012-10-31 19:24
Installing Oracle Event Processing 11g

Earlier this month I was involved in organizing the Monument Family History Day.  It was certainly a complex event, with dozens of presenters, guides and 100s of visitors.  So with that experience of a complex event under my belt I decided to refresh my acquaintance with Oracle Event Processing (CEP).

CEP has a developer side based on Eclipse and a runtime environment.

Server install

The server install is very straightforward (documentation).  It is recommended to use the JRockit JDK with CEP so the steps to set up a working CEP server environment are:

  1. Download required software
    • JRockit – I used Oracle “JRockit 6 - R28.2.5” which includes “JRockit Mission Control 4.1” and “JRockit Real Time 4.1”.
    • Oracle Event Processor – I used “Complex Event Processing Release 11gR1 (11.1.1.6.0)”
  2. Install JRockit
    • Run the JRockit installer, the download is an executable binary that just needs to be marked as executable.
  3. Install CEP
    • Unzip the downloaded file
    • Run the CEP installer,  the unzipped file is an executable binary that may need to be marked as executable.
    • Choose a custom install and add the examples if needed.
      • It is not recommended to add the examples to a production environment but they can be helpful in development.
Developer Install

The developer install requires several steps (documentation).  A developer install needs access to the software for the server install, although JRockit isn’t necessary for development use.

  1. Download required software
    • Eclipse  (Linux) – It is recommended to use version 3.6.2 (Helios)
  2. Install Eclipse
    • Unzip the download into the desired directory
  3. Start Eclipse
  4. Add Oracle CEP Repository in Eclipse
    • http://download.oracle.com/technology/software/cep-ide/11/
  5. Install Oracle CEP Tools for Eclipse 3.6
    • You may need to set the proxy if behind a firewall.
  6. Modify eclipse.ini
    • If using Windows edit with wordpad rather than notepad
    • Point to 1.6 JVM
      • Insert following lines before –vmargs
        • -vm
        • \PATH_TO_1.6_JDK\jre\bin\javaw.exe
    • Increase PermGen Memory
      • Insert following line at end of file
        • -XX:MaxPermSize=256M

Restart eclipse and verify that everything is installed as expected.

Voila The Deed Is Done

With CEP installed you are now ready to start a server, if you didn’t install the demoes then you will need to create a domain before starting the server.

Once the server is up and running (using startwlevs.sh) you can verify that the visualizer is available on http://hostname:port/wlevs, the default port for the demo domain is 9002.

With the server running you can test the IDE by creating a new “Oracle CEP Application Project” and creating a new target environment pointing at your CEP installation.

Much easier than organizing a Family History Day!

Oracle SOA Suite 11g Administrator's Handbook

Fri, 2012-10-12 12:06
SOA Administration Book

I have just received a copy of the “Oracle SOA Suite 11g Administrator's Handbook” so as soon as I have read it I will let you know what I think.  In the meantime the first thing that struck me was the author credentials, although I have never met either of them as I remember, I have read Admeds blog postings and they are a great community resource, so immediately I am well disposed towards the book.  Similarly Arun is an employee of my friend and co-author Matt Wright, and I have heard good things about him from Rubicon Red people.

A first glance at the table of contents looks encouraging, I particularly like their approach to performance tuning where they give a clear concise explanation of the knobs they are using.

More when I have read more.

Following the Thread in OSB

Wed, 2012-10-10 14:31
Threading in OSB

The Scenario

I recently led an OSB POC where we needed to get high throughput from an OSB pipeline that had the following logic:

1. Receive Request
2. Send Request to External System
3. If Response has a particular value
  3.1 Modify Request
  3.2 Resend Request to External System
4. Send Response back to Requestor

All looks very straightforward and no nasty wrinkles along the way.  The flow was implemented in OSB as follows (see diagram for more details):

  • Proxy Service to Receive Request and Send Response
  • Request Pipeline
    •   Copies Original Request for use in step 3
  • Route Node
    •   Sends Request to External System exposed as a Business Service
  • Response Pipeline
    •   Checks Response to Check If Request Needs to Be Resubmitted
      • Modify Request
      • Callout to External System (same Business Service as Route Node)

The Proxy and the Business Service were each assigned their own Work Manager, effectively giving each of them their own thread pool.

The Surprise

Imagine our surprise when, on stressing the system we saw it lock up, with large numbers of blocked threads.  The reason for the lock up is due to some subtleties in the OSB thread model which is the topic of this post.

 

Basic Thread Model

OSB goes to great lengths to avoid holding on to threads.  Lets start by looking at how how OSB deals with a simple request/response routing to a business service in a route node.

Most Business Services are implemented by OSB in two parts.  The first part uses the request thread to send the request to the target.  In the diagram this is represented by the thread T1.  After sending the request to the target (the Business Service in our diagram) the request thread is released back to whatever pool it came from.  A multiplexor (muxer) is used to wait for the response.  When the response is received the muxer hands off the response to a new thread that is used to execute the response pipeline, this is represented in the diagram by T2.

OSB allows you to assign different Work Managers and hence different thread pools to each Proxy Service and Business Service.  In out example we have the “Proxy Service Work Manager” assigned to the Proxy Service and the “Business Service Work Manager” assigned to the Business Service.  Note that the Business Service Work Manager is only used to assign the thread to process the response, it is never used to process the request.

This architecture means that while waiting for a response from a business service there are no threads in use, which makes for better scalability in terms of thread usage.

First Wrinkle

Note that if the Proxy and the Business Service both use the same Work Manager then there is potential for starvation.  For example:

  • Request Pipeline makes a blocking callout, say to perform a database read.
  • Business Service response tries to allocate a thread from thread pool but all threads are blocked in the database read.
  • New requests arrive and contend with responses arriving for the available threads.

Similar problems can occur if the response pipeline blocks for some reason, maybe a database update for example.

Solution

The solution to this is to make sure that the Proxy and Business Service use different Work Managers so that they do not contend with each other for threads.

Do Nothing Route Thread Model

So what happens if there is no route node?  In this case OSB just echoes the Request message as a Response message, but what happens to the threads?  OSB still uses a separate thread for the response, but in this case the Work Manager used is the Default Work Manager.

So this is really a special case of the Basic Thread Model discussed above, except that the response pipeline will always execute on the Default Work Manager.

 

Proxy Chaining Thread Model

So what happens when the route node is actually calling a Proxy Service rather than a Business Service, does the second Proxy Service use its own Thread or does it re-use the thread of the original Request Pipeline?

Well as you can see from the diagram when a route node calls another proxy service then the original Work Manager is used for both request pipelines.  Similarly the response pipeline uses the Work Manager associated with the ultimate Business Service invoked via a Route Node.  This actually fits in with the earlier description I gave about Business Services and by extension Route Nodes they “… uses the request thread to send the request to the target”.

Call Out Threading Model

So what happens when you make a Service Callout to a Business Service from within a pipeline.  The documentation says that “The pipeline processor will block the thread until the response arrives asynchronously” when using a Service Callout.  What this means is that the target Business Service is called using the pipeline thread but the response is also handled by the pipeline thread.  This implies that the pipeline thread blocks waiting for a response.  It is the handling of this response that behaves in an unexpected way.

When a Business Service is called via a Service Callout, the calling thread is suspended after sending the request, but unlike the Route Node case the thread is not released, it waits for the response.  The muxer uses the Business Service Work Manager to allocate a thread to process the response, but in this case processing the response means getting the response and notifying the blocked pipeline thread that the response is available.  The original pipeline thread can then continue to process the response.

Second Wrinkle

This leads to an unfortunate wrinkle.  If the Business Service is using the same Work Manager as the Pipeline then it is possible for starvation or a deadlock to occur.  The scenario is as follows:

  • Pipeline makes a Callout and the thread is suspended but still allocated
  • Multiple Pipeline instances using the same Work Manager are in this state (common for a system under load)
  • Response comes back but all Work Manager threads are allocated to blocked pipelines.
  • Response cannot be processed and so pipeline threads never unblock – deadlock!
Solution

The solution to this is to make sure that any Business Services used by a Callout in a pipeline use a different Work Manager to the pipeline itself.

The Solution to My Problem

Looking back at my original workflow we see that the same Business Service is called twice, once in a Routing Node and once in a Response Pipeline Callout.  This was what was causing my problem because the response pipeline was using the Business Service Work Manager, but the Service Callout wanted to use the same Work Manager to handle the responses and so eventually my Response Pipeline hogged all the available threads so no responses could be processed.

The solution was to create a second Business Service pointing to the same location as the original Business Service, the only difference was to assign a different Work Manager to this Business Service.  This ensured that when the Service Callout completed there were always threads available to process the response because the response processing from the Service Callout had its own dedicated Work Manager.

Summary
  • Request Pipeline
    • Executes on Proxy Work Manager (WM) Thread so limited by setting of that WM.  If no WM specified then uses WLS default WM.
  • Route Node
    • Request sent using Proxy WM Thread
    • Proxy WM Thread is released before getting response
    • Muxer is used to handle response
    • Muxer hands off response to Business Service (BS) WM
  • Response Pipeline
    • Executes on Routed Business Service WM Thread so limited by setting of that WM.  If no WM specified then uses WLS default WM.
  • No Route Node (Echo functionality)
    • Proxy WM thread released
    • New thread from the default WM used for response pipeline
  • Service Callout
    • Request sent using proxy pipeline thread
    • Proxy thread is suspended (not released) until the response comes back
    • Notification of response handled by BS WM thread so limited by setting of that WM.  If no WM specified then uses WLS default WM.
      • Note this is a very short lived use of the thread
    • After notification by callout BS WM thread that thread is released and execution continues on the original pipeline thread.
  • Route/Callout to Proxy Service
    • Request Pipeline of callee executes on requestor thread
    • Response Pipeline of caller executes on response thread of requested proxy
  • Throttling
    • Request message may be queued if limit reached.
    • Requesting thread is released (route node) or suspended (callout)

So what this means is that you may get deadlocks caused by thread starvation if you use the same thread pool for the business service in a route node and the business service in a callout from the response pipeline because the callout will need a notification thread from the same thread pool as the response pipeline.  This was the problem we were having.
You get a similar problem if you use the same work manager for the proxy request pipeline and a business service callout from that request pipeline.
It also means you may want to have different work managers for the proxy and business service in the route node.
Basically you need to think carefully about how threading impacts your proxy services.

References

Thanks to Jay Kasi, Gerald Nunn and Deb Ayers for helping to explain this to me.  Any errors are my own and not theirs.  Also thanks to my colleagues Milind Pandit and Prasad Bopardikar who travelled this road with me.

Open World Day 4

Mon, 2012-10-08 12:25
A Day in the Life of an OpenWorld Attendee Part V

Last day at OpenWorld.  The exhibits are closed, and the final few presentations are being given.  I spent much of the day meeting with customers to talk about SOA/OSB and Coherence.  Main event of the day was the farewell party which was loud and surprisingly well attended.  I was able to have lunch with Dave Felcey, Coherence PM, who has a great blog and is always ready to share his expertise with people.

So that was OpenWOrld for another year.  I met a friend of a friend who attends OpenWorld every year and attends the Demo Grounds with a list of questions to ask people.  I think that illustrates the point that everyone approaches OpenWorld in a different way and looks to get different things from it.  For me OpenWorld is a great experience to feel the energy in Oracle and network with customers and partners.  Hope to see you there next year!

Open World Day 3

Fri, 2012-10-05 14:37
A Day in the Life of an Oracle OpenWorld Attendee Part IV

My third day was exhibition day for me!  I took the opportunity to wander around the JavaOne and OpenWorld exhibitions to see what might be useful for me when selling WebLogic, Coherence & SOA Suite.  I found a number of interesting vendors and thought I would share what I found here.  These are not necessarily endorsements, but observations on companies that I thought had interesting looking products that fill a need I have seen at customers.

Highly Available EBS Upgrades

A few years ago I worked with a customer that was a port authority.  They wanted to tie E-Business Suite into their operations to provide faster processing of cargo and passengers.  However they only had a 2 hour downtime window to perform upgrades.  This was not a problem for core database and middleware technology, this could accommodate those upgrade timescales easily.  It was a problem for EBS however so I intrigued to find Rapid E-Suite Inc offering an 11i to 12i upgrade service that claims to require no outage.  This could be a real boon to EBS customers like my port friends that need to upgrade without disruption to their business.

Mobile on WebLogic

I have come across a number of customers who want a comprehensive mobile solution, connected and disconnected operation and so forth.  ADF only addresses part of these requirements currently so I was excited to discover mFrontiers Inc offering an apparently comprehensive solution that should integrate easily with Oracle SOA Suite to mobile enable a SOA infrastructure.  The ability to operate without a network is important for many applications, particularly in industries that require their engineers to enter buildings to perform maintenance or repairs, because network access is not always available – many of my colleagues don’t have mobile access from their homes because they live in the middle of nowhere – and disconnected support is crucial in these situations.

Sharepoint Connector for WebCenter Content

Obviously Sharepoint is an evil pernicious intrusion into a companies IT estate Winking smile but it is widely deployed and many people like it but also would like to take advantage of Oracle products such as WebCenter Content.  So I was encouraged to see that Fishbowl Solutions have created a connector for Sharepoint that allows it to bring in content from WebCenter, it looks like a valuable way to maintain the Sharepoint interface end users are used to but extend the range of content by pulling stuff (technical term for content) from WebCenter.

 

Load Balancing

The Enterprise Deployment Guides are Oracles bible on building highly available FMW environments, and each of them requires a front end load balancer.  I have been asked to help configure F5 Load Balancers on a number of occasions over my time at Oracle and each time I come back to it I find more useful features have been added to the BigIP line of load balancers that F5 sell, many of their documents are tailored to FMW.  I like F5, they provide (relatively) easy to use products that do what they say on the side of the box.  They may not have all the bells and whistles of some of their more expensive competitors but they do the job and do it well!  Besides which I like their logo!

Other Stuff

I saw lots of other interesting products and services, such as a lightweight monitoring tool for Coherence, Forms migration services, JCAPS migration services and lots of cool freebies to take home to the children!

A Quiet Night

Wednesday night was the partner appreciation event and I had decided to go back to the hotel and have an early night.  I decided to attend the last session of the day – a Maven/Hudson/WebLogic tutorial.  I got the wrong hotel for the session and snuck in 20 minutes late at the back and starting working on the hands on workshop.  One of my co-attendees raised his hand for help and as the presenter came over to help he suddenly stopped and yelled – “Is that Antony”!  It was my old friend Steve Button who used to be based in Redwood Shores but is now a WebLogic guru PM in Australia.  It was good to catch up with him.  As he yelled out a guy with really bad posture turned around to see who he was talking to, this turned out to be my friend Simon Haslan, Oracle ACE from the UK.  After the tutorial Simon and I retired to the coffee shop to catch up and share stories.  2 and half hours later we decided it was time to retire, so much for an early night but great to renew old friendships and find out what real customers are worrying about.

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