How to avoid consuming a file from shared directory from multiple fuse server nodes configured in cluster using fabric master ?

Solution Unverified - Updated -

Environment

  • Red Hat JBoss Fuse
    • 6.1.0

Issue

  • 2 Fuse servers set on Active run into race condition
  • 2 Fuse servers set to pick inbound files from a shared location. When the file come in, they are zipped and only one node is supposed to unzip and process the file
  • A way to ensure that only a single consumer in a cluster consumes from a given endpoint using Master component from the camel route in fabric
  • File reading in a clustered environment

Resolution

  • The Master component provides a way to ensure that only a single consumer in a cluster consumes from a given endpoint.
  • The Master component can only be used in the context of a fabric-enabled Red Hat JBoss Fuse container. You must ensure that the fabric-camel feature is installed.
  • Steps to create a cluster
    • If you do not already have a fabric, enter the following console command to create one
  JBossFuse:karaf@root> fabric:create  --wait-for-provisioning
  • You just created the fabric on a clean installation of JBoss Fuse . In this case, the root container ought to include the jboss-fuse-full profile by default. You can check whether this is the case by entering the fabric:container-list console command, as follows:
JBossFuse:karaf@root> fabric:container-list 
[id]    [version] [connected] [profiles]                                         [provision status]
root*   1.0       true        fabric, fabric-ensemble-0000-1, jboss-fuse-full    success
  • Create the master-example profile, which will be used to deploy a simple Apache Camel route that uses the Master component. Enter the following console command to create the profile:
JBossFuse:karaf@root> fabric:profile-create --parents default master-example
  • Add the requisite Karaf features to the master-example profile. Enter the following console commands: 
fabric:profile-edit --features fabric-camel master-example
  • Define the simple Camel route as a resource in the master-example profile. Invoke the built-in text editor to create a new camelFile.xml resource, as follows:
fabric:profile-edit --resource camelFile.xml master-example
  • Copy and paste the following content into the built-in text editor: 
 <?xml version="1.0" encoding="UTF-8"?>
 <blueprint xmlns="http://www.osgi.org/xmlns/blueprint/v1.0.0"
           xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">

    <reference id="curator" interface="org.apache.curator.framework.CuratorFramework"/>

    <camelContext id="camel" xmlns="http://camel.apache.org/schema/blueprint">
         <route>
      <from uri="master:lockhandle:file:/home/kkakarla/Development/sample?delay=900"/>
       <to uri="file:/home/kkakarla/Development"/>
       <log message="Completed"/>
    </route>

    </camelContext>

 </blueprint>
  • To save and exit from the text editor, type Ctrl-S, Ctrl-X.
  • Configure the master-example profile to deploy the camelFile.xml resource as an OSGi bundle. Enter the following console command to create a new entry in the master-example agent properties:
fabric:profile-edit --bundles blueprint:profile:camelFile.xml master-example
  • Create two new child containers, so that you can deploy the master-example profile as a cluster (one master and one slave). Enter the following console command:
fabric:container-create-child root child1
fabric:container-create-child root child2
  • Now deploy both the master-example profile to each of the child containers, as follows: 
fabric:container-change-profile child1 master-example 
fabric:container-change-profile child2 master-example

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