Fluo 1.2.0 documentation  >>  Administration  >>  Initialize Application

Initialize Application

Overview

Before a Fluo Application can run, it must be initialized. Below is an overview of what initialization does and some of the properties that may be set for initialization.

  • Initialize ZooKeeper - Each application has its own area in ZooKeeper used for configuration, Oracle state, and worker coordination. All properties, except fluo.connections.*, are copied into ZooKeeper. For example, if fluo.worker.num.threads=128 was set, then when a worker process starts it will read this from ZooKeeper.
  • Copy Observer jars to DFS - Fluo workers processes need the jars containing observers. These are provided in one of the following ways.
    • Set the property fluo.observer.init.dir to a local directory containing observer jars. The jars in this directory are copied to DFS under <fluo.dfs.root>/<app name>. When a worker is started, the jars are pulled from DFS and added to its classpath.
    • Set the property fluo.observer.jars.url to a directory in DFS containing observer jars. No copying is done. When a worker is started, the jars are pulled from this location and added to its classpath.
    • Do not set any of the properties above and have the mechanism that starts the worker process add the needed jars to the classpath.
  • Create Accumulo table - Each Fluo application creates and configures an Accumulo table. The fluo.accumulo.* properties determine which Accumulo instance is used. For performance reasons, Fluo runs its own code in Accumulo tablet servers. Fluo attempts to copy Fluo jars into DFS and configure Accumulo to use them. Fluo first checks the property fluo.accumulo.jars and if set, copies the jars listed there. If that property is not set, then Fluo looks on the classpath to find jars. Jars are copied to a location under <fluo.dfs.root>/<app name>.

Instructions

Below are the steps to initialize an application from the command line. It is also possible to initialize an application using Fluo’s Java API.

  1. Create a copy of fluo-app.properties for your Fluo application.

     cp $FLUO_HOME/conf/fluo-app.properties /path/to/myapp/fluo-app.properties
    
  2. Edit your copy of fluo-app.properties and make sure to set the following:

    • Class name of your ObserverProvider
    • Paths to your Fluo observer jars
    • Accumulo configuration
    • DFS configuration

    When configuring the observer section of fluo-app.properties, you can configure your instance for the phrasecount application if you have not created your own application. See the phrasecount example for instructions. You can also choose not to configure any observers but your workers will be idle when started.

  3. Run the command below to initialize your Fluo application. Change myapp to your application name:

     fluo init myapp /path/to/myapp/fluo-app.properties
    

    A Fluo application only needs to be initialized once. After initialization, the Fluo application name is used to start/stop the application and scan the Fluo table.

  4. Run fluo list which connects to Fluo and lists applications to verify initialization.

  5. Run fluo config myapp to see what configuration is stored in ZooKeeper.

Next Steps

Run your Fluo application using one of the methods below:

Also, learn how to manage Fluo applications.

Find documentation for all Fluo releases in the archive