BASE Administrator documentation Adding job agents

BASE 2.0 - Administrator documentation: Adding job agents

1. What is a job agent?

A job agent is a program running on another computer that is regularly checking the BASE job queue for jobs that are awaiting execution. When the job agent finds a job that it is able to execute it loads the plugin and executes it.

A job agent supports lots of configuration options that are not supported by the internal job queue. For example, you can:

• Specify exactly which plugins each job agent should be able to execute.
• Give some plugins higher priority than others.
• Specify which users/groups/projects that should be able to use the job agent.
• Override memory settings, etc. for each plugin.
• Execute plugins in separate processes. Thus, a misbehaving plugin doesn't bring the web server down with it.
• Add more computers with more job agents if the need arises.

All these options make it possible to create a very flexible setup. For example one job agent can be assigned for importing data only. Another job agent can be assigned for running analysis plugins for specific project only. A third may be a catch-all job agent that does all low-priority jobs.

2. How to install a job agent

It is not very difficult to install a job agent, but it requires some manual configuration. Therefore, no job agent is installed by default. Here is how to do it:

2.1 Things to do on the web server

1. Disable the internal job queue on the web server

We don't recommend using the internal job queue at the same time as job agents. The setting jobqueue.internal.enabled should be changed to false for the web server. This setting is found in the www/WEB-INF/classes/base.config file. After you have changed the setting the web server must be restarted.

2. Enable the job agent user account

The default installation creates a user account that the job agent uses to log in to BASE. This user account is disabled by default. You must enable the account and give it a password. This password goes into the jobagent.properties file in step 2.3.3 below.

2.2 Things to do on the database server

1. Create a user account on the database

This is the same step as step iv) in the regular BASE installation. You must create an account in the database that is allowed to connect from the job agent server. MySQL example:

GRANT ALL ON base2.* TO base2user@job.agent.host IDENTIFIED BY 'password';
GRANT ALL ON base2dynamic.* TO base2user@job.agent.host;

Replace job.agent.host with the host name of the server that is going to run the job agent. You should also change the password. This password goes into the base.config file in step 2.3.2 below.

2.3 Things to do on the job agent server

1. Download and unpack the regular BASE 2 distribution

You must use the same version on the web server and all job agents. You find the downloads here: http://base.thep.lu.se/wiki/DownloadPage

2. Edit the base.config file

The www/WEB-INF/classes/base.config file must be configured to use the same database as the web server application. The most important settings are:

• db.username: The database user you added in step 2.2.1
• db.password: The password for the user
• db.url: The connection url to the database
• userfile: The path to the directory where user files are located. This directory must be accessible from all job agents.

See the base.config reference for more information about the settings in this file.

3. Edit the jobagent.properties file

The www/WEB-INF/classes/jobagent.properties file contains settings for the job agent. The most important ones to specify value for are:

• agent.password: The password you gave to the job agent user account in step 2.1.2 above.
• agent.id: An ID that must be unique for each job agent
• agent.remotecontrol: The name/ip address of the web server if you want it to be able to display info about running jobs. The job agent will only allow connections from computers specified in this setting.

The jobagent.properties file contains many more configuration options. See the jobagent.properties reference for more information.

4. Register the job agent

From the bin directory, register the job agent with

./jobagent.sh register

5. Start the job agent

From the bin directory, start the job agent with

./jobagent.sh start &

See the jobagent.sh reference for more information about what you can do with the command line interface.

3. Configuring the job agent

Before the job agent starts executing jobs for you it must be configured. The configuration is done through the web interface.

1. Configure the plugins the job agent should handle

• Go to the Administrate -> Plugins -> Job agents menu.
• Select the job agent and click on the Edit button.
• On the Plugins tab you can specify which plugins the job agent should handle. Note that if you have installed external plugins on the web server, those plugins must be installed on the job agent as well. It is possible to specify different paths to the JAR file for each job agent.

2. Give users access to the job agent

Use the regular Share functionality to specify which users/groups/projects should be able to use the job agent. You must give them at least USE permission.