|Home > Apache Geronimo v2.0 > Documentation > Administration > Multiple Repositories and Server Instances|
This article describes running multiple server instances from one installation instance of Geronimo, where the server instances share as much of the base Geronimo artifacts and file system space as possible. These are the geronimo directories, all sub-directories of <geronimo_home> by default:
<geronimo_home> is the directory where you installed Geronimo. bin, lib and schema are read-only, and thus may be shared between instances. The disk space taken up by a typical vanilla freshly installed Geronimo instance is equally split between var and repository at almost 50 MB each, with the rest being noise. Most of var is 40 MB of ActiveMQ journal files.This motivates the idea of a second repository, in particular, one for each server instance.
In addition to a simple read/write partition of capabilities, security may well come into play as we access permissions on a set of directories. Each server instance should be able to read or write only its var directory, for instance.
A server instance is easy to create in Geronimo:
First, we consider the case single server instance case, and just add a second repository. Say we want to leave Geronimo in its repository, but add a second repository to deploy our applications. Adding a second repository is pretty easy.
Using the new repository is a little tricky, and is only supported from the command line currently.The essence is to use the --targets option of the deploy command to target your module to deploy in your new repository. First, use the deployer list-targets command to see the repositories. The target names are long and cumbersome:
java deployer.jar list-targets
|The use of environment variables is recommended for command-line use. For example, set REPO2= org.example.configs/myrepo/2.0-SNAPSHOT/car?ServiceModule=org.example.configs/myrepo/2.0-SNAPSHOT/car,j2eeType=ConfigurationStore,name=Local2.|
To deploy to the new repository, use: deploy --targets %REPO2% sample.war
deploy list-modules also gives those long target names on each module. However, deploy list-modules %REPO2% gives the accustomed short output.
The syntax to undeploy from a repo is: java deployer.jar undeploy "%REPO2%|geronimo/jsp-examples/1.1.1/war".
|Note the | character separates the repository name from the module name. The " quotes are used around the entire parameter to escape this special character from command shell interpretation.|
|If no --targets are given on the deploy command, the module is deployed to all repositories. This certainly seems undesirable. If you only want to put the module in one repository, be sure to use the --targets option!|
In the case of multiple server instances, a separate path may be given for the Maven2Repository root attribute for each server. This might be done with config.xml overrides for each server instance. A better solution is to add a resolveToServer attribute to this GBean, so that the root attribute may be set to repository, and it will thus be unique for each server instance with no changes required for each instance. Each server instance would then have a repository located at <geronimo_home>/<instance_name>/repository.
|What's lacking is console support for multiple repositories, and support for hot deployment and plugins.|
|An interesting wrinkle here is in what repository is the new repository deployed? It's clear that the second repository (say repo2.xml above) will be deployed in the first repository. Thus, making this first repository read-only will not work for dynamically adding repositories. Perhaps a second repository is added to contain these server-unique repositories. The second repository must be shared and read-write, so it does not fit nicely in the use case.|