User Grid Descriptor

This is an XML file which allows users to describe their grid as a collection of clusters.

<grid>
        <!-- Cluster Descriptor Template -->
        <cluster name="Sample" host="Cluster_1_User_Identifier" installRootPath="" databaseRootPath="" queueSize="25" maxHijackSecs="3600" maxIdleSecs="300" />
        
        <!-- Local Machine as Cluster Sample -->
        <cluster name="LOCAL" host="localhost" queueSize="3" maxHijackSecs="-1" maxIdleSecs="300"/>
        
        <!-- BIRN Cluster Sample -->
        <cluster name="BIRN" host="birn-cluster0.nbirn.net" installRootPath="/home/[USER]" queueSize="25" maxHijackSecs="7200" maxIdleSecs="300"/>
</grid>

The grid parent element contains 0 to many cluster elements, each of which represent a particular cluster head node information; which is composed of the following fields:

By default GWE client applications will try to connect to the first cluster defined in this grid element to act as a grid controller to coordinate efforts. If you decide not to use the default cluster descriptor, you can do so by selecting it by its friendly user name in the way detailed in the 'Overriding The Default Criteria To Locate Configuration Items' section below.

NOTE: Right now an order will be executed in the cluster where it was submitted; which means that load balancing across the clusters of the grid defined, will not be available, as the the functionality to dynamically split and prioritize the parallelization of these processes across clusters, has not been finalized yet.

<grid>
        <cluster name="LOCALHOST" installationRootPath="/home/[USER]" host="localhost" queueSize="2" maxWaitMins="0.5" maxHijackMins="120" maxIdleMins="5" >
                <p2elVar name="SLICER_HOME" value="[SLICER_LOCATION_ON_LOCAL_MACHINE]" />
        </cluster>
        
        <cluster name="BIRN" host="birn-cluster0.nbirn.net" installationRootPath="/home/[USER]" databaseRootPath="/tmp/[PATH]" queueSize="50" maxHijackMins="120" maxIdleMins="5" >
                <p2elVar name="SLICER_HOME" value="[SLICER_LOCATION_ON_BIRN_CLUSTER]" />
        </cluster>
</grid>

User Key Store

This is an XML file which allows users to state the authentication information they use to access network enabled resources. This is necessary for GWE to access those resource on behalf of the user as part of executing their processes in the grid.

<keystore>
        <accessControl>
                <account user="[ACCOUNT_USER_NAME]" passphrase="?" privateKeyFileName="[PRIVATE_KEY_FULL_PATH]"/>
                <realms>
                        <!-- General domain realm template -->
                        <realm schemes="ssh;sftp" domain="*.[SUB_DOMAIN]" testHost="[HOST].[SUB_DOMAIN]"/>
                        
                        <!-- Domain realm template for BIRN cluster resources -->
                        <realm schemes="ssh;sftp" domain="*.nbirn.net" testHost="birn-cluster0.nbirn.net"/>
                        
                        <!-- Domain realm template for "www.whatever.com" machine -->
                        <realm schemes="ssh;sftp" domain="www.whatever.org" testHost="www.whatever.org"/>
                </realms>
        </accessControl>
</keystore>

The keystore parent element contains 0 to many accessControl elements, each of which represent the authentication information to access a particular network device group. It revolves around the concept of the user having authentication information (account ) at its disposal to access these network device groups (realms ). The following are the forms that can take the account element to provide the authentication information:

<!-- Account authenticated using private keys and stated passphrase -->
<account user="[ACCOUNT_USER_NAME]" passphrase="[PASSPHRASE]" privateKeyFileName="[PRIVATE_KEY_FULL_PATH]"/>

<!-- Account authenticated using private keys and passphrase to be securely read at runtime -->
<account user="[ACCOUNT_USER_NAME]" passphrase="?" privateKeyFileName="[PRIVATE_KEY_FULL_PATH]"/>

<!-- Account authenticated using private keys (and overriding default public key file name "[PRIVATE_KEY_FULL_PATH].pub") and passphrase to be securely read at runtime -->
<account user="[ACCOUNT_USER_NAME]" passphrase="?" privateKeyFileName="[PRIVATE_KEY_FULL_PATH]" publicKeyFileName="[PUBLIC_KEY_FULL_PATH]"/>

<!-- Account authenticated using stated password -->
<account user="[ACCOUNT_USER_NAME]" password="[PASSWORD]"/>

<!-- Account authenticated using password to be securely read at runtime -->
<account user="[ACCOUNT_USER_NAME]" password="?"/>

The realm section will be used to provide the network context to which the associated account has access, in terms of protocols and network domains. It also allows the user to provide the FULL host name of an actual host against which the particular credential can be tested. Finally, a security feature is available to the user to avoid explicitly stating his/her passwords/passphrases. The user can do this by assigning to these fields the wildcard value of "?". This will indicate the GWE clients to securely read these fields at runtime and stored them in disk encrypted for future usage.

WARNING: It is mandatory that the 'homeDir' directory has enough disk space and quotas to have a GWE daemon installed there (if your 'grid descriptor' file implicitly declared it needs a daemon there of course). A GWE daemon installation requires a minimum of about 500MB of disk space to operate (base installation, database, logs, etc.). Additionally, its virtual file system will require enough space to download and manipulate files corresponding to the amount of parallel jobs it may be able to run (size of the daemon's queue configured in the 'grid descriptor' ). Failure to appropriately allocate disk space will most likely result in catastrophic failure since, the operating system may very well deny access to the GWE daemon database, which would corrupt the whole installation.

User Macro Library

This is a text file which contents will be interpreted by GWE as the library of P2EL macros to load into its P2EL interpreter. This library is simply a list of macro definitions separated by new lines. The following is a sample of a macro library file consisting of 2 macros: xcat and slicer .

$xcat($${CONTENTS}) {
        $${ENTRIES}=$xpath($${CONTENTS},//entry)
        $${URI}=$xpath($${ENTRIES},/entry/@URI)
        $${CACHEPATH}=$xpath($${ENTRIES},/entry/@cachePath)
        $${NAME}=$xpath($${ENTRIES},/entry/@name)
        $${ID}=$xpath($${ENTRIES},/entry/@ID)
        $${DESCRIPTION}=$xpath($${ENTRIES},/entry/@description)
        $${CONTENT}=$xpath($${ENTRIES},/entry/@content)
        $${FORMAT}=$xpath($${ENTRIES},/entry/@format)
}

$slicer($${HOME},$${MODULE}) {
        $${CMD}=$const($${HOME}/Slicer3 --launch $${HOME}/lib/Slicer3/Plugins/$${MODULE})
}

// TITLE: Slicer Module Base Command
// DESCRIPTION: Creates the base command to launch a Slicer3 module given its 
// installation directory and the module name.
// HOME: Path to the Slicer installation
// MODULE: Name of the Slicer module to launch
// CMD: Base command to launch the Slicer3 module specified

// TITLE: Slicer Module Base Command
// DESCRIPTION: Creates the base command to launch a Slicer3 module given its 
// installation directory and the module name.
// HOME: Path to the Slicer installation
// MODULE: Name of the Slicer module to launch
// CMD: Base command to launch the Slicer3 module specified

$slicer($${HOME},$${MODULE}) {
        $${CMD}=$const($${HOME}/Slicer3 --launch $${HOME}/lib/Slicer3/Plugins/$${MODULE})
}