Btrplace Specification Language

The btrplace specification language (btrpsl) allows to express constraints related to the placement of virtual machines in a datacenters.

This language is dedicated to datacenters administrators and applications administrators that use Btrplace to manage their nodes and virtual machines.

Integration

The maven artifacts are in private repositories so you have first to edit your pom.xml to declare them:

<repositories>
    <repository>
        <id>btrp-releases</id>
        <url>http://btrp.inria.fr/repos/releases</url>
    </repository>
    <repository>
        <id>btrp-snapshots</id>
        <url>http://btrp.inria.fr/repos/snapshot-releases</url>
    </repository>
</repositories>

Next, just declare the dependency:

<dependency>
   <groupId>btrplace</groupId>
   <artifactId>btrpsl</artifactId>
   <version>1.5</version>
</dependency>

Building from sources

Requirements:

JDK 7+
maven 3+

The source of the released versions are directly available in the Tag section. You can also download them using github features. Once downloaded, move to the source directory then execute the following command to make the jar:

$ mvn clean install

If the build succeeded, the resulting jar will be automatically installed in your local maven repository and available in the target sub-folder.

Basic examples

Describing a datacenter

The following script specifies a datacenter composed of 251 nodes. Nodes are stacked by 40 into racks. 250 of the nodes are working nodes, dedicated to the hosting of client. They are labelled from node-1 to node-250. The last node is a service node and run some service VMs. This node is labelled node-frontend. The whole datacenter can not run more than 2000 VMs simultaneously while each node can not host more than 15 VMs at the same time.

namespace datacenter;

@node-[1..250,frontend] : xen<boot=60>;

$nodes = @node-[1..250,frontend];
cumulatedRunningCapacity($nodes, 2000);

for $n in $nodes {
    singleRunningCapacity($n, 15);
}

$R[1..7] = $nodes % 40;

export $nodes,$R[1..7] to *;

Describing a virtualized application

Following script is a specification from a application administrator that describes a 3-tiers Web applications. Each replica of a same tier should be placed on a distinct nodes for fault tolerance to hardware failures, while the last tier must be running into a single rack to have a low latency. Last, the application administrator does not want its VMs to be collocated with other VMs for security purpose.

namespace myApp;

import datacenter;

VM[1..10] : tinyInstance<clone,boot=7,halt=10>;
VM[11..20] : microInstance;
VM[21..24] : largeMemoryInstance;

$T1 = VM[1..10];
$T2 = VM[11..20];
$T3 = VM[21..24];

lonely(VM[1..24]);
for $t in $T[1..3] {
   spread($t);
}

among($T3, $datacenter.R[1..7]);

Documentation

releases: http://btrp.inria.fr/btrpsl/ (apidocs always refers to the last release)
snapshot-releases: http://btrp.inria.fr/btrpsl/apidocs-snapshot

Read a script

The following example parse a script, decorate a model and solve a problem with regards to the stated constraints.

//Set the environment
Model mo = new DefaultModel();

//Make the builder and add the sources location to the include path
ScriptBuilder scrBuilder = new ScriptBuilder(mo);

//Build the script
Script myScript = scrBuilder.build(...);

ReconfigurationAlgorithm ra = ...
ra.solve(mo, myApp.getConstraints());

fhermeni/btrplace-btrpsl