How-to: Control containers
Overview
This example illustrates how the Docker plugin can be used to test the runtime state of a Docker container.
Extension of another example
This example modifies the container configuration example How-to: Configure Docker containers (Exposed ports).
Please consult that example for details about Pineapple configuration, modules and models describes how Pineapple can be used to install Docker on a Vagrant box for the purpose of the example.
Define the module model
The model file for definition of the image and the container:
<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<mmd:models xmlns:mmd="http://pineapple.dev.java.net/ns/module_model_1_0"
xmlns:dkp="http://pineapple.dev.java.net/ns/plugin/docker_1_0" continue="false" >
<mmd:model target-resource="docker-node" target-operation="deploy-configuration" description="Define Docker image: busybox:latest" >
<mmd:content>
<dkp:docker>
<dkp:image repository="busybox" tag="latest" />
<dkp:container name="alpha01" state="running" >
<dkp:image repository="docker.io/busybox" tag="latest" />
</dkp:container>
</dkp:docker>
</mmd:content>
</mmd:model>
</mmd:models>
The configuration details
Definition of the runtime state in the model
The container element contains an optional state attribute. The attribute defines which state the container should be put in when the model is invoked with a deploy-configuration operation, i.e. when the container is created. The attribute is used in this example to start the container by putting it into the running state.
Testing the the runtime state
When the model is invoked with the deploy-configuration operation then the container is created.
When the model is invoked with the test operation then the actual container runtime state is validated with the expected runtime state in the model.
If the states match the validation succeeds. If the container doesn't exist the validation fails.