diaats

#diaats

Docker-image-as-a-tsuru-service is a tool for generating a tsuru service API based on Docker images.

Each registered Docker image is a plan, and they're defined in the IMAGE_PLANS environment variable. The value of this variable must be a valid JSON. For example:

IMAGE_PLANS='[{"image":"elasticsearch","plan":"elasticsearch","args":["elasticsearch","-Des.node.name=\"TestNode\""},{"image":"memcached","plan":"memcached"},{"image":"registry.mycompany.com/team/memcached:1.4,"plan":"custom_memcached_64mb","args":["-m", "64"]}]'

Other relevant environment variables include:

• DOCKER_HOST: the address of the host. It might be a Swarm cluster. This setting is mandatory.
• DOCKER_CONFIG: a JSON representing a HostConfig instance. This environment variable is optional.
• API_USERNAME and API_PASSWORD: in case the user wants to enable basic authentication in the API, these environment variables must be defined. They might be omitted, which means no authentication.
• MONGODB_URL: the MongoDB connection string. The API will use MongoDB to store metadata about the instances in the service. This setting is mandatory.

What the API does:

• on service-add, it creates a container on the configured Docker host
• on service-bind, it returns a list of endpoints in the format [host_ip]:[host_port], for each port exported by the Docker image
• on service-unbind, it doesn't do anything
• on service-remove, it removes the container from the configured Docker host

##Deployment example

Users could deploy this API as a "memcached" service, offering multiple versions of memcached, as available in the Docker Hub. Each version will be a plan, and each container will have 256 MB of RAM memory. The configuration for doing so would be:

IMAGE_PLANS='[{"image":"memcached:1","plan":"memcached_1"},{"image":"memcached:1.3","plan":"memcached_1_4"},{"image":"memcached:1.4.21","plan":"memcached_1_4_21"},{"image":"memcached:1.4.22","plan":"memcached_1_4_22"},{"image":"memcached:1.4.23","plan":"memcached_1_4_23"},{"image":"memcached:1.4.24","plan":"memcached_1_4_24"}]'
DOCKER_HOST='tcp://10.10.10.10:2376'
DOCKER_CONFIG='{"Memory":268435456}'