A Basic Service

Problem

In this tutorial we will configure the bare essentials. Everything in the configuration is required. Further tutorials will look at some of the optional parameters.

The configuration below will result in a single container running in an AWS ECS cluster. The container is built from a simple nginx based hello-world image available on http://dockerhub.com, named tutum/hello-world.

Setup

In order to deploy this configuration, you will need an AWS ECS cluster, containing at least one EC2 machine, on which to run the container. You can either create a cluster named hello-world-cluster or change the cluster parameter in the configuration file to correspond to the name of the cluster that you created.

Configuration

Here’s the configuration for this service:

services:
  - name: hello-world-test
    cluster: hello-world-cluster
    count: 1
    family: hello-world
    containers:
      - name: hello-world
        image: tutum/hello-world
        cpu: 128
        memory: 256

AWS ECS is made up of services, tasks, and task definitions. The task definitions define the task or service. A task is a container that runs and exits, while a service is a container that stays running, like a web server, and will be restarted by ECS if it shuts down unexpectedly.

The configuration files you will use with deployfish are YAML based. A typical project or application will have a single deployfish.yml file, containing all of the project’s relevant services. This initial example only defines a single service.

If you want to define additional services, you simply have to add another name to the services array, along with its corresponding parameters:

services:
    - name: name1
      cluster: cluster1
      ...
    - name: name2
      cluster: cluster2
      ...

Required Service Parameters

Each service contains at least the five following required parameters:

name: The name of the ECS service. In this case, it is hello-world-test. This has to be unique.
cluster: The ECS cluster that will run the resultant container.
count: The number of containers to run, which is 1 in this case.
family: The base name of the task definition. Each revision of your image will have its own task definition consisting of the base name and the revision number. We are naming this base name hello-world.
container: This parameter defines the containers to be run.

Required Container Parameters

Each container in the service contains at least the four following required parameters:

name

The name of the container.

image

The Docker image to use. If your image is in AWS ECR, you will use the full format:

<account number>.dkr.ecr.<region>.amazonaws.com/<image>:<version>

Since we’re pulling an image from Dockerhub, we just need to supply the image name:

tutum/hello-world

cpu

The number of cpu units to reserve for the container.

memory

The hard limit of memory (in MB) available to the container.

Deploy

To deploy this service, add your configuration to the deployfish.yml file and in the same directory as your configuration file run:

deploy create hello-world-test

If you have named your configuration file something else, you can run:

deploy -f myconfigfile.yml create hello-world-test

Assuming everything ran successfully, you should be able to see the relevant info with:

deploy info hello-world-test

If you make a change and would like to update the service run:

deploy update hello-world-test