Docker Compose Demo Application
The demp application primary has three microservices
- Flask App
- Redis backend
- Celery based queue mechanism
Flask API & Celery service both talks to Redis backend and all of these three have to be deployed in separate containers.
Create an AWS Docker context and list available contexts
To initialize the Docker ECS integration, you will need to run the setup
command. This will create a Docker context that works with AWS ECS.
➜ example git:(master) ✗ docker ecs setup
Enter context name: aws
> new profile
Enter profile name: sandbox
Enter region: ap-southeast-1
Enter credentials: y
Enter AWS Access Key ID: *************************
Enter AWS Secret Access Key: ***************************
You can verify that the context was created by listing your Docker contexts:
$ docker context ls
Test locally
The first step is to test your application works locally. To do this, you will need to switch to using the default local context so that you are targeting your local machine.
docker context use default
You can then run the application using docker-compose
:
docker-compose up
Once the application has started, you can navigate to http://localhost:5000 using your Web browser using the following command:
open http://localhost:5000
Try out all the APIs are working file. Primarily there are two things to check -
- localhost:5000 will be serving an HTML template, which will eventually to talk flask server and that talks to Redis bacekend
- Second thing to test is /download API, in which Flask App talks to celery service and sends a background task to take place
Push images to Docker Hub for ECS (ECS cannot see your local image cache)
In order to run your application in the cloud, you will need your container images to be in a registry. You can push them from your local machine using:
docker-compose push
You can verify that this command pushed to the Docker Hub by
logging in and looking for the timestamper
repository under your user name.
Switch to ECS context and launch the app
Now that you've tested the application works locally and that you've pushed the
container images to the Docker Hub, you can switch to using the aws
context
you created earlier.
docker context use aws
Running the application on ECS is then as simple as doing a compose up
:
docker ecs compose up
Check out the CLI
Once the application is running in ECS, you can list the running containers with
the ps
command. Note that you will need to run this from the directory where
you Compose file is.
docker ecs compose ps
You can also read the application logs using compose logs
:
docker ecs compose logs
Check out the AWS console
You can see all the AWS components created for your running application in the AWS console. There you will find:
- CloudFormation being used to manage all the infrastructure
- CloudWatch for logs
- Security Groups for network policies
- Load balancers (ELB for this example / ALB if your app only uses 80/443)
Checkout CloudFormation
The ECS Docker CLI integration has the ability to output the CloudFormation
template used to create the application in the compose convert
command. You
can see this by running:
docker ecs compose convert
Stop the meters
To shut down your application, you simply need to run:
docker ecs compose down
Steps for Deploying Containers on ACI (Azure Container Instances)
The first thing we have to do is login to azure using below command, it will open up Azure Portal page for you to login and enter creds, once you do that, the login will be successful on CLI.
docker login azure
Post that, the same way we created context in the case AWS ECS, we'll now create context for Azure ACI.
docker context create aci azure
Now, let's switch to Azure Context using below command -
docker context use azure
Once it is done, we can check the context using following command -
docker context ls
It should be giving similar output -
After that it the same as we saw in AWS ECS deployment -
docker compose up
docker ps
Above commands can be used to deploy the containers and check the current status of containers deployed.
To clean it up we can use
docker compose down
Disclaimer
Some part of this demo application is taken from a demo which happened in AWS Cloud Containers Conference on 2020-07-09. Rest part of the code is added to introduce more complexity in sample code. All credits of code are with this original repo - https://github.com/docker/ecs-plugin/tree/master/example :)