CODEWITHSUNDEEP
amazon-web-servicesaws-fargate
Tim van Beek
Tim van Beek

Reputation: 195

How to provide a config file to a Fargate Task?

What is the easiest way to provide one or several external configuration file(s) to an app running as an AWS Fargate task?

*It is an important aspect of our applications to not depend on the AWS SDK, because we need to be able to deploy to different cloud platforms, so solutions that avoid this are preferable.

It would be nice to just be able to define this in the task definition, so that Fargate mounts a couple of files in the container. Is this or a similar low-key solution available?

Upvotes: 12

Views: 6874

Answers (4)

Andrey
Andrey

Reputation: 21285

I had exactly the same problem - on container start in Fargate I needed to pull configuration from AWS SSM Parameter Store, and secrets from AWS Secrets Manager.

I went with a simple soution, and created an entrypoint script component-entry.sh that pulls those configs/secrets into the container using aws cli, and then starts the actual service. On docker build, I copy that file from host, and I add that script to the image entry point ENTRYPOINT [ "/home/docker/component-entry.sh" ]

Upvotes: 0

kking-biometrica
kking-biometrica

Reputation: 131

You can specify your AWS AppConfig dependency as a separate container. AWS gives you the option to set container dependency execution conditions in your Task Definition. See: https://docs.aws.amazon.com/AmazonECS/latest/APIReference/API_ContainerDependency.html

You could set your container dependency status to COMPLETE for the container that pulls the config files from AppConfig and then just treat the files as a dumb mount, separating the AWS dependency completely. For Example:

    "containerDefinitions": [
    {
        "name": "app-config-script",
        "image": "1234567890.dkr.ecr.SOME_REGION.amazonaws.com/app-config-script:ver",
        "essential": false,
        "mountPoints": [
            {
                "sourceVolume": "config",
                "containerPath": "/data/config/nginx",
                "readOnly": ""
            }
        ],
        "dependsOn": null,
        "repositoryCredentials": {
            "credentialsParameter": ""
        }
    },
    {
        "name": "nginx",
        "image": "nginx",
        "essential": true,
        "portMappings": [
            {
                "containerPort": "80",
                "protocol": "tcp"
            },
            {
                "containerPort": "443",
                "protocol": "tcp"
            }
        ],
        "mountPoints": [
            {
                "sourceVolume": "config",
                "containerPath": "/etc/nginx",
                "readOnly": true
            }
        ],
        "dependsOn": [
            {
                "containerName": "app-config-script",
                "condition": "COMPLETE"
            }
        ],
        "repositoryCredentials": {
            "credentialsParameter": ""
        }
    }
],

Your Entrypoint/CMD script in the bootstrap container would then be something like:

#!/bin/sh
token=$(aws appconfigdata start-configuration-session --application-identifier "${APPLICATION_ID}" --environment-identifier "${ENVIRONMENT_ID}" --configuration-profile-identifier "${CONFIGURATION_ID}" | jq -r .InitialConfigurationToken)
aws appconfigdata get-latest-configuration --configuration-token "${token}" /data/config/nginx/nginx.conf

Upvotes: 2

Kayes
Kayes

Reputation: 592

Not an answer to the question but in case someone comes here looking for solutions, we had the same requirements but did not find an easy solution to deploy configuration file directly in ECS instance for the container to read. I'm sure it's possible, just would make is difficult to configure, therefore we did not see the effort worthy.

What we did:

  1. Added EnvironmentConfigBuilder as discribed in MS docs here
  2. Passed in configuration values using environment variables as described in AWS docs here.

Upvotes: 0

Dennis Traub
Dennis Traub

Reputation: 51634

There's a specific feature of AWS Systems Manager for that purpose, called AWS AppConfig. It helps you deploy application configuration just like code deployments, but without the need to re-deploy the code if a configuration value changes.

The following article illustrates the integration between containers and AWS AppConfig: Application configuration deployment to container workloads using AWS AppConfig.

Upvotes: 4

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