I am defining a task in AWS which I already have working using aws_ecs_task_definition module. I am setting up some environtment variables using the environtment var in terraform module but some of the will be provided throug AWS SSM. The normal creation without AWS SSM is:

environment : [
        {
          name : "user",
          value : "name"
        },
      ],

This works like a charm.

Then I tried:

environment : [
        {
          name : "user",
          valueFrom : "my_env_var_name_in_ssm"
        },
      ],

But it doesn't work. When I go to the UI of the task definition the ENV variable is not there, neither in the UI's json definition.

Then I tried to create them in the UI and the task work perfect and I saw that when you setup valueFrom, the ENV variable is created under the secrets section of the json definition. So I tried to replicate it in Terraform such as:

secrets : [
        {
          name : "user",
          valueFrom : "my_env_var_name_in_ssm"
        },
      ],

But it doesn't work neither. The task definition json is:

{
  "ipcMode": null,
  "executionRoleArn": "arn",
  "containerDefinitions": [
    {
      "dnsSearchDomains": null,
      "environmentFiles": null,
      "logConfiguration": null,
      "entryPoint": null,
      "portMappings": [
        {
          "hostPort": 8080,
          "protocol": "tcp",
          "containerPort": 8080
        },
        {
          "hostPort": 8793,
          "protocol": "tcp",
          "containerPort": 8793
        }
      ],
      "command": null,
      "linuxParameters": null,
      "cpu": 7,
      "environment": [
        {
          "name": "name",
          "value": "harcoded"
        },
      ],
      "resourceRequirements": null,
      "ulimits": null,
      "dnsServers": null,
      "mountPoints": [],
      "workingDirectory": null,
      "secrets": null,
      "dockerSecurityOptions": null,
      "memory": null,
      "memoryReservation": 128,
      "volumesFrom": [],
      "stopTimeout": null,
      "image": "image_arn",
      "startTimeout": null,
      "firelensConfiguration": null,
      "dependsOn": null,
      "disableNetworking": null,
      "interactive": null,
      "healthCheck": null,
      "essential": true,
      "links": null,
      "hostname": null,
      "extraHosts": null,
      "pseudoTerminal": null,
      "user": null,
      "readonlyRootFilesystem": null,
      "dockerLabels": null,
      "systemControls": null,
      "privileged": null,
      "name": "my-name"
    }
  ],
  "placementConstraints": [],
  "memory": null,
  "taskRoleArn": "arn",
  "compatibilities": [
    "EC2"
  ],
  "taskDefinitionArn": "arn",
  "family": "family-name",
  "requiresAttributes": [
    {
      "targetId": null,
      "targetType": null,
      "value": null,
      "name": "com.amazonaws.ecs.capability.ecr-auth"
    },
    {
      "targetId": null,
      "targetType": null,
      "value": null,
      "name": "com.amazonaws.ecs.capability.docker-remote-api.1.21"
    },
    {
      "targetId": null,
      "targetType": null,
      "value": null,
      "name": "com.amazonaws.ecs.capability.task-iam-role"
    },
    {
      "targetId": null,
      "targetType": null,
      "value": null,
      "name": "ecs.capability.execution-role-ecr-pull"
    },
    {
      "targetId": null,
      "targetType": null,
      "value": null,
      "name": "com.amazonaws.ecs.capability.docker-remote-api.1.18"
    },
    {
      "targetId": null,
      "targetType": null,
      "value": null,
      "name": "ecs.capability.task-eni"
    }
  ],
  "pidMode": null,
  "requiresCompatibilities": [],
  "networkMode": "awsvpc",
  "cpu": null,
  "revision": 2,
  "status": "ACTIVE",
  "inferenceAccelerators": null,
  "proxyConfiguration": null,
  "volumes": []
}

As you can see the json returns: "secrets": null, When the terraform run a container_definitions like this:

container_definitions = jsonencode(
  [
    {
      name = aws_ecs_cluster.cluster.name,
      image = "${var.image_url}:latest",
      cpu = 7,
      dnsSearchDomains = null,
      network_configuration = "awsvpc",
      entryPoint = null,
      portMappings = [
        {
          hostPort = 8080,
          protocol = "tcp",
          containerPort = 8080
        },
        {
          hostPort = 8793,
          protocol = "tcp",
          containerPort = 8793
        }
      ],
      command : null,
      linuxParameters : null,
      environment : [
        {
          name : "name",
          value : "harcoded"
        },
      ],
      secrets : [
        {
          name : "parameter-name",
          valueFrom : "arn:aws:ssm:eu-west-2:111111111:parameter/my_env_var_name_in_ssm"
        },
      ],
      resourceRequirements : null,
      ulimits : null,
      dnsServers : null,
      mountPoints : null,
      workingDirectory : null,
      secrets : null,
      dockerSecurityOptions : null,
      memoryReservation : 128,
      volumesFrom : [],
      stopTimeout : null,
      startTimeout : null,
      firelensConfiguration : null,
      dependsOn : null,
      disableNetworking : null,
      interactive : null,
      healthCheck: null
      essential : true,
      links : null,
      hostname : null,
      extraHosts : null,
      pseudoTerminal : null,
      user : null,
      readonlyRootFilesystem : null,
      dockerLabels : null,
      systemControls : null,
      privileged : null
    }
  ]
  )
}

terraform apply worked fine but the secrets are not in the output of the terraform performed actions, so it's normal that the json definition shows null. Then I guess the real issue is how to writte it in terraform.

How can I use AWS SSM as a valueFrom in AWS ECS task defined in Terraform? As you can see the json is

CodePudding user response：

Your task definition has secrets defined twice. Once with a value, and once with null:

See the first and last lines in this block I copied from the code you posted:

  secrets : [
    {
      name : "parameter-name",
      valueFrom : "arn:aws:ssm:eu-west-2:111111111:parameter/my_env_var_name_in_ssm"
    },
  ],
  resourceRequirements : null,
  ulimits : null,
  dnsServers : null,
  mountPoints : null,
  workingDirectory : null,
  secrets : null,

You need to remove the line secrets : null because it is overriding the earlier setting.