How to set placement constraints for ECS in Shippable

[tkumark]

ECS offers 2 places where placement constraints are available on is the task definition level and service definition

Task Definition level

Service Definition level

In the documention Docker Option I only saw schedulinStrategy under service but nothing under nothing under taskDefinition.

    placementStrategy:
     - field: <string>
       type: <string>
     - field: <string>
       type: <string>
    schedulingStrategy: <string>

Should I put my placement constraints under schedulingStragtegy? Is there something for taskdefintion

[a-murphy]

The taskDefinition section will accept a placementStrategy, with the same fields and types as the service, but not schedulingStrategy. I think you might be looking for placementConstraints in taskDefinition, which is an array of objects with type (memberOf or distinctInstance) and expression.

[tkumark]

@a-murphy if were to set placementConstraints at the service level would it be like this?

service:
        placementStrategy:
         - field: attribute:appname == myapp
           type: memberof

[a-murphy]

service:
  placementConstraints:
    - field: "attribute:appname == myapp"
      type: memberOf

should be valid assuming you have an appname attribute on the instances. It is still placementConstraints whether it is in the task definition or service with those settings. The placementStrategy can only be binpack, random, or spread.

[tkumark]

@a-murphy thanks you right the appname attribute is set in the instances. I am adding at userdata echo ECS_INSTANCE_ATTRIBUTES={\"appname\":\"myapp\"} >> /etc/ecs/ecs.config;echo

[tkumark]

Set placement constrainst for custome attribute.

  - name: myresourceName
    type: dockerOptions
    version:
      service:
        placementConstraints:
          - expression: "attribute:appname == myapp"
            type: memberOf