Nextflow ECS Service and ALB

[tthyer]

Primarily:

• Adds ECS Service
• Adds application load balancer

Secondarily:

• Removes nextflow-ecs-capacity stack in favor of ApplicationAutoscaling resources in service stack
• Move security group out of ecs cluster stack to decouple aurora stack from ecs cluster stack
• Adds a Route 53 record set
• Parameterizes values for easier updates and sharing values between stacks

Related JIRA tickets: WORKFLOWS-37 and WORKFLOWS-38

[tthyer]

This list will be built out more later -- this configuration does not appear to be taking hold. Waiting to hear back from support about this.

[tthyer]

Note this is the setting I discovered that we need in ECS last year. Got rate-limited again while testing this infrastructure -- it was crashing, so kept trying to re-pull all the images.

[BrunoGrandePhD]

I did my best reviewing this PR since there are a lot of resources that I haven't used or written CFN templates for. It looks good to me! 🚀

I only had a few questions for my own personal curiosity.

[BrunoGrandePhD]

For my own information, is there an advantage of using GetAtt over Ref in this case? I can see how it's more readable.

[tthyer]

There is an important difference b/tw Ref and GetAtt. Most CFN resources have some default value they return when you use the Ref function. For example, the security group documentation indicates that Ref returns the resource id rather than the group id. Many CFN resources allow one to access additional fields -- this is always through GetAtt. For a security group the additional fields are the GroupId and the VpcId.

See https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/aws-properties-ec2-security-group.html#aws-properties-ec2-security-group-return-values-ref

[BrunoGrandePhD]

Oh, I was under the impression that in this case, the resource ID returned by Ref would be the security group ID.

[tthyer]

I think in the case of security groups resource id == group id but can't recall.

[zaro0508]

phew, that was a wopper!