And thanks again! I went through all the steps and it's working fine!

BTW, @Yuri Marx , the part for creating registry, building and pushing docker image into it could be omitted by using Github Registry.

Github provides a free of charge registry for public images. Everyone can create a public image automatically just by adding one workflow file into the repository, .e.g. this one. And this action builds and publishes x86 image to Github Registry in a form: ghcr.io/account_name/repo_name:tag. for iris-rest-api-template repository the image is:

ghcr.io/intersystems-community/iris-rest-api-template:latest

So with AWS we can start from cluster creation and use this image in a task.

Tested it now - works fine!