Best way to set one variable string, different values, for each instance?

[turian]

I am hoping to spin up a fleet of spotty instances, each identical except for having one variable (hyperparameter set name) different for each.

Something like: HYPERPARAMETERS = ["model1", "model2", etc.] with each instance having a different value.

I guess an environment variable makes the most sense. I see the ability to add envs to the containers. But I don't find the documentation on what happens if you have multiple containers:

• Do all the containers go onto one instance? If so then I would pick the container I want when I call spotty for that instance?
• Or is it one container per instance? In that case, I don't find the documentation on how to specify which container you want for a particular instance.

One workaround would be to have a separate spotty.yaml for each instance (and hyperparameter set name) but that seems janky.

[turian]

Alternately, I would like to have files 'local.py.template1', 'local.py.template2', etc. and specify the file for each instance, and it becomes 'local.py'

[apls777]

Each container has a name. By default, it's default, but you can change it using the name parameter (see here). This name is used to assign the container to a specific instance. By default, the container with the name default will be assigned to all your instances, but it can be changed using the containerName parameter in the instance configuration (see here).

So, in your case, I would create several containers with different environmental variables as you suggested. Then, based on the environmental variable, your script could pick up correct hyperparameters for the model. To reduce the amount of copy-pasting, you can use YAML aliases. Something like that:

containers:
  - &DEFAULT_CONTAINER
    projectDir: /workspace/project
    file: docker/Dockerfile.spotty.gpu
    volumeMounts:
      - name: project
        mountPath: /workspace/project
    env: &COMMON_ENVS
      PYTHONPATH: /workspace/project
    # ...

  - <<: *DEFAULT_CONTAINER
    name: model-1
    env:
      <<: *COMMON_ENVS
      MODEL_NAME: model1

  - <<: *DEFAULT_CONTAINER
    name: model-2
    env:
      <<: *COMMON_ENVS
      MODEL_NAME: model2

instances:
  - name: aws-1
    provider: aws
    parameters: &INSTANCE_PARAMS
      containerName: model-1
      region: eu-central-1
      instanceType: p3.2xlarge
      # ...
  - name: aws-2
    provider: aws
    parameters: 
      <<: *INSTANCE_PARAMS
      containerName: model-2