[packer] support session manager plugin

[skeggse]

The provided packer image builds on alpine, which doesn't appear to have session-manager-plugin support: https://github.com/hashicorp/packer/issues/8242. It'd be nice if the provided image or some variant did have support for that plugin.

[SwampDragons]

Rather than installing every possible dependency Packer may need on that docker image, we think it makes more sense to supply the image with the bare minimum and allow users to build on top of it if they need more dependencies.

[skeggse]

I ended up going that route. I think I'm mostly commenting on the choice of base image here, which precludes using prebuilt binaries for the session-manager-plugin. I was unable to use this as a base image as a result, so packer-ssm duplicates the work in this repo but atop ubuntu.

[SwampDragons]

Ah, I understand. Thanks.

[ghost]

@SwampDragons - idk if "we provide the base" is valid in all use-cases - consider Github self hosted actions runners - your provided actions runner https://github.com/hashicorp/packer-github-actions references hashicorp/packer:light as the base container, and the base container doesn't handle things like ISO creation (requires mkisofs / xorriso) which isn't part of the container.

There's no way I've found thus far to call uses: hashicorp/packer-github-actions@master and also have it pass a command to the container once generated for something like apk add cdrkit, meaning we're sort of pushed down the road of either forking and adding a RUN statement to the Dockerfile (https://github.com/stuhall-t2/packer-github-actions/blob/master/Dockerfile) or not using the provided packer-github-actions and using actions steps to generate the container on the fly.

I know this is an old issue, but I didn't want to open a new one on this prior to getting your thoughts on whether there should perhaps be a hashicorp/packer:reallyfull and associated hashicorp/packer-github-actions@reallyfull action.