Devcontainer VM Templates

[bpmct]

• feat(examples/templates): add aws vm devcontainer template #11248
• feat(examples/templates): add GCP VM devcontainer template #11246
• Azure VMs

This is simular to architecture of other CDE platforms, a single VM which runs a container!

[matifali]

That would be useful. We may use it for implementing #8462 too.

[matifali]

I am taking this one.

[ggjulio]

Nice templates.

Does envbuilder works fine with theses two devcontainer features inside the VM ?

• docker-in-docker (used by default in codespaces)
• docker-outside-docker

If it works, could we add automatically the docker-in-docker feature by default in the devcontainer ?

Why ?

It ease the developer's life, no need to explicity add the feature in the devcontainer.json

Why docker-in-docker and not docker-outside-docker ?

When using docker-in-docker, docker ps will only show containers that has been started within the devcontainer.
Which is more user friendly than docker-outside-docker as it hides the devcontainer itself.

It works by running a new docker daemon inside the current container.
However /var/lib/docker must be bind mounted in order to run a new dockerd.
The bind mount is directly defined in the docker-in-docker feature.

So if envbuilder implements this part of the devcontainer spec, it should work out of the box.

---

The dind hack implementation is here if needed :

• https://github.com/devcontainers/features/blob/main/src/docker-in-docker/install.sh#L348
• https://github.com/moby/moby/blob/master/hack/dind

[matifali]

@ggjulio not at the moment. Please see

• Docs: How to run docker in docker with envbuilder envbuilder#25

[matifali]

@kylecarbs can we make docker work inside devcontainer built by the envbuilder?
Or at least make the host docker docker available.

[ggjulio]

@matifali thanks for the answer !

I forgot to mention this option of docker-in-docker feature:

It seem to be an hack to make DNS works fine for codespaces (They use azure)

sources:

• https://github.com/devcontainers/features/blob/main/src/docker-in-docker/devcontainer-feature.json#L33
• https://github.com/devcontainers/features/blob/main/src/docker-in-docker/install.sh#L407
• https://learn.microsoft.com/en-us/azure/architecture/example-scenario/networking/azure-dns-private-resolver#use-a-dns-forwarder-vm

So envbuilder + dind may work fine on Azure, but probably not completely on other cloud providers.
In that case a PR to update the docker-in-docker feature could be needed.

[ggjulio]

Is it acceptable to use the devcontainer cli instead of envbuilder for VM templates ?

I know the devcontainer cli is not perfect... and require node to be installed.
Which add up to the initial provisioning time.

But the devcontainer cli could be a first step for supporting the dind feature on coder platform.

[matifali]

@ggjulio, you can use whatever you wish to create a custom template. envbuilder is mainly focused on building an image from devcontainer spec to be run in Kubernetes workspaces.