ttl.sh registry images are treated as docker.io and fail to pull

[eddiewebb]

🏷️ Discussion Type

Bug

Body

I was testing changes to a devcontainer used by codespaces and thought using ttl.sh would be an easy/fast way to publish images locally and ensure they spun up on codespaces successfully.

Images pushed to ttl.sh use the fully qualified name of ttl.sh/<image-name>:<tag> and docker and k8s are perfectly content to use this fully qualified path to successfully push/pull images from this ephemeral repo.

When I set this as my image in .devcontainer.json though I got an error starting up since it's treated only as a path on the default docker.io registry, not a fully qualified name.

Locally pushing/pulling with docker works fine

docker push ttl.sh/devcontainer:24h                                                                                                                                    [8:58:49]
The push refers to repository [ttl.sh/devcontainer]
... # layers pushed
24h: digest: sha256:4d56ad009425e61b030b65624b9b7c0fe5aa08ce30246203fedcf4e1f9a570e6 size: 5371

Codespace says "docker.io don't have that"

devcontainer.json

...
	"image": "ttl.sh/devcontainer:24h",
...

creation.log

2026-05-29 12:59:26.657Z: $ devcontainer up [...]
2026-05-29 12:59:26.801Z: @devcontainers/cli 0.83.3. Node.js v18.20.8. linux 6.8.0-1052-azure x64.
2026-05-29 12:59:27.142Z: Error fetching image details: No manifest found for docker.io/ttl.sh/devcontainer:24h.

Steps to reproduce

1. Write simple Dockerfile
2. Docker push to ttl.sh/<some-name>:<interval-tag> i.e. ttl.sh/tester-image:2h
3. Use the FQ location in your devcontainer.json
4. rebuild codespace on github

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