This doesn’t work since Fly’s remote builders don’t fetch images from private repositories: Feature request: Images from private Docker registries - #2 by kurt
You can choose to push your private docker images to Fly, however: Session affinity ("sticky sessions")? - #9 by kurt | Requesting recommendations for making Fly less flaky for CI - #2 by ignoramous
I haven’t seen this before, but sounds like docker may be running with tighter permissions than usual: jenkins - Docker: Got permission denied while trying to connect to the Docker daemon socket at unix:///var/run/docker.sock - Stack Overflow