Error during connect: Post http://docker:2375/v1.40/auth: dial tcp: lookup docker on 169.254.169.254:53: no such host

edit config.toml and change volumes option

before

[[runners]]
  ...
  [runners.docker]
    volumes = ["/cache"]
    ...

after

[[runners]]
  ...
  [runners.docker]
    volumes = ["/var/run/docker.sock:/var/run/docker.sock", "/cache"]
    ...

issue