Can't connect to the docker daemon

[jeanbza]

$ docker run -it --privileged docker:dind /bin/sh
/ # docker ps
error during connect: Get http://docker:2375/v1.40/containers/json: dial tcp: lookup docker on 192.168.65.1:53: no such host
/ #

Am I missing something? Is there no way to connect to the daemon without linking another container outside of this container?

---

Things I've tried:

• dockerd &

• dockerd-entrypoint.sh &

• Trying to grok dockerd-entrypoint.sh and reverse-engineer

• Trying to set DOCKER_HOST=localhost (based on Can't make docker login to work from within container #188)

  $ docker run --rm -ti --privileged -e DOCKER_HOST=localhost docker:dind sh
  / # docker ps
  Cannot connect to the Docker daemon at tcp://localhost:2375. Is the docker daemon running?
  

[yosifkit]

dockerd-entrypoint.sh & is sort of on the right track. The reason it is not working, is that the dockerd started by the entrypoint listens with tls and the local socket (#166).

When you run the container with sh, docker-entrypoint.sh gets run at the end of dockerd-entrypoint.sh and doesn't detect a locally running dockerd and so sets DOCKER_HOST to tcp://docker:2375 before starting the shell (since it also doesn't detect any certs in the certificate directory). So you need to unset DOCKER_HOST so that it will use the unix socket (or use --entrypoint=sh to skip the auto detection of docker-entrypoint.sh).

But the better solution would be to just run the dind container and docker exec into it:

$ docker run -d --name=dindy --privileged docker:dind
5168e1749054efe4dd271935f119c60b2fd8dfe937c57257ffaa233f227eb5b1
$ docker exec -it dindy docker ps
CONTAINER ID        IMAGE               COMMAND             CREATED             STATUS              PORTS               NAMES
$ docker exec -it dindy docker info
Client:
 Debug Mode: false

Server:
 Containers: 0
  Running: 0
  Paused: 0
  Stopped: 0
 Images: 0
 Server Version: 19.03.4
 Storage Driver: overlay2
  Backing Filesystem: extfs
  Supports d_type: true
  Native Overlay Diff: true
 Logging Driver: json-file
 Cgroup Driver: cgroupfs
 Plugins:
  Volume: local
  Network: bridge host ipvlan macvlan null overlay
  Log: awslogs fluentd gcplogs gelf journald json-file local logentries splunk syslog
 Swarm: inactive
 Runtimes: runc
 Default Runtime: runc
 Init Binary: docker-init
 containerd version: b34a5c8af56e510852c35414db4c1f4fa6172339
 runc version: 3e425f80a8c931f88e6d94a8c831b9d5aa481657
 init version: fec3683
 Security Options:
  seccomp
   Profile: default
 Kernel Version: 4.19.81-gentoo
 Operating System: Alpine Linux v3.10 (containerized)
 OSType: linux
 Architecture: x86_64
 CPUs: 8
 Total Memory: 30.87GiB
 Name: 5168e1749054
 ID: 44JU:LN6F:PHL4:ODXN:AGFB:VZID:SADW:RB5P:RE5X:T6LJ:XCYF:6KLS
 Docker Root Dir: /var/lib/docker
 Debug Mode: false
 Registry: https://index.docker.io/v1/
 Labels:
 Experimental: false
 Insecure Registries:
  127.0.0.0/8
 Live Restore Enabled: false
 Product License: Community Engine

WARNING: bridge-nf-call-iptables is disabled
WARNING: bridge-nf-call-ip6tables is disabled

[jeanbza]

Thank you!