docker
Docker-outside-of-Docker (DooD) can't connect to socket / docker outside
Description
I was trying to run DooD in MacOS running Docker Desktop and running a countainer where I mount the docker socket but I can't get it to work.
Reproduce
Run DooD with the docker image:
$ docker run \
--rm \
--volume /Users/jjmaestro/.docker/run/docker.sock:/var/run/docker.sock \
docker version
Cannot connect to the Docker daemon at unix:///var/run/docker.sock. Is the docker daemon running?
Client:
Version: 27.1.1
API version: 1.46
Go version: go1.21.12
Git commit: 6312585
Built: Tue Jul 23 19:55:52 2024
OS/Arch: linux/arm64
Context: default
Just in case, I've also tried with other custom images where I change permissions to the socket (chmod 777), change ownership (chown root:docker), making sure there's no DOCKER_HOST environment variable set, and that the context is the default one, and running --privileged. Nothing works.
Expected behavior
I shouldn't get a Cannot connect to the Docker daemon at unix:///var/run/docker.sock. Is the docker daemon running? error, it should be able to connect to the outside docker.
docker version
% docker version
Client:
Version: 27.1.1
API version: 1.46
Go version: go1.21.12
Git commit: 6312585
Built: Tue Jul 23 19:54:12 2024
OS/Arch: darwin/arm64
Context: desktop-linux
Server: Docker Desktop 4.33.0 (160616)
Engine:
Version: 27.1.1
API version: 1.46 (minimum version 1.24)
Go version: go1.21.12
Git commit: cc13f95
Built: Tue Jul 23 19:57:14 2024
OS/Arch: linux/arm64
Experimental: false
containerd:
Version: 1.7.19
GitCommit: 2bf793ef6dc9a18e00cb12efb64355c2c9d5eb41
runc:
Version: 1.7.19
GitCommit: v1.1.13-0-g58aa920
docker-init:
Version: 0.19.0
GitCommit: de40ad0
docker info
% docker info
Client:
Version: 27.1.1
Context: desktop-linux
Debug Mode: false
Plugins:
buildx: Docker Buildx (Docker Inc.)
Version: v0.16.1-desktop.1
Path: /Users/jjmaestro/.docker/cli-plugins/docker-buildx
compose: Docker Compose (Docker Inc.)
Version: v2.29.1-desktop.1
Path: /Users/jjmaestro/.docker/cli-plugins/docker-compose
debug: Get a shell into any image or container (Docker Inc.)
Version: 0.0.34
Path: /Users/jjmaestro/.docker/cli-plugins/docker-debug
desktop: Docker Desktop commands (Alpha) (Docker Inc.)
Version: v0.0.14
Path: /Users/jjmaestro/.docker/cli-plugins/docker-desktop
dev: Docker Dev Environments (Docker Inc.)
Version: v0.1.2
Path: /Users/jjmaestro/.docker/cli-plugins/docker-dev
extension: Manages Docker extensions (Docker Inc.)
Version: v0.2.25
Path: /Users/jjmaestro/.docker/cli-plugins/docker-extension
feedback: Provide feedback, right in your terminal! (Docker Inc.)
Version: v1.0.5
Path: /Users/jjmaestro/.docker/cli-plugins/docker-feedback
init: Creates Docker-related starter files for your project (Docker Inc.)
Version: v1.3.0
Path: /Users/jjmaestro/.docker/cli-plugins/docker-init
sbom: View the packaged-based Software Bill Of Materials (SBOM) for an image (Anchore Inc.)
Version: 0.6.0
Path: /Users/jjmaestro/.docker/cli-plugins/docker-sbom
scout: Docker Scout (Docker Inc.)
Version: v1.11.0
Path: /Users/jjmaestro/.docker/cli-plugins/docker-scout
Server:
Containers: 21
Running: 0
Paused: 0
Stopped: 21
Images: 3
Server Version: 27.1.1
Storage Driver: overlayfs
driver-type: io.containerd.snapshotter.v1
Logging Driver: json-file
Cgroup Driver: cgroupfs
Cgroup Version: 2
Plugins:
Volume: local
Network: bridge host ipvlan macvlan null overlay
Log: awslogs fluentd gcplogs gelf journald json-file local splunk syslog
Swarm: inactive
Runtimes: io.containerd.runc.v2 runc
Default Runtime: runc
Init Binary: docker-init
containerd version: 2bf793ef6dc9a18e00cb12efb64355c2c9d5eb41
runc version: v1.1.13-0-g58aa920
init version: de40ad0
Security Options:
seccomp
Profile: unconfined
cgroupns
Kernel Version: 6.10.0-linuxkit
Operating System: Docker Desktop
OSType: linux
Architecture: aarch64
CPUs: 10
Total Memory: 7.655GiB
Name: docker-desktop
ID: c325dcca-aa54-4f90-9f8e-f43f6ca069e3
Docker Root Dir: /var/lib/docker
Debug Mode: false
HTTP Proxy: http.docker.internal:3128
HTTPS Proxy: http.docker.internal:3128
No Proxy: hubproxy.docker.internal
Labels:
com.docker.desktop.address=unix:///Users/jjmaestro/Library/Containers/com.docker.docker/Data/docker-cli.sock
Experimental: false
Insecure Registries:
hubproxy.docker.internal:5555
127.0.0.0/8
Live Restore Enabled: false
WARNING: daemon is not using the default seccomp profile
Diagnostics ID
7B54016F-97E6-428E-92C4-F7D32BCF51F6/20240810001351
Additional Info
% docker context list
NAME DESCRIPTION DOCKER ENDPOINT ERROR
default Current DOCKER_HOST based configuration unix:///var/run/docker.sock
desktop-linux * Docker Desktop unix:///Users/jjmaestro/.docker/run/docker.sock
% ls -l /Users/jjmaestro/.docker/run/docker.sock
srwxrwxrwx@ 1 jjmaestro staff 0 Aug 1 13:02 /Users/jjmaestro/.docker/run/docker.sock
Huh, I just tried the following and it works!
$ docker run \
--rm \
--volume /var/run/docker.sock:/var/run/docker.sock \
docker version
Client:
Version: 27.1.1
API version: 1.46
Go version: go1.21.12
Git commit: 6312585
Built: Tue Jul 23 19:55:52 2024
OS/Arch: linux/arm64
Context: default
Server: Docker Desktop 4.33.0 (160616)
Engine:
Version: 27.1.1
API version: 1.46 (minimum version 1.24)
Go version: go1.21.12
Git commit: cc13f95
Built: Tue Jul 23 19:57:14 2024
OS/Arch: linux/arm64
Experimental: false
containerd:
Version: 1.7.19
GitCommit: 2bf793ef6dc9a18e00cb12efb64355c2c9d5eb41
runc:
Version: 1.7.19
GitCommit: v1.1.13-0-g58aa920
docker-init:
Version: 0.19.0
GitCommit: de40ad0
Then, I checked the Docker on Mac VM and sure enough, that's the docker socket inside the Linux VM.
Yes, I think this is the expected behavior; bind mounts happen from the host where the daemon runs (on desktop, that's inside the VM); the socket on the host is a proxy for that socket, and also handles various conversions (host paths to vm paths etc), so to access the daemon socket, using the standard (/var/run/docker.sock) path should be the way to go
@thaJeztah Sure, but then, how come I can bind mount e.g. a folder in my home directory? or any other path in Mac, for that matter? It's because / is mounted in /host_mnt/ inside the VM, correct? If so, that's why I would expect mounting the "outside socket" to work. Is there something else that's failing here?
@thaJeztah is there a way to "run docker context list in the Docker VM"? For example, if I want to script getting the path to the socket in the VM, I can do this in e.g. Lima:
DOCKER_CONTEXT_VM="$(limactl shell "$VM_NAME" docker context show)"
DOCKER_HOST_VM="$(limactl shell "$VM_NAME" \
docker context inspect --format "{{.Endpoints.docker.Host}}" "$DOCKER_CONTEXT_VM"
)"
Can I do something like that in the Docker VM? All I've found so far is "Getting a Shell in the Docker Desktop Mac VM" but I can't run docker context (or any docker command) in that shell.
Thanks!