I am using a docker container to build and deploy my software to a collection of ec2's. In the deployment script I build my software and then package it in a docker image. The image is pushed to my private registry, pulled by my production ec2's and then run. So essentially I will need to run docker within a docker container.
The problem is that I can't actually start docker on my container. If I try
service docker start
I get
bash: service: command not found
And if I try
docker -d
I get
2014/10/07 15:54:35 docker daemon: 0.11.1-dev 02d20af/0.11.1; execdriver: native; graphdriver:
[e2feb6f9] +job serveapi(unix:///var/run/docker.sock)
[e2feb6f9] +job initserver()
[e2feb6f9.initserver()] Creating server
2014/10/07 15:54:35 Listening for HTTP on unix (/var/run/docker.sock)
[error] attach_loopback.go:42 There are no more loopback device available.
loopback mounting failed
[e2feb6f9] -job initserver() = ERR (1)
2014/10/07 15:54:35 loopback mounting failed
The service command doesn't exist on the docker container so I can't start docker. I'm not sure what I should be doing now to start docker so I'm a bit stuck here, any help is appreciated.
A bit more information
Host machine is running fedora 20 (will eventually be running amazon linux on an ec2)
Docker container is running centos 7.0
Host is running Docker version 1.2.0, build fa7b24f/1.2.0
Container is running docker-0.11.1-22.el7.centos.x86_64
How about not running 'docker inside docker' and run docker on your host, but from within your docker container? Just mount your docker.sock and docker binary:
docker run -v /var/run/docker.sock:/run/docker.sock -v $(which docker):/bin/docker [your image]
https://github.com/sameersbn/docker-gitlab uses this approach to spin up docker containers, take a look at this image.
You can also take a look at: https://registry.hub.docker.com/u/mattgruter/doubledocker/
UPDATE on july 2016
The most current approach is to use docker:dind image, as described here:
https://hub.docker.com/_/docker/
Short summary:
$ docker run --privileged --name some-docker -d docker:dind
and then:
$ docker run --rm --link some-docker:docker docker info
While in almost all cases I would suggest following #cthulhu's answer and not running "docker in docker", in the cases when you must (e.g. a test suite which tests against multiple docker version), use the following to create additional loopback devices:
#!/bin/bash
for i in {0..6}
do
mknod -m0660 /dev/loop$i b 7 $i
done
(Taken from the thread for Docker Issue #7058)
You can simply run docker inside the docker container using dind. Try this image from Jerome, as follows:
docker run --privileged -t -i jpetazzo/dind
Check this page for more details:
https://github.com/jpetazzo/dind
Related
I am new to docker. On Mac OSX I installed docker and docker-machine and ran the following based on what I saw elsewhere online and on stackoverflow. Why is the daemon not connecting? Do I need to change my config to unix sockets for communications? Did I start my docker daemon correctly via docker-machine?
docker-machine create --driver virtualbox default
...
Setting Docker configuration on the remote daemon...
Checking connection to Docker...
Docker is up and running!
To see how to connect your Docker Client to the Docker Engine running
on this virtual machine, run: docker-machine env default
..
docker run debian echo "Hello World"
docker: Cannot connect to the Docker daemon at
unix:///var/run/docker.sock. Is the docker daemon running?.
See 'docker run --help'.
To see how to connect your Docker Client to the Docker Engine running
on this virtual machine, run: docker-machine env default
The command you're missing is eval "$(docker-machine env default)" which will update your environment with $DOCKER_HOST and $DOCKER_TLS_VERIFY settings you can use to connect to the daemon.
One possible reason could be change in your IP address.
simply restart the docker (click on the right-top of your screen a docker-whale). Then again try to run the docker. Use Docker desktop app for mac
Currently I've the following setup:
An Hyper-V VM running Windows 10 on which is my dev machine. My CPU doesn't support nested virtualization.
Docker for Windows is installed on the host machine which runs Windows 10 too.
Is it possible to run docker build from the VM against Docker on the host machine?
Yes, you can. According to the documentation, there is 3 ways to do this,
# with Git repo
docker -H xxx build https://github.com/docker/rootfs.git#container:docker
# Tarball contexts
docker -H xxx build http://server/context.tar.gz
Text files
docker -H xxx build - < Dockerfile
When doing this, you need to make sure that,
your client have docker installed.
all the dependent files are accessible by the host.
At the end, the docker image will be created in your host.
Update
the docker options is documented here now.
export DOCKER_HOST=ssh://sammy#your_server_ip
then you can run docker build on your host machine
reference
There is (from my understanding) 3 different way of building a docker using a remote docker host / daemon:
Using the DOCKER_HOST variable
Using contexts
Using -H cli option
as in :
DOCKER_HOST="ssh://user#docker-build.dev" docker build -t toto .
docker use context remote-build-host && docker build -t toto .
docker -H ssh://user#docker-build.dev:22 build -t toto .
Please note the port is required in the last form (-H)
See this page and this one too for more info.
Is there away to log into host VM's shell, similarly to how can we easily enter into running containers bash?
docker exec -it bash
I accidentally broke one container's crucial file, so that it couldn't start. Unfortunately, that container stored it's data inside. The result was that whenever I tried to run it, it couldn't start. The only solutions I saw were about navigating to host docker daemon's files. However, I'm running docker VM on windows, and I cannot access the files inside VM (MobyLinuxVM).
I'm using Docker for Windows, version 1.12.3-beta30.1 (8711)
Hack your way in
run a container with full root access to MobyLinuxVM and no seccomp profile (so you can mount stuff)
docker run --net=host --ipc=host --uts=host --pid=host -it --security-opt=seccomp=unconfined --privileged --rm -v /:/host alpine /bin/sh
https://forums.docker.com/t/how-can-i-ssh-into-the-betas-mobylinuxvm/10991/6
I'm runner Docker for OSX, and having trouble getting the Docker remote API to work.
My situation is this:
Docker daemon running natively on OSX (https://www.docker.com/products/docker#/mac, so not the boot2docker variant)
Jenkins running as docker image
No I want to use the Jenkins docker-build-step plugin to build a docker image, but I want it to use the docker daemon on the host machine, so in Jenkins settings, DOCKER_URL should be something like :2375. (Reason for this is I don't want to install docker on the jenkins container if I already have it on my host machine).
Is there a way to to this or is de Docker for Mac currently not supporting this? I tried fiddling with export DOCKER_OPTS or DOCKER_HOST options but still get a Connection refused on calling http://localhost:2375/images/json for example.
Basicly the question is more about enabling the Docker for OSX remote api, with use case calling it from a Jenkins docker container.
You could consider using socat. It solved my problem, which seem to be similar.
socat TCP-LISTEN:2375,reuseaddr,fork UNIX-CONNECT:/var/run/docker.sock &
This allows you to access your macOS host Docker API from a Docker container using: tcp://[host IP address]:2375
On macOS socat can be installed like this:
brew install socat
See here for a long discussion on this topic: Plugin: Docker fails to connect via unix:// on Mac OS X
If you already added an SSH public key to your remote server, then you can use this ssh credentials for your docker connection, too. You don't need to configure the remote api on the server for this approach.
When connecting to macOS Docker Desktop, you could use ssh (after you have enabled it on Mac)
docker -H ssh:user#192.168.64.1 images
or
export DOCKER_HOST=ssh:user#192.168.64.1
docker images
I had the same issue but with mysql. I needed to expose the port of my docker hosts on port 43306 to docker image mysql running on port 3306.
Solution:
Create your docker image with -p parameter.
Example:
#> docker run -p 0.0.0.0:43306:3306 --name mysql-5.7.23xx -e MYSQL_ROOT_PASSWORD=myrootdba -d mysql/mysql-server:5.7.23 --character-set-server=utf8mb4 --collation-server=utf8mb4_unicode_ci
Now I can connect from my host docker server on port 43306 to mysql docker image.
So getting boot2docker up and running, and pulling containers from the Docker Hub are non-issue on a windows environment. But if I wish to create a container and run it, how do I go about doing this? I've read about using fig, but is fig installed via Windows or from the container? I've attempted to do it from the container, but it often results in a permissions error, and even CHOWNing the folder doesn't solve the issue of not being able to call fig in the container.
Is it even possible to just run docker via Boot2Docker on windows as a development environment? Or should I just use Vagrant as the host VM and play with a bunch of docker containers in it?
Just some clarification and direction would be appreciated.
Fig is a tool for working with Docker. It runs on the host (which could mean your Windows host communicating with Docker via the TCP socket, or could mean your boot2docker VM which is a guest of your windows machine and a host of your Docker containers).
All that Fig's doing is streamlining the process of pulling, building and starting Docker images. For example, this fig.yml
db:
image: postgres
app:
build: .
links:
- "db:db"
environment:
- FOO=bar
is (roughly) the same as this series of Docker commands in Bash:
docker run -d --name db postgres
docker build -t app .
docker run -d --name app --link=db:db --env=FOO=bar app