Docker Stuff

Docker machines

For boot2docker

$ docker-machine create -d virtualbox dev

For RancherOS

$ docker-machine create -d virtualbox --virtualbox-boot2docker-url https://github.com/rancher/os/releases/download/v0.3.3/machine-rancheros.iso ros

Info

$ docker version
$ docker info
$ docker events

Shell access to host

$ docker-machine ssh dev

$ docker-machine scp /etc/hosts dev:/tmp/

Port NATing to localhost

# PURELY COSMETIC: enable access to common ports on the docker host VM
# this will nat the ports from $(docker-machine ip dev) to 'localhost'

$ docker-machine stop dev

$ VBoxManage modifyvm "dev" --natpf1 "tcp-port3000,tcp,,3000,,3000"
$ VBoxManage modifyvm "dev" --natpf1 "tcp-port4000,tcp,,4000,,4000"
$ VBoxManage modifyvm "dev" --natpf1 "tcp-port8000,tcp,,8000,,8000"
$ VBoxManage modifyvm "dev" --natpf1 "tcp-port8001,tcp,,8001,,8001"
$ VBoxManage modifyvm "dev" --natpf1 "tcp-port8080,tcp,,8080,,8080"
$ VBoxManage modifyvm "dev" --natpf1 "tcp-port9000,tcp,,9000,,9000"
$ VBoxManage modifyvm "dev" --natpf1 "tcp-port9001,tcp,,9001,,9001"

$ docker-machine start dev

eval "$(docker-machine env dev)"

Images

List

$ docker images

Pull New

$ docker pull centos

Other interesting images include busybox debian ubuntu-upstart nginx node mysql redis java golang rails ruby jruby gcc haskell mongo nats pypy mono couchbase postgres cassandra swarm logstash kibana

Note: If you see something like "Network timed out while trying to connect to https://index.docker.io/v1/repositories/library/mysql/images.", you might want to restart your vm!

Remove

$ docker rmi centos

# remove all images
$ docker rmi $(docker images -qf "dangling=true")

Visualize the tree of images

Install dockviz

$ dockviz images --tree
$ alias d-tree='dockviz images -t'
$ alias d-graph='dockviz images -d | dot -Tpng -o /tmp/dockviz && open /tmp/dockviz'
$ alias dc-graph='dockviz containers -d | dot -Tpng -o /tmp/dockviz && open /tmp/dockviz'

Packaging an image to a tar

$ docker save -o /tmp/cool-file-image.tar cool_file_image

# you can see the layers by
$ tar -tf /tmp/cool-file-image.tar

Loading image from file

$ docker load -i /tmp/cool-file-image.tar

Containers

Run in Foreground (interactive)

$ docker run -it --rm --name shell alpine /bin/sh
$ docker run -it --rm --name pinger alpine /bin/sh -c "ping 8.8.8.8"

# --rm for automatically removing container on exit
# -i for interactive
# -t for tty

# to detach, do: ctrl+p, ctrl+q

Run in Background (detached)

$ docker run -d --name pinger alpine /bin/sh -c "ping 8.8.8.8"
$ docker run -d --name pinger --restart=always alpine ping -c4 8.8.8.8

# -d for detached
# --restart for restart policy (no, always, on-failure, on-failure:10)

List Containers

$ docker ps # running containers
$ docker ps -a # include terminated

Stopping

$ docker stop pinger
$ docker kill pinger
$ docker kill -s SIGKILL pinger

Starting

$ docker start pinger

Pausing

$ docker pause pinger
$ docker unpause pinger

Attaching

$ docker attach pinger

# to detach, do: ctrl+p, ctrl+q

Inspecting

$ docker inspect pinger
$ docker inspect pinger | grep -i PID

Ports

$ docker run --name web1 -d -P nginx
$ docker run --name web2 -d -p 8080:80 nginx

$ docker port web1
$ docker port web1 80

$ curl "$(docker-machine ip dev):$(docker port web1 80 | cut -d':' -f2)"
$ curl "$(docker-machine ip dev):$(docker port web2 80 | cut -d':' -f2)"

Volumes

$ mkdir site && cd site
$ echo 'Man, docker volumes!' > index.html
$ docker run --name web -d -P -v $PWD:/usr/share/nginx/html nginx
# To mount in readonly mode, $ docker run --name web -d -P -v $PWD:/usr/share/nginx/html:ro nginx

$ curl "$(docker-machine ip dev):$(docker port web 80 | cut -d':' -f2)"
# you should see: "Man, docker volumes!"

$ echo 'Another cool page!' > cool.html
$ curl "$(docker-machine ip dev):$(docker port web 80 | cut -d':' -f2)/cool.html"
# you should see: "Another cool page!"

$ cd .. && rm -rf site

Live statistics

$ docker stats pinger

Top

$ docker top pinger

Logs

$ docker logs -f pinger

Diff

$ docker diff pinger

Debug

Run a new command in an already running container

$ docker exec -it pinger /bin/sh

If you have nsenter on host, you can also do

$ nsenter -m -u -n -p -i -t 19867 /bin/bash

# where 19867 is the process id of the guest process in the host system, ref: inspect

Removing Container

$ docker rm -f pinger

# remove all stopped containers
$ docker rm $(docker ps -q -f status=exited)

# remove all stopped containers, force stop if needed
$ docker rm -f `docker ps --no-trunc -aq`

$ docker ps -a | grep 'weeks ago' | awk '{print $1}' | xargs --no-run-if-empty docker rm

Saving changes made to a container into an image

Make change to file system

$ docker run --name cool_file_container alpine /bin/sh -c "echo 'cool content' > /tmp/cool-file"

Save container

$ docker commit cool_file_container cool_file_image

History

$ docker history --no-trunc=true cool_file_image