Docker

Docker

• docs.docker.com: Dockerizing a Node.js web app
• github: docker: docker

Container Orchestration

• kubernetes.io

Manage Images

• docs.docker.com: images
• blog.thoward37.me: where-are-docker-images-stored

Size on disk

volumes

/var/lib/docker# du -sh volumes/

containers

/var/lib/docker# du -sh containers/

images

sudo du -sh /var/lib/docker/image/

devicemapper

sudo cd /var/lib/docker && sudo du -sh devicemapper/
sudo cd /var/lib/docker && sudo du -sh devicemapper/mnt
sudo cd /var/lib/docker && sudo du -sh devicemapper/devicemapper

Starting and stopping

start docker service

$ sudo service docker start or $ /bin/systemctl start docker.service

list images

$ sudo docker images

remove image

$ sudo docker rmi [image]

remove all images

$ sudo docker rmi -f $(sudo docker images -aq)

before images can be removed, containers based on the image have to be deleted

list containers

only running containers

$ sudo docker ps

all containers

$ sudo docker ps -a

stop containers

stop container

$ sudo docker stop CONTAINER_IMAGE

remove containers

remove all containers

$ sudo docker rm $(sudo docker ps -aq)

Docker Engine

• docker-engine
• github: engine-1.9.0: wiki

Training

• training.docker.com

Installation

Debian

• docs.docker.com: Install Docker on Debian

Fedora

• Linux Fedora
• fedoraproject.org: wiki: Docker

Red Hat Enterprise Linux

• docs.docker.com: Red Hat Enterprise Linux

Requirements

Red Hat Enterprise Linux 6.5 Installation You will need 64 bit RHEL 6.5 or later, with a RHEL 6 kernel version 2.6.32-431 or higher as this has specific kernel fixes to allow Docker to work.

check kernel version

$ uname -r

Docker is available for RHEL6.5 on EPEL. Please note that this package is part of Extra Packages for Enterprise Linux (EPEL), a community effort to create and maintain additional packages for the RHEL distribution.

Installation

To proceed with docker-io installation, you may need to remove the docker package first.

$ sudo yum -y remove docker

Next, let’s install the docker-io package which will install Docker on our host.

$ sudo yum install docker-io

To update the docker-io package

$ sudo yum -y update docker-io

Now that it’s installed, let’s start the Docker daemon.

$ sudo service docker start (or $ sudo systemctl start docker)

If we want Docker to start at boot, we should also:

$ sudo chkconfig docker on

Now let’s verify that Docker is working.

$ sudo docker run -i -t fedora /bin/bash

Note: If you get a Cannot start container error mentioning SELinux or permission denied, you may need to update the SELinux policies. This can be done using sudo yum upgrade selinux-policy and then rebooting. Done!

Transfer Image

save

docker save -o <save image to path> <image name>

load

docker load -i <path to image tar file>

R (Rocker)

• dirk.eddelbuettel.com: Introducing Rocker
• github.com: rocker-org: rocker

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Published

08 August 2015

Category

technical