Docker
Docker
Container Orchestration
Manage Images
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
Training
Installation
Debian
Fedora
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)
Published
08 August 2015