Dockers:
As per wiki:
Docker is an opensource project that automates the deployment of applications inside software containers,by providing an additional layer of abstraction and automation of operating system-level virtualization on linux.
Does it runs only on Linux??
The Docker daemon uses Linux-specific kernel features, you can’t run Docker natively in Windows. Instead, you must use docker-machine to create and
attach to a Docker VM on your machine. This VM hosts Docker for you on your Windows system.The Docker VM is lightweight Linux virtual machine made specifically to run the Docker daemon on Windows. The VirtualBox VM runs completely from RAM, is a small ~24MB download, and boots in approximately 5s.
Dockers Installation:
In this section we will be installing dockers on centos 7.
– Install epel pakage , for epel repository.
yum install epel-release
– Update the packages
yum update
– Install the docker pakcage, Incase of centos its “docker-io”
yum install docker-io
-Start and configure the service
service docker start
ps aux |grep docker
chkconfig docker on
-Check Docker Version
docker version
<command output>
Client version: 1.7.1
Client API version: 1.19
Package Version (client): docker-1.7.1-108.el7.centos.x86_64
Go version (client): go1.4.2
Git commit (client): 3043001/1.7.1
OS/Arch (client): linux/amd64
Server version: 1.7.1
Server API version: 1.19
Package Version (server): docker-1.7.1-108.el7.centos.x86_64
Go version (server): go1.4.2
Git commit (server): 3043001/1.7.1
OS/Arch (server): linux/amd64
docker info
#Below is command output
Containers: 0
Images: 0
Storage Driver: devicemapper
Pool Name: docker-202:1-75739270-pool
Pool Blocksize: 65.54 kB
Backing Filesystem: xfs
Data file: /dev/loop0
Metadata file: /dev/loop1
Data Space Used: 307.2 MB
Data Space Total: 107.4 GB
Data Space Available: 16.05 GB
Metadata Space Used: 729.1 kB
Metadata Space Total: 2.147 GB
Metadata Space Available: 2.147 GB
Udev Sync Supported: true
Deferred Removal Enabled: false
Data loop file: /var/lib/docker/devicemapper/devicemapper/data
Metadata loop file: /var/lib/docker/devicemapper/devicemapper/metadata
Library Version: 1.02.93-RHEL7 (2015-01-28)
Execution Driver: native-0.2
Logging Driver: json-file
Kernel Version: 3.10.0-229.11.1.el7.x86_64
Operating System: CentOS Linux 7 (Core)
CPUs: 1
Total Memory: 992.1 MiB
Name: mylab.mytest.com
ID: WLFQ:JBXB:W6KR:5UZ6:WH5J:T4OC:HQOF:SMBX:AI2U:UI5H:CP7X:VQK7
– Pull ubuntu image using docker command line:
docker pull ubuntu:latest
<output>latest: Pulling from docker.io/ubuntu
d3a1f33e8a5a: Pull complete
c22013c84729: Pull complete
d74508fb6632: Pull complete
91e54dfb1179: Pull complete
docker.io/ubuntu:latest: The image you are pulling has been verified. Important: image verification is a tech preview feature and should not be relied on to provide security.
Digest: sha256:73fbe2308f5f5cb6e343425831b8ab44f10bbd77070ecdfbe4081daa4dbe3ed1
Status: Downloaded newer image for docker.io/ubuntu:latest
-List the Docker images
docker images
REPOSITORY TAG IMAGE ID CREATED VIRTUAL SIZE
docker.io/ubuntu latest 91e54dfb1179 3 weeks ago 188.3 MB
-Run the container image
docker run -i -t ubuntu /bin/bash
root@a165ac32dec0:/# uname -a
Linux a165ac32dec0 3.10.0-229.11.1.el7.x86_64 #1 SMP Thu Aug 6 01:06:18 UTC 2015 x86_64 x86_64 x86_64 GNU/Linux
root@a1d068a9c409:/# ps aux
USER PID %CPU %MEM VSZ RSS TTY STAT START TIME COMMAND
root 1 0.2 0.1 18164 1880 ? Ss 04:58 0:00 /bin/bash
root 15 0.0 0.1 15564 1144 ? R+ 04:58 0:00 ps aux
In next segment we will see some advance level of command !!