Install Docker on CentOS 7/RHEL7
Docker is an open-source tool that makes creating & managing Linux containers(LXC) easy. Containers are like lightweight VMs which can be started & stopped in milliseconds. Dockers help the system admin & coders to develop their application in a container and can further scale up to 1000 of nodes.
The main difference between container and VM(Virtual machine) is that dockers provide process based isolation , whereas VM provides full isolation of resources. Virtual machine takes a minute to start where as container can be started in a second or less than a second. Container uses the Kernel of host OS , whereas VM uses the separate Kernel.
One of the limitation of Docker is that it can be used only on 64bit hosts OS.
Installation of Docker on CentOS 7
Docker package is included in the default CentOS-Extras repository. So to install docker , simply run below yum command :
[root@localhost ~]# yum install docker
Start the Docker Service
Once the Installation is finished , start docker service and enable it at boot using below commands
[root@localhost ~]# service docker start
[root@localhost ~]# chkconfig docker on
Download the official Centos images Locally
Run a Docker Container :
[root@localhost ~]# docker run -i -t centos /bin/bash
[root@dbf66395436d /]#
As we can see centos container has been started and we got the bash shell. In docker command we have used options like ‘-i attaches stdin and stdout’ and ‘-t allocates a terminal or console’ . To disconnect from container type exit .
[root@cd05639b3f5c /]# cat /etc/redhat-release
CentOS Linux release 7.0.1406 (Core)
We can also search Containers based on fedora & ubuntu OS.
[root@localhost ~]# docker search ubuntu
[root@localhost ~]# docker search fedora
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Docker is an open-source tool that makes creating & managing Linux containers(LXC) easy. Containers are like lightweight VMs which can be started & stopped in milliseconds. Dockers help the system admin & coders to develop their application in a container and can further scale up to 1000 of nodes.
The main difference between container and VM(Virtual machine) is that dockers provide process based isolation , whereas VM provides full isolation of resources. Virtual machine takes a minute to start where as container can be started in a second or less than a second. Container uses the Kernel of host OS , whereas VM uses the separate Kernel.
One of the limitation of Docker is that it can be used only on 64bit hosts OS.
Installation of Docker on CentOS 7
Docker package is included in the default CentOS-Extras repository. So to install docker , simply run below yum command :
[root@localhost ~]# yum install docker
Start the Docker Service
Once the Installation is finished , start docker service and enable it at boot using below commands
[root@localhost ~]# service docker start
[root@localhost ~]# chkconfig docker on
Download the official Centos images Locally
[root@localhost ~]# docker pull centos
Pulling repository centos
192178b11d36: Download complete
70441cac1ed5: Download complete
ae0c2d0bdc10: Download complete
511136ea3c5a: Download complete
5b12ef8fd570: Download complete
Verify CentOS images that have been fetched :
[root@localhost ~]# docker images centos
REPOSITORY TAG IMAGE ID CREATED VIRTUAL SIZE
centos centos5 192178b11d36 2 weeks ago 466.9 MB
centos centos6 70441cac1ed5 2 weeks ago 215.8 MB
centos centos7 ae0c2d0bdc10 2 weeks ago 224 MB
centos latest ae0c2d0bdc10 2 weeks ago 224 MB
Run a Docker Container :
[root@localhost ~]# docker run -i -t centos /bin/bash
[root@dbf66395436d /]#
As we can see centos container has been started and we got the bash shell. In docker command we have used options like ‘-i attaches stdin and stdout’ and ‘-t allocates a terminal or console’ . To disconnect from container type exit .
[root@cd05639b3f5c /]# cat /etc/redhat-release
CentOS Linux release 7.0.1406 (Core)
We can also search Containers based on fedora & ubuntu OS.
[root@localhost ~]# docker search ubuntu
[root@localhost ~]# docker search fedora
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