I. Overview
Docker is an application container engine open source, so developers can package their applications and dependencies into a portable container and then posted to any popular Linux machine or Windows machine, can be virtualized, the container is completely use the sandbox mechanism will not have any interface with each other.
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DockerClient client
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Docker Daemon Daemon
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Docker Image Mirror
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Docker Container vessel
The core technology of the container has the following core technologies:
1.cgroups resource management (limit space)
2.Namespace process isolation
3.SElinux security
Here are a comparison chart docker container and traditional virtualization technology, it is clear to see why docker faster speed than traditional virtualization, because the operating system does not docker
That it can be understood as a program (not account for memory, cpu, speed) and this is the biggest difference between traditional virtualization
docker also has its own shortcomings
1. Isolation of the container is not strong virtualization
2. Shared Linux kernel, security birth defects
3.selinux restive
4. Monitoring container and troubleshooting
II: Installation Requirements
1.64 operating system
2. At least RHEL6.5 version of the above, the personal version is strongly recommended RHEL7.0
3. Turn off the firewall (not required)
4. The kernel version must be 3.10 or more, you can check the kernel version by command uname -r
Three: Installation docker
1. docker already installed, you need to uninstall
命令：yum -y remove docker docker-client docker-client-latest docker-common docker-latest docker-latest-logrotate docker-logrotate docker-selinux docker-engine-selinux docker-engine
Because I am a new virtual machine, docker history does not install
2. Installation docker dependencies
命令：yum -y install yum-utils device-mapper-persistent-data lvm2
There are two ways to download docker sources, one official, one is cloud Ali, Ali recommended to use personal cloud
Command: cd /etc/yum.repos.d/
Official website address: yum-config-Manager - the Add-repo HTTPS: //download.docker.com/linux/centos/docker-ce.repo
Ali Cloud Address: yum-config-Manager - the Add-repo HTTP: //mirrors.aliyun.com/docker-ce/linux/centos/docker-ce.repo 
3. formal installation docker
命令：yum -y install docker-ce
4. Start docker and testing
Command: systemctl start docker # start docker
Testing: docker run hello-world
After executing the command docker, if the content is consistent with the following figure indicates success
Or enter ip a (ifconfig) will appear as shown, the installation is successful
to sum up:. . . . . . . Omitted here a million words