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This article introduces the knowledge of "how to install Docker in CentOS 7". In the operation of practical cases, many people will encounter such a dilemma, so let the editor lead you to learn how to deal with these situations. I hope you can read it carefully and be able to achieve something!

First, getting started with Docker

1.1 introduction to Docker

Official website: https://hub.docker.com/

It can be simply considered that the container is a super lightweight virtual machine (host), and the processes between the container and the container are isolated from each other.

The benefits of using containers: providing nodes that can be used as a host

1.2 differences between containers and virtual machines

Three basic concepts: image (mirror), Container (container), Reository (warehouse)

Second, install Docker

CentOS 7 install Docker: https://docs.docker.com/engine/install/centos/

* * 2.1.Uninstall the old version of Docker * *

Yum remove-y docker docker-client docker-client-latest docker-common\

Docker-latest docker-latest-logrotate docker-logrotate\

Docker-selinux docker-engine-selinux docker-engine

2.2. Execute the following installation command to install the dependency package

Yum install-y yum-utils device-mapper-persistent-data lvm2

Sudo yum-config-manager\

-- add-repo\

Https://download.docker.com/linux/centos/docker-ce.repo

[root@centos7] yum-y install docker-ce docker-ce-cli containerd.io

[root@centos7 ~] # docker ps-- View docker

Cannot connect to the Docker daemon at unix:///var/run/docker.sock. Is the docker daemon running?-- docker did not start

2.3.Starting Docker

[root@centos7 ~] # systemctl enable docker

Created symlink from / etc/systemd/system/multi-user.target.wants/docker.service to / usr/lib/systemd/system/docker.service.

[root@centos7 ~] # systemctl start docker

[root@centos7 ~] # systemctl status docker

● docker.service-Docker Application Container Engine

Loaded: loaded (/ usr/lib/systemd/system/docker.service; enabled; vendor preset: disabled)

Active: active (running) since Sat 2021-01-16 18:47:43 EST; 6s ago

Docs: https://docs.docker.com

Main PID: 2435 (dockerd)

Memory: 45.1M

CGroup: / system.slice/docker.service

└─ 2435 / usr/bin/dockerd-H fd://-- containerd=/run/containerd/containerd.sock

Jan 16 18:47:43 centos7 dockerd [2435]: time= "2021-01-16T18:47:43.051980834-05:00" >

Jan 16 18:47:43 centos7 dockerd [2435]: time= "2021-01-16T18:47:43.051989827-05:00" level=info msg= "ClientConn switchin...e=grpc"

Jan 16 18:47:43 centos7 dockerd [2435]: time= "2021-01-16T18:47:43.077331225-05:00" level=info msg= "Loading containers: start."

Jan 16 18:47:43 centos7 dockerd [2435]: time= "2021-01-16T18:47:43.382655173-05:00" level=info msg= "Default bridge (doc...dress"

Jan 16 18:47:43 centos7 dockerd [2435]: time= "2021-01-16T18:47:43.449861379-05:00" level=info msg= "Loading containers: done."

Jan 16 18:47:43 centos7 dockerd [2435]: time= "2021-01-16T18:47:43.463137686-05:00" level=warning msg= "Not using native...erlay2"

Jan 16 18:47:43 centos7 dockerd [2435]: time= "2021-01-16T18:47:43.463311349-05:00" level=info msg= "Docker daemon" comm...0.10.2

Jan 16 18:47:43 centos7 dockerd [2435]: time= "2021-01-16T18:47:43.463380194-05:00" level=info msg= "Daemon has complete...ation"

Jan 16 18:47:43 centos7 systemd [1]: Started Docker Application Container Engine.

Jan 16 18:47:43 centos7 dockerd [2435]: time= "2021-01-16T18:47:43.493313812-05:00" level=info msg= "API listen on / var/....sock"

Hint: Some lines were ellipsized, use-l to show in full.

[root@centos7 ~] # docker ps-- View the container

[root@centos7 ~] # docker version-- View version

[root@centos7 ~] # docker info-- View version

# Open all ports (optional)

Firewall-cmd-add-port=0-65535/tcp-permanent

Firewall-cmd-reload

Firewall-cmd-list-ports

We can also install Docker directly with a single command:

[root@centos7 ~] # curl-fsSL get.docker.com-o get-docker.sh-download the sh script

[root@centos7 ~] # sh get-docker.sh-execute script

* * 2.4.The method of modifying the storage location of Docker local images and containers

By default, the location of Docker is: / var/lib/docker

You can view the location with the command: docker info | grep "Docker Root Dir"

Modify to another directory

First stop the Docker service:

Systemctl stop docker

Then move the entire / var/lib/docker directory to the destination path

Mkdir-p / root/data/docker

Mv / var/lib/docker / root/data/docker

Ln-s / root/data/docker / var/lib/docker-shortcuts

3. Docker command

Domestic image: https://hub.daocloud.io/

Docker pull daocloud.io/library/centos:8.2.2004

3.1 create a container

# pull an image from the network

Docker pull centos:7.8.2003

# create a container that includes some of the basic environments in which CentOS 7.8 runs

# docker images-Image

REPOSITORY TAG IMAGE ID CREATED SIZE

Daocloud.io/library/centos 8.2.2004 831691599b88 7 months ago 215MB

* * centos 7.8.2003 * * afb6fca791e0 8 months ago 203MB

Docker run-d-name centos7.8-h centos7.8\

-p 220V 22-p 3387R 3389\

-- privileged=true\

Centos:7.8.2003 / usr/sbin/init

# I want to have an environment of linux 8.2

Docker run-d-name centos8.2-h centos8.2\

-p 230VR 22-p 3386VR 3389\

-- privileged=true\

Daocloud.io/library/centos:8.2.2004 init

# enter the container

Docker exec-it centos7.8 bash

Docker exec-it centos8.2 bash

Cat / etc/redhat-release-- View the system version

# make an image

Docker commit centos7.8 centos7.8_test:1.0-name + version number

That's all for "how to install Docker in CentOS 7". Thank you for reading. If you want to know more about the industry, you can follow the website, the editor will output more high-quality practical articles for you!

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