1. Install the latest version of Docker

The default version of centos7 is 1.13. To install a new version, uninstall the older version first

1.1 Delete an earlier Version

• Tell the docker service systemctl to stop the docker

• View the current version of the RPM – qa | grep docker

• Uninstalling software Packages

  yum erase docker \
                    docker-client \
                    docker-client-latest \
                    docker-common \
                    docker-latest \
                    docker-latest-logrotate \
                    docker-logrotate \
                    docker-selinux \
                    docker-engine-selinux \
                    docker-engine \
                    docker-ce
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• Deleting Related Configurations

  find /etc/systemd -name '*docker*' -exec rm -f {} \;
  find /etc/systemd -name '*docker*' -exec rm -f {} \;
  find /lib/systemd -name '*docker*' -exec rm -f {} \;
  rm -rf /var/lib/docker   Delete the existing image and container, not necessary
  rm -rf /var/run/docker 
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1.2 Installing the latest version

• Upgrading the System Package

  yum update

• Software Package Installation

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

• Add yum source

  yum-config-manager \
  --add-repo \
      https://download.docker.com/linux/centos/docker-ce.repo
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• View installable versions

  yum list docker-ce --showduplicates | sort -r

• Install the latest version

  yum install docker-ce -y

• Start and enable autoboot

  systemctl start docker
  systemctl enable docker
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• View the Docker version

  docker version

2. Solve the problem that the Internet cannot access the Docker port after it is mapped to the host in Linux

Conf or vi /usr/lib/sysctl.d/00-system.conf add the following code: Net.ipv4. ip_forward=1 Restart the network service systemctl restart network and check whether the IP address is changed successfully If net.ipv4.ip_forward = 1 is displayed, the system succeedsCopy the code

3. Docker starts automatically after startup

sudo systemctl enable docker
sudo systemctl start docker
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4. Docker views logs

docker logs -f -t --since="2017-05-31"--tail=10 edu_web_1 docker logs [OPTIONS] CONTAINER OPTIONS: --details Displays more information-fSince string Outputs the start date of the log, i.e., only outputs logs after the specified date. --tail string Displays the last number of lines of the log. The default is all (-tail=10: views the last 10 lines of the log.)Copy the code

5. Clean up the docker disk space and migrate the /var/lib/docker directory

1. View disk usage

   du -hs /var/lib/docker/

2. Migrate the /var/lib/docker-/ directory

   • Stop the Docker service

     systemctl stop docker

   • To create a new docker directory, run df -h to find a large disk. /home/ docker-lib /lib /home/ docker-lib /lib /home

     mkdir -p /home/docker/lib

   • Migrate files under /var/lib/docker directory to /home/docker-lib

     rsync -avz /var/lib/docker /home/docker/lib/

   • Configure the/etc/systemd/system/docker. Service. D/devicemapper. Conf. Check whether devicemapper.conf exists. If it does not exist, create one

     mkdir -p /etc/systemd/system/docker.service.d/
     vi /etc/systemd/system/docker.service.d/devicemapper.conf
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   • /home/docker/lib/docker/devicemapper.conf/devicemapper.conf/devicemapper.conf

     [Service]
     ExecStart=
     ExecStart=/usr/bin/dockerd  --graph=/home/docker/lib/docker
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   • Reload the Docker

     systemctl daemon-reload
      
     systemctl restart docker
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   • To make sure everything goes well, run the docker info command to check the root directory of the Docker. It will be changed to /home/dock/lib/docker

     . Docker Root Dir: /home/docker/lib/docker Debug Mode (client):false
     Debug Mode (server): false
     Registry: https://index.docker.io/v1/
     
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   • After successful startup, confirm that the previous image is still there: Docker Images

   • Delete the files in the /var/lib/docker-/ directory

6. Docker limits the container log size

• Create /etc/docker-daemon. json if it already exists, do not create it

• Add the log-opts parameter

  "log-driver":"json-file"."log-opts": {"max-size" :"50m"."max-file":"1"}
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• Load the configuration file and restart

  systemctl daemon-reload
  systemctl restart docker
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