Installing JDK, Git, and Docker on a Linux Host

1. Creating the java folder in /usr/local: sudo mkdir /usr/local/java
2. Copying the downloaded package to java: cp jdk-8u144-linux-x64.tar.gz /usr/local/java
3. Going to java: cd /usr/local/java
4. Decompressing the package: sudo tar -xvf jdk-8u144-linux-x64.tar.gz
5. Deleting the package: sudo rm jdk-8u144-linux-x64.tar.gz

Modify /etc/profile, which is an environment variable shared by all users.

1. Run the sudo vim /etc/profile command to open the /etc/profile file.
2. Add the following code segment to the end of the file:

   export JAVA_HOME=/usr/local/java/jdk1.8.0_144
   export JRE_HOME=/usr/local/java/jdk1.8.0_144/jre
   export CLASSPATH=.:$JAVA_HOME/LIB/DT.JAR:$JAVA_HOME/lib/tools.jar:$JAVA_HOME/lib:$CLASSPATH
   export PATH=$JAVA_HOME/bin:$PATH

   

   When adding the preceding code, pay attention to the following:

   • Do not add spaces before or after an equal sign (=).
   • Separate variables with colons (:), not semicolons (;).
3. Press Esc, enter :wq!, and press Enter to save the modified file.
4. Reload the /etc/profile file.

   source /etc/profile

If the following information is displayed, installation is successful.

If the following information is displayed, installation is successful.

1. Decompressing the package: tar zxvf docker-19.03.15.tgz
2. Moving the docker package to /usr/bin/: mv ./docker/* /usr/bin/

1. Run the vim /usr/lib/systemd/system/docker.service command to open the docker.service file.
2. Press I and copy the following content to the file:

   [Unit]
   Description=Docker Application Container Engine
   Documentation=https://docs.docker.com
   After=network-online.target firewalld.service
   Wants=network-online.target
   
   [Service]
   Type=notify
   # the default is not to use systemd for cgroups because the delegate issues still
   # exists and systemd currently does not support the cgroup feature set required
   # for containers run by docker
   ExecStart=/usr/bin/dockerd
   ExecReload=/bin/kill -s HUP $MAINPID
   # Having non-zero Limit*s causes performance problems due to accounting overhead
   # in the kernel. We recommend using cgroups to do container-local accounting.
   LimitNOFILE=infinity
   LimitNPROC=infinity
   LimitCORE=infinity
   # Uncomment TasksMax if your systemd version supports it.
   # Only systemd 226 and above support this version.
   #TasksMax=infinity
   TimeoutStartSec=0
   # set delegate yes so that systemd does not reset the cgroups of docker containers
   Delegate=yes
   # kill only the docker process, not all processes in the cgroup
   KillMode=process
   # restart the docker process if it exits prematurely
   Restart=on-failure
   StartLimitBurst=3
   StartLimitInterval=60s
   
   [Install]
   WantedBy=multi-user.target

3. Press Esc, enter :wq!, and press Enter to save the modified file.

systemctl daemon-reload

systemctl enable docker.service

systemctl restart docker.service

If the following information is displayed, installation is successful.