Detailed installation process of Jenkins on Linux

			contos7
			jdk1.8
			jenkins-2.190.3-1.1

		Xiaobai recommends downloading directly with the command yum install java-1.8.0-openjdk* -y

		Download the official JDK1.8 package:
			http://www.oracle.com/technetwork/java/javase/downloads/jdk8-downloads-2133151.html
			
		Copy to the server:
			There are many ways to do this: I download xftp7 and then drag it in directly		
		Unzip:
			tar -zxvf jdk-****-linux-x64.tar.gz
			
		Open the configuration environment variables:
			vim/etc/profiles

		Update environment variables: 
			Source /etc/profile
		Input View:
			Java -version

		Command to switch to your own download directory and download directly with command wget http://pkg.jenkins-ci.org/redhat-stable/jenkins-2.190.3-1.1.noarch.rpm
		Download and install directly rpm -ivh jenkins-2.190.3-1.1.noarch.rpm

		vi /etc/syscofig/jenkins
		Modify the port as follows:
		JENKINS_PORT="8888"

		Start command: systemctl start jenkins

 	Open the file: vim /etc/init.d/jenkins  
 	Configure the JDK path in Jenkins

Run the systemctl daemon-reload command to reload the configuration file. Run the systemctl start jenkins command to start Jenkins.
Execute the systemctl status jenkins.service command to view the status of the Jenkins service.

	CentoS7
			1. Open the firewall systemctl start firewalld
			2. Open the specified port firewall-cmd --zone=public --add-port=８８８８/tcp --permanent
			 Command meaning:
			--zone #scope --add-port=８８８８/tcp #Add port, the format is: port/communication protocol --permanent #Permanently effective, without this parameter, it will become invalid after restart 3. Restart the firewall firewall-cmd --reload
			4. Check the port number netstat -ntlp // View all current TCP ports

	Visit: http://192.168.5.53:8888

	Command input:
		cat /var/lib/jenkins/secrets/initialAdminPassword

		It is recommended to click "Select plugin to install"
		Then on the next screen, uncheck all the selected plugins. Because Jenkins connects to the official by default, the speed is very slow and will fail, so skip the plugin installation first.

		1) Create a user according to the prompts (no big problem)
		2) Instance configuration (default is fine)
		3) If you see Jenkins is ready, it means everything is fine. Click Start and wait for a while.