CentOS7.9安裝Jenkins
参考jenkins官网文档进行安装，Jenkins download and deployment
sudo wget -O /etc/yum.repos.d/jenkins.repo https://pkg.jenkins.io/redhat-stable/jenkins.repo
sudo rpm --import https://pkg.jenkins.io/redhat-stable/jenkins.io-2023.key
yum install fontconfig java-11-openjdk
yum install jenkins
启动Jenkins
参考jenkins官网执行启动命令，Linux (jenkins.io)
sudo systemctl start jenkins
參考Jenkins官方文档、安装后执行启动命令、报错： Failed to start Jenkins Continuous Integration Server.
解决Jenkins启动报错
使用systemctl 启动时不会使用上述的etc/init.d/jenkins配置文件。
而是会使用/usr/lib/systemd/system/jenkins.service文件，
需要修改/usr/lib/systemd/system/jenkins.service文件配置
使用vim打开/usr/lib/systemd/system/jenkins.service文件，修改成如下配置
# Unix account that runs the Jenkins daemon
# Be careful when you change this, as you need to update the permissions of
# $JENKINS_HOME, $JENKINS_LOG, and (if you have already run Jenkins)
# $JENKINS_WEBROOT.
User=root
Group=root
# The Java home directory. When left empty, JENKINS_JAVA_CMD and PATH are consulted.
Environment="JAVA_HOME=/usr/lib/jvm/jre-11-openjdk"
修改完成，使用:qw保存退出，此时jenkins.service已在磁盘上更改。运行“systemctl daemon reload”以重新加载单元。
systemctl daemon reload
重新加载单元后，运行Jenkins
sudo systemctl start jenkins
访问Jenkins
http://{你的ip}:8080进行访问，打开/var/lib/jenkins/secrets/initialAdminPassword文件查询密码，进入
相关截图参考
/usr/lib/systemd/system/jenkins.service 文件修改整体配置:
#
# This file is managed by systemd(1). Do NOT edit this file manually!
# To override these settings, run:
#
# systemctl edit jenkins
#
# For more information about drop-in files, see:
#
# https://www.freedesktop.org/software/systemd/man/systemd.unit.html
#
[Unit]
Description=Jenkins Continuous Integration Server
Requires=network.target
After=network.target
[Service]
Type=notify
NotifyAccess=main
ExecStart=/usr/bin/jenkins
Restart=on-failure
SuccessExitStatus=143
# Configures the time to wait for start-up. If Jenkins does not signal start-up
# completion within the configured time, the service will be considered failed
# and will be shut down again. Takes a unit-less value in seconds, or a time span
# value such as "5min 20s". Pass "infinity" to disable the timeout logic.
#TimeoutStartSec=90
# Unix account that runs the Jenkins daemon
# Be careful when you change this, as you need to update the permissions of
# $JENKINS_HOME, $JENKINS_LOG, and (if you have already run Jenkins)
# $JENKINS_WEBROOT.
User=root
Group=root
# Directory where Jenkins stores its configuration and workspaces
Environment="JENKINS_HOME=/var/lib/jenkins"
WorkingDirectory=/var/lib/jenkins
# Location of the Jenkins WAR
#Environment="JENKINS_WAR=/usr/share/java/jenkins.war"
# Location of the exploded WAR
Environment="JENKINS_WEBROOT=%C/jenkins/war"
# Location of the Jenkins log. By default, systemd-journald(8) is used.
#Environment="JENKINS_LOG=%L/jenkins/jenkins.log"
# The Java home directory. When left empty, JENKINS_JAVA_CMD and PATH are consulted.
Environment="JAVA_HOME=/usr/lib/jvm/jre-11-openjdk"
# The Java executable. When left empty, JAVA_HOME and PATH are consulted.
#Environment="JENKINS_JAVA_CMD=/etc/alternatives/java"
# Arguments for the Jenkins JVM
Environment="JAVA_OPTS=-Djava.awt.headless=true"
# IP address to listen on for HTTP requests.
# The default is to listen on all interfaces (0.0.0.0).
#Environment="JENKINS_LISTEN_ADDRESS="
# Port to listen on for HTTP requests. Set to -1 to disable.
# To be able to listen on privileged ports (port numbers less than 1024),
# add the CAP_NET_BIND_SERVICE capability to the AmbientCapabilities
# directive below.
Environment="JENKINS_PORT=8080"
# IP address to listen on for HTTPS requests. Default is disabled.
#Environment="JENKINS_HTTPS_LISTEN_ADDRESS="
# Port to listen on for HTTPS requests. Default is disabled.
# To be able to listen on privileged ports (port numbers less than 1024),
# add the CAP_NET_BIND_SERVICE capability to the AmbientCapabilities
# directive below.
#Environment="JENKINS_HTTPS_PORT=443"
# Path to the keystore in JKS format (as created by the JDK's keytool).
# Default is disabled.
#Environment="JENKINS_HTTPS_KEYSTORE=/path/to/keystore.jks"
# Password to access the keystore defined in JENKINS_HTTPS_KEYSTORE.
# Default is disabled.
#Environment="JENKINS_HTTPS_KEYSTORE_PASSWORD=s3cR3tPa55w0rD"
# IP address to listen on for HTTP2 requests. Default is disabled.
#Environment="JENKINS_HTTP2_LISTEN_ADDRESS="
# HTTP2 port to listen on. Default is disabled.
# To be able to listen on privileged ports (port numbers less than 1024),
# add the CAP_NET_BIND_SERVICE capability to the AmbientCapabilities
# directive below.
#Environment="JENKINS_HTTP2_PORT="
# Controls which capabilities to include in the ambient capability set for the
# executed process. Takes a whitespace-separated list of capability names, e.g.
# CAP_SYS_ADMIN, CAP_DAC_OVERRIDE, CAP_SYS_PTRACE. Ambient capability sets are
# useful if you want to execute a process as a non-privileged user but still
# want to give it some capabilities. For example, add the CAP_NET_BIND_SERVICE
# capability to be able to listen on privileged ports (port numbers less than
# 1024).
#AmbientCapabilities=CAP_NET_BIND_SERVICE
# Debug level for logs. The higher the value, the more verbose. 5 is INFO.
#Environment="JENKINS_DEBUG_LEVEL=5"
# Set to true to enable logging to /var/log/jenkins/access_log.
#Environment="JENKINS_ENABLE_ACCESS_LOG=false"
# Servlet context (important if you want to use reverse proxying)
#Environment="JENKINS_PREFIX=/jenkins"
# Arbitrary additional arguments to pass to Jenkins.
# Full option list: java -jar jenkins.war --help
#Environment="JENKINS_OPTS="
# Maximum core file size. If unset, the value from the OS is inherited.
#LimitCORE=infinity
# Maximum file size. If unset, the value from the OS is inherited.
#LimitFSIZE=infinity
# File descriptor limit. If unset, the value from the OS is inherited.
#LimitNOFILE=8192
# Maximum number of processes. If unset, the value from the OS is inherited.
#LimitNPROC=32768
# Set the umask to control the permission bits of files that Jenkins creates.
#
# 0027 makes files read-only for group and inaccessible for others, which some
# security sensitive users might consider beneficial, especially if Jenkins
# is running on a server that is used for multiple purposes. Beware that 0027
# permissions would interfere with sudo scripts that run on the controller
# (see JENKINS-25065).
#
# Note also that the particularly sensitive parts of $JENKINS_HOME (such as
# credentials) are always written without 'other' access. So the umask values
# only affect job configuration, build records, etc.
#
# If unset, the value from the OS is inherited, which is normally 0022.
# The default umask comes from pam_umask(8) and /etc/login.defs.
#UMask=0022
[Install]
WantedBy=multi-user.target