1、查看jenkins旧版本
jenkins页面端提示需要升级jenkins 2.361.1，由于是测试服务器，所以就升级下，然后就有不可描述的事情发生了。
代码语言：javascript复制[root@linux-01 ~]# ps -ef |grep jenkins
jenkins 6816 1 0 14:34 ? 00:01:25 /usr/local/jdk1.8/bin/java -Dcom.sun.akuma.Daemon=daemonized -Djava.awt.headless=true -DJENKINS_HOME=/var/lib/jenkins -jar /usr/lib/jenkins/jenkins.war --logfile=/var/log/jenkins/jenkins.log --webroot=/var/cache/jenkins/war --daemon --httpPort=8080 --debug=5 --handlerCountMax=100 --handlerCountMaxIdle=20
root 10645 8043 0 18:47 pts/1 00:00:00 grep --color=auto jenkins通过服务器上ps的jenkins进程可以查看到jenkins的war包所在目录是：/usr/lib/jenkins/；jdk使用的是8的版本。
2、下载jenkins最新版本2.361.1
代码语言：javascript复制[root@linux-01 ~]# wget https://mirrors.tuna.tsinghua.edu.cn/jenkins/war-stable/2.361.1/jenkins.war --no-check-certificate
# 省略下载过程3、替换war包
代码语言：javascript复制[root@linux-01 ~]# cd /usr/lib/jenkins/
[root@linux-01 jenkins]# mv jenkins.war jenkins.war.bak
[root@linux-01 jenkins]# mv ~/jenkins.war ./
[root@linux-01 jenkins]# ll
总用量 156212
-r-------- 1 root root 93504273 9月 7 18:05 jenkins.war
-rw-r--r-- 1 root root 66452488 8月 12 2020 jenkins.war.bak4、重新启动jenkins出问题
代码语言：javascript复制[root@linux-01 jenkins]# /etc/init.d/jenkins stop
Stopping jenkins (via systemctl): [ 确定 ]
[root@linux-01 jenkins]# /etc/init.d/jenkins start
Starting jenkins (via systemctl): [ 确定 ]
[root@linux-01 jenkins]#
[root@linux-01 jenkins]#
[root@linux-01 jenkins]# !ps
ps -ef |grep jenkins
root 26750 8043 0 19:04 pts/1 00:00:00 grep --color=auto jenkins
[root@linux-01 jenkins]# ll
总用量 156212启动jenkins的时候发现无法启动jenkins，然后就查看了jenkins的状态
代码语言：javascript复制[root@linux-01 jenkins]# service jenkins status
● jenkins.service - LSB: Jenkins Automation Server
Loaded: loaded (/etc/rc.d/init.d/jenkins; bad; vendor preset: disabled)
Active: active (exited) since 一 2022-09-19 19:03:30 CST; 1min 39s ago
Docs: man:systemd-sysv-generator(8)
Process: 25966 ExecStop=/etc/rc.d/init.d/jenkins stop (code=exited, status=0/SUCCESS)
Process: 26141 ExecStart=/etc/rc.d/init.d/jenkins start (code=exited, status=0/SUCCESS)
9月 19 19:03:30 linux-01 jenkins[26141]: java.lang.UnsupportedClassVersionError: 52.0
9月 19 19:03:30 linux-01 jenkins[26141]: at executable.Main.verifyJavaVersion(Main.java:145)
9月 19 19:03:30 linux-01 jenkins[26141]: at executable.Main.main(Main.java:109)
9月 19 19:03:30 linux-01 jenkins[26141]: Jenkins requires Java versions [17, 11] but you are running with Java 1.8 from /usr/local/jdk1.8/jre
9月 19 19:03:30 linux-01 jenkins[26141]: java.lang.UnsupportedClassVersionError: 52.0
9月 19 19:03:30 linux-01 jenkins[26141]: at executable.Main.verifyJavaVersion(Main.java:145)
9月 19 19:03:30 linux-01 jenkins[26141]: at executable.Main.main(Main.java:109)
9月 19 19:03:30 linux-01 runuser[26147]: pam_unix(runuser:session): session closed for user jenkins
9月 19 19:03:30 linux-01 jenkins[26141]: [ 确定 ]
9月 19 19:03:30 linux-01 systemd[1]: Started LSB: Jenkins Automation Server.发现报了一个java的错误：java.lang.UnsupportedClassVersionError: 52.0 去官网查询了下，发现需要升级jdk版本，8的版本无法启用最新的jenkins，可以通过如下图看到升级到2.361.1版本需要java 11或者java 17，我采用了java 17版本。
5、下载安装新版本的JDK
代码语言：javascript复制[root@linux-01 jenkins]# cd
[root@linux-01 ~]# wget https://mirror.nju.edu.cn/adoptium/17/jdk/x64/linux/OpenJDK17U-jdk_x64_linux_hotspot_17.0.4.1_1.tar.gz
下载省略jdk8以上的版本貌似就有没有jre目录，需要生成下
代码语言：javascript复制[root@linux-01 ~]# tar -xvf OpenJDK17U-jdk_x64_linux_hotspot_17.0.4.1_1.tar.gz -C /usr/local/
# 解压省略
[root@linux-01 ~]# cd /usr/local/
[root@linux-01 local]# mv jdk-17.0.4.1 1 jdk17
# 修改系统环境变量
[root@linux-01 local]# vim /etc/profile
[root@linux-01 local]# source /etc/profile
export JAVA_HOME=/usr/local/jdk17/
export CLASSPATH=.:$JAVA_HOME/jre/lib/rt.jar:$JAVA_HOME/lib/dt.jar:$JAVA_HOME/lib/tools.jar
[root@linux-01 local]# source /etc/profile
[root@linux-01 ~]# java --version
openjdk 17.0.4.1 2022-08-12
OpenJDK Runtime Environment Temurin-17.0.4.1 1 (build 17.0.4.1 1)
OpenJDK 64-Bit Server VM Temurin-17.0.4.1 1 (build 17.0.4.1 1, mixed mode, sharing)jdk17是没有jre目录的，顺变生成下jre目录
代码语言：javascript复制[root@linux-01 ~]# ll /usr/local/jdk17/
总用量 24
drwxr-xr-x 2 root root 4096 8月 17 19:56 bin
drwxr-xr-x 5 root root 123 8月 17 19:55 conf
drwxr-xr-x 3 root root 132 8月 17 19:55 include
drwxr-xr-x 2 root root 4096 8月 17 19:55 jmods
drwxr-xr-x 72 root root 4096 8月 17 19:55 legal
drwxr-xr-x 5 root root 4096 8月 17 19:56 lib
drwxr-xr-x 3 root root 18 8月 17 19:55 man
-rw-r--r-- 1 root root 2439 8月 17 19:56 NOTICE
-rw-r--r-- 1 root root 1566 8月 17 19:55 release
[root@linux-01 ~]# cd $!
cd /usr/local/jdk17/
[root@linux-01 jdk17]# ./bin/jlink.exe --module-path jmods --add-modules java.desktop --output jre
[root@linux-01 jdk17]# ll
总用量 24
drwxr-xr-x 2 root root 4096 8月 17 19:56 bin
drwxr-xr-x 5 root root 123 8月 17 19:55 conf
drwxr-xr-x 3 root root 132 8月 17 19:55 include
drwxr-xr-x 2 root root 4096 8月 17 19:55 jmods
drwxr-xr-x 8 root root 94 9月 19 20:24 jre
drwxr-xr-x 72 root root 4096 8月 17 19:55 legal
drwxr-xr-x 5 root root 4096 8月 17 19:56 lib
drwxr-xr-x 3 root root 18 8月 17 19:55 man
-rw-r--r-- 1 root root 2439 8月 17 19:56 NOTICE
-rw-r--r-- 1 root root 1566 8月 17 19:55 release6、重新启动jenkins，发现还是有问题
代码语言：javascript复制[root@linux-01 local]# /etc/init.d/jenkins start
Starting jenkins (via systemctl): [ 确定 ]
[root@linux-01 local]# ps -ef |grep jenkins
root 10850 7462 0 19:39 pts/0 00:00:00 grep --color=auto jenkins
[root@linux-01 local]#
[root@linux-01 local]#
[root@linux-01 local]# /etc/init.d/jenkins status
● jenkins.service - LSB: Jenkins Automation Server
Loaded: loaded (/etc/rc.d/init.d/jenkins; bad; vendor preset: disabled)
Active: active (exited) since 一 2022-09-19 19:33:27 CST; 6min ago
Docs: man:systemd-sysv-generator(8)
Process: 6407 ExecStart=/etc/rc.d/init.d/jenkins start (code=exited, status=0/SUCCESS)
9月 19 19:33:27 linux-01 jenkins[6407]: java.lang.UnsupportedClassVersionError: 62.0
9月 19 19:33:27 linux-01 jenkins[6407]: at Main.verifyJavaVersion(Main.java:174)
9月 19 19:33:27 linux-01 jenkins[6407]: at Main.main(Main.java:142)
9月 19 19:33:27 linux-01 jenkins[6407]: Jenkins requires Java versions [8, 11] but you are running with Java 18 from /usr/local/jdk1.8
9月 19 19:33:27 linux-01 jenkins[6407]: java.lang.UnsupportedClassVersionError: 62.0
9月 19 19:33:27 linux-01 jenkins[6407]: at Main.verifyJavaVersion(Main.java:174)
9月 19 19:33:27 linux-01 jenkins[6407]: at Main.main(Main.java:142)
9月 19 19:33:27 linux-01 runuser[6419]: pam_unix(runuser:session): session closed for user jenkins
9月 19 19:33:27 linux-01 jenkins[6407]: [ 确定 ]
9月 19 19:33:27 linux-01 systemd[1]: Started LSB: Jenkins Automation Server.
[root@linux-01 local]# /etc/init.d/jenkins status
● jenkins.service - LSB: Jenkins Automation Server
Loaded: loaded (/etc/rc.d/init.d/jenkins; bad; vendor preset: disabled)
Active: active (exited) since 一 2022-09-19 19:33:27 CST; 6min ago
Docs: man:systemd-sysv-generator(8)
Process: 6407 ExecStart=/etc/rc.d/init.d/jenkins start (code=exited, status=0/SUCCESS)6.1 yum升级jenkins
本身jdk版本系统中已经更换为了jdk17，但是jenkins启动的时候无法识别到这个jdk。中间通过命令的方式启动jenkins的，还是会报错。
代码语言：javascript复制[root@linux-01 jdk17]# yum list |grep jenkins
https://dl.bintray.com/rabbitmq/rpm/rabbitmq-server/v3.8.x/el/7/repodata/repomd.xml: [Errno 14] HTTPS Error 502 - Bad Gateway
正在尝试其它镜像。
jenkins.noarch 2.235.4-1.1 installed
jenkins.noarch 2.361.1-1.1 jenkins
python2-jenkins.noarch 0.4.16-2.el7 epel
python2-jenkins-job-builder.noarch 1.4.0-3.el7 epel
python36-jenkins.noarch 0.4.16-2.el7 epel 通过yum list可以查看到有新的jenkins的版本，所以直接通过yum update jenkins升级。
代码语言：javascript复制[root@linux-01 jdk17]# yum update jenkins升级过后需要修改下jenkins启动脚本的jdk参数。
代码语言：javascript复制[root@linux-01 jdk17]# cat /usr/lib/systemd/system/jenkins.service
[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
User=jenkins
Group=jenkins
Environment="JENKINS_HOME=/var/lib/jenkins"
WorkingDirectory=/var/lib/jenkins
Environment="JENKINS_WEBROOT=%C/jenkins/war"
Environment="JAVA_HOME=/usr/local/jdk17/" #修改了此处的jdk信息
Environment="JAVA_OPTS=-Djava.awt.headless=true"
Environment="JENKINS_PORT=8080"
[Install]
WantedBy=multi-user.target
[root@linux-01 jdk17]# systemctl daemon-reload 使用这个脚本启动jenkins，发现有进程，端口也启动成功。
代码语言：javascript复制[root@linux-01 ~]# systemctl start jenkins
[root@linux-01 ~]# ps -ef |grep jenkins
root 111601 24934 0 20:35 pts/2 00:00:00 systemctl start jenkins
jenkins 111607 1 9 20:35 ? 00:00:08 /usr/local/jdk17//bin/java -Djava.awt.headless=true -jar /usr/share/java/jenkins.war --webroot=%C/jenkins/war --httpPort=8080
root 114734 7462 0 20:36 pts/0 00:00:00 grep --color=auto jenkins
[root@linux-01 ~]# netstat -lntp
Active Internet connections (only servers)
Proto Recv-Q Send-Q Local Address Foreign Address State PID/Program name
tcp 0 0 0.0.0.0:22 0.0.0.0:* LISTEN 6403/sshd
tcp 0 0 127.0.0.1:25 0.0.0.0:* LISTEN 6682/master
tcp6 0 0 :::8080 :::* LISTEN 107113/java
tcp6 0 0 :::22 :::* LISTEN 6403/sshd
tcp6 0 0 ::1:25 :::* LISTEN 6682/master 7、页面出问题
本以为端口启动成功后，可以正常访问网页，访问网页后发现出了java的报错
访问网址：https://www.jenkins.io/redirect/troubleshooting/java.awt.headless
通过上文可以查看到centos7 需要安装一个fontconfig
代码语言：javascript复制[root@linux-01 jdk17]# yum install fontconfig -y
安装省略8、大功告成，终于可以正常访问
9、修改init.d下的jenkins脚本
代码语言：javascript复制[root@linux-01 ~]# vim /etc/init.d/jenkins
# 修改candidates的参数为如下，也可以正常启动和关闭jenkins服务
candidates="
/usr/local/jdk17/bin/java
/usr/local/jdk17/jre/bin/java
"
[root@linux-01 ~]# service jenkins stop
Stopping jenkins (via systemctl): [ 确定 ]
[root@linux-01 ~]# ps -ef |grep jenkins
root 5719 7462 0 22:57 pts/0 00:00:00 grep --color=auto jenkins
[root@linux-01 ~]#
[root@linux-01 ~]#
[root@linux-01 ~]# service jenkins start
Starting jenkins (via systemctl): [ 确定 ]
[root@linux-01 ~]# !ps
ps -ef |grep jenkins
jenkins 6040 1 59 22:57 ? 00:00:20 /usr/local/jdk17//bin/java -Djava.awt.headless=true -jar /usr/share/java/jenkins.war --webroot=%C/jenkins/war --httpPort=8080
root 7293 7462 0 22:58 pts/0 00:00:00 grep --color=auto jenkins
