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直接安装jenkins后，对于jdk11，jenkins是跑不起来的。会提示需要jdk1.8

jenkins安装

下载依赖

sudo wget -O /etc/yum.repos.d/jenkins.repo https://pkg.jenkins.io/redhat-stable/jenkins.repo

导入秘钥

sudo rpm --import https://pkg.jenkins.io/redhat-stable/jenkins.io.key

安装

yum install jenkins #等待安装时间较长，约25min

配置

安装JDK后，Jenkins无法启动，需要修改vi /etc/rc.d/init.d/jenkins， 查找，输入/java, 添加新的jre路径

# Search usable Java. We do this because various reports indicated
# that /usr/bin/java may not always point to Java >= 1.6
# see http://www.nabble.com/guinea-pigs-wanted-----Hudson-RPM-for-RedHat-Linux-td25673707.html
candidates="
/etc/alternatives/java
/usr/lib/jvm/java-1.6.0/bin/java
/usr/lib/jvm/jre-1.6.0/bin/java
/usr/lib/jvm/java-1.7.0/bin/java
/usr/lib/jvm/jre-1.7.0/bin/java
/usr/lib/jvm/java-1.8.0/bin/java
/usr/lib/jvm/jre-1.8.0/bin/java
/usr/bin/java
/data/java/jdk1.8.0_101/bin/java
"

jenkins相关目录释义

• /usr/lib/jenkins/：jenkins安装目录，war包会放在这里。
• /etc/sysconfig/jenkins：jenkins配置文件，“端口”，“JENKINS_HOME”等都可以在这里配置。
• /var/lib/jenkins/：默认的JENKINS_HOME。
• /var/log/jenkins/jenkins.log：jenkins日志文件。

java11时Jenkins出错解决方案

上面启动之后会报错，不支持jdk11，解决如下：
参考手册：https://jenkins.io/blog/2018/06/17/running-jenkins-with-java10-11/

具体操作：先将Jenkins的进程 kill 掉，然后下载四个jar包：

wget http://central.maven.org/maven2/javax/xml/bind/jaxb-api/2.3.0/jaxb-api-2.3.0.jar
wget http://central.maven.org/maven2/com/sun/xml/bind/jaxb-core/2.3.0.1/jaxb-core-2.3.0.1.jar
wget http://central.maven.org/maven2/com/sun/xml/bind/jaxb-impl/2.3.0.1/jaxb-impl-2.3.0.1.jar
wget https://github.com/javaee/activation/releases/download/JAF-1_2_0/javax.activation.jar

修改jar包的名称：

mv jaxb-api-2.3.0.jar jaxb-api.jar
mv jaxb-core-2.3.0.1.jar jaxb-core.jar
mv jaxb-impl-2.3.0.1.jar jaxb-impl.jar
将上面四个jar拷贝到jenkins.war的目录（方便执行启动命令）

运行命令：

nohup java -p jaxb-api.jar:javax.activation.jar --add-modules java.xml.bind,java.activation -cp jaxb-core.jar:jaxb-impl.jar -jar jenkins.war --enable-future-java &
这里你可以不用输出日志到nohup，如果长期下去，日志会打满硬盘，记得定时清除

结果启动报错，然后接着查找原因：
运行：

yum install dejavu-sans-fonts
yum install fontconfig

然后再次运行以上的启动命令，成功

参考

https://www.jianshu.com/p/0d7a615165ae
https://wiki.jenkins.io/display/JENKINS/Jenkins+got+java.awt.headless+problem
https://jenkins.io/blog/2018/06/17/running-jenkins-with-java10-11/