报错信息：
java.lang.RuntimeException: unsupported Java version: 11 at org.jruby.RubyInstanceConfig.initGlobalJavaVersion(RubyInstanceConfig.java:1674) at org.jruby.RubyInstanceConfig.<clinit>(RubyInstanceConfig.java:1387) Caused: java.lang.ExceptionInInitializerError at org.jruby.embed.internal.AbstractLocalContextProvider.<init>(AbstractLocalContextProvider.java:42) at org.jruby.embed.internal.SingleThreadLocalContextProvider.<init>(SingleThreadLocalContextProvider.java:43) at org.jruby.embed.ScriptingContainer.getProviderInstance(ScriptingContainer.java:242) at org.jruby.embed.ScriptingContainer.<init>(ScriptingContainer.java:226) at org.jruby.embed.ScriptingContainer.<init>(ScriptingContainer.java:192) at org.kohsuke.stapler.jelly.jruby.JRubyFacet.<init>(JRubyFacet.java:65) at ruby.RubyRuntimePlugin.registerJRubyFacet(RubyRuntimePlugin.java:39) at ruby.RubyRuntimePlugin.start(RubyRuntimePlugin.java:30) at hudson.ClassicPluginStrategy.startPlugin(ClassicPluginStrategy.java:408) at hudson.ClassicPluginStrategy.load(ClassicPluginStrategy.java:397) Caused: java.io.IOException: Failed to initialize at hudson.ClassicPluginStrategy.load(ClassicPluginStrategy.java:400) at hudson.PluginManager.dynamicLoad(PluginManager.java:922) Caused: java.io.IOException: Failed to install ruby-runtime plugin at hudson.PluginManager.dynamicLoad(PluginManager.java:934) at hudson.model.UpdateCenter$InstallationJob._run(UpdateCenter.java:2183) Caused: java.io.IOException: Failed to dynamically deploy this plugin at hudson.model.UpdateCenter$InstallationJob._run(UpdateCenter.java:2187) at hudson.model.UpdateCenter$DownloadJob.run(UpdateCenter.java:1850) at java.base/java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:515) at java.base/java.util.concurrent.FutureTask.run(FutureTask.java:264) at hudson.remoting.AtmostOneThreadExecutor$Worker.run(AtmostOneThreadExecutor.java:121) at java.base/java.lang.Thread.run(Thread.java:829)
解决：
从上面的报错信息分析可能是由于Jenkins容器中的Java 11版本过高。我们单独下载一个低版本的jdk，然后将低版本的jdk拷贝到Jenkins容器中替换掉之前的Java 11版本。
[root@k8s-master ~]# wget https://builds.openlogic.com/downloadJDK/openlogic-openjdk/8u262-b10/openlogic-openjdk-8u262-b10-linux-x64.tar.gz //下载jdk8 [root@k8s-master ~]# ll openlogic-openjdk-8u262-b10-linux-x64.tar.gz -rw-r--r-- 1 root root 104479130 7月 26 2020 openlogic-openjdk-8u262-b10-linux-x64.tar.gz [root@k8s-master ~]# docker ps | grep jenkins 2324d2daa74d jenkins/jenkins:lts "/sbin/tini -- /usr/…" 6 weeks ago Up 2 hours 0.0.0.0:8080->8080/tcp, 0.0.0.0:50000->50000/tcp jenkins [root@k8s-master ~]# docker cp openlogic-openjdk-8u262-b10-linux-x64.tar.gz jenkins:/usr/local/ //将下载的jdk拷贝到jenkins容器中 [root@k8s-master ~]# docker exec -it -u root jenkins /bin/bash //进入jenkins容器 root@2324d2daa74d:/# java -version //可以看到现在jenkins容器的jdk版本是11.0.12 openjdk version "11.0.12" 2021-07-20 OpenJDK Runtime Environment Temurin-11.0.12+7 (build 11.0.12+7) OpenJDK 64-Bit Server VM Temurin-11.0.12+7 (build 11.0.12+7, mixed mode) root@2324d2daa74d:/# cd /usr/local/ root@2324d2daa74d:/usr/local# tar -xvf openlogic-openjdk-8u262-b10-linux-x64.tar.gz //解压我们刚才拷贝到jenkins容器中的jdk低版本 root@2324d2daa74d:/usr/local# ls bin games lib openlogic-openjdk-8u262-b10-linux-64 sbin src etc include man openlogic-openjdk-8u262-b10-linux-x64.tar.gz share root@2324d2daa74d:/usr/local# mv openlogic-openjdk-8u262-b10-linux-64/ jdk8 //将解压后的jdk低版本目录名称修改为jdk8 root@2324d2daa74d:/usr/local# ls bin etc games include jdk8 lib man openlogic-openjdk-8u262-b10-linux-x64.tar.gz sbin share src root@2324d2daa74d:/usr/local# whereis java //查看jenkins容器中的java安装位置 java: /opt/java/openjdk/bin/java root@2324d2daa74d:/usr/local# mv /opt/java/openjdk/bin/java /opt/java/openjdk/bin/java11.bak //备份jenkins容器中的原java11版本 root@2324d2daa74d:/usr/local# ln -s /usr/local/jdk8/bin/java /opt/java/openjdk/bin/java //将/usr/local/jdk8/bin/中低版本的java作为/opt/java/openjdk/bin/中的java软连接 root@2324d2daa74d:/usr/local# java -version //查看“替换”后的java版本 openjdk version "1.8.0-262" OpenJDK Runtime Environment (build 1.8.0-262-b10) OpenJDK 64-Bit Server VM (build 25.71-b10, mixed mode)
再次安装ruby-runtime插件，若还是失败，可以在Jenkins首页重启一下再安装即可。（重启Jenkins后ruby-runtime插件默认就会加载成功）
插件安装完成后我们再将Jenkins容器中的Java版本修改回来。（根据情况，也可以不改回来）
root@2324d2daa74d:~# rm -rf /opt/java/openjdk/bin/java #删除了之前替换的java8 root@2324d2daa74d:~# mv /opt/java/openjdk/bin/java11.bak /opt/java/openjdk/bin/java #换回了java11 root@2324d2daa74d:~# java -version openjdk version "11.0.12" 2021-07-20 OpenJDK Runtime Environment Temurin-11.0.12+7 (build 11.0.12+7) OpenJDK 64-Bit Server VM Temurin-11.0.12+7 (build 11.0.12+7, mixed mode)
