1. Jenkins 在线安装插件失败

• 报错：

Caused: java.io.IOException: Failed to load https://updates.jenkins.io/download/plugins/login-theme/244.vd67c77f0c4c8/login-theme.hpi to /var/jenkins_home/plugins/login-theme.jpi.tmp
        at hudson.model.UpdateCenter$UpdateCenterConfiguration.download(UpdateCenter.java:1363)
Caused: java.io.IOException: Failed to download from https://updates.jenkins.io/download/plugins/login-theme/244.vd67c77f0c4c8/login-theme.hpi
        at hudson.model.UpdateCenter$UpdateCenterConfiguration.download(UpdateCenter.java:1390)
        at hudson.model.UpdateCenter$DownloadJob._run(UpdateCenter.java:2038)
        at hudson.model.UpdateCenter$InstallationJob._run(UpdateCenter.java:2366)
        at hudson.model.UpdateCenter$DownloadJob.run(UpdateCenter.java:2012)
        at java.base/java.util.concurrent.Executors$RunnableAdapter.call(Unknown Source)
        at java.base/java.util.concurrent.FutureTask.run(Unknown Source)
        at hudson.remoting.AtmostOneThreadExecutor$Worker.run(AtmostOneThreadExecutor.java:121)
        at java.base/java.lang.Thread.run(Unknown Source)

尝试了一些解决方法没有解决，只能离线安装了。

2. 下载所需插件

插件官网

3. 搜索所需要插件：Login Theme

4. 点击搜索的插件

5. 选择对应版本，点击direct link进行下载

6. 安装下载好的插件

系统管理–>插件管理–>Advanced settings

7. 安装成功

8. 验证插件

系统管理–>Appearance

• 成功安装