问题在于您定义虚拟主机的方式。ServerName不懂/什么的，只懂域名。

选项1定义域名前缀。

<VirtualHost *:80>
    ServerName sonar.server.name
    
    ProxyPass /sonar http://localhost:9000/sonar/
    ProxyPassReverse /sonar http://localhost:9000/sonar/
    
    ErrorLog logs/sonar/error.log
    CustomLog logs/sonar/access.log common
</VirtualHost>

<VirtualHost *:80>
    ServerName jenkins.server.name
    
    ProxyPass /jenkins http://localhost:8080/jenkins/
    ProxyPassReverse /jenkins http://localhost:8080/jenkins/
    
    ErrorLog logs/jenkins/error.log
    CustomLog logs/jenkins/access.log common
</VirtualHost>

然后必须使用http://jenkins.server.name/jenkins/或http://sonar.server.name/sonar/。

选项2与选项1类似，但没有/sonar或/jenkins，这些都不再需要。

<VirtualHost *:80>
    ServerName sonar.server.name
    
    ProxyPass / http://localhost:9000/sonar/
    ProxyPassReverse / http://localhost:9000/sonar/
    
    ErrorLog logs/sonar/error.log
    CustomLog logs/sonar/access.log common
</VirtualHost>

<VirtualHost *:80>
    ServerName jenkins.server.name
    
    ProxyPass / http://localhost:8080/jenkins/
    ProxyPassReverse / http://localhost:8080/jenkins/
    
    ErrorLog logs/jenkins/error.log
    CustomLog logs/jenkins/access.log common
</VirtualHost>

这里，使用http://jenkins.server.name/或http://sonar.server.name/。

选项3保留一个域，没有前缀，在/something上拆分

所有在一个虚拟主机。像这样：

<VirtualHost *:80>
    ServerName server.name
    
    ProxyPass /sonar http://localhost:9000/sonar/
    ProxyPassReverse /sonar http://localhost:9000/sonar/

    ProxyPass /jenkins http://localhost:8080/jenkins/
    ProxyPassReverse /jenkins http://localhost:8080/jenkins/
    
    ErrorLog logs/error.log
    CustomLog logs/access.log common
</VirtualHost>

可悲的是，这样做会丢失单独的日志文件。CustomLog仅适用于全局服务器配置或VirtualHost内部。
使用http://server.name/jenkins/或http://server.name/sonar/。
最后，确保您加载模块mod_proxy_html沿着其他代理模块。