Much of the Hadoop metrics and status info is available via JMX, especially since 0.20.100, and 0.22+ (
HDFS-1318, HADOOP-6728 etc.) For operations staff not familiar JMX setup, especially JMX with SSL and firewall tunnelling, the usage can be daunting. Using a JMXProxyServlet (a la Tomcat) to translate JMX attributes into JSON output would make a lot of non-Java admins happy.
We could probably use Tomcat's JMXProxyServlet code directly, if it's already output some standard format (JSON or XML etc.) The code is simple enough to port over and can probably integrate with the common HttpServer as one of the default servelet (maybe /jmx) for the pluggable security.