Operations.md

Operational Menu

The server exposes an administration / operations interface on a different port, [8081 by default] (http://localhost:8081/). Through this API you can:

1. Check that the server is responding to requests ([local url] (http://localhost:8081/ping)):

   Example:

   $ curl -s "http://localhost:8081/ping"
   pong
   

2. Check that the server's dependencies appear to be healthy (eg. ping Cassandra) ([local url] (http://localhost:8081/healthcheck)):

   Example:

   $ curl -s "http://localhost:8081/healthcheck"
   * deadlocks: OK
   * emo-cassandra: OK
     127.0.0.1(127.0.0.1):9160 879us
   

3. Get a stack dump of all Java threads ([local url] (http://localhost:8081/threads)):

   Example:

   $ curl -s "http://localhost:8081/threads"
   main id=1 state=WAITING
       - waiting on <0x008d41f2> (a java.lang.Object)
       - locked <0x008d41f2> (a java.lang.Object)
       at java.lang.Object.wait(Native Method)
       at java.lang.Object.wait(Object.java:485)
       at org.eclipse.jetty.util.thread.QueuedThreadPool.join(QueuedThreadPool.java:386)
       at org.eclipse.jetty.server.Server.join(Server.java:398)
   ...
   

4. Get a JSON description of the performance of many aspects of the server, including per-API call counts and average response times ([local url] (http://localhost:8081/metrics?pretty=true))

   Example:

   $ curl -s "http://localhost:8081/metrics" | jsonpp
   {
     "jvm" : {
       "memory" : {
         "totalInit" : 8.501344E7,
         "totalUsed" : 3.3927232E7,
         "totalMax" : 1.0551296E9,
         "totalCommitted" : 1.00401152E8,
         "heapInit" : 6.5876928E7,
         "heapUsed" : 1.57754E7,
         "heapMax" : 9.37689088E8,
         "heapCommitted" : 8.0478208E7,
         "heap_usage" : 0.016823700096209288,
         "non_heap_usage" : 0.15456192834036692,
         "memory_pool_usages" : {
           "Code Cache" : 0.013985951741536459,
           "PS Eden Space" : 0.03663812032560023,
           "PS Old Gen" : 2.7373963283943716E-4,
           "PS Perm Gen" : 0.25999391078948975,
           "PS Survivor Space" : 0.8124847412109375
         }
       },
   ...