SERVER-18810 FSM support multiple mongos connections, alternating per workload thread.

3 files changed, 10 insertions, 5 deletions

diff --git a/jstests/concurrency/fsm_libs/cluster.js b/jstests/concurrency/fsm_libs/cluster.js
index 52f46699993..9e7f18eb2ab 100644
--- a/jstests/concurrency/fsm_libs/cluster.js
+++ b/jstests/concurrency/fsm_libs/cluster.js
@@ -63,6 +63,7 @@ var Cluster = function(options) {
         mongos: [],
         mongod: []
     };
+    var nextConn = 0;
 
     validateClusterOptions(options);
     Object.freeze(options);
@@ -75,10 +76,10 @@ var Cluster = function(options) {
         }
 
         if (options.sharded) {
-            // TODO: allow 'options' to specify the number of shards
+            // TODO: allow 'options' to specify the number of shards and mongos processes
             var shardConfig = {
                 shards: 2,
-                mongos: 1,
+                mongos: 2,
                 verbose: verbosityLevel
             };
 
@@ -234,6 +235,10 @@ var Cluster = function(options) {
             throw new Error('cluster has not been initialized yet');
         }
 
+        // Alternate mongos connections for sharded clusters
+        if (this.isSharded()) {
+            return _conns.mongos[nextConn++ % _conns.mongos.length].host;
+        }
         return conn.host;
     };
 
diff --git a/jstests/concurrency/fsm_libs/runner.js b/jstests/concurrency/fsm_libs/runner.js
index 5e417ba6d9e..8df72679773 100644
--- a/jstests/concurrency/fsm_libs/runner.js
+++ b/jstests/concurrency/fsm_libs/runner.js
@@ -360,7 +360,7 @@ var runner = (function() {
 
                     startTime = new Date();
                     threadMgr.init(workloads, context, maxAllowedConnections);
-                    threadMgr.spawnAll(cluster.getHost(), executionOptions);
+                    threadMgr.spawnAll(cluster, executionOptions);
                     threadMgr.checkFailed(0.2);
 
                     errors = threadMgr.joinAll();
diff --git a/jstests/concurrency/fsm_libs/thread_mgr.js b/jstests/concurrency/fsm_libs/thread_mgr.js
index 03e5607ed2c..93c15efffd0 100644
--- a/jstests/concurrency/fsm_libs/thread_mgr.js
+++ b/jstests/concurrency/fsm_libs/thread_mgr.js
@@ -87,7 +87,7 @@ var ThreadManager = function(clusterOptions, executionMode) {
         initialized = true;
     };
 
-    this.spawnAll = function spawnAll(host, options) {
+    this.spawnAll = function spawnAll(cluster, options) {
         if (!initialized) {
             throw new Error('thread manager has not been initialized yet');
         }
@@ -110,7 +110,7 @@ var ThreadManager = function(clusterOptions, executionMode) {
                 var args = {
                     tid: tid++,
                     data: workloadData,
-                    host: host,
+                    host: cluster.getHost(),
                     latch: latch,
                     dbName: _context[workload].dbName,
                     collName: _context[workload].collName,