I just set up a brand new shard cluster and received the following error when trying to create an index on a non-sharded collection. I tried the command multiple times and got the same error, but after I restart the mongo client the command worked.

ubuntu@mongo1:~/mongodb-linux-x86_64-2.0.2$ bin/mongo
MongoDB shell version: 2.0.2
connecting to: test
mongos> use pb2
switched to db pb2
mongos> db.adminCommand(

{addShard:"mongo1.foobar.com"}

)

{ "ok" : 0, "errmsg" : "can't add a mongos process as a shard" }

mongos> db.adminCommand(

{addShard:"mongo1.foobar.com:27018"}

)

{ "shardAdded" : "shard0000", "ok" : 1 }

mongos> db.adminCommand(

{addShard:"mongo2.foobar.com:27018"}

)

{ "shardAdded" : "shard0001", "ok" : 1 }

mongos> db.adminCommand(

{addShard:"mongo3.foobar.com:27018"}

)

{ "shardAdded" : "shard0002", "ok" : 1 }

mongos> db.adminCommand(

{enablesharding:'pb2'}

)

{ "ok" : 1 }

mongos> db.adminCommand(

{shardcollection:"pb2.hourly_stats"}

)

{ "ok" : 0, "errmsg" : "no shard key" }

mongos> db.adminCommand({shardcollection:"pb2.hourly_stats", key:{_id:1}})

{ "collectionsharded" : "pb2.hourly_stats", "ok" : 1 }

mongos> db.adminCommand({shardcollection:"pb2.aggregated_stats", key:{_id:1}})

{ "collectionsharded" : "pb2.aggregated_stats", "ok" : 1 }

mongos> show collections
aggregated_stats
hourly_stats
log_files
system.indexes
<At this point I run a script which inserts a bunch of objects into the log_files collection, implicitly creating it>
mongos> db.log_files.ensureIndex(

{status:1}

)
Sat Feb 4 06:07:08 uncaught exception: getlasterror failed: {
"assertion" : "nextSafe():

{ $err: \"unrecognized command: setShardVersion\", code: 13390 }

",
"assertionCode" : 13106,
"errmsg" : "db assertion failure",
"ok" : 0
}