Launch a MongoDB Cluster for testing

Here’s a bash script I use to create a sharded MongoDB Cluster for testing purposes. The key functions are mongo_setup_cluster and mongo_teardown_cluster. The script will created a Mongo Cluster with 2 shards, with 3 nodes each, 3 config server and 3 mongos servers.

UPDATE 2015/10/02 I’ve found out about an undocumented option available to set the WiredTiger cache size in megabytes rather than gigabytes. Useful on test machines with limited RAM. The option is –wiredTigerEngineConfigString. To set the cache size to 200 megabytes you would do… –wiredTigerEngineConfigString=”cache_size=200M”

set -e;
set -u;

function mongo_teardown_cluster()
{
	killall --quiet mongos && echo "mongos processes have been murdered.";
	killall --quiet mongod && echo "mongod processes have been murdered.";
	cd ~;
	rm -Rf rhys_sharded_cluster_test_temp && echo "Directory rhys_sharded_cluster_test_temp removed.";
}

function mongo_create_directories()
{
	cd ~;
	mkdir -p rhys_sharded_cluster_test_temp;
	cd rhys_sharded_cluster_test_temp;
	mkdir config1 config2 config3 mongos1 mongos2 mongos3 shard0_30001 shard0_30002 shard0_30003 shard1_30004 shard1_30005 shard1_30006;
}

function mongo_create_config_servers()
{
	mongod --configsvr --port 27019 --dbpath ./config1 --logpath config1.log --smallfiles --nojournal --fork
	mongod --configsvr --port 27020 --dbpath ./config2 --logpath config2.log --smallfiles --nojournal --fork
	mongod --configsvr --port 27021 --dbpath ./config3 --logpath config3.log --smallfiles --nojournal --fork
}

function mongo_create_mongos_servers()
{
		mongos --configdb "localhost.localdomain:27019,localhost.localdomain:27020,localhost.localdomain:27021" --logpath mongos1.log --port 27017 --fork
		mongos --configdb "localhost.localdomain:27019,localhost.localdomain:27020,localhost.localdomain:27021" --logpath mongos2.log --port 27018 --fork
		mongos --configdb "localhost.localdomain:27019,localhost.localdomain:27020,localhost.localdomain:27021" --logpath mongos3.log --port 27016 --fork
}

function mongo_create_mongod_shard_servers()
{
	# shard0 mongod instances
	mongod --smallfiles --nojournal --storageEngine wiredTiger --dbpath ./shard0_30001 --port 30001 --replSet "rs0" --logpath shard0_30001.log --fork
	mongod --smallfiles --nojournal --storageEngine wiredTiger --dbpath ./shard0_30002 --port 30002 --replSet "rs0" --logpath shard0_30002.log --fork
	mongod --smallfiles --nojournal --storageEngine wiredTiger --dbpath ./shard0_30003 --port 30003 --replSet "rs0" --logpath shard0_30003.log --fork
	# shard1 mongod instances
	mongod --smallfiles --nojournal --storageEngine wiredTiger --dbpath ./shard1_30004 --port 30004 --replSet "rs1" --logpath shard1_30004.log --fork
	mongod --smallfiles --nojournal --storageEngine wiredTiger --dbpath ./shard1_30005 --port 30005 --replSet "rs1" --logpath shard1_30005.log --fork
	mongod --smallfiles --nojournal --storageEngine wiredTiger --dbpath ./shard1_30006 --port 30006 --replSet "rs1" --logpath shard1_30006.log --fork
}

function mongo_configure_replicaset_rs0()
{
	mongo --port 30001 <<eof rs.initiate while print is not yet primary. waiting... rs.add eof status="$?;" return function mongo_configure_replicaset_rs1 mongo mongo_configure_sharding sh.addshard sh.enablesharding sh.shardcollection mongo_setup_cluster mongo_create_directories echo created directories mongo_create_config_servers started configuration servers. sleep mongo_create_mongos_servers mongos mongo_create_mongod_shard_servers mongod shard servers for sixty seconds before attempting replicaset configuration. mongo_configure_replicaset_rs0 configured rs0. rs1. sharding and sharded test.collection by t_u. add loading data into test.test_collection.>
<p>Usage is as follows...</p>
<pre lang="Bash">
. /path/to/mongo_cluster_script.sh; # Source the above bash functions
mongo_setup_cluster(); # Fire up a sharded cluster
</pre>
<p>To destroy the cluster...</p>
<pre lang="Bash">
mongo_teardown_cluster();
</pre>
<p>Note this will kill all mongo processes and remove all data directories!</p>
</eof>