Script for creating a complex mongodb shard for testing purpose on the local machine. Wrote for the Mongodb 102 course (week6) to facilitate the setup. Change the settings on the top of the script and run it. All commands are passed to mongo via subprocess, no pyMongo required. I keep it as mongo shell reference.

gistfile1.py

#!/bin/env python
# @author: Dario Varotto

"""
	Script for creating a complex mongodb shard for testing purpose on the local machine.
	Wrote for the Mongodb 102 course (week6) to facilitate the setup.
	
	Change the settings on the top of the script and run it.
	All commands are passed to mongo via subprocess, no pyMongo required.
	I keep it as mongo shell reference.
	
"""

# SETTINGS *******************************************************************

dataDir = "data"
logDir = "log"
mongo_start_port = 27000  # the mongod will be there (grouped by replica set)
# there will be replica*shards mongod shard server
# then the config servers and then the mongos
replicaPrefix = "bigR"

n_replica = 3
n_shards = 4

n_config = 3
n_mongos = 4

hostname = "localhost"  # to pass as mongos config

# ****************************************************************************

import os
import sys
import subprocess
from subprocess import Popen, PIPE
import time

def doRun(cmd):
	print cmd
	subprocess.Popen(cmd)
	time.sleep(1)


def startDaemons():
	# lets start with config servers
	try:
		os.makedirs(logDir)
	except:
		pass

	for i in range(n_config):
		settings = {
			"port":mongo_start_port + n_replica * n_shards + i,
			"db":os.path.join(dataDir, "config%d" % (i + 1)),
			"log":os.path.join(logDir, "config%d" % (i + 1)),
		}
		try:
			os.makedirs(settings["db"])
		except:
			pass
		cmd = "mongod --configsvr --port %(port)d --smallfiles --oplogSize 50 --dbpath %(db)s --logappend --logpath %(log)s" % settings
		doRun(cmd)

	# now the mongoD processes
	for i in range(n_shards):
		for j in range(n_replica):
			settings = {
				"port":mongo_start_port + (i * 3) + j,
				"db":os.path.join(dataDir, "mongod%d.%d" % ((i + 1), (j + 1))),
				"log":os.path.join(logDir, "mongod%d.%d" % ((i + 1), (j + 1))),
				"replicaName":"%s%d" % (replicaPrefix, i + 1),
			}
			try:
				os.makedirs(settings["db"])
			except:
				pass
			cmd = "mongod --shardsvr --replSet %(replicaName)s --port %(port)d --smallfiles --oplogSize 50 --dbpath %(db)s --logappend --logpath %(log)s" % settings
			doRun(cmd)

	# finally the mongos
	for i in range(n_mongos):
		settings = {
			"port":mongo_start_port + n_replica * n_shards + n_config + i,
			"log":os.path.join(logDir, "mongos%d" % (i)),
			"configServers":",".join(["%s:%d" % (hostname, port) for port in range(mongo_start_port + n_replica * n_shards, mongo_start_port + n_replica * n_shards + n_config,)])
		}
		cmd = "mongos --port %(port)d --logappend -logpath %(log)s --configdb %(configServers)s" % settings
		doRun(cmd)

# now we can initiate the replicaset
def initializeReplicas():
	for i in range(n_shards):
		hostlist = []
		for j in range(n_replica):
			memberhost = "%s:%d" % (hostname, mongo_start_port + (i * 3) + j)
			hostlist.append(memberhost)
		settings = {
				"replicaName":"%s%d" % (replicaPrefix, i + 1),
				"hostlist": ", ".join(['{_id:%d, host:"%s"}' % (j, memberhost) for j, memberhost in enumerate(hostlist) ])
			}
		pipe = Popen("mongo --port %d " % (mongo_start_port + (i * 3)), stdin=PIPE)
		print "Initiate on %s%d" % (replicaPrefix, i + 1)
		command = """
					rs.initiate( 
						{
							_id:"%(replicaName)s",
							members: [%(hostlist)s]
						}
					);
					  ''
				""" % settings
		print command
		pipe.stdin.write(command)
		time.sleep(1)

# 		for j in range(n_replica - 1):  # add other hosts to the replica
# 			print " adding host on port %d" % (mongo_start_port + (i * 3) + 1 + j)
# 			command = 'rs.add("%s:%d")\n' % (hostname, mongo_start_port + (i * 3) + 1 + j)
# 			pipe.stdin.write(command)
		pipe.stdin.close()

# now create shards, the name will be the name of the replicaset
def createShards():
	# let's connect to the first mongos
	pipe = Popen("mongo --port %d " % (mongo_start_port + n_replica * n_shards + n_config), stdin=PIPE)
	for i in range(n_shards):
		settings = {
			"replicaName":"%s%d" % (replicaPrefix, i + 1),
			'firstHost':"%s:%d" % (hostname, mongo_start_port + (i * 3)),
		}
		print "Initiating shard %s" % settings["replicaName"]
		command = 'sh.addShard("%(replicaName)s/%(firstHost)s");\n' % settings
		print command
		pipe.stdin.write(command)
		time.sleep(1)

startDaemons()
initializeReplicas()

print "The end."