mongodb replset

In this homework you will build a small replica set on your own computer. We will check that it works with validate.py, which you should download in week6-lessonfiles.tar or week6-lessonfiles.zip. 

Create three directories for the three mongod processes. On unix, this could be done as follows:
mkdir -p /data/rs1 /data/rs2 /data/rs3
Now start three mongo instances as follows. Note that are three commands. The browser is probably wrapping them visually.
./mongod --replSet m101 --logpath "1.log" --dbpath /data/rs1 --port 27017 --smallfiles --fork

./mongod --replSet m101 --logpath "2.log" --dbpath /data/rs2 --port 27018 --smallfiles --fork

./mongod --replSet m101 --logpath "3.log" --dbpath /data/rs3 --port 27019 --smallfiles --fork
Now connect to a mongo shell and make sure it comes up
./mongo --port 27017
Now you will create the replica set. Type the following commands into the mongo shell:
config = { _id: "m101", members:[
          { _id : 0, host : "localhost:27017"},
          { _id : 1, host : "localhost:27018"},
          { _id : 2, host : "localhost:27019"} ]
};
rs.initiate(config);
At this point, the replica set should be coming up. You can type
rs.status()
to see the state of replication. 

Now run validate.py to confirm that it works.
python validate.py
Validate connects to your local replica set and checks that it has three nodes. It has been tested under Pymongo 2.3 and 2.4. Type the validation code below.