Meteor: Set up Oplog Tailing on Ubuntu --> https://github.com/LeCoupa/awesome-cheatsheets

meteor-mongo-oplog-ubuntu.bash

# How to set up Oplog Tailing on your Meteor application on Ubuntu. (production environment)
# We are going to create a replica set with only one member (the primary) so as to benefit from oplog tailing.
# More: https://github.com/meteor/meteor/wiki/Oplog-Observe-Driver


# 1. Stop MongoDB

$ sudo service mongodb stop


# 2. Edit the MongoDB configuration.

$ sudo nano /etc/mongodb.conf


# 3. Uncomment the default port, the replSet parameter
#    and add fork at the bottom of the file

port = 27017
replSet = rs0  # set to something you can easily remember
fork = true  # so that you can use your shell after spawning the server instance


# 4. Start the replication member.

$ mongod --config /etc/mongodb.conf
$ ps aux | grep mongo  # to check that the process is running


# 5. Be sure your admin user have the clusterAdmin role.

$ mongo
> use admin
> db.auth('admin', 'pwd')
> db.users.update({'user':'admin'}, {$addToSet: {'roles' :'clusterAdmin'}})


# 6. Start the replication set.

> rs.initiate()


# 7. Your prompt should change to rs0:PRIMARY>. Then, add the oplogger user into the admin database.

rs0:PRIMARY> rs.status()  # check the status and display replica set members.
rs0:PRIMARY> use admin

# For MongoDB 2.4
rs0:PRIMARY> db.addUser({ user:'oplogger', pwd:'pwd', roles:[], otherDBRoles:{ local: ['read'] } })  # can read everything that is written to the local database.

# For MongoDB 2.6
rs0:PRIMARY> db.createUser({ user:'oplogger', pwd:'pwd', roles:[] })
rs0:PRIMARY> db.runCommand({ createRole: "oplogger", privileges: [   { resource: { db: 'local', collection: 'system.replset'}, actions: ['find']}, ], roles: [{role: 'read', db: 'local'}] })
rs0:PRIMARY> db.runCommand({ grantRolesToUser: 'oplogger', roles: ['oplogger']})

rs0:PRIMARY> show users  # you should see the new oplogger user appear


# 8. Launch Meteor with the environment variable "MONGO_OPLOG_URL". (in production)
#    Note: Of course, you need to set MONGO_URL as usual.

$ export PORT=58080
$ export ROOT_URL='http://localhost/'
$ export MONGO_URL='mongodb://userDB:[email protected]:27017/DB'
$ export MONGO_OPLOG_URL='mongodb://oplogger:[email protected]:27017/local?authSource=admin'
$ forever start --append --uid "meteorApp" main.js


# 9. How to tell if your queries are using OplogObserveDriver?
#    https://github.com/meteor/meteor/wiki/Oplog-Observe-Driver#how-to-tell-if-your-queries-are-using-oplogobservedriver