Clustering on two machines

mutahar ali

Hi,
We have successfully deployed NodeBB on 1 machine with 3 NodeBB processes on the same machine at different and using nginx to load balance between the 3. We are using MongoDB as the database, and have also setup redis for inter-process communication.

Now we plan to add another machine to further increase user capacity. Both machines will have 3 NodeBB processes each. We have the following questions:

Do we start the NodeBB processes on the machine 2 and have the same redis server in the config so the processes can communicate?
Do we set isCluster to true?
How do we make a MongoDB replica? Do we add the IPs of both mongo instances in the config file of nodebb on both machines?

Any help will be appreciated. Thanks!

<baris>

Do we start the NodeBB processes on the machine 2 and have the same redis server in the config so the processes can communicate?

Yes

Do we set isCluster to true?

You don't have to set isCluster: true since you are running more than one process on each machine, nodebb will detect it automatically. You should set jobsDisabled: true on machine 2 so it doesn't run digests and other cronjobs.

How do we make a MongoDB replica? Do we add the IPs of both mongo instances in the config file of nodebb on both machines?

You can use the mongo:uri property to define the mongodb replicaset.

mutahar ali

@baris Thanks alot! That clears up a lot of confusion.

Also, I wasn't able to find a guide on how to create a MongoDB replica for my nodebb database. If it's not too much trouble, could you explain the steps at a high level? Any direction would be highly appreciated.

Thanks again for the help!

<baris>

https://www.mongodb.com/docs/manual/tutorial/deploy-replica-set/#deploy-a-replica-set-in-the-terminal

https://www.mongodb.com/docs/manual/reference/connection-string/#replica-set-option

Once you deploy it you can use the uri property in nodebb config.json to use the replica set.

mutahar ali

Have successfully completed my setup. Thanks!

mutahar ali

@baris One related question. I am aiming to make the system fault tolerant so if one of the servers go down, the other one can still server users. In this case, how would I go configuring redis in the NodeBB config file?
Currently redis is running on server 1 only and server 2's NodeBB config has it's server 1's IP for redis.

julian

@mutahar-ali You'd probably want to move the redis server to another machine in that case. Either a separate one, or on the same machine as the Mongo database.