How to setup primary DB for replica Mongo DB

Question

I am trying run a nodejs application. In order to do that I need to setup replica mongodb. I couldn't understand what should I do where. I need step by step explanation like my IQ is around room tempratures.

So this is the ENV variable for DB

MAIN_DATABASE=mongodb://127.0.0.1:27017,localhost:27018/maindb?replicaSet=rs0

I am running this command and starting a replica mongodb

mongod --port 27021 --dbpath "/data" --replSet rs0

And this is the error message that I get

-> no primary found in replicaset or invalid replica set name

I have ip's of 2 mongo db's running

62.210.**.**  mongo1
212.129.**.** mongo2

Do I need the db users and passwords of these 2 db's? And can it be done one command on my side? Do I need to configuration on those 2 db's? — Erenn, Jul 23 '20 at 03:46
Here are a tutorial: [Deploy a Replica Set for Testing and Development](https://docs.mongodb.com/manual/tutorial/deploy-replica-set-for-testing/). — prasad_, Jul 23 '20 at 07:31
Just one question. Do I need to change something on primary db? — Erenn, Jul 24 '20 at 04:23
There is no such thing as ""primary db" in a replica-set. A replica-set can have 1 to 50 nodes. So, your replica-set has how many nodes? Of these nodes only one can be a primary node. To setup a replica-set means (i) start all nodes, (ii) connect to one node using `mongo`, and (iii) initiate the replica-set. I suggest, stop all `mongod` processes and follow the tutorial I had provided as a link. — prasad_, Jul 25 '20 at 10:43
I see now. I have access to one secondary node. I will initiate replica-set and I will provide my local pc's ip address to that secondary node. Am I right? — Erenn, Jul 25 '20 at 11:51
Also, see this about [Replication](https://docs.mongodb.com/manual/replication/index.html) (in general, and what it means). — prasad_, Jul 28 '20 at 04:48

score 1 · Accepted Answer · edited Aug 01 '20 at 08:01

You just need to restart your Mongo (killall mongod and then start) with the following:

mongod --replSet "rs0" --bind_ip localhost,hostname|62.210.**.**,hostname1|62.210.**.**

Alternatively, you can also specify the replica set name and the IP addresses in a configuration file:

replication:
   replSetName: "rs0"
net:
   bindIp: localhost,<hostname(s)|ip address(es)>

To start mongod with a configuration file, specify the configuration file’s path with the --config option:

mongod --config <path-to-config>

How to setup primary DB for replica Mongo DB

1 Answers1