在Google Cloud Platform上部署mongodb？

Question

Hello all actually for my startup i am using google cloud platform, now i am using app engine with node.js this part is working fine but now for database, as i am mongoDB i saw this for mongoDB https://console.cloud.google.com/launcher/details/click-to-deploy-images/mongodb?q=mongo now when i launched it on my server now it created three instances in my compute engine but now i don't know which is primary instance and which is secondary, also one more thing as i read that primary instance should be used for writing data and secondary for reading, now when i will query my database should i provide secondary instance url and for updating/inserting data in my mongodb database should i provide primary instance url otherwise which url should i use for CRUD operations on my mongodb database ?? also after launcing this do i have to make any changes in any conf file or in any file manually or they already done that for me ?? Also do i have to make instance groups of all three instances or not ??

Please if any one of you think i have not done any research on this or its not a valid stackoverflow question then i am so sorry google cloud platform is very much new that's why there is not much documentation on it also this is my first time here in deploying my code on servers that's why i am completely noob in this field Thanks Anyways please help me ut of here guys.

Answer 1

but now i don't know which is primary instance and which is secondary,

Generally the Cloud Launcher will name the primary with suffix -1 (dash one). For example by default it would create mongodb-1-server-1 instance as the primary.

Although you can also discover which one is the primary by running rs.status() on any of the instances via the mongo shell . As an example:

mongo --host <External instance IP> --port <Port Number>

You can get the list of external IPs of the instances using gcloud . For example:

gcloud compute instances list

By default you won't be able to connect straight away, you need to create a firewall rule for the compute engines to open port(s). For example :

gcloud compute firewall-rules create default-allow-mongo --allow tcp:<PORT NUMBER> --source-ranges 0.0.0.0/0 --target-tags mongodb --description "Allow mongodb access to all IPs"

Insert a sensible port number, please avoid using the default value. You may also want to limit the source IP ranges. ie your office IP. See also Cloud Platform: Networking

i read that primary instance should be used for writing data and secondary for reading,

Generally replication is to provide redundancy and high availability. Where the primary instance is being used to read and write, and secondaries act as replicas to provide a level of fault tolerance. ie the loss of primary server.

See also:

• MongoDB Replication .
• Replication Read Preference .
• MongoDB Sharding .

now when i will query my database should i provide secondary instance url and for updating/inserting data in my mongodb database should i provide primary instance url otherwise which url should i use for CRUD operations on my mongodb database

You can provide both in MongoDB URI and the driver will figure out where to read/write. For example in your Node.js you could have:

mongodb://<instance 1>:<port 1>,<instance 2>:<port 2>/<database name>?replicaSet=<replica set name>

The default replica set name set by Cloud Launcher is rs0 . Also see:

• Node Driver: URI .
• Node Driver: Read Preference .

also after launcing this do i have to make any changes in any conf file or in any file manually or they already done that for me ?? Also do i have to make instance groups of all three instances or not ??

This depends on your application use case, but if you are launching through click and deploy the MongoDB config should all be taken care of.

For a complete guide please follow tutorial : Deploy MongoDB with Node.js . I would also recommend to check out MongoDB security checklist .

Hope that helps.