The awesome of MongoDB

Documentations and Articles

Setup

• Medium - High-availability MongoDB Cluster Configuration Solutions
• Medium - Configure 3 nodes replica set of MongoDB on AWS EC2
• MongoDB - Deploy a Self-Managed Replica Set

Tips & Configuration

• Medium - Solving curious case of excess memory consumption by MongoDB

Install MongoDB Tools

Mongoshell

You can download and install mongosh. If you already use linux, you can follow my guideline

wget https://downloads.mongodb.com/compass/mongodb-mongosh_2.4.2_amd64.deb
chmod +x  mongodb-mongosh_2.4.2_amd64.deb
sudo dpkg -i mongodb-mongosh_2.4.2_amd64.deb

After download, you can validate the mongosh by

mongosh --version

Backup and Restore

To backup and restore, we need to use MongoDB Database Tools, such as mongodump and mongorestore. Following the guideline to install

wget https://fastdl.mongodb.org/tools/db/mongodb-database-tools-debian10-x86_64-100.12.0.deb
chmod +x mongodb-database-tools-debian10-x86_64-100.12.0.deb
sudo dpkg -i mongodb-database-tools-debian10-x86_64-100.12.0.deb

Knowledge

Use MongoDB Connect with DirectConnection

This configuration relate in configuration of MongoDB, when you set replicaset mode for your MongoDB, when you double-check the configuration member, you can see this at

• MongoDB - Self-Managed Replica Set Configuration
• MongoDB - Connect to a Replica Set

For the configuration, you can use command with mongosh

rs.conf()

It will show your replicaset configuration in MongoDB, like this

{
  _id: <string>,
  version: <int>,
  term: <int>,
  protocolVersion: <number>,
  writeConcernMajorityJournalDefault: <boolean>,
  configsvr: <boolean>,
  members: [
    {
      _id: <int>,
      host: <string>,
      arbiterOnly: <boolean>,
      buildIndexes: <boolean>,
      hidden: <boolean>,
      priority: <number>,
      tags: <document>,
      secondaryDelaySecs: <int>,
      votes: <number>
    },
    ...
  ],
  settings: {
    chainingAllowed : <boolean>,
    heartbeatIntervalMillis : <int>,
    heartbeatTimeoutSecs: <int>,
    electionTimeoutMillis : <int>,
    catchUpTimeoutMillis : <int>,
    getLastErrorModes : <document>,
    getLastErrorDefaults : <document>,
    replicaSetId: <ObjectId>
  }
}

If It returns your host configuration as private ip address, you can encounter some problems about connection when this IP range same as IP range used for your network, that why sometime it will show connection timeout. So for fix this problem, you should connect directly into replicaset via directConnection=true parameter

mongosh 'mongodb://username:password@server-uri/db?directConnection=true'

Info

In some situations, you can bypass this configuration because it will add default into your connection string, like

• The replicaSet query parameter is present in the connection string.
• The connection string uses the mongodb+srv:// connection string format.
• The connection string contains a seed list with multiple hosts.
• The connection string already contains a directConnection parameter.

MongoDB CLI Usage

Login into cluster

# Connect via parameter
mongosh --host <host> --port <port> -u <username> -p <password>
 
# Connect via connection string
mongosh 'mongodb://<user>:<pass>@<host>:<port>/<collection>'