Guides - Deploy a MongoDB Cluster through the Linode Marketplace

MongoDB is a database engine that provides access to non-relational, document-oriented databases. It is part of the growing NoSQL movement, along with databases like Redis and Cassandra (although there are vast differences among the many non-relational databases).

MongoDB seeks to provide an alternative to traditional relational database management systems (RDBMS). In addition to its schema-free design and scalable architecture, MongoDB provides a JSON output and specialized, language-specific bindings that make it particularly attractive for use in custom application development and rapid prototyping. MongoDB has been used in a number of large scale production deployments and is currently one of the most popular database engines across all systems.

The Linode Marketplace allows you to easily deploy an application cluster on Compute Instances using the Cloud Manager. See Get Started with Marketplace Apps for complete steps.

1. Log in to the Cloud Manager and select the Marketplace link from the left navigation menu. This displays the Linode Create page with the Marketplace tab pre-selected.

2. Under the Select App section, select the cluster app you would like to deploy. Marketplace Apps that are deployed as clusters have a cluster label next to the app’s name.

3. Complete the form by following the steps and advice within the Creating a Compute Instance guide. Depending on the Marketplace App you selected, there may be additional configuration options available. See the Configuration Options section below for compatible distributions, recommended plans, and any additional configuration options available for this Marketplace App.

4. Click the Create Linode button. Once the first Compute Instance has been provisioned and has fully powered on, wait for the software installation to complete. If the instance is powered off or restarted before this time, the other Compute Instances may never be deployed and the software installation will likely fail.

To verify that the app has been fully installed, see Get Started with Marketplace Apps > Verify Installation. Once installed, follow the instructions within the Getting Started After Deployment section to access the application and start using it.

• Supported distributions: Ubuntu 22.04 LTS
• Recommended minimum plan: All plan types and sizes can be used, though consider using a High Memory Compute Instance for larger databases in a production environment.

• Linode API Token (required): Your API token is used to deploy additional Compute Instances as part of this cluster. At a minimum, this token must have Read/Write access to Linodes. If you do not yet have an API token, see Get an API Access Token to create one.

• Limited sudo user (required): A limited user account with sudo access is created as part of this cluster deployment. Enter your preferred username for this limited user. Please note that the password is automatically created. See Obtaining Usernames and Passwords.

• Domain (required): The domain name you wish to use, such as example.com. This domain name is only used as part of the system’s hostname and when creating the TLS/SSL certificate. No domain records are created within Linode’s DNS Manager.

• Add SSH Keys to all nodes? If you select yes, any SSH Keys that are added to the root user account (in the SSH Keys section), are also added to your limited user account on all deployed Compute Instances.

• MongoDB cluster size: This field cannot be edited, but is used to inform you of the number of Compute Instances that are created as part of this cluster.

The following fields (in addition to the domain field above) are used when creating your self-signed TLS/SSL certificate.

• Country or region (required): Enter the country or region for you or your organization.
• State or province (required): Enter the state or province for you or your organization.
• Locality (required): Enter the town or other locality for you or your organization.
• Organization (required): Enter the name of your organization.
• Email address (required): Enter the email address you wish to use for your certificate file. This email address may receive notifications about the state of your certificate, including when it is expired.
• CA Common name: This is the common name for the self-signed Certificate Authority.
• Common name: This is the common name that is used for the domain.

After your cluster has been fully provisioned, use the instructs below to obtain and save passwords that were generated on your behalf during deployment.

1. Log in to your new Compute Instance through Lish or SSH using the root user and the associated password you entered when creating the instance. If you opted to include your SSH keys as part of this deployment, you can also log in using those keys as either the root user or the limited user account you specified during deployment.

2. The passwords have been saved in a .deployment-secrets.txt file located in your user’s home directory. You can view this file in your preferred text editor or through the cat command. In the command below, replace [username] with the limited sudo user you created during deployment.

   cat /home/[username]/.deployment-secrets.txt

   The file contains your MongoDB admin username and password, the MongoDB root username and password, and your system’s limited username and password.

   File: /home/[user]/.deployment-secrets.txt

   1 2 3 4 5 6 7 8 9 10 11 12 13 14 15

   # BEGIN ANSIBLE MANAGED BLOCK # mongodb users user: mongo-admin password: 6nYPwXAtgM+xwAJCFlqjrr78/zuDF0+wd6xCCUwNpVk= user: mongo-root password: ltDpEM2AL1nS1j7L5JocZ7zj+7dXDSgTFDybdgaiGyU= user: example-user password: W?lXvW1dZ!o^?..Ea<[9Y9eN3)2MCIr* # SSL ca password mHGsxB@z{r(aCKmoJ<2U/cEg` # END ANSIBLE MANAGED BLOCK

After MongoDB has finished deploying, you can access and administer it directly from the console.

1. Log in to your Compute Instance via SSH or Lish.

2. Launch the mongo shell by running the following command. When prompted, enter the admin user password you set when creating this instance.

   mongo -u admin -p --authenticationDatabase admin

   The -u, -p, and --authenticationDatabase options in the above command are required in order to authenticate connections to the shell. Without authentication, the MongoDB shell can be accessed but will not allow connections to databases.

   The admin user is purely administrative based on the roles specified. It is defined as an administrator of users for all databases, but does not have any database permissions itself. You may use it to create additional users and define their roles. If you are using multiple applications with MongoDB, set up different users with custom permissions for their corresponding databases.

1. As the admin user, create a new database to store regular user data for authentication. The following example calls this database user-data:

   use user-data

2. Permissions for different databases are handled in separate roles objects. This example creates the user, example-user, with read-only permissions for the user-data database and has read and write permissions for the exampleDB database that we’ll create in the Manage Data and Collections section below.

   Create a new, non-administrative user to enter test data. Change both example-user and password to something relevant and secure:

   db.createUser({user: "example-user", pwd: "password", roles:[{role: "read", db: "user-data"}, {role:"readWrite", db: "exampleDB"}]})

   To create additional users, repeat this step as the administrative user, creating new usernames, passwords and roles by substituting the appropriate values.

3. Exit the mongo shell:

   quit()

For more information on access control and user management, as well as other tips on securing your databases, refer to the MongoDB Security Documentation.

Much of MongoDB’s popularity comes from its ease of integration. Interactions with databases are done via JavaScript methods, but drivers for other languages are available. This section will demonstrate a few basic features, but we encourage you to do further research based on your specific use case.

1. Open the MongoDB shell using the example-user we created above:

   mongo -u example-user -p --authenticationDatabase user-data
   

2. Create a new database. This example calls it exampleDB:

   use exampleDB
   

   Make sure that this database name corresponds with the one for which the user has read and write permissions (we added these permissions in the previous section).

   To show the name of the current working database, run the db command.

3. Create a new collection called exampleCollection:

   db.createCollection("exampleCollection", {capped: false})
   

   If you’re not familiar with MongoDB terminology, you can think of a collection as analogous to a table in a relational database management system. For more information on creating new collections, see the MongoDB documentation on the db.createCollection() method.

   Note

   Collection names should not include certain punctuation such as hyphens. However, exceptions may not be raised until you attempt to use or modify the collection. For more information, refer to MongoDB’s naming restrictions.

4. Create sample data for entry into the test database. MongoDB accepts input as documents in the form of JSON objects such as those below. The a and b variables are used to simplify entry; objects can be inserted directly via functions as well.

   var a = { name : "John Doe",  attributes: { age : 30, address : "123 Main St", phone : 8675309 }}
   var b = { name : "Jane Doe",  attributes: { age : 29, address : "321 Main Rd", favorites : { food : "Spaghetti", animal : "Dog" } }}
   

   Note that documents inserted into a collection need not have the same schema, which is one of many benefits of using a NoSQL database.

5. Insert the data into exampleCollection, using the insert method:

   db.exampleCollection.insert(a)
   db.exampleCollection.insert(b)
   

   The output for each of these operations will show the number of objects successfully written to the current working database:

   WriteResult({ "nInserted" : 1 })

6. Confirm that the exampleCollection collection was properly created:

   show collections
   

   The output will list all collections containing data within the current working database:

   exampleCollection

7. View unfiltered data in the exampleCollection collection using the find method. This returns up to the first 20 documents in a collection, if a query is not passed:

   db.exampleCollection.find()
   

   The output will resemble the following:

   { "_id" : ObjectId("5e68d4618bd4ea23cc3f5e96"), "name" : "John Doe", "attributes" : { "age" : 30, "address" : "123 Main St", "phone" : 8675309 } }
   { "_id" : ObjectId("5e68d4628bd4ea23cc3f5e97"), "name" : "Jane Doe", "attributes" : { "age" : 29, "address" : "321 Main Rd", "favorites" : { "food" : "Spaghetti", "animal" : "Dog" } } }

   You may notice the objects we entered are preceded by _id keys and ObjectId values. These are unique indexes generated by MongoDB when an _id value is not explicitly defined. ObjectId values can be used as primary keys when entering queries, although for ease of use, you may wish to create your own index as you would with any other database system.

   The find method can also be used to search for a specific document or field by entering a search term parameter (in the form of an object) rather than leaving it empty. For example:

   db.exampleCollection.find({"name" : "John Doe"})
   

   Running the command above returns a list of documents containing the {"name" : "John Doe"} object:

   { "_id" : ObjectId("5e68d4618bd4ea23cc3f5e96"), "name" : "John Doe", "attributes" : { "age" : 30, "address" : "123 Main St", "phone" : 8675309 } }

For more on MongoDB, checkout the following guides:

• Creating a MongoDB Replica Set
• Building Database Clusters with MongoDB

More Information

You may wish to consult the following resources for additional information on this topic. While these are provided in the hope that they will be useful, please note that we cannot vouch for the accuracy or timeliness of externally hosted materials.

• Official MongoDB Documentation
• MongoDB Project
• Language-Specific MongoDB Drivers