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Create a Cluster

Atlas-managed MongoDB deployments, or “clusters”, can be either a replica set or a sharded cluster. All Atlas clusters run using the WiredTiger storage engine. This tutorial covers creating and configuring a new Atlas cluster.

For a tutorial on modifying an existing Atlas cluster, see Modify a Cluster.

Important

Atlas supports creating VPC peering connections between your Atlas dedicated M10+ clusters and other AWS VPCs in the same region.

If this is the first M10+ dedicated paid cluster for the selected region or regions and you plan on creating one or more VPC peering connections, please review the documentation on VPC Peering Connections before continuing.

A. Open the Create New Cluster Dialog

Note

Before creating a cluster, check that you have the correct organization and project selected. Click the Context drop down in the top left corner to select a specific organization or project. For more information on creating and managing organizations and projects, see Organizations and Projects.

Each Atlas project supports up to 50 clusters. Please contact Atlas support for questions or assistance regarding the cluster limit. To contact support, select Support from the left-hand navigation bar of the Atlas UI.

Go to the Clusters view and click the Add New Cluster or Build a New Cluster button to display the Create New Cluster dialog. As you build your cluster, Atlas displays the associated costs at the bottom of the screen. You can hover over the displayed cost for additional estimates.

B. Configure the Cluster Cloud Provider & Region

Select your preferred cloud provider and region. The choice of cloud provider and region affects the configuration options for the available instance sizes, network latency for clients accessing your cluster, the geographic location of the nodes in your cluster, and the cost of running the cluster.

Regions marked as Free Tier Available support deploying M0 Free Tier clusters.

Regions marked as ★ are Recommended regions that provide higher availability compared to other regions. For more information, see:

The number of availability zones, zones, or fault domains in a region has no affect on the number of MongoDB nodes Atlas can deploy. MongoDB Atlas clusters are always made of replica sets with a minimum of three MongoDB nodes.

From the Cloud Provider & Region section, you can also Configure the Cluster Across Multiple Regions.

Configure the Cluster Across Multiple Regions

To deploy a cross-region cluster, toggle Configure clusters across multiple regions (M10 and up) to Yes.

AWS Only

If this is the first M10+ dedicated paid cluster for the selected region or regions and you plan on creating one or more VPC peering connections, please review the documentation on VPC Peering Connections before continuing.

The following options are available when configuring cross-region clusters:

Deploy across multiple regions

Click Add a node to add a new row for region selection and select the region from the dropdown. Specify the desired number of Nodes for the region.

The first row lists the Preferred Region. Atlas prioritizes nodes in the preferred region for primary elegibility.

Backup Data Center Location

If this is the first cluster in the project and you intend to enable continuous snapshot backups, Atlas selects the backup data center location for the project based on the geographical location of the cluster’s Preferred Region. See Backup a Cluster for more information.

When selecting a Region, regions marked as Recommended provide higher availability compared to other regions. For more information, see:

Each node in the selected regions can participate in elections, and can become the primary as long as the majority of nodes in the replica set are available. The total number of electable nodes across all regions, excluding read-only regions, must be 3, 5, or 7.

You can also use this option to increase the replication factor of single-region clusters by modifying the number of Nodes for your Preferred Region only. You do not have to add additional regions to modify the replication factor of your Preferred Region.

To remove a region, click the X next to that region. You cannot remove the Preferred Region.

Atlas provides checks for whether your selected cross-regional configuration provides availability during partial or whole regional outages.

Deploy read-only replicas

Click Add a node to deploy read-only nodes to the selected region.

Each node in the region cannot participate in elections, and cannot become the primary. Read-only regions do not provide high availability.

To remove a read-only region, click the X next to that region.

Note

Having a large number of regions or having nodes spread across long distances may lead to long election times or replication lag.

Important

For a given region in an Atlas project with multi-region clusters, the total sum of MongoDB nodes on all other regions in that project cannot exceed 40. This limit applies across all cloud service providers.

For example, if an Atlas project has 20 nodes in Region A and 20 nodes in Region B, you can deploy no more than 20 additional nodes in that project in any given region. This limit applies even if Region A and Region B are backed by different cloud service providers.

For Atlas projects where every cluster is deployed to a single region, you cannot create a multi-region cluster in that project if there are already 40 or more nodes in that single region.

C. Select the Cluster Tier

Select your preferred cluster instance size. The selected instance size dictates the memory, storage, and IOPS specification for each data-bearing server [1] in the cluster.

Atlas categorizes the instance sizes into tiers as follows:

Shared Clusters

Sandbox instances for getting started with MongoDB, such as the M0 Free Tier instance.

These instances support replica set deployments in a shared environment with access to a subset of Atlas features and functionality.

Dedicated Development Clusters

Instances that support development environments and low-traffic applications.

These instances support replica set deployments only, but otherwise provide full access to Atlas features and functionality.

Dedicated Production Clusters

Instances that support production environments with high traffic applications and large datasets.

These instances support replica set and sharded cluster deployments with full access to Atlas features and functionality.

Some instances have variants, denoted by the ❯ character. When you select these instances, Atlas lists the variants and tags each instance to distinguish their key characteristics.

Atlas provides an option to deploy one M0 Free Tier replica set per project. You can upgrade an M0 Free Tier cluster to an M2+ paid cluster at any time.

M2 and M5 instances are low-cost shared starter clusters with the same features as and functionality as M0, but with increased storage and the ability to deploy into a subset of regions on Amazon Web Service (AWS), Google Cloud Platform (GCP), and Microsoft Azure.

Beta

Support for M2 and M5 clusters is available as a Beta feature. These clusters do not yet support backups.

The following table highlights key differences between an M0 Free Tier cluster, an M2 or M5 shared starter cluster, and an M10+ dedicated cluster.

  Free Tier Cluster (M0) Shared Starter Cluster (M2 and M5) Dedicated Cluster (M10 and larger)
Storage
512 MB
M2: 2 GB
M5: 5 GB
10 - 4000 GB
MongoDB Version Support 3.6 3.6 3.2, 3.4, 3.6
Data Visualization No No Atlas Data Explorer
Metrics and Alerts Limited Limited Full metrics, including the Real Time Performance Tab, and full alert configuration options.
VPC Peering (AWS clusters only) No No VPC Peering Connection wizard
Global Region Selection Atlas supports deploying M0 instances in a subset of regions in AWS only. Atlas supports deploying M2 and M5 clusters in a subset of regions in AWS, GCP, and Azure. Atlas supports deploying clusters globally on Amazon Web Services, Google Cloud Platform, and Microsoft Azure
Cross-Region Deployments No No Yes. Specify additional regions for high availability or local reads when creating or scaling a cluster.
Backups No No Yes, including queryable backups
Sharding No No Yes, for clusters using an M30+ instance
Dedicated Instance No, M0 Free Tier clusters run in a shared environment No, M2 and M5 clusters run in a shared environment Yes, M10+ clusters deploy each mongod process to its own instance.
Performance Advisor No No Yes
BI Connector for Atlas No No Yes

For a complete list of M0 (Free Tier), M2, and M5 limitations, see Atlas M0 (Free Tier), M2, and M5 Limitations.

Free Tier

To deploy a Atlas M0 Free Tier cluster, you must select the M0 instance size. If the M0 option is greyed out, check that:

  • The Cloud Provider is Amazon Web Services,
  • The Region is N. Virginia (us-east-1),
  • There is not already an M0 Free Tier cluster in the Atlas project, and
  • Under Additional Settings the MongoDB version is MongoDB 3.6 with WiredTiger

From the Cluster Tier section, you can also Customize Your Storage.

Customize Your Storage

Each cluster tier comes with a default set of resources. Select your preferred storage customizations under the Customize Your Storage heading.

Atlas can provide the following storage configuration options depending on the selected cloud provider and instance size.

  • Storage Capacity The size of the server root volume. To change this, either:

    • Move the slide bar until the text box displays your preferred disk size, or
    • Specify the exact disk size in the text box.

    Changes to storage capacity affects cost.

  • Storage Speed The input/output operations per second (IOPS) the system can perform. Changes to storage speed affects cost.

  • Auto-Expand Storage: When disk usage reaches 90%, automatically increase storage by an amount necessary to achieve 70% utilization. Changes to storage capacity affects cost.

    Note

    If the size of the cluster oplog is small, Atlas may be unable to automatically expand disk capacity.

For more information on the default resources and available configuration options for each cloud service provider, see:

D. Select any Additional Settings

Select the MongoDB Version of the Cluster

Select the new MongoDB version from the Select a version dropdown. Atlas always deploys the cluster with the latest stable release of the specified version.

Atlas supports creating M10+ paid tier clusters with the following MongoDB versions:

  • MongoDB 3.4
  • MongoDB 3.6

MongoDB Server 3.2 is planned for End of Life on September 2018. Atlas deprecated support for deploying clusters with MongoDB 3.2 in March, 2018.

M0 Free Tier and M2/M5 shared tier clusters built after April 23, 2018 only support MongoDB 3.6.

As new maintenance releases become available, Atlas automatically upgrades to these releases via a rolling process to maintain cluster availability.

You can upgrade an existing Atlas cluster to a newer major MongoDB version, if available, when you scale a cluster. However, you cannot downgrade a cluster’s MongoDB version.

Enable Backup for the Cluster

Important

The backup method that you choose when enabling backup for the first time for any cluster in a project is the only method allowed if you enable backup for other clusters in the project. For example, if you enable continuous backups for your first cluster, you may only perform continuous backups with any subsequent clusters in the project.

To change the backup method for the project, disable backups for all clusters in the project, then re-enable backups using your preferred backup methodology. Atlas deletes any stored snapshots when you disable backup for a cluster.

Consider creating a separate project for clusters where a different backup method is required.

To enable backups for the Atlas cluster, toggle Turn on Backup (M10 and up) to Yes. If enabled, Atlas takes snapshots of your databases at regular intervals and retains them according to your project’s retention policy.

The backup option chosen for the first cluster in a project dictates the backup option for all other subsequent clusters in the project. See Fully Managed Backup Service for more information.

Atlas provides the following backup options:

Backup Option Description
Continuous Backups

Atlas takes incremental snapshots of data in your cluster and allows you to restore from stored snapshots or from a selected point in time within the last 24 hours. You can also query a continuous backup snapshot.

Each project has one backup data center location dictated by the first backup-enabled cluster created in that project. See Snapshot Storage Location for more information.

Cloud Provider Snapshots (Azure Only)

Atlas takes full copy snapshots of data in your cluster and allows you to restore from those snapshots.

Atlas cloud provider snapshots are stored in the same region as the corresponding cluster. For multi-region clusters, snapshots are stored in the cluster’s preferred region. See Snapshot Storage Location for more information.

Deploy a Sharded Cluster

To deploy your cluster as a sharded cluster, toggle Shard your cluster (M30 and up) to Yes.

Sharded clusters support horizontal scaling and consist of shards, config servers and mongos routers:

  • Atlas deploys each shard as a three-node replica set by default. Atlas deploys each node using the selected instance size.

    For cross-region clusters, the number of nodes per shard is equal to the total number of electable and read-only nodes across all configured regions. Atlas distributes the shard nodes across the selected regions.

  • Atlas deploys the config servers as a three-node replica set. The config servers run on M30 instances.

    For cross-region clusters, Atlas distributes the config server replia set nodes to ensure optimal availability. For example, Atlas might deploy the config servers across three distinct availability zones and three distinct regions if supported by the selected cloud service provider and region configuration.

  • Atlas deploys one mongos router for each node in each shard. For cross-region clusters, this allows clients using a MongoDB driver to connect to the geographically “nearest” mongos.

    To calculate the number of mongos routers in a cluster, multiply the number of shards by the number of replica set nodes per shard.

Atlas deploys mongod process to its own instance. For sharded clusters, the six routers (the mongos processes) run on six of the shard servers; i.e. each of the six mongos processes shares an instance with one mongod process.

For details on how the number of server instances affect cost, see Number of Servers.

For more information on sharded clusters, see Sharding in the MongoDB manual.

Configure the Number of Shards

This field is visible only if the deployment is a sharded cluster.

You can set the number of shards to deploy with the sharded cluster. You cannot have fewer than two shards.

Enable BI Connector for Atlas

To enable the BI Connector for Atlas for this cluster, toggle Enable Business Intelligence Connector (M10 and up) to Yes.

If enabled, select the node type from which the BI Connector for Atlas should read. For high traffic production environments, the secondary node may be preferable to the primary node.

The BI Connector for Atlas is only available for M10+ clusters.

E. Enter the Cluster Name

This is the cluster name as it appears in Atlas. You cannot change the cluster name once Atlas deploys the cluster.

F. Enter your Payment Information and Deploy your Cluster

Click Confirm & Deploy to enter payment information. For Atlas M0 Free Tier cluster, Atlas does not require payment information to deploy the cluster.

See Billing Overview for more information on Atlas billing and payments.

G. (Optional) Create a MongoDB Administrative User

Atlas only allows client connections to the cluster from entries in the project IP whitelist. Clients must also authenticate as a MongoDB database user associated to the project.

If you have not configured the project IP whitelist or MongoDB users, follow the prompts in the Atlas Clusters view to configure basic project security.

When creating your first MongoDB database user, select the Atlas admin role from the user configuration dialog to create an administrative user. See MongoDB Database User Privileges for more information on MongoDB user privileges.

If you need to modify your existing project security settings, click the Security tab from the Clusters view. See Security Features and Setup for complete documentation on Atlas project security settings.

H. Connect to your cluster

Once Atlas deploys your cluster, click Connect on the cluster to open the Connect dialog. Follow the instructions to connect to your cluster. See Connect to a Cluster for more information.
[1]For replica sets, the data-bearing servers are the servers hosting the replica set nodes. For sharded clusters, the data-bearing servers are the servers hosting the shards. For sharded clusters, Atlas also deploys servers for the config servers; these are charged at a rate separate from the instance costs.