Live Migrate (Push) a MongoDB 6.0.8 or Later Cluster Monitored by Cloud Manager into Atlas

On this page

Restrictions

Migration Path and Supported Platforms
Required Access
Prerequisites
Considerations
Migrate Your Cluster
Push Live Migration APIs
Push Live Migration CLI Commands
Migration Support

If both the source and destination clusters are running MongoDB 6.0.8 or later, and Cloud Manager monitors the source cluster, Atlas can push a source cluster to an Atlas cluster using the procedure described in this section.

This process uses mongosync as the underlying data migration tool, enabling faster live migrations with less downtime:

Atlas syncs data from the source to the destination cluster until you cut your applications over to the destination Atlas replica set.
Once you reach the cutover step in the following procedure:
- Stop writes to the source cluster.
- Stop your application instances, point them to the Atlas cluster, and restart them.

Restrictions

This live migration has the following limitations:

The FCV for source and destination clusters is at least 6.0 and is the same on source and destination clusters.
You can't run this live migration procedure for source or destination clusters with MongoDB versions earlier than MongoDB 6.0.8. To learn more, see Server Release Notes.
This live migration procedure doesn't support MongoDB rapid releases, such as 6.1 or 6.2. Only major MongoDB releases, such as 6.0.x (starting from 6.0.8 and later) are supported. To learn more, see MongoDB versioning.
You can't use Serverless instances as destination clusters.
You can't select an M0 (Free Tier) or M2/M5 shared cluster as the source or destination for live migration. To migrate data from an M0 (Free Tier) or M2/M5 shared cluster to a paid cluster, change the cluster tier and type.
You can't live migrate using this migration procedure to an Atlas destination cluster that has BI Connector for Atlas enabled.
During live migration, Atlas disables host alerts.
Time series collections are not supported. The migration process skips any time series collections on the source cluster.
Clustered collections with expireAfterSeconds set aren't supported.
convertToCapped and cloneCollectionAsCapped commands aren't supported.
If in your source cluster you used applyOps operations, they aren't supported on the destination cluster.
Documents that have dollar ($) prefixed field names aren't supported. See Field Names with Periods and Dollar Signs.
Queryable Encryption is not supported.
You can't sync a collection that has a unique index and a non-unique index defined on the same fields.
Within a collection, the _id field must be unique across all of the shards in the cluster. To learn more, see Sharded Clusters and Unique Indexes.
You can't use the movePrimary command to reassign the primary shard while running this live migration process.
You can't add or remove shards while running this live migration process.
This live migration process only migrates indexes that exist on all shards and that have consistent specs on all shards.
You can't refine a shard key while running this live migration process.
You can't modify the shard key using reshardCollection during this live migration process.
The maximum number of shard key indexes is one lower than normal, 63 instead of 64.
You can't use this live migration process to sync one source cluster to many destination clusters.
Network compression isn't supported.
This live migration process replicates data, it doesn't replicate zone configuration.
System collections aren't replicated with this live migration process.
If you issue a dropDatabase command on the source cluster, this change isn't directly applied on the destination cluster. Instead, this live migration process drops user collections and views in the database on the destination cluster, but it doesn't drop system collections on that database. For example, on the destination cluster, the drop operation doesn't affect a user-created system.js collection. If you enable profiling, the system.profile collection remains. If you create views on the source cluster and then drop the database, replicating the drop with this live migration process removes the views, but leaves an empty system.views collection. In these cases, the live migration of the dropDatabase results removes all user-created collections from the database, but leaves its system collections on the destination cluster.

Support for VPC Peering and Private Endpoints

The following table lists the current support status for VPC peering and private endpoints for source and destination clusters that you live migrate to Atlas. Select the tab for replica sets or sharded clusters.

Migration Path and Supported Platforms

Live Migration from Cloud Manager to Atlas is supported for all platforms on which you can provision a host for mongosync. For a full list of supported platforms on which you can provision a host for mongosync, see mongosync platforms.

Atlas live migration (push) supports the following migration paths:

Source Cluster MongoDB Version	Destination Atlas Cluster MongoDB Version
6.0.8	6.0.8
7.0+	7.0+

Required Access

To live migrate your data, you must have Project Owner access to Atlas.

Users with Organization Owner access must add themselves to the project as a Project Owner.

Prerequisites

Before you begin the push live migration from a cluster running MongoDB 6.0.8 or later monitored in Cloud Manager to Atlas:

Upgrade the source cluster to MongoDB 6.0.8 or later.
Create an Atlas Account.
Create an Atlas organization and then create a project in this organization.
Deploy your cluster in this project.
Connect to your cluster from all client servers where your applications run.
Consider configuring a VPC peering connection or a private endpoint between each migration host and the destination Atlas cluster on the same cloud provider and in the same region as the destination cluster.
Note
If you choose not to use VPC peering or private endpoints when migrating replica sets, the live migration process runs over public IP addresses that you add to the Atlas project's IP access list as part of the live migration procedure in this section.
On your source cluster in Cloud Manager, provision a migration host in Cloud Manager.
- The username and password used to connect to the source cluster.
- If you aren't using a private endpoint between the migration host and the destination Atlas cluster, obtain the external IP addresses or CIDR blocks of the provisioned migration hosts in Cloud Manager from your Cloud Manager administrator.
- If the source cluster uses TLS/SSL with a Custom Root Certificate Authority, to ensure the hosts can read the certificate, add the source cluster's CA file to the migration hosts.
During the live migration process, Atlas validates that it can collect MongoDB database statistics using dbStats. Before you live migrate to an Atlas cluster, review the project settings for the source cluster in Cloud Manager and ensure that the option Collect Database Specific Statistics is enabled. This option is enabled by default in Cloud Manager, and it should remain enabled so that the migration process passes validation.

Live Migration Workflow

This section outlines the workflow. For detailed steps, see the procedure for migrating a cluster from Cloud Manager to Atlas.

"To live migrate your deployment to Atlas, generate a link-token,
provision a migration host, and start live migration."

The stages in the live migration workflow are:

Stage 1: Link with Atlas. Perform this step in Atlas, after you have created your Atlas account, organization, and project; deployed your dedicated cluster in this project; and can connect to it.
1. In the Atlas organization, go to Live Migration.
2. Select Migrate from Cloud Manager and start the live migration wizard.
Stage 2: Provision Migration Host.
- provision a migration host in Cloud Manager. A migration host runs a dedicated MongoDB Agent that orchestrates the live migration process from Cloud Manager to Atlas.
  Note
  If you are migrating a source MongoDB deployment that hasn't used Cloud Manager before, add existing MongoDB processes to Cloud Manager.
- In the Live Migration: Connect to Atlas section of your Cloud Manager organization's Settings page, select Connect to Atlas and paste the link-token that you created in Atlas. To learn more, see Connect to Atlas for Live Migration in Cloud Manager.
Stage 3: Start the Migration. In Atlas, follow the steps in the wizard to start the live migration process.

External IP Address of the Migration Host in Cloud Manager

Before you begin the live migration procedure, add the IP addresses or CIDR blocks of your migration hosts to the project IP access list. Atlas allows connections to the destination cluster only from hosts with entries in the project's access list.

Pre-Migration Validation

Before starting the live migration procedure, Atlas runs validation checks on the source and destination clusters.

The source and destination cluster's MongoDB version is at least FCV 6.0 and is matching as described in Restrictions.
The source cluster's database user has the correct permissions as described in Source Cluster Security.
The source and destination clusters are either both replica sets, or they are both sharded clusters with the same number of shards.
If the source cluster is a standalone, before using this migration process, convert the standalone to a replica set.
If migrating a sharded cluster to another sharded cluster, the source sharded cluster must use CSRS (Config Server Replica Sets). See Replica Set Config Servers.
The source cluster enables collecting database statistics for its project in Cloud Manager. This allows Atlas to collect MongoDB database statistics during the live migration process. To confirm that the option Collect Database Specific Statistics is enabled, review the project settings for the source cluster in Cloud Manager.
The destination Atlas cluster doesn't have BI Connector for Atlas enabled.

Source Cluster Security

Various built-in roles provide sufficient privileges. For example:

For source replica sets running MongoDB 6.0.8 or later a MongoDB user must have the readAnyDatabase and backup roles.

For source sharded clusters running MongoDB 6.0.8 or later a MongoDB user must have the readAnyDatabase, backup, and clusterMonitor roles.

To verify that the database user who will run the live migration process has these roles, run the db.getUser() command on the admin database. For example, for a replica set, run:

use admin
db.getUser("admin")
{
    "_id" : "admin.admin",
    "user" : "admin",
    "db" : "admin",
    "roles" : [
  {
    "role" : "backup",
    "db" : "admin"
  },
  {
    "role" : "readAnyDatabase",
    "db" : "admin"
  }
 ]
} ...

Specify the username and password to Atlas when prompted by the walk-through screen of the live migration procedure.

Atlas only supports SCRAM for connecting to source clusters that enforce authentication.

Security Requirements for the Migration Host

For push-type live migrations, you're responsible for provisioning, securing, and running the migration host. The migration host only encrypts outbound communication with Atlas clusters.

To learn more about Atlas security, see the Atlas Security whitepaper.

Considerations

Network Encryption

During push live migrations, if the source cluster does not use TLS encryption for its data, the traffic from the source cluster to the migration host is not encrypted, but the traffic from the migration host to Atlas is encrypted. Determine if this is acceptable before you start a push live migration procedure.

Database Users and Roles

If the source cluster doesn't use authentication, you must create a user in Atlas because Atlas doesn't support running without authentication.

Atlas doesn't migrate any user or role data to the destination cluster.

If the source cluster enforced authentication, before you migrate you must re-create the appropriate authentication mechanism used by your applications on the destination Atlas cluster. The following table lists authentication mechanisms and how to configure them in Atlas.

Authentication Mechanism	Configuration Method
SCRAM	Create database users with SCRAM for password authentication.
LDAP	Set up LDAP.
AWS KMS, Azure Key Vault, Google Cloud KMS	Set up KMS encryption.

Destination Cluster Configuration

For the destination cluster, the following considerations apply:

The source and destination clusters are either both replica sets, or they are both sharded clusters with the same number of shards.
You can't select an M0 (Free Tier) or M2/M5 shared-tier cluster as the destination for live migration.

The destination cluster in Atlas must match or exceed the source deployment in terms of RAM, CPU, and storage. Provision a destination cluster of an adequate size so that it can accommodate both the migration process and the expected workload, or scale up the destination cluster to a tier with more processing power, bandwidth or disk IO.
To maximize migration performance, use at least an M40 cluster for the destination cluster. When migrating large data sets, use an M80 cluster with 6000 IOPS disks or higher.
You can also choose to temporarily increase the destination Atlas cluster's size for the duration of the migration process. Once you migrate your application's workload to a cluster in Atlas, contact support for assistance with further performance tuning and sizing of your destination cluster to minimize costs.
To avoid unexpected sizing changes, disable auto-scaling on the destination cluster. To learn more, see Manage Clusters.
To prevent unbounded growth of the oplog collection, set a fixed oplog size for the duration of the live migration process. To learn more, see Required Access and Atlas Configuration Options. If you are observing performance issues even after you've followed these recommendations, contact support.

Do not change the featureCompatibilityVersion flag while Atlas live migration is running.

Avoid Workloads on the Destination Cluster

Avoid running any workloads, including those that might be running on namespaces that don't overlap with the live migration process, on the destination cluster. This action avoids potential locking conflicts and performance degradation during the live migration process.

Don't run multiple migrations to the same destination cluster at the same time.

Don't start the cutover process for your applications to the destination cluster while the live migration process is syncing.

Avoid Cloud Backups

Atlas stops taking on-demand cloud backup snapshots of the target cluster during live migration. Once you complete the cutover step in the live migration procedure on this page, Atlas resumes taking cloud backup snapshots based on your backup policy.

Avoid Namespace Changes

Don't make any namespace changes during the migration process, such as using the renameCollection command or executing an aggregation pipeline that includes the $out aggregation stage.

Avoid Elections

The live migration process makes a best attempt to continue a migration during temporary network interruptions and elections on the source or destination clusters. However, these events might cause the live migration process to fail. If the live migration process can't recover automatically, restart it from the beginning.

Rolling Restarts

After the migration process completes, your cluster restarts each of its members one at a time. This is called a rolling restart, and as a consequence, a failover will occur on the primary. To ensure a smooth migration, consider running a Test Primary Failover procedure before migrating your data to the destination cluster.

Staging and Production Environments

Consider running the following procedure twice. Perform a partial migration that stops at the Perform the Cutover step first. This creates an up-to-date Atlas-backed staging cluster to test application behavior and performance using the latest driver version that supports the MongoDB version of the Atlas cluster.

After you test your application, run the full migration procedure using a separate Atlas cluster to create your Atlas-backed production environment.

Migrate Your Cluster

Important

Avoid making changes to the source cluster configuration while the live migration procedure runs, such as removing replica set members or modifying mongod runtime settings, such as featureCompatibilityVersion.

Procedure

Start the migration process.

In the left-side panel of your organization's page, click Live Migration.
Click Migrate from Ops Manager or Cloud Manager.
Note
The UI label mentions Ops Manager, however, for this procedure, you can only migrate to Atlas MongoDB deployments 6.0.8 or later that Cloud Manager monitors.
Click I'm Ready to Start.

Atlas displays a Live Migration wizard with instructions on how to proceed with the process. The process pushes the data from your source cluster to the new destination cluster. After you complete the wizard steps, you can point your application to the new cluster.

Link with Atlas.

Click Generate Link-Token. Atlas displays the page for generating a link-token.
Click Next to see a page that contains the generated link-token.
Copy the link-token and store it in a secure location. Atlas never displays the contents of the link-token. Atlas also does not display the link-token after generating it. Do not share it publicly.
Note
Use one unique link-token for live migrating all projects in one Cloud Manager organization to Atlas.
Click Done.

Paste the link-token into Cloud Manager.

Access the organization in Cloud Manager:
Open Cloud Manager, and navigate to the organization whose project's cluster you are live migrating to Atlas.
Click Settings in the left navigation panel.
In the Live Migration: Connect to Atlas section, click Connect to Atlas. The Connect to Atlas dialog opens.
Paste the link-token you generated in the previous step of the Live Migration wizard and click Connect to Atlas. Cloud Manager establishes the connection to Atlas. Use the Refresh button to send an update to Atlas, if needed.

Create the destination Atlas cluster.

If you haven't already, create a destination cluster in Atlas. See Required Access.

Initiate the migration from the destination cluster.

Click Select Target Cluster from Projects.
Go to your destination Atlas cluster's project and find your destination cluster.
Click and select Migrate Data to this Cluster from the dropdown list to start the migration. The Migrate Data to This Cluster page opens.
Click Migrate from Ops Manager or Cloud Manager.
Note
The UI label mentions Ops Manager, however, for this procedure, you can only migrate to Atlas MongoDB deployments 6.0.8 or later that Cloud Manager monitors.
Fill in the fields as follows:
- Select the source project in Cloud Manager, if it's not already selected.
- Select a migration host for handling the migration.
- If you aren't using a private endpoint, review the IP address access list and check that the migration host's external IP address is included in this list. If it's not added, add it now:
  - Click Set Network Access for Host
  - Click + Add IP Address
  - Return to the Live Migration wizard. Select the source cluster from the dropdown and choose Migrate data to this cluster under .
- Select the source cluster from the drop-down.
- If the source cluster enforces authentication, enter a username and password into the provided text boxes.
  See Source Cluster Security for guidance on the user permissions required by Atlas live migration.
- If you suspend the source cluster from automation in Cloud Manager, but continue to monitor the source cluster with the Monitoring Agent, the Username and Password display. If your deployment requires user authentication, provide the user name and password in these fields. The database user whose credentials you provide must have at least the backup role on the admin database and must be authenticated using both SCRAM-SHA-1 and SCRAM-SHA-256.
- If the source cluster uses TLS/SSL, toggle the Is encryption in transit enabled? button.
- If the source cluster uses TLS/SSL with a custom Root Certificate Authority (CA), copy the path to the CA file from your migration host and paste this path into the provided text box. The file must be present on the migration host to ensure the migration host can read the certificate. Atlas checks that the certificate is present and readable.
- If your destination cluster has data, and you want to preserve it, keep the Clear any existing data on your destination cluster option unchecked. The live migration service warns you if it finds duplicate namespaces. If you want to delete the existing data, check this option.
- Choose a connection to connect to the cluster. The Standard connection always shows as available in the UI. However, other connection options are enabled only if you have previously configured a VPC peering connection or a private endpoint for your clusters. If Atlas detects that you don't have VPC connections or private endpoints configured, these options are grayed out.
  - If you aren't using VPC peering or a private endpoint, click Standard connection and proceed to the Validation stage of this step.
  - If you configured a VPC peering connection between the migration host and the Atlas replica set, the VPC Peering option is active. Click VPC Peering to connect using VPC peering for live migration. If the VPC Peering option is grayed out, configure a VPC peering connection before starting this procedure. To learn more, see Support for VPC Peering and Private Endpoints.
  - If you configured a private endpoint between the migration host and the Atlas cluster, the Private Endpoint option is active. Click Private Endpoint to connect with a private endpoint, and then select a previously-configured private endpoint from the dropdown. Only private endpoints that are in AVAILABLE state are valid. If the Private Endpoint option is grayed out, configure a private endpoint before starting this procedure. To learn more, see Support for VPC Peering and Private Endpoints.
    Note
    For push live migrations where the source and destination clusters are running MongoDB 6.0.8 or later, private endpoints are supported only for clusters deployed within a single cloud provider and single region.
- Click Validate. The validation process verifies that your migration host is reachable, and performs the following validation checks to ensure that you can start live migration to Atlas.
  To take advantage of the following validation checks, upgrade the MongoDB Agent in Cloud Manager to the latest version. The following validation checks run during the live migration:
  - The migration host can connect to the destination cluster.
  - If the source cluster uses TLS/SSL with a custom Root Certificate Authority (CA), the migration host can access the source cluster using TLS/SSL.
  - The database user credentials are valid. This validation check runs only if you suspend the source cluster from automation in Cloud Manager, but continue to monitor the source cluster with the Monitoring Agent.
  - The migration process validates that the destination cluster has enough disk space based on the storage size of the compressed data. To learn more about data and storage sizes, see dbStats.
- If validation fails, check the migration host, the validity of your external IP addresses or CIDR block, and the link-token. Also check the database user credentials, your TLS/SSL certificates, and the amount of disk storage size on the destination cluster.
- If validation succeeds, click Next.

Start the migration.

Review the report listing your source organization, project and cluster, and the migration host that the live migration process will use.
Click Start the Migration.

Prepare to Cut Over.

When the lag timer and the Prepare to Cutover button turn green, click it to proceed to the next step.

Perform the cutover.

When Atlas detects that the source and destination clusters are nearly in sync, it starts an extendable 120 hour (5 day) timer to begin the cutover stage of the live migration procedure. After the 120 hour period passes, Atlas stops synchronizing with the source cluster. You can extend the time remaining by 24 hours by clicking Extend time below the <time> left to cut over timer.

Click Prepare to Cutover. Atlas displays a walk-through screen that states: Your migration is almost complete! The walk-through screen displays the following instructions on how to proceed with the cutover process:
1. Stop your application. This ensures that no more writes occur on the source cluster.
2. Wait for the optime gap to reach zero. When the counter reaches zero, the source and destination clusters are in sync.
3. Check the box that states: I confirm that I am ready to cut over the application to the destination cluser. By proceeding, Atlas will finalize the migration. This process will take a few seconds. Once it is complete you can point your application at the destination cluster and begin writing to it.
Click Cutover. Atlas completes the migration and displays the Connect page.
Decide when to resume writes on the destination cluster. You can do one of the following:
- Wait for the banner on your cluster card to state: Your cluster migration is complete and then resume writes on the destination cluster. If you choose to wait for the migration to complete, your application experiences a temporary pause in writes during the time period needed to finalize the migration.
  or
- Begin application's writes to the destination cluster without waiting for the migration to complete, while your cluster card banner states: Your destination cluster in Atlas is ready to accept writes, but we are still finalizing the migration. If you choose to move writes to the destination cluster without waiting until the end of the migration process, and live migration fails in the final stages and issues an error, you must redirect writes back to your source cluster and restart the live migration process.
When you are ready to redirect writes to the destination cluster in Atlas:
1. Use the destination cluster's connection string to connect to your application.
2. Confirm that your application is working with the destination Atlas cluster.

Atlas performs these actions to complete the process:

Removes the MongoDB live migration server subnets from the IP access list on the destination cluster.
Removes the database user that live migration used to import data to the destination cluster.
Marks the migration process as complete.

Push Live Migration APIs

To run tasks associated with the live migration procedure, see Push Live Migration API.

Note

The Live Migration APIs mention Cloud Manager or Ops Manager, however, the type of live migration described in this section only supports migrating source clusters monitored in Cloud Manager to destination clusters in Atlas.

Push Live Migration CLI Commands

To migrate a cluster using the Atlas CLI, you can perform the following steps:

Create or delete a link-token
Create or view a validation job
Create or view a migration job
Perform the cutover

For other steps in the live migration procedure, you must use the Cloud Manager UI or the Atlas UI. To learn more, see the live migration workflow.

Before you migrate a cluster using the Atlas CLI, complete the pre-migration validation.

Note

Before you run any Atlas CLI commands, you must:

Create or Delete a Link-Token

To create a new link-token using the Atlas CLI, run the following command:

atlas liveMigrations link create [options]

To delete the link-token you specify using the Atlas CLI, run the following command:

atlas liveMigrations link delete [options]

To learn more about the syntax and parameters for the previous commands, see the Atlas CLI documentation for atlas liveMigrations link create and atlas liveMigrations link delete.

If you are migrating from Ops Manager, request an external IP address and specify it in the link-token. To learn more, see Request an External IP Address in the Ops Manager documentation.

Create and View a Validation Job

To create a new validation request using the Atlas CLI, run the following command:

atlas liveMigrations validation create [options]

To return the details for the validation request you specify using the Atlas CLI, run the following command:

atlas liveMigrations validation describe [options]

To learn more about the syntax and parameters for the previous commands, see the Atlas CLI documentation for atlas liveMigrations validation create and atlas liveMigrations validation describe.

To learn what Atlas validates, see the Validate bullet in the Migrate Your Cluster section on this page.

Create and View a Migration Job

To create one new migration job using the Atlas CLI, run the following command:

atlas liveMigrations create [options]

To return the details of the migration job you specify using the Atlas CLI, run the following command:

atlas liveMigrations describe [options]

To learn more about the syntax and parameters for the previous commands, see the Atlas CLI documentation for atlas liveMigrations create and atlas liveMigrations describe.

Perform the Cutover

To start the cutover for live migration using the Atlas CLI, run the following command:

atlas liveMigrations cutover [options]

To learn more about the command syntax and parameters, see the Atlas CLI documentation for atlas liveMigrations cutover.

When the cutover completes, Atlas completes the live migration process and stops synchronizing with the source cluster. To learn more, see the Migrate Your Cluster section on this page.

Note

The Live Migration CLI commands might mention Cloud Manager or Ops Manager, however, the type of live migration described in this section only supports migrating source clusters monitored in Cloud Manager to destination clusters in Atlas.

Migration Support

If you have any questions regarding migration support beyond what is covered in this documentation, or if you encounter an error during migration, please request support through the Atlas UI.

To file a support ticket:

Click Support in the left-hand navigation.
Click Request Support.
For Issue Category, select Help with live migration.
For Priority, select the appropriate priority. For questions, please select Medium Priority. If there was a failure in migration, please select High Priority.
For Request Summary, please include Live Migration in your summary.
For More details, please include any other relevant details to your question or migration error.
Click the Request Support button to submit the form.

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