Using aws sfn with dms

Question

Pulumi · Accepted Answer

To integrate AWS Step Functions (SFN) with AWS Database Migration Service (DMS), you'll typically use Step Functions to orchestrate and manage DMS tasks. AWS DMS is a service that helps you migrate databases to AWS quickly and securely. The service supports migrations between various database platforms, such as moving data from on-premises databases to Amazon RDS or Amazon Redshift, or between databases in AWS.

Here's a high-level overview of what you'll do to use AWS SFN with AWS DMS:

1. **Define a DMS Replication Task**: This involves specifying the source, target, and the kind of migration you're performing (e.g., full load, change data capture, etc.).
   
2. **Create a State Machine in Step Functions**: This state machine will define the workflow of your database migration, such as preparing for migration, starting the DMS task, monitoring the progress, handling errors if any, and completing the migration.

3. **Linking State Machine Steps to DMS Operations**: You will need to create Lambda functions or integrate directly (if supported by the AWS SDK) with DMS to start, stop, and monitor replication tasks through your Step Function workflows.

Below is a simplified Pulumi TypeScript program that shows how you could set up a DMS Replication Task and a Step Function State Machine that could be used to manage it. Please note that for a real-world scenario, you need to provide your actual source and target endpoint ARNs, proper Role ARN, and other specifics for the DMS Task and relevant permissions for the Step Function to interact with DMS.

```typescript
import * as pulumi from "@pulumi/pulumi";
import * as aws from "@pulumi/aws";

// Create a DMS Replication Instance to use for the migration tasks.
const replicationInstance = new aws.dms.ReplicationInstance("my-replication-instance", {
    replicationInstanceClass: "dms.t2.micro",
    allocatedStorage: 20,
    // You need to set up additional parameters depending on your requirements, such as VPC, KMS Key, etc.
});

// Create a DMS Replication Task which defines the migration to perform.
const replicationTask = new aws.dms.ReplicationTask("my-replication-task", {
    // Replace with the real ARNs for your source and target endpoints.
    sourceEndpointArn: "arn:aws:dms:us-east-1:123456789012:endpoint:sourceEndpointArn",
    targetEndpointArn: "arn:aws:dms:us-east-1:123456789012:endpoint:targetEndpointArn",
    replicationInstanceArn: replicationInstance.replicationInstanceArn,
    tableMappings: JSON.stringify({
        rules: [
            {
                // Define your table mapping rules here.
            },
        ],
    }),
    // See the AWS DMS documentation for details on how to structure the replication task settings.
    replicationTaskSettings: "{\"TargetMetadata\":{\"TargetSchema\":\"\",\"SupportLobs\":true,\"FullLobMode\":false,\"LobChunkSize\":0,\"LimitedSizeLobMode\":true,\"LobMaxSize\":32,\"InlineLobMaxSize\":0},...}",
    migrationType: "full-load", // or 'cdc' for Change Data Capture, 'full-load-and-cdc', etc.
});

// Define the Step Function State Machine.
const role = new aws.iam.Role("my-state-machine-role", {
    // Replace with adequate policy
    assumeRolePolicy: JSON.stringify({
        Version: "2012-10-17",
        Statement: [
            {
                Action: "sts:AssumeRole",
                Effect: "Allow",
                Principal: {
                    Service: "states.amazonaws.com",
                },
            },
        ],
    }),
});

// An IAM policy that allows the Step Function to manage DMS Replication Tasks.
const policy = new aws.iam.Policy("my-state-machine-policy", {
    policy: pulumi.interpolate`{
        "Version": "2012-10-17",
        "Statement": [
            {
                "Effect": "Allow",
                "Action": [
                    "dms:StartReplicationTask",
                    "dms:DescribeReplicationTasks",
                    "dms:StopReplicationTask"
                    // Add more actions as necessary for your workflow.
                ],
                "Resource": [
                    "${replicationTask.arn}"
                ]
            }
        ]
    }`,
});

new aws.iam.RolePolicyAttachment("my-state-attachment", {
    role: role.name,
    policyArn: policy.arn,
});

const stateMachine = new aws.sfn.StateMachine("my-state-machine", {
    roleArn: role.arn,
    definition: `{
        "Comment": "A DMS State Machine",
        "StartAt": "StartMigration",
        "States": {
            "StartMigration": {
                "Type": "Task",
                "Resource": "arn:aws:states:::dms:startReplicationTask.sync",
                "Parameters": {
                    "ReplicationTaskArn": "${replicationTask.arn}",
                    "StartReplicationTaskType": "start-replication"
                },
                "Next": "MonitorMigration"
            },
            "MonitorMigration": {
                "Type": "Task",
                // This should invoke a Lambda that checks the DMS task status.
                "Resource": "arn:aws:lambda:your-region:123456789012:function:YourMonitorLambdaFunction",
                "End": true
            }
            // Add more states as needed for handling retries, errors, etc.
        }
    }`,
});

export const stateMachineArn = stateMachine.arn;
```

In this program, you replace `"sourceEndpointArn"` and `"targetEndpointArn"` with your actual DMS endpoints ARNs. You also need to specify proper table mapping and task settings for DMS. For the Step Function role and policy, replace with the policy that defines the permissions your state machine needs to interact with the DMS API properly.

A Lambda function named `YourMonitorLambdaFunction` is referenced in the state machine definition, which would need to be implemented to check the status of the DMS task. The state machine is left simple here for illustration; in a practical scenario, you would handle retries, failures, and other states as required for your migration workflow.

After creating the Step Function, you can trigger it to start the replication task, and the function will monitor the migration until completion. Make sure to have the appropriate IAM permissions and the necessary AWS SDK operations within the Lambda function to interact with DMS.

Finally, export the ARN of the state machine, which you can use to trigger executions or reference in other parts of your infrastructure.