# Creating prerequisites for premigration assessments
<a name="CHAP_Tasks.AssessmentReport.Prerequisites"></a>

This section describes the Amazon S3 and IAM resources you need to create a premigration assessment.

**Important**  
 The following prerequisites are only required if you supply your own Amazon S3 bucket and IAM role. 

## Create an S3 bucket
<a name="CHAP_Tasks.AssessmentReport.Prerequisites.S3"></a>

AWS DMS stores premigration assessment reports in an S3 bucket. To create the S3 bucket, do the following:

1. Sign in to the AWS Management Console and open the Amazon S3 console at [https://console.aws.amazon.com/s3/](https://console.aws.amazon.com/s3/).

1. Choose **Create bucket**.

1. On the **Create bucket** page, enter a globally unique name that includes your sign-in name for the bucket, such as dms-bucket-*yoursignin*.

1. Choose the AWS Region for the DMS migration task.

1. Leave the remaining settings as they are, and choose **Create bucket**.

## Create IAM resources
<a name="CHAP_Tasks.AssessmentReport.Prerequisites.IAM"></a>

DMS uses an IAM role and policy to access the S3 bucket to store premigration assessment results.

To create the IAM policy, do the following:

1. Sign in to the AWS Management Console and open the IAM console at [https://console.aws.amazon.com/iam/](https://console.aws.amazon.com/iam/).

1. In the navigation pane, choose **Policies**.

1. Choose **Create policy**.

1. In the **Create policy** page, choose the **JSON** tab.

1. Paste the following JSON code into the editor, replacing the example code. Replace *amzn-s3-demo-bucket* with the name of the Amazon S3 bucket that you created in the previous section.

------
#### [ JSON ]

****  

   ```
   {
      "Version":"2012-10-17",		 	 	 
      "Statement":[
         {
            "Effect":"Allow",
            "Action":[
               "s3:PutObject",
               "s3:DeleteObject",
               "s3:GetObject",
               "s3:PutObjectTagging"
            ],
            "Resource":[
               "arn:aws:s3:::amzn-s3-demo-bucket/*"
            ]
         },
         {
            "Effect":"Allow",
            "Action":[
               "s3:ListBucket",
               "s3:GetBucketLocation"
            ],
            "Resource":[
               "arn:aws:s3:::amzn-s3-demo-bucket"
            ]
         }
      ]
   }
   ```

------

1. Choose **Next: Tags**, then choose and **Next: Review**.

1. Enter **DMSPremigrationAssessmentS3Policy** for **Name\$1**, and then choose **Create policy**.

To create the IAM role, do the following:

1. In the IAM console, in the navigation pane, choose **Roles**.

1. Choose **Create role**.

1. On the **Select trusted entity** page, for **Trusted entity type**, choose **AWS Service**. For **Use cases for other AWS services**, choose **DMS.**

1. Check the **DMS** check box, and then choose **Next.**

1. On the **Add permissions** page, choose **DMSPremigrationAssessmentS3Policy**. Choose **Next**.

1. On the **Name, review, and create** page, enter **DMSPremigrationAssessmentS3Role** for **Role name**, then choose **Create role**.

1. On the **Roles** page, enter **DMSPremigrationAssessmentS3Role** for **Role name**. Choose **DMSPremigrationAssessmentS3Role**.

1. On the **DMSPremigrationAssessmentS3Role** page, choose the **Trust relationships** tab. Choose **Edit trust policy**.

1. On the **Edit trust policy** page, paste the following JSON into the editor, replacing the existing text.

------
#### [ JSON ]

****  

   ```
   {
      "Version":"2012-10-17",		 	 	 
      "Statement":[
         {
            "Sid":"",
            "Effect":"Allow",
            "Principal":{
               "Service":"dms.amazonaws.com"
            },
            "Action":"sts:AssumeRole"
         }
      ]
   }
   ```

------

   This policy grants the `sts:AssumeRole` permission to DMS to put the premigration assessment run results into the S3 bucket.

1. Choose **Update policy**.