DMS - Opensearch service as target - Failed to connect to database Aurora Mysql.

Question

>**Source System:** Aurora MySQL

>**Target System:** Amazon Opensearch Service

>**Middle man:** AWS Database Migration Service

Hi,

I have a replication instance in AWS DMS which is using Aurora MySQL as the source and Opensearch Service as the target. Test connection is working with the Aurora MySQL, but not with Opensearch Service. I get the following error:

Test Endpoint failed: Application-Status: 1020912, Application-Message: Failed to connect to database.

**Permission Defined in the policy:**

>{
    "Version": "2012-10-17",
    "Statement": [
        {
            "Effect": "Allow",
            "Action": "es:*",
            "Resource": "arn:aws:es:{REGION}:{ACCOUNT_ID}:domain/{DOMAIN_NAME}/*"
        },
        {
            "Effect": "Allow",
            "Action": "dms:*",
            "Resource": "*"
        },
        {
            "Effect": "Allow",
            "Action": [
                "rds:DescribeDBInstances",
                "rds:DescribeDBClusters"
            ],
            "Resource": "*"
        }
    ]
}

**Trust Relationship:**

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

Opensearch service is having public access and having Fine-grained access control enabled. So I can access opensearch dashboard with userid and password.

Please suggest what can be done to solve the issue.

Regards,
Sagar

Answer

I fixed it by
* Un-Check Enable fine-grained access while creating opensearch service domain
* Deploy it in a VPC instead of public. Because DMS supports only domains without fine-grained access control.
* Edit access policy like below
>{
  "Version": "2012-10-17",
   "Statement": [
    {
      "Effect": "Allow",
      "Principal": {
        "AWS": "*"
      },
      "Action": "es:*",
      "Resource": "arn:aws:es:{region}:{account_id}:domain/{your_domain}/*"
    }
  ]
}

DMS - Opensearch service as target - Failed to connect to database Aurora Mysql.

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