---
url: https://docs.realmsec.info/integration/aws-s3.md
---

# AWS S3 Integration

You can use AWS S3 as a source or a destination. Continue below to integrate as a source, or click here to integrate as a destination.

## AWS S3 as a Source

Realm supports ingesting AWS service logs delivered to S3, including **AWS CloudTrail**, **AWS ALB access logs**, and **VPC Flow Logs**. All three follow the same S3 source setup described below.

Realm supports two approaches for receiving logs from an S3 bucket:

* **Option 1 — Via SQS (S3 → SQS):** Configure S3 to send event notifications directly to a new SQS queue.
* **Option 2 — Via SNS & SQS (S3 → SNS → SQS):** Subscribe a new SQS queue to an existing SNS topic that already receives S3 events.

Both approaches share the same SQS queue, IAM policy, and IAM role (or IAM user) setup. Follow the relevant section below based on your setup.

***

### Option 1: Via SQS (S3 → SQS)

Use this approach if your S3 bucket does not already have an SNS topic configured for event notifications.

#### Step 1: Create SQS Queue

1. Go to **SQS > Queues**
2. Click **Create Queue**
3. Choose a queue name based on the bucket purpose

> **Name (examples)**: `rlm-s3-cloudtrail`, `rlm-s3-alb`

4. Click **Create Queue**
5. Copy the **ARN** of the queue — you will need it in the steps below

#### Step 2: Create IAM Policy

1. Go to **IAM > Policies**
2. Click **Create Policy**
3. Click **JSON** and replace the contents with the following, substituting `<s3_bucket_arn>` with your S3 bucket ARN and `<sqs_queue_arn>` with the SQS queue ARN from Step 1

```json
{
    "Version": "2012-10-17",
    "Statement": [
        {
            "Sid": "s3ReadObjects",
            "Effect": "Allow",
            "Action": [
                "s3:ListBucket",
                "s3:GetObject"
            ],
            "Resource": [
                "<s3_bucket_arn>",
                "<s3_bucket_arn>/*"
            ]
        },
        {
            "Sid": "sqsEventNotifications",
            "Effect": "Allow",
            "Action": [
                "sqs:ChangeMessageVisibility",
                "sqs:DeleteMessage",
                "sqs:GetQueueAttributes",
                "sqs:GetQueueUrl",
                "sqs:ReceiveMessage"
            ],
            "Resource": [
                "<sqs_queue_arn>"
            ]
        }
    ]
}
```

4. Click **Next**
5. Choose a policy name based on the bucket purpose

> **Name (examples):** `rlm-s3-notify-cloudtrail`, `rlm-s3-notify-alb`
> **Description:** Grant read access to S3 bucket and permission to receive S3 notifications from the SQS queue.

6. Click **Create Policy**

#### Step 3: Grant Realm Access

Choose one of the following methods:

* **Option A — IAM role (recommended):** Realm assumes a role in your AWS account. No access keys are created or shared.
* **Option B — IAM user with access keys:** Realm authenticates with an access key and secret access key.

##### Option A: Create IAM Role (Recommended)

Realm assumes this role from its own AWS account, so no long-lived access keys leave your account. The trust policy only allows Realm to assume the role when it presents the external ID for your Realm tenant.

1. Go to **IAM > Roles** and click **Create role**
2. Select **Custom trust policy**
3. Replace the policy JSON with the following, substituting `<realm_account_id>` with your Realm Account ID in **lowercase**

> **Note:** The Realm Account ID value is shown on the input feed details page.

```json
{
  "Version": "2012-10-17",
  "Statement": [
    {
      "Sid": "AllowRealmToAssumeRole",
      "Effect": "Allow",
      "Principal": {
        "AWS": "arn:aws:iam::851725633669:role/prod-us-tenant-pipeline"
      },
      "Action": "sts:AssumeRole",
      "Condition": {
        "StringEquals": {
          "sts:ExternalId": "tenant-<realm_account_id>"
        }
      }
    },
    {
      "Sid": "AllowRealmSessionTags",
      "Effect": "Allow",
      "Principal": {
        "AWS": "arn:aws:iam::851725633669:role/prod-us-tenant-pipeline"
      },
      "Action": "sts:TagSession"
    }
  ]
}
```

> **Note:** The external ID is case-sensitive. It must be `tenant-` followed by your Realm Account ID in all lowercase letters, for example `tenant-abcd1234efgh5678`.

> **Note:** Keep both statements. Realm passes session tags when it assumes the role, so the `sts:TagSession` statement is required. It does not grant access on its own; access still requires the external ID.

4. Click **Next**
5. Search for and select the policy created in Step 2
6. Click **Next**
7. Choose a role name based on the bucket purpose

> **Role name (examples):** `rlm-s3-cloudtrail`, `rlm-s3-alb`, `rlm-access`
> **Description:** Allows Realm.Security to read logs from the S3 bucket and SQS queue.

8. Click **Create role**
9. Open the role that was just created and copy its **ARN** — you will need it in Step 4 and when configuring the S3 input feed in Realm

> **IAM Role ARN:** `arn:aws:iam::<your_account_id>:role/rlm-s3-cloudtrail`

##### Option B: Create IAM User

1. Go to **IAM > Users** and click **Create User**
2. Choose a username based on the bucket purpose

> **Name (examples):** `rlm-s3-cloudtrail`, `rlm-s3-alb`

3. Click **Next**
4. Select **Attach policies directly**
5. Search for and select the policy created in Step 2
6. Click **Next**, then **Create user**
7. Open the user that was just created and copy its **ARN** — you will need it in Step 4
8. Go to **Security credentials** and click **Create access key**
9. Select **Third-party service**, check the confirmation checkbox, then click **Next**
10. Enter a description:

> `Credentials for Realm.Security to read logs from S3 bucket`

11. Click **Create access key**
12. Copy and save the **Access Key** and **Secret access key** — you will need these when configuring the S3 input feed in Realm

#### Step 4: Update SQS Access Policy

The SQS queue policy must allow S3 to publish notifications to the queue and allow the IAM role or IAM user to read from it.

1. Go to **SQS > Queues**
2. Select the SQS queue you created
3. Go to **Queue policies** and click **Edit**
4. Replace the policy JSON with the following, substituting `<sqs_queue_arn>` with the SQS queue ARN and `<iam_principal_arn>` with the IAM role ARN (Option A) or IAM user ARN (Option B) from Step 3

```json
{
  "Version": "2012-10-17",
  "Id": "__default_policy_ID",
  "Statement": [
    {
      "Sid": "AllowS3Publish",
      "Effect": "Allow",
      "Principal": {
        "Service": "s3.amazonaws.com"
      },
      "Action": "sqs:SendMessage",
      "Resource": "<sqs_queue_arn>"
    },
    {
      "Sid": "AllowRealmUser",
      "Effect": "Allow",
      "Principal": {
        "AWS": "<iam_principal_arn>"
      },
      "Action": [
        "sqs:ChangeMessageVisibility",
        "sqs:DeleteMessage",
        "sqs:ReceiveMessage"
      ],
      "Resource": "<sqs_queue_arn>"
    }
  ]
}
```

5. Click **Save**

#### Step 5: Configure S3 Event Notifications

1. Go to **S3 > Buckets** and select your bucket
2. Go to **Properties > Event notifications**
3. Click **Create event notification**
4. Fill out the details:

> **Event name:** `RlmCreateEvents`\
> Check **All object create events**\
> **Destination:** SQS Queue\
> Select the queue you created from the dropdown

5. Click **Save changes**

***

### Option 2: Via SNS → SQS

Use this approach to subscribe a new SQS queue to an SNS topic that receives S3 ObjectCreate notifications, then connect that queue to Realm.

#### Step 1: Create and Configure SNS Topic

> Skip this step if you already have an SNS topic configured to receive S3 ObjectCreate notifications. Copy its ARN and proceed to Step 2.

**Create the SNS topic:**

1. Go to **SNS > Topics**
2. Click **Create topic**
3. Select **Standard** as the type
4. Choose a topic name based on the bucket purpose

> **Name (examples):** `rlm-s3-notify-cloudtrail`, `rlm-s3-notify-alb`

5. Click **Create topic**
6. Copy the **ARN** of the topic — you will need it in the steps below

**Update the SNS topic access policy:**

The SNS topic policy must allow S3 to publish to it.

1. On the topic details page, go to **Access policy** and click **Edit**
2. Replace the policy JSON with the following, substituting `<sns_topic_arn>` with the SNS topic ARN and `<s3_bucket_arn>` with your S3 bucket ARN

```json
{
  "Version": "2012-10-17",
  "Statement": [
    {
      "Sid": "AllowS3Publish",
      "Effect": "Allow",
      "Principal": {
        "Service": "s3.amazonaws.com"
      },
      "Action": "sns:Publish",
      "Resource": "<sns_topic_arn>",
      "Condition": {
        "ArnLike": {
          "aws:SourceArn": "<s3_bucket_arn>"
        }
      }
    }
  ]
}
```

3. Click **Save changes**

**Configure S3 to send ObjectCreate notifications to the SNS topic:**

1. Go to **S3 > Buckets** and select your bucket
2. Go to **Properties > Event notifications**
3. Click **Create event notification**
4. Fill out the details:

> **Event name:** `RlmS3ToSnsEvents`\
> Check **All object create events**\
> **Destination:** SNS Topic\
> Select the SNS topic you created from the dropdown

5. Click **Save changes**

#### Step 2: Create SQS Queue

Follow the same steps as [Step 1 in Option 1](#step-1-create-sqs-queue) above to create a queue and copy its ARN.

#### Step 3: Create IAM Policy

Follow the same steps as [Step 2 in Option 1](#step-2-create-iam-policy) above to create a policy and copy its ARN.

#### Step 4: Grant Realm Access

Follow the same steps as [Step 3 in Option 1](#step-3-grant-realm-access) above. Save the IAM role ARN (Option A), or the IAM user ARN, Access Key, and Secret access key (Option B).

#### Step 5: Update SQS Access Policy

The SQS queue policy must allow the SNS topic to publish messages to the queue and allow the IAM role or IAM user to read from it.

1. Go to **SQS > Queues**
2. Select the queue you created
3. Go to **Queue policies** and click **Edit**
4. Replace the policy JSON with the following, substituting `<sqs_queue_arn>` with the SQS queue ARN, `<sns_topic_arn>` with the SNS topic ARN from Step 1, and `<iam_principal_arn>` with the IAM role ARN or IAM user ARN from Step 4

```json
{
  "Version": "2012-10-17",
  "Id": "__default_policy_ID",
  "Statement": [
    {
      "Sid": "AllowSNSPublish",
      "Effect": "Allow",
      "Principal": {
        "Service": "sns.amazonaws.com"
      },
      "Action": "sqs:SendMessage",
      "Resource": "<sqs_queue_arn>",
      "Condition": {
        "ArnEquals": {
          "aws:SourceArn": "<sns_topic_arn>"
        }
      }
    },
    {
      "Sid": "AllowRealmUser",
      "Effect": "Allow",
      "Principal": {
        "AWS": "<iam_principal_arn>"
      },
      "Action": [
        "sqs:ChangeMessageVisibility",
        "sqs:DeleteMessage",
        "sqs:ReceiveMessage"
      ],
      "Resource": "<sqs_queue_arn>"
    }
  ]
}
```

5. Click **Save**

#### Step 6: Subscribe SQS Queue to SNS Topic

1. Go to **SNS > Topics**
2. Select the SNS topic from Step 1
3. Click **Create subscription**
4. Fill out the details:

> **Protocol:** Amazon SQS\
> **Endpoint:** `<sqs_queue_arn>`

5. Click **Create subscription**

The subscription will be automatically confirmed since both resources are in the same AWS account.

#### Step 7: Verify the S3 → SNS → SQS Pipeline

* Navigate to S3 and open the bucket tied to your SNS topic.
* Go to Properties → Event notifications and confirm the existing notification is pointing to your SNS topic for s3:ObjectCreated:\* events.
* Upload a test object to the S3 bucket.
* Go back to your SQS queue and click Send and receive messages.
* Click Poll for messages — you should see a message appear containing the S3 event payload.

## AWS S3 as a Destination

### Send logs from Realm to S3 bucket

#### Step 1: Create S3 Bucket

1. Go to **S3 > Buckets**
2. Click **Create bucket**
3. Enter the bucket name:

> **Bucket name:** `rlm-demo-output`

4. Click **Create bucket**
5. Copy the bucket name — you will need it in the next step

> **Note:** Versioning is disabled by default.

#### Step 2: Create IAM Policy

1. Go to **IAM > Policies**
2. Click **Create policy**
3. Click **JSON** and replace the contents with the following, substituting `<BUCKET_NAME>` with the bucket name from Step 1

```json
{
    "Version": "2012-10-17",
    "Statement": [
        {
            "Sid": "S3WriteRealmBucket",
            "Effect": "Allow",
            "Action": [
                "s3:PutObject",
                "s3:ListBucket",
                "s3:PutObjectAcl"
            ],
            "Resource": [
                "arn:aws:s3:::<BUCKET_NAME>",
                "arn:aws:s3:::<BUCKET_NAME>/*"
            ]
        }
    ]
}
```

4. Click **Next**
5. Enter the policy details:

> **Name:** `rlm-s3-output-write`\
> **Description:** Grant Realm write access to the S3 output bucket.

6. Click **Create policy**

#### Step 3: Create IAM User

1. Go to **IAM > Users** and click **Create user**
2. Enter the username:

> **Name:** `<tenant_name>-realm.security-s3-output`

3. Click **Next**
4. Select **Attach policies directly**
5. Search for and select the `rlm-s3-output-write` policy created in Step 2
6. Click **Next**, then **Create user**
7. Open the user that was just created
8. Go to **Security credentials** and click **Create access key**
9. Select **Third-party service**, check the confirmation checkbox, then click **Next**
10. Enter a description:

> `Allows <tenant_name> to write to <bucket_name> S3 bucket`

11. Click **Create access key**
12. Copy and save the **Access Key** and **Secret access key** — you will need these when configuring the S3 output feed in Realm

### Output File Structure

By default, data is stored in the following path structure:

```
s3://{bucket_name}/{destination_name}/{source_name}/YYYY/MM/DD/*.log.gz
```

To use a custom prefix, update the **Key Prefix** field on the output feed. For example, setting `Key Prefix` to `foo` produces:

```
s3://{bucket_name}/foo/*.log.gz
```

You can include date components in the prefix using the placeholders `%Y`, `%m`, and `%d`:

| Key Prefix | Resulting path |
|---|---|
| `foo/year=%Y/month=%m/day=%d/` | `s3://{bucket_name}/foo/year=2025/month=10/day=23/` |
| `foo/%Y/%m/%d/` | `s3://{bucket_name}/foo/2025/10/23/` |

Each file is compressed with `zstd` and contains newline-delimited events. The event format (`RAW` or `JSON`) is set by the **Format** field on the S3 output feed.