How to Fix AWS ALB Access Logs Not Delivering to S3

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Are you having trouble with your ALB access logs not showing up in your S3 bucket? This can be frustrating, but there are clear steps you can follow to fix the issue and get those logs flowing in smoothly.

First, check your ALB configuration to ensure that logging is enabled. Sometimes, the logs won’t be sent because the setting is turned off. Log in to your AWS Management Console, navigate to your Application Load Balancer, and look for the “Access logs” section. Make sure the toggle is turned on.

Next, verify the S3 bucket permissions. The load balancer needs permission to write logs to your bucket. Confirm that your bucket policy grants write access to the load balancer. Usually, this involves adding a policy statement that allows the load balancer’s service to put objects into the bucket. Here’s a simple example of what that policy might look like:

json
{
“Version”: “2012-10-17”,
“Statement”: [
{
“Sid”: “AllowALBLogging”,
“Effect”: “Allow”,
“Principal”: {
“Service”: “delivery.logs.amazonaws.com”
},
“Action”: “s3:PutObject”,
“Resource”: “arn:aws:s3:::your-bucket-name/*”
}
]
}

Replace “your-bucket-name” with the name of your S3 bucket.

Another thing to check is the S3 bucket’s access control list (ACL). Make sure that the bucket allows the ALB logs to be saved. Usually, the default settings work fine, but it’s good to review.

After these changes, give it a little time. Sometimes, there’s a delay before logs start showing up, especially if it’s a new setup. If you still don’t see logs after a few hours, double-check the following:

– Confirm that the ALB is actually receiving traffic. Logs won’t be generated if the load balancer isn’t handling any requests.
– Check for any errors or alerts in your AWS Console that might hint at permission issues or misconfigurations.

By following these simple steps—enabling logging, ensuring correct permissions, and allowing some time—you should start seeing your ALB access logs appear in your S3 bucket. This helps you monitor your application’s traffic and troubleshoot issues more effectively.