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Troubleshoot log collection in AWS 🔗

See the following topics when experiencing issues collecting logs from AWS.

CloudFormation stack was not created 🔗

You fully control the process of creating the CloudFormation stack, which is executed with the permissions associated with your user. The template contains a lambda function and a role required to forward logs from Cloudwatch and S3 buckets. If any errors occur, AWS displays a specific error message.

To learn more about supported templates, see the README on GitHub.

I created an integration, but I don’t see any logs 🔗

If you created the integration recently, it might take some time for the logs to appear in your account. The job that makes your logs notify Splunk AWS Log Collector runs every minute, so it might take a short while to subscribe to a new resource. AWS logs delivery inside AWS (to CloudWatch log groups, or to S3 buckets) and AWS lambda triggering can introduce additional delay. Check AWS documentation for more details.

If you still don’t see any logs after 15 minutes, check the IAM policy you’ve used to set up the AWS connection. We recommend using the provided IAM policy. If you still don’t see the logs, please contact our support.

You can activate debug mode on the log forwarding lambda function: Add LOG_LEVEL=DEBUG in the Environment variables section under Configuration. If you see log forwarding calls fail due to a 503 HTTP error, you might be exceeding logs limit. To fix this, contact our support.

CloudFront access logs are not being collected 🔗

CloudFront is a global service, and its logs can be stored in any of the standard AWS regions. Each CloudFront instance can have an S3 target bucket to access configured logs. Splunk AWS log collection can only grab the logs if the S3 bucket is located in a region Splunk AWS log collection can access. Use the provided IAM policy to ensure the Splunk Observability Cloud back end has the required permissions.

I don’t see logs from some instances 🔗

Make sure your IAM policy allows access to the instances, their regions, or the regions where they send logs. If the service instance was recently created, it might take up to 15 minutes for the Splunk Observability Cloud back end to start gathering logs from it.

AWS allows you to configure only one notification of a given kind when a new log file appears, and S3 event files are created. If the bucket where an instance’s logs are stored already notifies another lambda function of a file creation, Splunk Observability Cloud cannot add its subscription on top of that. You can either remove the pre-existing notification configuration, or narrow it by specifying a prefix and a suffix in such a way that the log files won’t be triggering your pre-existing lambda function. If that’s not possible, contact us for assistance to modify your AWS architecture to work around the limitation.

I don’t see logs from some of my S3 buckets 🔗

Some AWS services use S3 buckets to store their logs, and sometimes the S3 bucket is located in a different region from the service that produces those logs. In such cases make sure to deploy the splunk-aws-logs-collector lambda function using the CloudFormation template in all AWS regions where S3 buckets with logs are located.

I have deactivated logs collection, but logs are still gathered by Splunk Observability Cloud 🔗

It might take up to 15 minutes for the Splunk Observability Cloud back end to cancel log subscriptions. There might be additional delays introduced by the AWS logs delivery process.

The back end needs log related permissions to cancel log subscriptions. If log related permissions are removed from the AWS IAM policy (or the entire policy is removed), the back end cannot run the cleanup procedure. Make sure to deactivate log collection on the Splunk Observability Cloud side first, and clean up on AWS side later.

I deactivated the integration or changed its settings, but logs are still being collected! 🔗

If you deactivate a part or all the integration, our back end job will attempt to clear all notifications and subscriptions it has previously created, which might take up to 15 minutes. However, if you also remove IAM permissions, the attempt might fail.

To stop sending any logs to Splunk Observability Cloud, delete the Splunk AWS Logs collector lambda from the region where you wish to stop collecting logs.

How does log subscription clean-up work? How can I try to clean up logs again? 🔗

When you deactivate log synchronization (or an entire AWS integration), Splunk Observability Cloud attempts to clear all the log-related notifications and subscriptions that had been created. This process might take up to 15 minutes and removes both notifications from S3 buckets and subscriptions from CloudWatch Log Groups.

The clean-up procedure might fail if you remove IAM permissions or due to throttling, for example if there are too many API calls to update CloudWatch Log Groups subscriptions.

To retry the clean-up process, you have two options:

  • Splunk Observability Cloud UI (beta feature - limited availability): Go to the context menu in the integration list and select Cleanup.

  • API: Set logsSyncState to the CANCELLING state.

Assisted log subscription clean-up failed. How do I clean up log subscriptions manually? 🔗

Log synchronization on your AWS account is handled by the Splunk AWS Logs Collector lambda function, which is deployed using one of the available CloudFormation templates.

To manually remove log sync in all your AWS regions, you need to either remove the entire Cloud Formation stack (recommended) or just the lambda function.

Optionally you might also need to review your S3 buckets notifications settings and CloudWatch Log Groups subscription filters and remove Splunk Log Collector related entries.

For S3 bucket notifications, remove all event notifications with the destination set to the splunk-aws-logs-collector lambda.

This image shows notifications for S3 buckets.

For CloudWatch Log Groups, remove the subscription filter called Splunk Log Collector from all log groups.

This image shows subscription filters for the Log Collector.