App Service plan deployment throwing an error 429 frequently.. and throttling

Question

Operation 429.. It's in still progress from a long time... Issue?

Answer 1

Hi @shantanu singh
If any member faces a 429 error during an App Service Plan deployment, the issue usually occurs because Azure is throttling the request after too many create or update operations are sent in a short period, causing Azure Resource Manager to return “Too Many Requests,” often with a Retry-After header. In this situation, the best immediate action is to slow down deployments, avoid running parallel operations, and implement exponential backoff so retries wait for the required time. To diagnose further, the member should review the Activity Log and deployment operations in the Azure Portal to confirm the exact throttling event and examine the response headers for subcodes such as SubscriptionRequestsThrottled. For long-term prevention, reducing deployment bursts, following retry best practices, and monitoring subscription limits will help avoid repeated throttling.
https://learn.microsoft.com/en-us/azure/cosmos-db/nosql/troubleshoot-request-rate-too-large?tabs=resource-specific
https://learn.microsoft.com/en-us/azure/azure-resource-manager/management/request-limits-and-throttling#retry-guidance
Let me know if you have any further assistances needed.

Answer 2

HI @Shantanu Singh

It sounds like you're facing a frustrating issue with the 429 Too Many Requests error during your App Service deployment. This error typically arises when the rate limits for Azure resources are exceeded, leading to throttling, which can be caused by a few different factors. Here’s a breakdown of what you can do to address this issue:

Steps to Resolve the 429 Error:

1. Space Out Operations:
   • If you're running multiple operations (like create, update, delete) on the same resource, avoid executing them back-to-back. Ensure that one operation completes successfully before starting another.
2. Reduce Automated Script Frequency:
   • If you have scripts that frequently execute operations (especially LIST or GET requests), consider reducing their execution frequency or adjusting the queries to be more specific rather than broad.
3. Implement Retry Logic:
   • You can enhance your automation with retry logic that includes exponential backoff. Make sure to respect the Retry-After header in the 429 responses, which indicates how long to wait before retrying your request.
4. Monitor Your Quota:
   • Use Azure Monitor Metrics or Diagnostic Logs to check if you are hitting any service limits. This can help inform whether you need to adjust your usage patterns or upgrade your service tier.
5. Distribute Workloads:
   • If possible, spread your deployments across multiple subscriptions to reduce load on any single subscription.
6. Check Azure Service Health:
   • Occasionally, throttling issues can be exacerbated by temporary service outages or maintenance. Reference the Azure Service Health dashboard to see if there are any known issues in your region.

Monitoring and Verification:

After applying the changes:

• Review Azure Monitor Metrics or Diagnostic Logs to confirm that the occurrence of the 429 error has decreased.
• Ensure that operations such as resource creation, update, and deletion are now completing without interruptions.

Additional Considerations:

If you're still encountering issues after trying these steps, it may be worth reviewing the provisioning limits associated with your current subscription and considering an upgrade if necessary.

Hope this helps! If you're encountering further issues or need any clarification on specific steps, feel free to ask!

Reference Documentation:

1. Retry Guidance for Azure Resource Manager requests
2. Diagnose and troubleshoot "Request rate too large" (429) exceptions
3. Azure Monitor Overview
4. Azure Service Health

Let me know if you have any other questions!

Answer 3

The error code 429 indicates that your requests are being throttled, which means that you are exceeding the allowed limits for the Azure App Service plan. This can happen if there are too many requests being made in a short period of time, leading to throttling by Azure's infrastructure.

To resolve this issue, you can consider the following steps:

1. Space Out Deployments: If you are deploying multiple resources or making several changes in quick succession, try to space out these operations to avoid hitting the throttling limits.
2. Monitor Resource Usage: Check your App Service plan's resource usage and ensure that it is not being maxed out. Upgrading to a higher tier may help if you consistently hit limits.
3. Review Access Patterns: Examine your application's access patterns to see if there are any automated scripts or processes that are making excessive requests. Adjusting these can help reduce the load.
4. Retry Logic: Implement retry logic in your deployment scripts to handle transient errors like 429. This will allow your application to wait and retry the request after a brief pause.

If the problem persists, you may want to reach out to Azure support for further assistance.