Why does Azure Function App deployment sometimes reflect in 10 minutes and sometimes take 2–3 hours?

Question

We are currently facing an intermittent deployment issue with our Azure Function App. The deployment completes successfully, but the updated code does not consistently reflect on the server.

Sometimes the changes reflect within 10 minutes, but at other times it takes 2–3 hours, or the changes do not reflect at all. We have tried multiple actions including:

• Redeploying the code several times
• Restarting the Function App

Checking logs for any deployment errors

However, the issue persists.

This inconsistency in code reflection time is impacting our testing and production updates.

We need help understanding:

Why the deployment reflection time fluctuates between 10 minutes and 2–3 hours

Whether this issue is related to caching, WEBSITE_RUN_FROM_PACKAGE, or Azure backend sync delays

How to ensure stable and predictable deployment updates for Azure Function Apps

Any insights, guidance, or recommended troubleshooting steps would be greatly appreciated.

Answer 1

Hello Hemanth MY [EXT]

Thanks for reaching out on Microsoft Q&A

you’re having issues with your Azure Function App deployments taking inconsistent amounts of time to reflect code changes.

Steps:

1. Caching Issues: Sometimes, older versions of your code might be cached either by the Azure Function infrastructure or due to local caching mechanisms in your deployment tools. This can cause a delay in the new version being recognized.
2. WEBSITE_RUN_FROM_PACKAGE Setting: If your Function App is set to run from a package, it can lead to deployment behavior that might not immediately show changes. When you deploy with this setting, the code is loaded from a package stored in Azure Storage. If there are any issues with that storage or if the deployment doesn’t complete successfully, it can lead to delays.
3. Azure Backend Sync Delays: At times, there can be backend sync delays on Azure's side that can affect how quickly updates are applied. This is particularly common during peak times or if there are ongoing service issues in your region.
4. Deployment Slot Issues: If you're using multiple deployment slots or direct deployments, ensure that the slot settings are properly configured to avoid conflicts or incorrect deployments.

To assist you further, I have a couple of questions that might help narrow down the issue:

Are you using WEBSITE_RUN_FROM_PACKAGE, and if so, have you encountered any specific errors during deployment?

What deployment method are you utilizing (e.g., Visual Studio, Azure CLI, etc.)?

Are you deploying into a specific region that might have performance issues?

Have you noticed any patterns related to when the deployments take longer (e.g., specific times of day or after certain tasks)?

If you can provide some insights on these, I’ll be happy to help you further!

• Deploying Function Apps
• Application Insights
• Storage Considerations for Functions
• Continuous Deployment for Azure Functions 

Thanks