Timer Trigger Azure Function App not firing on hourly schedule

Question

Problem: Deployed Azure Function app is not firing on hourly CHRON schedule I have configured.

What I've done

• Verified my CHRON expression is correct for hourly schedule ("0 0 * * * *")
• Verified function works by manually triggering via Code+Test section in the portal
• Set WEBSITE_TIME_ZONE environment variable to "Pacific Standard Time"

Note: I'm using Premium app service plan so I don't have the options to set "Always On" configuration setting

Answer 1

@Marcellus Davenport Thanks for reaching out.

Your CORN expression looks good (0 0 * * * *) and it should trigger your function every hour.

Have you review Diagnose and solve problems blade on your function app for the detector "Timer Trigger Incomplete Execution Detection" and "Timer Trigger Issue Analysis" to get more insights on the issue why your timer trigger was not triggered. I will also suggest to validate if there are any run time errors on your function using the diagnose blade or application insights logs to get more insights on the issue.

The most common cause for Azure Functions not getting triggered is that triggers are not synced properly. You can sync triggers as documented here.

In case if you are still not able to find the insights on figure out the issue then please let me know.

Answer 2

Hello @Marcellus Davenport

Since you are using a Premium app service plan, you do not have the option to set the Always On configuration setting. One thing to note is that the timer trigger for Azure Functions uses a storage lock to ensure that there is only one timer instance when a function app scales out to multiple instances.

If two function apps share the same identifying configuration and each uses a timer trigger, only one timer runs. Additionally, the timer trigger does not retry after a function fails. When a function fails, it isn't called again until the next time on the schedule.

If you have ruled out all of the above possibilities, it's possible that there may be an issue with the Azure Function app itself. In this case, I would recommend checking the Azure Functions logs for any errors or warnings that may be preventing the function from running on schedule. You can also set up monitoring and alerting for Azure Functions by using Azure Application Insights.

I hope this helps

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