Azure Application Gateway Unavailability and generate Alert

Mishra, Arpit 1

Hi Team,

My Use case is, as soon as App Gateway gets down due to any reason an alert should have generate and follow its action.

However when i tried to put a resource health alert in Azure, it seems Azure Doesn't provide the Unavailable Event for it. Hence, when app gateway went down it didn't generate any alert but when it back to available state, alert generated consisting its current health status and can have previous health status as well.

App Gateway Metrics, i didn't find much which exactly fix my use case. and same with kusto queries.

I have also tried with Azure Service Health Alert but that wont help me as it comes at region level.

Can you please help me is there anyway by which i can fix my use case.

KapilAnanth-MSFT 35,251 Reputation points Microsoft Employee

2023-03-03T10:54:54.2733333+00:00

@Mishra, Arpit

Welcome to the Microsoft Q&A Platform. Thank you for reaching out & I hope you are doing well.

I understand that you would like to monitor Application gateway and trigger an alert.

What I believe can be a good metric here is to use the "Response status (4xx, 5xx) crosses threshold" .

Refer : App Gateway Alerts

You should observe the gateway in production to determine static threshold or use dynamic threshold for the alert.

Please let me know if this helps or you require further information on this.

Cheers,

Kapil
KapilAnanth-MSFT 35,251 Reputation points Microsoft Employee

2023-03-06T06:02:08.9933333+00:00

@Mishra, Arpit

Can you please update us if the action plan provided was helpful?

Should there be any follow-up questions or concerns, please let us know and we shall try to address them.

Thanks,

Kapil
Mishra, Arpit 1 Reputation point

2023-03-06T12:53:05.02+00:00

Hi @KapilAnanth-MSFT pls let me try today and will update.
Mishra, Arpit 1 Reputation point

2023-03-07T07:08:33.93+00:00

Hi @KapilAnanth-MSFT , i have tried the configuring 5xx status metrics but it didnt throw an alert when i manually stop the app gateway. pasting screenshots.
Mishra, Arpit 1 Reputation point

2023-03-07T07:09:20.0366667+00:00

can you please help me if anything i'm missing here
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KapilAnanth-MSFT 35,251 Reputation points Microsoft Employee

2023-03-07T10:36:41.4633333+00:00
@Mishra, Arpit

The behavior is expected when you stop the App Gateway.

App Gateway, when it's stopped, won't give any 5xx responses and instead will time out.

Had you stopped the backends, the App gateway would have given 5xx responses to the clients, and this will be logged and the Alert would have worked.

For platform related issues, you can configure "Azure Resource Health".

Again, I believe stopping the App gateway will bot be reflected in the "Resource Health"

Can you please stop the backend services and check if the Alert is triggered.

Also, make sure Clients are making requests when the backend is disabled for metrics to be created.

Cheers,

Kapil
KapilAnanth-MSFT 35,251 Reputation points Microsoft Employee

2023-03-08T09:03:50.8366667+00:00

@Mishra, Arpit

Could you please provide an update on this post?

Kindly let us know if the below helps or you need further assistance on this issue.

Thanks,

Kapil

1 answer

KapilAnanth-MSFT 35,251 Reputation points Microsoft Employee

2023-03-10T09:56:18.1066667+00:00

@Mishra, Arpit

Welcome to the Microsoft Q&A Platform. Thank you for reaching out & I hope you are doing well.

I understand that you would like to monitor Application gateway and trigger an alert.

For platform related errors, you can configure "Azure Resource Health".

For Backend related errors (where client gets a 4XX or 5XX error)

The metric to use here is "Response status (4xx, 5xx) crosses threshold" and create an alert when the client gets a abnormally more number of such responses

Refer : App Gateway Alerts

You should observe the gateway in production to determine static threshold or use dynamic threshold for the alert.

Kindly let us know if the above helps or you need further assistance on this issue.

Thanks,

Kapil

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Mishra, Arpit 1 Reputation point

2023-03-10T10:31:02.37+00:00

resource alerts doesnt have Unavailability events .. but let me check the backend status as well. will update it soon
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