Monitor the following categories : Performance limit, Utilization Limit, Compute Unit of application gateway of waf v2 tier and standard v2 tier.

Question

Monitor the following categories : Performance limit, Utilization Limit, Compute Unit of application gateway of waf v2 tier and standard v2 tier.

Murarisetty Yamuna 145

Currently I need to monitor the app gateway(WAF V2 & Standard V2 skus) based on following categories : Performance limit, Utilization limit, Compute Units using the application gateway Metrics available in Azure Monitor .
Is the instance count is dependent on the performance or utilization.
Is there any limit of the count of capacity units consumed to load balance the traffic. How to identify the maximum count of capacity units and the compute units.
Is there any limit of Current connections of the gateway based on the type of SKU. Not able to identify the no. of concurrent connections of the gateway.
When the threshold reaches the specified limit for the above categories need to notify an alert.

ChaitanyaNaykodi-MSFT 27,481 Reputation points Microsoft Employee Moderator

2023-12-19T18:54:01.1433333+00:00

@Murarisetty Yamuna

Just checking in to see if the below answer helped. If this answers your query, please don’t forget to click "Accept the answer" which might be beneficial to other community members reading this thread. And, if you have any further query do let us know.
Murarisetty Yamuna 145 Reputation points

2023-12-22T16:31:57.67+00:00

@ChaitanyaNaykodi-MSFT Thanks for detailed information.

I have a couple of questions that are mentioned below:

To monitor the Performance of the gateway, key metric is Total requests, however the app gateway is WAF V2 sku, max instance : 125 and min instance : 1 and Autoscale is enabled. To set the logalert for the Total requests, how much traffic(total requests) is handled by one instance at a time?
ChaitanyaNaykodi-MSFT 27,481 Reputation points Microsoft Employee Moderator

2023-12-28T05:22:46.1466667+00:00

@Murarisetty Yamuna

Thank you for getting back.

As documented here Total requests is the count of successful requests that Application Gateway has served by the backend pool targets. I do not think Total requests will be the correct way to depict the performance of the Application Gateway. As the number of successful requests served will vary as the traffic from clients will vary throughout the day and a specific number of total requests a application gateway instance can serve also cannot be determined as it will depend on the request processed/ received.

I think the Timing metrics described here will be the correct way to determine the performance of Application gateway, especially Application gateway total time this is the interval from the time when Application Gateway receives the first byte of the HTTP request to the time when the last response byte has been sent to the client. This includes the processing time taken by Application Gateway, the Backend last byte response time, and the time taken by Application Gateway to send all the response.

If the Application gateway total time has a spike but the Backend last byte response time is stable, then it can either be a sign of performance bottleneck at the Application Gateway or a bottleneck in the network between client and Application Gateway.

In order to set and alert for Application gateway total time I will suggest that you observe the metric for a week or as per your timeline and set a threshold and if the Application gateway total time crosses that time then generate an alert. As shown here

Hope this helps! Please let me know if you have any additional questions. Thank you!
Murarisetty Yamuna 145 Reputation points

2023-12-29T16:10:59.4233333+00:00

@ChaitanyaNaykodi-MSFT , Thanks for the detailed answer.

As per the information provided, to determine the performance of Application gateway, Application gateway total time is the metric to monitor.

However, to create the alert for the metric signal Application gateway total time, is it possible to monitor dynamically? If so, there is threshold sensitivity option which has possible values High, medium, Low. What is the best option to monitor application gateway performance dynamically?

What is the recommendation if performance of the gateway affects?
ChaitanyaNaykodi-MSFT 27,481 Reputation points Microsoft Employee Moderator

2024-01-03T03:31:46.9766667+00:00

@Murarisetty Yamuna

Thank you for getting back.

Based on your question above.

However, to create the alert for the metric signal Application gateway total time, is it possible to monitor dynamically?

Yes, it is possible to monitor the Application gateway total time metric dynamically.

If so, there is threshold sensitivity option which has possible values High, medium, Low. What is the best option to monitor application gateway performance dynamically?

This will actually depend on how Application gateway total time values are for your application Gateway. Like if there are too many deviations and if the threshold sensitivity is high it might result into high number of alerts. You can find additional details here.

What is the recommendation if performance of the gateway affects?

If you find a sign of performance bottleneck at the Application Gateway. Firstly, check if it is not due to high utilization and increase the instance count. And if the utilization is still not high and there is still a performance issue, the recommended approach is to create a support request as deeper troubleshooting will be required.

Hope this helps! Please let me know if you have any additional questions. Thank you!
Murarisetty Yamuna 145 Reputation points

2024-01-05T16:12:50.3466667+00:00

@ChaitanyaNaykodi-MSFT , Thank you for detailed answer.

As per the recommended performance guidelines for the gateway, if utilization is high, it is advisable to increase the instance count. However, in cases where Autoscaling is enabled with a minimum instance count set to 1 and a maximum instance count set to 125, the question arises whether it is still necessary to manually increase the instance count when utilization is high.
ChaitanyaNaykodi-MSFT 27,481 Reputation points Microsoft Employee Moderator

2024-01-05T18:56:29.02+00:00

@Murarisetty Yamuna

Thank you for getting back.

If autoscaling is enabled with maximum instance count set to 125, then there is no need to increase the instance count manually.

Hope this helps! Please let me know if you have any additional questions. Thank you!
Murarisetty Yamuna 145 Reputation points

2024-01-18T09:07:28.56+00:00
ChaitanyaNaykodi-MSFT ,

The current configuration of the application gateways includes recommendations such as utilizing the V2 SKU, enabling autoscale, and setting the maximum instance count to 125.

As per MS Document each instance can uses a minimum of 10 capacity units for processing capability-got this from Instance count Reference: (https://learn.microsoft.com/en-us/azure/application-gateway/understanding-pricing#v2-skus). Then the maximum capacity units is 1250(125*10).

This is my question:

To monitor instances approaching the maximum limit in application gateway , Is the metric signal "Current Capacity Unit " is the precise or not?

Is creating an alert on the capacity units with a threshold value of 940 (75%) is the precise solution for continuously monitoring instances, ensuring awareness as they approach the maximum limit?

NOTE: The aggregation type is average(this is only one option is giving in the alert creation), operation: count and Threshold value:940
Murarisetty Yamuna 145 Reputation points

2024-01-23T16:39:31.41+00:00

@ChaitanyaNaykodi-MSFT , Can you please look into the above question and kindly help on this.

Accepted answer

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Your answer

ChaitanyaNaykodi-MSFT 27,481 Reputation points Microsoft Employee Moderator

2023-12-19T18:54:01.1433333+00:00

@Murarisetty Yamuna

Just checking in to see if the below answer helped. If this answers your query, please don’t forget to click "Accept the answer" which might be beneficial to other community members reading this thread. And, if you have any further query do let us know.
Murarisetty Yamuna 145 Reputation points

2023-12-22T16:31:57.67+00:00

@ChaitanyaNaykodi-MSFT Thanks for detailed information.

I have a couple of questions that are mentioned below:

To monitor the Performance of the gateway, key metric is Total requests, however the app gateway is WAF V2 sku, max instance : 125 and min instance : 1 and Autoscale is enabled. To set the logalert for the Total requests, how much traffic(total requests) is handled by one instance at a time?
ChaitanyaNaykodi-MSFT 27,481 Reputation points Microsoft Employee Moderator

2023-12-28T05:22:46.1466667+00:00

@Murarisetty Yamuna

Thank you for getting back.

As documented here Total requests is the count of successful requests that Application Gateway has served by the backend pool targets. I do not think Total requests will be the correct way to depict the performance of the Application Gateway. As the number of successful requests served will vary as the traffic from clients will vary throughout the day and a specific number of total requests a application gateway instance can serve also cannot be determined as it will depend on the request processed/ received.

I think the Timing metrics described here will be the correct way to determine the performance of Application gateway, especially Application gateway total time this is the interval from the time when Application Gateway receives the first byte of the HTTP request to the time when the last response byte has been sent to the client. This includes the processing time taken by Application Gateway, the Backend last byte response time, and the time taken by Application Gateway to send all the response.

If the Application gateway total time has a spike but the Backend last byte response time is stable, then it can either be a sign of performance bottleneck at the Application Gateway or a bottleneck in the network between client and Application Gateway.

In order to set and alert for Application gateway total time I will suggest that you observe the metric for a week or as per your timeline and set a threshold and if the Application gateway total time crosses that time then generate an alert. As shown here

Hope this helps! Please let me know if you have any additional questions. Thank you!
Murarisetty Yamuna 145 Reputation points

2023-12-29T16:10:59.4233333+00:00

@ChaitanyaNaykodi-MSFT , Thanks for the detailed answer.

As per the information provided, to determine the performance of Application gateway, Application gateway total time is the metric to monitor.

However, to create the alert for the metric signal Application gateway total time, is it possible to monitor dynamically? If so, there is threshold sensitivity option which has possible values High, medium, Low. What is the best option to monitor application gateway performance dynamically?

What is the recommendation if performance of the gateway affects?
ChaitanyaNaykodi-MSFT 27,481 Reputation points Microsoft Employee Moderator

2024-01-03T03:31:46.9766667+00:00

@Murarisetty Yamuna

Thank you for getting back.

Based on your question above.

However, to create the alert for the metric signal Application gateway total time, is it possible to monitor dynamically?

Yes, it is possible to monitor the Application gateway total time metric dynamically.

If so, there is threshold sensitivity option which has possible values High, medium, Low. What is the best option to monitor application gateway performance dynamically?

This will actually depend on how Application gateway total time values are for your application Gateway. Like if there are too many deviations and if the threshold sensitivity is high it might result into high number of alerts. You can find additional details here.

What is the recommendation if performance of the gateway affects?

If you find a sign of performance bottleneck at the Application Gateway. Firstly, check if it is not due to high utilization and increase the instance count. And if the utilization is still not high and there is still a performance issue, the recommended approach is to create a support request as deeper troubleshooting will be required.

Hope this helps! Please let me know if you have any additional questions. Thank you!
Murarisetty Yamuna 145 Reputation points

2024-01-05T16:12:50.3466667+00:00

@ChaitanyaNaykodi-MSFT , Thank you for detailed answer.

As per the recommended performance guidelines for the gateway, if utilization is high, it is advisable to increase the instance count. However, in cases where Autoscaling is enabled with a minimum instance count set to 1 and a maximum instance count set to 125, the question arises whether it is still necessary to manually increase the instance count when utilization is high.
ChaitanyaNaykodi-MSFT 27,481 Reputation points Microsoft Employee Moderator

2024-01-05T18:56:29.02+00:00

@Murarisetty Yamuna

Thank you for getting back.

If autoscaling is enabled with maximum instance count set to 125, then there is no need to increase the instance count manually.

Hope this helps! Please let me know if you have any additional questions. Thank you!
Murarisetty Yamuna 145 Reputation points

2024-01-18T09:07:28.56+00:00

ChaitanyaNaykodi-MSFT ,

The current configuration of the application gateways includes recommendations such as utilizing the V2 SKU, enabling autoscale, and setting the maximum instance count to 125.

As per MS Document each instance can uses a minimum of 10 capacity units for processing capability-got this from Instance count Reference: (https://learn.microsoft.com/en-us/azure/application-gateway/understanding-pricing#v2-skus). Then the maximum capacity units is 1250(125*10).

This is my question:

To monitor instances approaching the maximum limit in application gateway , Is the metric signal "Current Capacity Unit " is the precise or not?

Is creating an alert on the capacity units with a threshold value of 940 (75%) is the precise solution for continuously monitoring instances, ensuring awareness as they approach the maximum limit?

NOTE: The aggregation type is average(this is only one option is giving in the alert creation), operation: count and Threshold value:940
Murarisetty Yamuna 145 Reputation points

2024-01-23T16:39:31.41+00:00

@ChaitanyaNaykodi-MSFT , Can you please look into the above question and kindly help on this.

Answer 1

@Murarisetty Yamuna

Thank you for reaching out and apologies for the delay here.

Based on your questions above.

Currently I need to monitor the app gateway(WAF V2 & Standard V2 skus) based on following categories : Performance limit, Utilization limit, Compute Units using the application gateway Metrics available in Azure Monitor .

I understand you wish to monitor the Application Gateway for Performance limit, Utilization limit, Compute Units using application gateway Metrics available. Out of the available metrics here for application gateway I think monitoring following metrics can help

Current compute units: Compute unit metric is a representation of your gateway's CPU utilization. As documented here Compute Unit is the measure of compute capacity consumed. Factors affecting compute unit consumption are TLS connections/sec, URL Rewrite computations, and WAF rule processing. The number of requests a compute unit can handle depends on various criteria like TLS certificate key size, key exchange algorithm, header rewrites, and in case of WAF - incoming request size.

Current capacity units: Capacity units represent overall gateway utilization in terms of throughput, compute, and connection count.

As documented here Capacity Unit is the measure of capacity utilization for an Application Gateway across multiple parameters.

A single Capacity Unit consists of the following parameters:

2500 Persistent connections
2.22-Mbps throughput
1 Compute Unit

If any of these parameters are exceeded, then another N capacity units are necessary, even if the other two parameters don’t exceed this single capacity unit’s limits. The parameter with the highest utilization among the three above will be internally used for calculating capacity units, which is in turn billed.

Is the instance count is dependent on the performance or utilization.

Yes, Instance count depicts the utilization and if the instance count has reached the maximum limit then it may cause performance issues. An instance guarantees a minimum of 10 capacity units in terms of processing capability. The same instance could potentially support more than 10 capacity units for different traffic patterns depending upon the Capacity Unit parameters described above.

Is there any limit of the count of capacity units consumed to load balance the traffic. How to identify the maximum count of capacity units and the compute units.

Depending on the scaling mechanism selected for the Application gateway and the instance count opted, each instance is roughly equivalent to 10 more reserved Capacity Units. Currently Azure Application Gateway can support maximum 125 instance counts. To identify the maximum capacity units available, multiply the maximum instance count opted times 10.

Is there any limit of Current connections of the gateway based on the type of SKU. Not able to identify the no. of concurrent connections of the gateway.

Yes, as explained in this example here

A Capacity Unit can handle 2500 persistent connections and then additional capacity unit is added as this limit is reached.

Currently the Current connections metric provides the total number of concurrent connections active from clients to the Application Gateway

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When the threshold reaches the specified limit for the above categories need to notify an alert.

Yes for application Gateway V2 you can set alerts as described here

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You can refer to this documentation to understand how to set-up alerts for Application gateway.

Hope this helps! Please let me know if you have any additional questions. Thank you!

Please "Accept the answer" if the information helped you. This will help us and others in the community as well.

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Monitor the following categories : Performance limit, Utilization Limit, Compute Unit of application gateway of waf v2 tier and standard v2 tier.

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