Exam AZ-204 topic 1 question 16 discussion

For anyone wondering why it's --window-size and not --evaluation-frequency: you want the average across 5 minutes. With --evaluation-frequency you don't go for averages, you simply check what the given value is at specific intervals.

Correct, Eng reference is here https://docs.microsoft.com/en-us/cli/azure/monitor/metrics/alert?view=azure-cli-latest

Example Scenario: Suppose you want to create a metric alert for when the CPU usage of your Web App exceeds 85% over a 5-minute window, and you want Azure to check this every 1 minute. --window-size: 5 minutes (you want the CPU usage to exceed 85% for a full 5-minute period before triggering the alert). --evaluation-frequency: 1 minute (Azure will check the CPU usage every minute to see if the 5-minute period still holds).

Using AVG Percentage CPU ensures that your alert will be triggered when the average CPU usage over a 5-minute period exceeds 85%

Window size is the period of time over which Azure Monitor will collect metrics for a metric alert rule. Evaluation frequency is the frequency with which Azure Monitor will evaluate the metric alert rule for violations. if you set the window size to 5 minutes and the evaluation frequency to 1 minute, Azure Monitor will collect metrics for the previous 5 minutes and then evaluate the metric alert rule for violations every minute. This means that if there is a violation in the 5 minute window, Azure Monitor will detect it within 1 minute. We want to get percent “over a 5 minute period”, we have to use window size parameter. Only use evaluation frequency parameter is not enough for getting question request.

az monitor metrics alert create -n alert1 -g {ResourceGroup} --scopes {VirtualMachineID} --condition "avg Percentage CPU > 90" --window-size 5m --evaluation-frequency 1m --action "/subscriptions/<subscriptionId>/resourceGroups/<resourceGroupName>/providers/Microsoft.Insights/actionGroups/<actionGroupName>" apiKey={APIKey} type=HighCPU --description "High CPU" https://learn.microsoft.com/en-us/cli/azure/monitor/metrics/alert?view=azure-cli-latest#az-monitor-metrics-alert-create-examples

Hello, may I know why Box 1 is 'avg Percentage CPU ', instead of 'Percentage CPU '. It wants to be notified whenever over than 85. Whenever, meaning the maximum, not the average?

1. avg Percentage CPU, 2. window size

az monitor metrics alert create -n alert1 -g {ResourceGroup} --scopes {VirtualMachineID} \ --condition "avg Percentage CPU > 90" --window-size 5m --evaluation-frequency 1m \ --action "/subscriptions/<subscriptionId>/resourceGroups/<resourceGroupName>/providers/Microsoft.Insights/actionGroups/<actionGroupName>" apiKey={APIKey} type=HighCPU \ --description "High CPU"

Box 2: --window-size Time over which to aggregate metrics in "##h##m##s" format. https://learn.microsoft.com/en-us/cli/azure/monitor/metrics/alert?view=azure-cli-latest

Box 2: Window Size az monitor metrics alert create -n alert1 -g {ResourceGroup} --scopes {VirtualMachineID} \ --condition "avg Percentage CPU > 90" --window-size 5m --evaluation-frequency 1m \ --action "/subscriptions/<subscriptionId>/resourceGroups/<resourceGroupName>/providers/Microsoft.Insights/actionGroups/<actionGroupName>" apiKey={APIKey} type=HighCPU \ --description "High CPU"

what is the correct value for box2?

--window-size : Time over which to aggregate metrics in "##h##m##s" format.

the param --window size has a typo, missing a dash?

Given answer is correct https://learn.microsoft.com/en-us/cli/azure/monitor/metrics/alert?view=azure-cli-latest#az-monitor-metrics-alert-create az monitor metrics alert create -n alert1 -g {ResourceGroup} --scopes {VirtualMachineID} \ --condition "avg Percentage CPU > 90" --window-size 5m --evaluation-frequency 1m \ --action "/subscriptions/<subscriptionId>/resourceGroups/<resourceGroupName>/providers/Microsoft.Insights/actionGroups/<actionGroupName>" apiKey={APIKey} type=HighCPU \ --description "High CPU"

Box 1: avg Percentage CPU > 85 Box 2: --evaluation-frequency 5m

Box 1: avg Percentage CPU > 85 Box 2: --evaluation-frequency 5m