Why do I keep getting an alert for diskUsedPercentage on my AKS node

Kenny 1 Reputation point
2021-08-12T19:23:04.797+00:00

I enabled the recommended alerts on my AKS cluster. Every day I get an alert now that my DiskUsagePercentage exceeded the 80% threshold:

Metric name DiskUsedPercentage
Time Aggregation Average
Period Over the last 5 mins
Value 80.000186
Operator GreaterThan
Threshold 80
Criterion Type StaticThresholdCriterion

If I look at the AVG aggregation diskUsedPercentage for the node it's near constant at around 40%.
If I look at the MIN aggregation diskUsedPercentage for the node it's near constant at around 0.2%.
If I look at the MAX aggregation diskUsedPercentage for the node it's near constant at around 80%.

This doesn't make sense to me. When I read these numbers, it seems as though my disk used percentage is going up/down/up/down from 0.2% -> 80% each 5 min time bucket. That seems wrong to me. I have a small stable web application that doesn't write anything to disk. Not even logs.

What is going on here?

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  1. SUNOJ KUMAR YELURU 13,946 Reputation points MVP
    2021-09-03T09:39:22.903+00:00

    Hi @Kenny

    Thank You for posting in Q & A.

    Based on your details, If the disk usage reaching >80% then alert will trigger.

    Please modify monitoring alerts rule >Operator GreaterThan Threshold 85%

    Recommended metric alerts (preview) from Container insights

    If the Answer is helpful, please click Accept Answer and up-vote, so that it can help others in the community looking for help on similar topics.

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