Is it necessary to set up an alert for CPU, and how to determine the trigger level?

Yes, setting up an alert for CPU is necessary to respond promptly to high load and prevent service degradation. The trigger level depends on the application's specifics and infrastructure, but generally:

• Warning alert is set when CPU load exceeds 70-80% for several minutes.
• Critical alert is triggered when load exceeds 90-95%, which can lead to performance deterioration or failures.

It is important to consider average load and peak values, as well as the context: for example, high load may be normal for batch tasks. Alert configuration should be accompanied by analysis of historical data and testing to minimize false positives.