The FluentdPredictedBufferGrowth alert is very sensitive

[kingnarmer]

I am receiving many FluentdPredictedBufferGrowth alerts even though logs are being processed smoothly. One suggestion to fine-tune the alert rule is to add a condition that considers the current buffer value combined with a linear prediction.

Proposed updated condition:

(sum(predict_linear(fluentd_output_status_buffer_total_bytes{job="logging-operator-fluentd-metrics", namespace="cattle-logging-system"}[10m], 600)) > 
 sum(fluentd_output_status_buffer_total_bytes{job="logging-operator-fluentd-metrics", namespace="cattle-logging-system"}) * 1.5) 
and 
(sum(fluentd_output_status_buffer_total_bytes{job="logging-operator-fluentd-metrics", namespace="cattle-logging-system"}) > 10 * 1024 * 1024)

This modification adds a threshold to ensure the alert only triggers if both the predicted growth exceeds 1.5x the current buffer and the current buffer size is greater than 10 MB. This should reduce unnecessary alerts while maintaining accuracy.