What is the best way to get error rate (errors as a proportion of responses) monitoring for an nginx
app on an EC2 server in AWS?
I'd like an alarm if the percentage of 500 responses goes above a certain threshold, say 10%.
I have tried adding a Cloudwatch Log Metric, but that can only measure the number of 500 responses or the number of responses. I can't seem to get it to measure the percentage of responses which are errors.