How to tell if a kinesis stream is not being processed

Question

When processing an AWS Kinesis stream, how to tell if a consumer is no longer processing the stream? Is there a metric in Kinesis that I can use for alarming for example?

There is a metric for IteratorAgeMilliseconds however, this metric is only written when a stream is being processed. So in case a consumer is down and the stream is backing up with messages, we would know that this happened only when we resume processing.

Answer 1

You can use GetRecords.Bytes to determine whether the stream is being read.

If you have only one consumer, you could use metric math to compare it with PutRecords.Bytes and/or PutRecord.Bytes . With more than one consumer you'd need to divide the gets by the number of consumers, and if you have a variable number of consumers that isn't going to work.

You could also enable anomaly detection on the stream. I haven't done this, so can't tell you how well it works.

But the approach that I prefer (and have used successfully multiple times) is to have your consumer write a custom metric, such as the number of records that it's processed. Then you can set up an alarm on the consumer not reporting that metric.