Cloudwatch is Amazon’s monitoring and alerting service.
Some questions and answers re: this awesome service.
- How can you create custom metrics?
- Cloudwatch doesn’t limit you to the metrics it collects by default (at the hypervisor level). You can push any metric that makes sense up the the statistics repository, using custom metrics.
- What protocol does cloudwatch use? ICMP or SNMP?
- I couldn’t find a definitive answer. For custom metrics, use the api as you would for any other AWS service. Cloudwatch also gathers metrics from the hypervisor and the host machine.
- What are cloudwatch logs?
- A way for you to push logfiles from ec2 instances up to Cloudwatch, parse them, and create metrics out of them (“how many 404 errors has this application had in the last 30 minutes?”). More here.
- Does cloudwatch allow you to setup different metric thresholds at different times? For example, set an alarm at 70% CPU on Wed night but 90% on Sat night?
- No, but you could do this with custom metrics. You could read the cloudwatch default metrics and have an ‘cpualarm’ metric which would be 1 or 0 depending on if certain parameters were set. Then you could vary the parameters over time. Then you could set an alarm on the ‘cpualarm’ metric.