Build out basic alarms about terraform-aws-quorum-cluster HOT 2 CLOSED

For each of these alarms (and any others we come up with), we'll need to define terms like "Large number" and "prolonged period" and define these as CloudWatch metrics.

Some alarms we probably want:

• Large number of quorum process crashes
• Large number of node crashes
• Memory usage approaching instance memory limit for a prolonged period
• Storage space running low
• Blocks no longer being mined (Not sure if we can do this from the existing block number metrics)
• Large number of nodes have very few peers for a prolonged period
• Large number of nodes are far behind the head of the chain on sync progress.

from terraform-aws-quorum-cluster.

"Storage Space running low" and "Blocks no longer being mined" need new metrics

from terraform-aws-quorum-cluster.