Monitor etcd performance to ensure consistent Docker configuration

Etcd is a distributed key-value store designed by CoreOS to manage configuration settings across clusters of Docker containers, machines, or both. By enabling the etcd integration within Datadog, you can ensure that configurations provided to your machines are consistent and up to date throughout your cluster. The dashboard includes throughput metrics tracking successful directory or key creation, writes, updates, deletes, and two atomic operations for "compare and swap" and "compare and delete". Additionally, it provides package and bandwidth send and receive rates, append requests, error failure rates, and latency between the leader and its followers. Depending on your application, you may also want to use metrics such as the number of queries watching for changes to a value or directory, and the rate at which values or directories are expiring due to TTL.