Consul vs Serf vs etcd

Service Discovery - Consul makes it simple for services to register themselves and to discover other services via a DNS or HTTP interface. External services such as SaaS providers can be registered as well.;Health Checking - Health Checking enables Consul to quickly alert operators about any issues in a cluster. The integration with service discovery prevents routing traffic to unhealthy hosts and enables service level circuit breakers.;Key/Value Storage - A flexible key/value store enables storing dynamic configuration, feature flagging, coordination, leader election and more. The simple HTTP API makes it easy to use anywhere.;Multi-Datacenter - Consul is built to be datacenter aware, and can support any number of regions without complex configuration.

Membership: Serf maintains cluster membership lists and is able to execute custom handler scripts when that membership changes. For example, Serf can maintain the list of web servers for a load balancer and notify that load balancer whenever a node comes online or goes offline.;Failure detection and recovery: Serf automatically detects failed nodes within seconds, notifies the rest of the cluster, and executes handler scripts allowing you to handle these events. Serf will attempt to recover failed nodes by reconnecting to them periodically.;Custom event propagation: Serf can broadcast custom events and queries to the cluster. These can be used to trigger deploys, propagate configuration, etc. Events are simply fire-and-forget broadcast, and Serf makes a best effort to deliver messages in the face of offline nodes or network partitions. Queries provide a simple realtime request/response mechanism.