Gossip Protocol

Consul makes use of two different gossip pools. We refer to each pool as the LAN or WAN pool respectively. Each datacenter Consul operates in has a LAN gossip pool containing all members of the datacenter, both clients and servers. The LAN pool is used for a few purposes. Membership information allows clients to automatically discover servers, reducing the amount of configuration needed. The distributed failure detection allows the work of failure detection to be shared by the entire cluster instead of concentrated on a few servers. Lastly, the gossip pool allows for reliable and fast event broadcasts.

All of these features are provided by leveraging Serf. It is used as an embedded library to provide these features. From a user perspective, this is not important, since the abstraction should be masked by Consul. It can be useful however as a developer to understand how this library is leveraged.

Lifeguard Enhancements

Lifeguard completely resolves this issue with novel enhancements to SWIM.