open-nomad/website/source/docs/internals/gossip.html.md

---
layout: "docs"
page_title: "Gossip Protocol"
sidebar_current: "docs-internals-gossip"
description: |-
  Nomad uses a gossip protocol to manage membership. All of this is provided
  through the use of the Serf library.
---

# Gossip Protocol

Nomad uses a [gossip protocol](https://en.wikipedia.org/wiki/Gossip_protocol)
to manage membership. This is provided through the use of the [Serf library](https://www.serf.io/).
The gossip protocol used by Serf is based on
["SWIM: Scalable Weakly-consistent Infection-style Process Group Membership Protocol"](https://www.cs.cornell.edu/projects/Quicksilver/public_pdfs/SWIM.pdf),
with a few minor adaptations. There are more details about [Serf's protocol here](https://www.serf.io/docs/internals/gossip.html).

~> **Advanced Topic!** This page covers technical details of
the internals of Nomad. You do not need to know these details to effectively
operate and use Nomad. These details are documented here for those who wish
to learn about them without having to go spelunking through the source code.

## Gossip in Nomad

Nomad makes use of a single global WAN gossip pool that all servers participate in.
Membership information provided by the gossip pool allows servers to perform cross region
requests. The integrated failure detection allows Nomad to gracefully handle an entire region
losing connectivity, or just a single server in a remote region. The gossip protocol
is also used to detect servers in the same region to perform automatic clustering
via the [consensus protocol](/docs/internals/consensus.html).

All of these features are provided by leveraging [Serf](https://www.serf.io/). 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 Nomad. It can be useful
however as a developer to understand how this library is leveraged.