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The serf.io site is being taken down, so change all our links to point to the repo docs instead. Ref: https://github.com/hashicorp/serf/pull/743
41 lines
1.8 KiB
Plaintext
41 lines
1.8 KiB
Plaintext
---
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layout: docs
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page_title: Gossip Protocol
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description: |-
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Nomad uses a gossip protocol to manage membership. All of this is provided
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through the use of the Serf library.
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---
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# Gossip Protocol
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Nomad uses the [Serf library][serf] to provide a [gossip
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protocol](https://en.wikipedia.org/wiki/Gossip_protocol) to manage membership.
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The gossip protocol used by Serf is based on ["SWIM: Scalable Weakly-consistent
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Infection-style Process Group Membership Protocol"][swim], with a few minor
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adaptations. There are more details about [Serf's protocol here][gossip].
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~> **Advanced Topic!** This page covers technical details of
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the internals of Nomad. You do not need to know these details to effectively
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operate and use Nomad. These details are documented here for those who wish
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to learn about them without having to go spelunking through the source code.
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## Gossip in Nomad
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Nomad makes use of a single global WAN gossip pool that all servers participate
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in. Membership information provided by the gossip pool allows servers to perform
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cross region requests. The integrated failure detection allows Nomad to
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gracefully handle an entire region losing connectivity, or just a single server
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in a remote region. Nomad also uses the gossip protocol to detect servers in the
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same region to perform automatic clustering via the [consensus
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protocol](/nomad/docs/concepts/consensus).
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To provide all these features, Nomad uses [Serf][serf] as an embedded
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library. From a user perspective, this is not important, since Nomad masks the
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abstraction. However, developers may find it useful to understand how Nomad
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leverages the Serf library.
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[serf]: https://github.com/hashicorp/serf
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[gossip]: https://github.com/hashicorp/serf/blob/master/docs/internals/gossip.html.markdown
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[swim]: https://www.cs.cornell.edu/projects/Quicksilver/public_pdfs/SWIM.pdf
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