consul/website/source/discovery.html.erb

---
description: |-
  Consul is a highly available and distributed service discovery and KV
  store designed with support for the modern data center to make distributed
  systems and configuration easy.
---

<div class='consul-connect'>

  <section class='g-hero'>
    <h1>Service discovery made easy</h1>
    <p>Service registry, integrated health checks, and DNS and HTTP interfaces
      enable any service to discover and be discovered by other services</p>
    <div>
      <a href="/downloads.html" class="g-btn download">
        <svg xmlns="http://www.w3.org/2000/svg" width="20" height="22" viewBox="0 0 20 22">
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        Download
      </a>
      <a href="/intro/getting-started/services.html" class="g-btn dark-outline">Explore Docs</a>
    </div>
  </section>

  <section class='g-section'>
    <div class='g-container'>
      <div class='g-timeline no-intro'>
        <div>
          <span class='line'></span>
          <span class='line'>
            <svg xmlns="http://www.w3.org/2000/svg" width="11" height="15" viewBox="0 0 11 15">
                <path fill="#CA2171" d="M0 0v15l5.499-3.751L11 7.5 5.499 3.749.002 0z"/>
            </svg>
          </span>
          <span class='dot'></span>
          <h3>The Challenge</h3>
          <span class='sub-heading'>Service load balancers aren't efficient in a dynamic world.</span>
          <div id='discovery-challenge-animation' class='g-animation-block'>
            <%= inline_svg 'consul-connect/svgs/discovery-challenge.svg' %>
          </div>
          <p>Load balancers are often used to front a service tier and provide a static IP. These load balancers add cost, increase latency, introduce single points of failure, and must be updated as services scale up/down.</p>
        </div>
        <div>
          <span class='dot'></span>
          <h3>The Solution</h3>
          <span class='sub-heading'>Service discovery for dynamic infrastructure.</span>
          <div id='discovery-solution-animation' class='g-animation-block'>
            <%= inline_svg 'consul-connect/svgs/discovery-solution.svg' %>
          </div>
          <p>Instead of load balancers, connectivity in dynamic infrastructure is best solved with service discovery. Service discovery uses a registry to keep a real-time list of services, their location, and their health. Services query the registry to discover the location of upstream services and then connect directly. This allows services to scale up/down and gracefully handle failure without a load balancer intermediary.</p>
        </div>
      </div>
    </div>
  </section>

  <section class='g-section border-top'>
    <div class='g-container'>
      <div class='intro'>
        <h2>Features</h2>
      </div>
      <div class='g-text-asset large'>
        <div>
          <div>
            <h3>Service Registry</h3>
            <p>Consul provides a registry of all the running nodes and services, along with their current health status. This allows operators to understand the environment, and applications and automation tools to interact with dynamic infrastructure using an HTTP API.</p>
            <p>
              <a class="learn-more" href='/intro/getting-started/services.html'>Learn more<svg xmlns="http://www.w3.org/2000/svg" width="6" height="10" viewBox="0 0 6 10"><g fill="none" fill-rule="evenodd" transform="translate(-6 -3)"><mask id="a" fill="#fff"><path d="M7.138 3.529a.666.666 0 1 0-.942.942l3.528 3.53-3.529 3.528a.666.666 0 1 0 .943.943l4-4a.666.666 0 0 0 0-.943l-4-4z"/></mask><g fill="#1563FF" mask="url(#a)"><path d="M0 0h16v16H0z"/></g></g></svg></a>
            </p>
          </div>
        </div>
        <div>
          <picture>
            <source type="image/webp" srcset="
              /assets/images/consul-connect/ui-health-checks/ui-health-checks_230.webp 230w,
              /assets/images/consul-connect/ui-health-checks/ui-health-checks_690.webp 690w,
              /assets/images/consul-connect/ui-health-checks/ui-health-checks_1290.webp 1290w" />
             <source type="image/jpg" srcset="
              /assets/images/consul-connect/ui-health-checks/ui-health-checks_230.jpg 230w,
              /assets/images/consul-connect/ui-health-checks/ui-health-checks_690.jpg 690w,
              /assets/images/consul-connect/ui-health-checks/ui-health-checks_1290.jpg 1290w" />
              <img src='/assets/images/consul-connect/ui-health-checks/ui-health-checks_1290.jpg' alt='Service Registry'>
          </picture>
        </div>
      </div>
    </div>
  </section>

  <section class='g-section border-top'>
    <div class='g-container'>
      <div class='g-text-asset reverse'>
        <div>
          <div>
            <h3>DNS Query Interface</h3>
            <p>Consul enables service discovery using a built-in DNS server. This allows existing applications to easily integrate, as almost all applications support using DNS to resolve IP addresses. Using DNS instead of a static IP address allows services to scale up/down and route around failures easily.</p>
            <p>
              <a class="learn-more" href='/intro/getting-started/services.html#querying-services'>Learn more<svg xmlns="http://www.w3.org/2000/svg" width="6" height="10" viewBox="0 0 6 10"><g fill="none" fill-rule="evenodd" transform="translate(-6 -3)"><mask id="a" fill="#fff"><path d="M7.138 3.529a.666.666 0 1 0-.942.942l3.528 3.53-3.529 3.528a.666.666 0 1 0 .943.943l4-4a.666.666 0 0 0 0-.943l-4-4z"/></mask><g fill="#1563FF" mask="url(#a)"><path d="M0 0h16v16H0z"/></g></g></svg></a>
            </p>
          </div>
        </div>
        <div class='code-sample'>
          <div>
            <span></span>
            <div class='code'><code>
$ dig <code class='keyword'>web-frontend.service.consul.</code> ANY

; <<>> DiG 9.8.3-P1 <<>> web-frontend.service.consul. ANY
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 29981
;; flags: qr aa rd ra; QUERY: 1, ANSWER: 2, AUTHORITY: 0, ADDITIONAL: 0

;; QUESTION SECTION:
;web-frontend.service.consul. IN ANY

;; ANSWER SECTION:
web-frontend.service.consul. 0 IN A <code class='keyword'>10.0.3.83</code>
web-frontend.service.consul. 0 IN A <code class='keyword'>10.0.1.109</code></code>
            </div>
          </div>
        </div>
      </div>
    </div>
  </section>

  <section class='g-section border-top'>
    <div class='g-container'>
      <div class='g-text-asset'>
        <div>
          <div>
            <h3>HTTP API with Edge Triggers</h3>
            <p>Consul provides an HTTP API to query the service registry for nodes, services, and health check information. The API also supports blocking queries, or long-polling for any changes. This allows automation tools to react to services being registered or health status changes to change configurations or traffic routing in real time.</p>
            <p>
              <a class="learn-more" href='/intro/getting-started/services.html#http-api'>Learn more<svg xmlns="http://www.w3.org/2000/svg" width="6" height="10" viewBox="0 0 6 10"><g fill="none" fill-rule="evenodd" transform="translate(-6 -3)"><mask id="a" fill="#fff"><path d="M7.138 3.529a.666.666 0 1 0-.942.942l3.528 3.53-3.529 3.528a.666.666 0 1 0 .943.943l4-4a.666.666 0 0 0 0-.943l-4-4z"/></mask><g fill="#1563FF" mask="url(#a)"><path d="M0 0h16v16H0z"/></g></g></svg></a>
            </p>
          </div>
        </div>
        <div class='code-sample'>
          <div>
            <span></span>
            <div class='code'>
              <code>$ curl <code class='keyword'>http://localhost:8500/v1/health/service/web?index=11&wait=30s</code>
{
  ...
  "Node": "10-0-1-109",
  "CheckID": "service:web",
  "Name": "Service 'web' check",
  "Status": <code class='keyword'>"critical"</code>,
  "ServiceID": "web",
  "ServiceName": "web",
  "CreateIndex": 10,
  "ModifyIndex": 20
  ...
}
</code>
            </div>
          </div>
        </div>
      </div>
    </div>
  </section>

  <section class='g-section border-top'>
    <div class='g-container'>
      <div class='g-text-asset reverse'>
        <div>
          <div>
            <h3>Multi Datacenter</h3>
            <p>Consul supports multiple datacenters out of the box with no complicated configuration. Look up services in other datacenters or keep the request local. Advanced features like Prepared Queries enable automatic failover to other datacenters.</p>
            <p>
              <a class="learn-more" href='/docs/guides/datacenters.html'>Learn more<svg xmlns="http://www.w3.org/2000/svg" width="6" height="10" viewBox="0 0 6 10"><g fill="none" fill-rule="evenodd" transform="translate(-6 -3)"><mask id="a" fill="#fff"><path d="M7.138 3.529a.666.666 0 1 0-.942.942l3.528 3.53-3.529 3.528a.666.666 0 1 0 .943.943l4-4a.666.666 0 0 0 0-.943l-4-4z"/></mask><g fill="#1563FF" mask="url(#a)"><path d="M0 0h16v16H0z"/></g></g></svg></a>
            </p>
          </div>
        </div>
        <div class='code-sample'>
          <div>
            <span></span>
            <div class='code'>
              <code>$ curl http://localhost:8500/v1/catalog/datacenters
<code class='keyword'>["dc1", "dc2"]</code>$ curl http://localhost:8500/v1/catalog/nodes?<code class='keyword'>dc=dc2</code>
[
    {
        "ID": "7081dcdf-fdc0-0432-f2e8-a357d36084e1",
        "Node": "10-0-1-109",
        "Address": "10.0.1.109",
        "Datacenter": "dc2",
        "TaggedAddresses": {
            "lan": "10.0.1.109",
            "wan": "10.0.1.109"
        },
        "CreateIndex": 112,
        "ModifyIndex": 125
    },
...</code>
            </div>
          </div>
        </div>
      </div>
    </div>
  </section>

  <section class='g-section border-top'>
    <div class='g-container'>
      <div class='g-text-asset large'>
        <div>
          <div>
            <h3>Health Checks</h3>
            <p>Pairing service discovery with health checking prevents routing requests to unhealthy hosts and enables services to easily provide circuit breakers.</p>
            <p>
              <a class="learn-more" href='/intro/getting-started/checks.html'>Learn more<svg xmlns="http://www.w3.org/2000/svg" width="6" height="10" viewBox="0 0 6 10"><g fill="none" fill-rule="evenodd" transform="translate(-6 -3)"><mask id="a" fill="#fff"><path d="M7.138 3.529a.666.666 0 1 0-.942.942l3.528 3.53-3.529 3.528a.666.666 0 1 0 .943.943l4-4a.666.666 0 0 0 0-.943l-4-4z"/></mask><g fill="#1563FF" mask="url(#a)"><path d="M0 0h16v16H0z"/></g></g></svg></a>
            </p>
          </div>
        </div>
        <div>
          <picture>
            <source type="image/webp" srcset="
              /assets/images/consul-connect/ui-health-checks/ui-health-checks_230.webp 230w,
              /assets/images/consul-connect/ui-health-checks/ui-health-checks_690.webp 690w,
              /assets/images/consul-connect/ui-health-checks/ui-health-checks_1290.webp 1290w" />
             <source type="image/jpg" srcset="
              /assets/images/consul-connect/ui-health-checks/ui-health-checks_230.jpg 230w,
              /assets/images/consul-connect/ui-health-checks/ui-health-checks_690.jpg 690w,
              /assets/images/consul-connect/ui-health-checks/ui-health-checks_1290.jpg 1290w" />
              <img src='/assets/images/consul-connect/ui-health-checks/ui-health-checks_1290.jpg' alt='Health Checks'>
          </picture>
        </div>
      </div>
    </div>
  </section>

  <section class='g-section bg-dark'>
    <div class='g-container'>
      <div class='intro'>
        <h2>Case Studies</h2>
      </div>
      <div class='g-carousel'>
        <div class="siema">
          <div class='card' href='#'>
            <div>
              <img src='/assets/images/consul-connect/case-studies/case-study_01.jpg' alt=''>
            </div>
            <div class='content'>
              <span class='tag video'>Video</span>
              <h4>Twitch - Driving Towards a Modern Infrastructure</h4>
              <p>In this talk from HashiConf 2015, Tarrant Rollins discusses how Twitch uses HashiCorp Consul to overcome legacy infrastructure and solve complex problems.</p>
              <a href='https://www.hashicorp.com/resources/twitch-driving-towards-a-modern-infrastructure'>Watch</a>
            </div>
          </div>
          <div class='card' href='#'>
            <div>
              <img src='/assets/images/consul-connect/case-studies/case-study_02.jpg' alt=''>
            </div>
            <div class='content'>
              <span class='tag video'>Video</span>
              <h4>Jet.com - Nomad Auto-Proxy with Consul-Template and NGINX</h4>
              <p>Justen Walker explains how Jet.com uses HashiCorp Consul and Nomad to allow hundreds of developers to have self-service access, despite relying on NGINX static configs—and with a remarkably small DevOps team.</p>
              <a href='https://www.hashicorp.com/resources/jet-com-nomad-auto-proxy-consul-template-nginx'>Watch</a>
            </div>
          </div>
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      <h2>Ready to get started?</h2>
      <a href="/downloads.html" class="g-btn white download">
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<% content_for :scripts do %>
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