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<p>The <strong>Heron API server</strong> is a necessary component</p>
<blockquote>
<p>If you're running Heron <a href="../../getting-started">locally</a> on your laptop, you won't need to run the Heron API server separately; its functions will be handled automatically.</p>
</blockquote>
<h2><a class="anchor" aria-hidden="true" id="installation"></a><a href="#installation" aria-hidden="true" class="hash-link"><svg class="hash-link-icon" aria-hidden="true" height="16" version="1.1" viewBox="0 0 16 16" width="16"><path fill-rule="evenodd" d="M4 9h1v1H4c-1.5 0-3-1.69-3-3.5S2.55 3 4 3h4c1.45 0 3 1.69 3 3.5 0 1.41-.91 2.72-2 3.25V8.59c.58-.45 1-1.27 1-2.09C10 5.22 8.98 4 8 4H4c-.98 0-2 1.22-2 2.5S3 9 4 9zm9-3h-1v1h1c1 0 2 1.22 2 2.5S13.98 12 13 12H9c-.98 0-2-1.22-2-2.5 0-.83.42-1.64 1-2.09V6.25c-1.09.53-2 1.84-2 3.25C6 11.31 7.55 13 9 13h4c1.45 0 3-1.69 3-3.5S14.5 6 13 6z"></path></svg></a>Installation</h2>
<p>The Heron API server executable (<code>heron-apiserver</code>) is installed automatically when you install the <a href="getting-started-local-single-node#step-1-download-the-heron-tools">Heron tools</a>.</p>
<h2><a class="anchor" aria-hidden="true" id="running-the-heron-api-server"></a><a href="#running-the-heron-api-server" aria-hidden="true" class="hash-link"><svg class="hash-link-icon" aria-hidden="true" height="16" version="1.1" viewBox="0 0 16 16" width="16"><path fill-rule="evenodd" d="M4 9h1v1H4c-1.5 0-3-1.69-3-3.5S2.55 3 4 3h4c1.45 0 3 1.69 3 3.5 0 1.41-.91 2.72-2 3.25V8.59c.58-.45 1-1.27 1-2.09C10 5.22 8.98 4 8 4H4c-.98 0-2 1.22-2 2.5S3 9 4 9zm9-3h-1v1h1c1 0 2 1.22 2 2.5S13.98 12 13 12H9c-.98 0-2-1.22-2-2.5 0-.83.42-1.64 1-2.09V6.25c-1.09.53-2 1.84-2 3.25C6 11.31 7.55 13 9 13h4c1.45 0 3-1.69 3-3.5S14.5 6 13 6z"></path></svg></a>Running the Heron API server</h2>
<p>You can start up the Heron API server using the <code>heron-apiserver</code> command. When you do so you'll need to specify two things:</p>
<ul>
<li>A <a href="#base-templates">base template</a> for the scheduler that the API server will be interacting with</li>
<li>A <a href="#cluster-name">cluster name</a> for the Heron cluster</li>
</ul>
<p>Here's an example:</p>
<pre><code class="hljs css language-bash">$ heron-apiserver \
  --base-template mesos \
  --cluster sandbox
</code></pre>
<h2><a class="anchor" aria-hidden="true" id="base-templates"></a><a href="#base-templates" aria-hidden="true" class="hash-link"><svg class="hash-link-icon" aria-hidden="true" height="16" version="1.1" viewBox="0 0 16 16" width="16"><path fill-rule="evenodd" d="M4 9h1v1H4c-1.5 0-3-1.69-3-3.5S2.55 3 4 3h4c1.45 0 3 1.69 3 3.5 0 1.41-.91 2.72-2 3.25V8.59c.58-.45 1-1.27 1-2.09C10 5.22 8.98 4 8 4H4c-.98 0-2 1.22-2 2.5S3 9 4 9zm9-3h-1v1h1c1 0 2 1.22 2 2.5S13.98 12 13 12H9c-.98 0-2-1.22-2-2.5 0-.83.42-1.64 1-2.09V6.25c-1.09.53-2 1.84-2 3.25C6 11.31 7.55 13 9 13h4c1.45 0 3-1.69 3-3.5S14.5 6 13 6z"></path></svg></a>Base templates</h2>
<p>The Heron API server works by accepting incoming commands from the <a href="user-manuals-heron-cli">Heron CLI tool</a> and interacts with a variety of Heron components, including:</p>
<ul>
<li>a scheduler (<a href="schedulers-mesos-local-mac">Mesos</a>, <a href="schedulers-aurora-cluster">Aurora</a>, the <a href="schedulers-local">local filesystem</a>, etc.)</li>
<li>an uploader (<a href="uploaders-amazon-s3">Amazon S3</a>, the <a href="uploaders-local-fs">local filesystem</a>, etc.)</li>
</ul>
<p>When you <a href="#installation">install</a> the Heron tools, a directory will automatically be created in <code>~/.herontools/conf</code> on MacOS and <code>/usr/local/herontools/conf</code> on other platforms. That directory contains a number of base templates for all of the currently supported schedulers. Modify the configuration for your scheduler, for example <a href="schedulers-mesos-local-mac">Mesos</a> using the YAML files in the <code>mesos</code> folder, and then select the proper base template using the <code>--base-template</code> flag. Here's an example for Mesos:</p>
<pre><code class="hljs css language-bash">$ heron-apiserver \
  --base-template mesos \
  --cluster my-cluster
</code></pre>
<blockquote>
<p>For a full guide to Heron configuration, see <a href="cluster-config-overview">Configuring a cluster</a>.</p>
</blockquote>
<h2><a class="anchor" aria-hidden="true" id="cluster-name"></a><a href="#cluster-name" aria-hidden="true" class="hash-link"><svg class="hash-link-icon" aria-hidden="true" height="16" version="1.1" viewBox="0 0 16 16" width="16"><path fill-rule="evenodd" d="M4 9h1v1H4c-1.5 0-3-1.69-3-3.5S2.55 3 4 3h4c1.45 0 3 1.69 3 3.5 0 1.41-.91 2.72-2 3.25V8.59c.58-.45 1-1.27 1-2.09C10 5.22 8.98 4 8 4H4c-.98 0-2 1.22-2 2.5S3 9 4 9zm9-3h-1v1h1c1 0 2 1.22 2 2.5S13.98 12 13 12H9c-.98 0-2-1.22-2-2.5 0-.83.42-1.64 1-2.09V6.25c-1.09.53-2 1.84-2 3.25C6 11.31 7.55 13 9 13h4c1.45 0 3-1.69 3-3.5S14.5 6 13 6z"></path></svg></a>Cluster name</h2>
<p>In addition to specifying a base template when starting up the API server, you also need to specify a name for the cluster that the Heron API server will be serving. Here's an example:</p>
<pre><code class="hljs css language-bash">$ heron-apiserver \
  --base-template mesos \
  --cluster us-west-prod
</code></pre>
<p>{{&lt; alert &quot;api-server-cluster-name&quot; &gt;}}</p>
<h2><a class="anchor" aria-hidden="true" id="other-options"></a><a href="#other-options" aria-hidden="true" class="hash-link"><svg class="hash-link-icon" aria-hidden="true" height="16" version="1.1" viewBox="0 0 16 16" width="16"><path fill-rule="evenodd" d="M4 9h1v1H4c-1.5 0-3-1.69-3-3.5S2.55 3 4 3h4c1.45 0 3 1.69 3 3.5 0 1.41-.91 2.72-2 3.25V8.59c.58-.45 1-1.27 1-2.09C10 5.22 8.98 4 8 4H4c-.98 0-2 1.22-2 2.5S3 9 4 9zm9-3h-1v1h1c1 0 2 1.22 2 2.5S13.98 12 13 12H9c-.98 0-2-1.22-2-2.5 0-.83.42-1.64 1-2.09V6.25c-1.09.53-2 1.84-2 3.25C6 11.31 7.55 13 9 13h4c1.45 0 3-1.69 3-3.5S14.5 6 13 6z"></path></svg></a>Other options</h2>
<p>In addition to specifying a base template and cluster name, you can also specify:</p>
<table>
<thead>
<tr><th style="text-align:left">Flag</th><th style="text-align:left">Description</th></tr>
</thead>
<tbody>
<tr><td style="text-align:left"><code>--config-path</code></td><td style="text-align:left">A non-default path to a base configuration</td></tr>
<tr><td style="text-align:left"><code>--port</code></td><td style="text-align:left">The port to bind to (the default is 9000)</td></tr>
</tbody>
</table>
<h2><a class="anchor" aria-hidden="true" id="configuration-overrides"></a><a href="#configuration-overrides" aria-hidden="true" class="hash-link"><svg class="hash-link-icon" aria-hidden="true" height="16" version="1.1" viewBox="0 0 16 16" width="16"><path fill-rule="evenodd" d="M4 9h1v1H4c-1.5 0-3-1.69-3-3.5S2.55 3 4 3h4c1.45 0 3 1.69 3 3.5 0 1.41-.91 2.72-2 3.25V8.59c.58-.45 1-1.27 1-2.09C10 5.22 8.98 4 8 4H4c-.98 0-2 1.22-2 2.5S3 9 4 9zm9-3h-1v1h1c1 0 2 1.22 2 2.5S13.98 12 13 12H9c-.98 0-2-1.22-2-2.5 0-.83.42-1.64 1-2.09V6.25c-1.09.53-2 1.84-2 3.25C6 11.31 7.55 13 9 13h4c1.45 0 3-1.69 3-3.5S14.5 6 13 6z"></path></svg></a>Configuration overrides</h2>
<p>When you specify a <a href="#base-templates">base template</a> when running the Heron API server, the server will use whatever configuration is found in the template files. You can override configuration on a per-parameter basis, however, using the <code>-D</code> flag. Here's an example:</p>
<pre><code class="hljs css language-bash">$ heron-apiserver \
  --base-template aurora \
  --cluster us-west-prod \
  -D heron.statemgr.connection.string=zk-1:2181,zk-2:2181,zk-3:2181 \
  -D heron.class.uploader=com.acme.uploaders.MyCustomUploader
</code></pre>
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