<p>I want to deploy nextcloud with helm and a custom <code>value.yaml</code> file that fits my needs. Do i have to specify all values given from the original <code>value.yaml</code> or is it possible to only change the values needed, Eg if the only thing I want to change is the host adress my file can look like this:</p>
<pre class="lang-yaml prettyprint-override"><code>nextlcoud:
    host: 192.168.178.10
</code></pre>
<p>instead of copying <a href="https://github.com/nextcloud/helm/blob/master/charts/nextcloud/values.yaml" rel="nofollow noreferrer">this file</a> and changing only a few values.</p>

8bit
<p>As the underlying issue was resolved by the answer of user @Kun Li, I wanted to add some examples when customizing Helm charts as well as some additional reference.</p>
<p>As asked in the question:</p>
<blockquote>
<p>Do i have to specify all values given from the original value.yaml or is it possible to only change the values needed</p>
</blockquote>
<p>In short you don't need to specify all of the values. You can change only some of them (like the <code>host</code> from your question).
The ways to change the values are following:</p>
<blockquote>
<ul>
<li>Individual parameters passed with <code>--set</code> (such as <code>helm install --set foo=bar ./mychart</code>)</li>
<li>A values file if passed into <code>helm install</code> or <code>helm upgrade</code> with the <code>-f</code> flag (<code>helm install -f myvals.yaml ./mychart</code>)</li>
<li>If this is a subchart, the <code>values.yaml</code> file of a parent chart</li>
<li>The <code>values.yaml</code> file in the chart</li>
</ul>
</blockquote>
<p>You can read more about it by following official <code>Helm</code> documentation:</p>
<ul>
<li><em><a href="https://helm.sh/docs/chart_template_guide/values_files/" rel="nofollow noreferrer">Helm.sh: Docs: Chart template guide: Values files</a></em></li>
</ul>
<blockquote>
<p><strong>A side note!</strong></p>
<p>Above points are set in the order of priority. The first one (<code>--set</code>) will have the highest priority to override the values.</p>
</blockquote>
<hr />
<h3>Example</h3>
<blockquote>
<p>A side note!</p>
<p>This examples assume that you are in the directory of a pulled Helm chart and you are using Helm v3</p>
</blockquote>
<p>Using the <code>nextcloud</code> Helm chart used in the question you can set the <code>nextcloud.host</code> value by:</p>
<ul>
<li>Pulling the Helm chart and editing the values.yaml</li>
<li>Creating additional <code>new-values.yaml</code> to pass it in (the <code>values.yaml</code> from Helm chart will be used regardless with lower priority):
<ul>
<li><code>$ helm install NAME . -f new-values.yaml</code></li>
</ul>
</li>
</ul>
<p><code>new-values.yaml</code></p>
<pre class="lang-yaml prettyprint-override"><code>nextcloud:
  host: 192.168.0.2
</code></pre>
<ul>
<li>Setting the value with <code>helm install NAME . --set nextcloud.host=192.168.0.2</code></li>
</ul>
<p>You can check if the changes were done correctly by either:</p>
<ul>
<li><code>$ helm template .</code> - as pointed by user @David Maze</li>
<li><code>$ helm install NAME . --dry-run --debug</code></li>
</ul>
