<p>There are 2 questions about Calico applying to k8s cluster.</p>

<ol>
<li><p>Calico creates etcd for own data, but I don't want to create another etcd because k8s already have it. Can I use k8s etcd for Calico?</p></li>
<li><p>Calico prepares Typha for using Kubernetes API Datastore. Then, What does Typha exactly do? I read Typha's code, and assumed that Typha takes snapshots and deltas for adapting network policy and constantly broadcast them to all client which Typha connects to. But I'm not familiar with golang so I don't have confidence of my understanding.</p></li>
</ol>

<p>I'm absolutely new to Calico and k8s, so I'm sorry if I miss some document related to above questions.</p>

<ol>
<li>From the <a href="https://docs.projectcalico.org/v1.5/getting-started/kubernetes/installation/" rel="nofollow noreferrer">calico docs on adding it to K8s</a>:</li>
</ol>
<blockquote>
<p><strong>Requirements</strong></p>
<p>An etcd cluster accessible by all nodes in the Kubernetes cluster</p>
<ul>
<li>Calico can share the etcd cluster used by Kubernetes, but it’s recommended that a separate cluster is set up.</li>
</ul>
</blockquote>
<ol start="2">
<li>I don't know much about how Typha works, but maybe the <a href="https://docs.projectcalico.org/v3.5/reference/architecture/" rel="nofollow noreferrer">docs</a> and the <a href="https://github.com/projectcalico/typha" rel="nofollow noreferrer">github repo</a> have some more info on it.</li>
</ol>
