<p>When I'm learning kubernetes with book <em>KubernetesInAction</em> Ch.09 and make some pratice.</p>
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<p>I use <code>kubectl rolling-update kubia-v1 kubia-v2 --image=luksa/kubia:v2</code></p>
<p>and he tell me <code>Error: unknown command &quot;rolling-update&quot; for &quot;kubectl&quot;</code></p>
<p>I find it in github <a href="https://github.com/kubernetes/kubectl/commit/d3af7e08624bfa7c2f52714b47cfe96a52d15fc0" rel="nofollow noreferrer">Remove deprecated rolling-update command</a>.</p>
<p>I'm confused why they removed this command?</p>
<p>Hope to get an answer, thank you!</p>

<p>The reason is that in production, you cannot guarantee the network is always stable. If the network lost, you'd end up in a immediate state where different version of pods running together.</p>
<p>Another important thing is that kubernetes is designed for you telling kubernetes the final status and it help you do it. It's not just like this way kubectl need to tell each detailed steps for the upgrade.</p>
<p>So that deployment resource is introduced.</p>
