The actual reason you really need a proper PID 1 is not explained in this post, but a couple of clicks away at [0]:<p><pre><code>  &gt;[...] the init process must also wait for child processes to terminate, 
  &gt;before terminating itself.
  &gt;If the init process terminates prematurely then all children are terminated uncleanly by the kernel.
</code></pre>
0: <a href="https:&#x2F;&#x2F;blog.phusion.nl&#x2F;2015&#x2F;01&#x2F;20&#x2F;docker-and-the-pid-1-zombie-reaping-problem&#x2F;" rel="nofollow">https:&#x2F;&#x2F;blog.phusion.nl&#x2F;2015&#x2F;01&#x2F;20&#x2F;docker-and-the-pid-1-zomb...</a>