title: How disable the RNGD service from Yocto?
body: <p>Background: I am running Yocto Zeus, and Linux Kernel 4.14 using SystemD.  My target is an embedded i.MX6.</p>
  <p>I have been attempting to disable the RNGD service at startup.  It consumes all the cores for many seconds after bootup, and when I manually disable (via <strong>systemctl disable rngd</strong> it is actually disabled and there are no ill-effects (our software doesn't use /dev/random).</p>
  <p>I have looked through <a href="https://stackoverflow.com/questions/50651371/disable-a-standard-systemd-service-in-yocto-build?noredirect=1&amp;lq=1">Disable a standard systemd service in Yocto build</a> and have tried both the package remove and deleting the link, and neither seem to work.  Here are the contents of my <em>systemd_%.bbappend</em> file in my layer.</p>
  <pre><code># To remove the package completely, add it to this space separated list.
  # Not all services can be removed.
  PACKAGECONFIG_remove = &quot;timesyncd kmod rngd&quot;
  
  do_install_append() {
      rmdir ${D}${sysconfdir}/systemd/network
      ln -sfn /var/local/etc/systemd/network ${D}${sysconfdir}/systemd/network
  
      rm -f ${D}${sysconfdir}/systemd/system/multi-user.target.wants/rngd.service
  }
  </code></pre>
  <p>Is there a way to delete this service?  Even with both of those, I still see rngd running at boot.  I am reasonably confident my changes are being included, I can see them if I run <strong>bitbake -e systemd | grep rngd</strong>:</p>
  <pre><code>gen-ccm-root@ubuntu:~/workdir/tools/poky/build-dev$ bitbake -e systemd | grep rngd
  #     &quot;timesyncd kmod rngd&quot;
      rm -f /home/gen-ccm-root/workdir/tools/poky/build-dev/tmp/work/armv7at2hf-neon-poky-linux-gnueabi/systemd/1_243+AUTOINC+efb536d0cb-r0/image/etc/systemd/system/multi-user.target.wants/rngd.service
  </code></pre>
  <p>I have also confirmed that the other things in that file are actually taking effect.  The network link is being properly made and I have confirmed that the <code>timesyncd</code> service is removed.  I have confirmed that the file I am removing is the link that systemctl disable would remove:</p>
  <pre><code>~# systemctl disable rngd
  Removed /etc/systemd/system/multi-user.target.wants/rngd.service.
  </code></pre>