nginx will not start on boot, but starts fine manually. The logs say something like

nginx: [emerg] host not found in upstream "{some hostname}" in /etc/nginx/conf.d/some_site.conf
nginx: configuration file /etc/nginx/nginx.conf test failed

Failed to start A high performance web server and a reverse proxy server.
nginx.service: Unit entered failed state.
nginx.service: Failed with result 'exit-code'.

It seems that on bootup dns is not ready yet and nginx is trying to lookup a hostname that I have in as a reverse proxy.


After some research it turns out systemd uses the file below to startup nginx


The file on Ubuntu 15.04, Ubuntu 15.10, and even the nginx site itself say to use the After line like below


This makes a person think that the network should up and ready to go. However, I found the link http://www.freedesktop.org/wiki/Software/systemd/NetworkTarget/ that says

network.target has very little meaning during start-up. It only indicates that the network management stack is up after it has been reached.

The link goes on to say

network-online.target is a target that actively waits until the nework is "up", where the definition of "up" is defined by the network management software.

So I changed the After use that instead like


Now nginx starts up fine on bootup. I am not claiming this is the fully correct solution as it is possible that a different After target should be used that would be more correct in some other way, but this seems to work for the last couple of reboots.

  • I keep getting the host not found in upstream error even with After=network-online.target nss-lookup.target. – KillianDS Feb 12 '16 at 10:00
  • I have the same problem on RHEL (nginx starts so quickly that upstream connectivity is not yet established). I am a bit hesitant with this solution however. The documentation which you linked also states that "It is strongly recommended not to pull in this target too liberally: for example network server software should generally not pull this in (since server software generally is happy to accept local connections even before any routable network interface is up)". I would much rather fix this in nginx somehow. – Vilsepi Jun 29 '16 at 11:59
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    Yea, this solution worked on a "slow" computer. I upgraded my computer and now it fails again. So I don't know how to fix this. – Paul Jul 5 '16 at 14:49

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