How do I restart nginx only after the configuration test was successful on Ubuntu

Question

When I restart the nginx service on a command line on an Ubuntu server  the service crashes when a nginx configuration file has errors  On a multi-site server this puts down all the sites  even the ones without configuration errors   To prevent this  I run the nginx configuration test first   nginx -t   After the test ran successful  I could restart the service    etc init d nginx restart   Or only reload the nignx site configs without a restart   nginx -s reload   Is there a way to combine those two commands where the restart command is conditional to the configuration test s result   I couldn t find this online and the official documentation on this is rather basic  I don t know my way around Linux that well  so I don t know if what I m looking for is right in front of me or not possible at all   I m using nginx v1 1 19

User · Answer

As of nginx 1 8 0  the correct solution is  sudo nginx -t  amp  amp  sudo service nginx reload   Note that due to a bug  configtest always returns a zero exit code even if the config file has an error

User · Answer

At least on Debian the nginx startup script has a reload function which does   reload    log daemon msg  Reloading  DESC configuration    NAME    test nginx config   start-stop-daemon --stop --signal HUP --quiet --pidfile  PID      --oknodo --exec  DAEMON   log end msg           Seems like all you d need to do is call service nginx reload instead of restart since it calls test nginx config

User · Answer

alias nginx start  sudo nginx -c  etc nginx nginx conf  alias nginx stop  sudo nginx -s stop  alias nginx reload  sudo nginx -s reload  alias nginx config  sudo nginx -t  alias nginx restart  nginx config  amp  amp  nginx stop  amp  amp  nginx start  alias nginx errors  tail -250f  var logs nginx error log  alias nginx access  tail -250f  var logs nginx access log  alias nginx logs default access  tail -250f  var logs nginx default access log  alias nginx logs default-ssl access  tail -250f  var logs nginx default ssl log    and then use commands  nginx reload  etc

User · Answer

Actually  as far as I know  nginx would show an empty message and it wouldn t actually restart if the configuration is bad   The only way to screw it up is by doing an nginx stop and then start again  It would succeed to stop  but fail to start

User · Answer

I use the following command to reload Nginx  version 1 5 9  only if a configuration test was successful    etc init d nginx configtest  amp  amp  sudo  etc init d nginx reload   If you need to do this often  you may want to use an alias  I use the following   alias n   etc init d nginx configtest  amp  amp  sudo  etc init d nginx reload    The trick here is done by the   amp  amp   which only executes the second command if the first was successful  You can see here a more detailed explanation of the use of the   amp  amp   operator   You can use  restart  instead of  reload  if you really want to restart the server

User · Answer

You can use signals to control nginx    According to documentation  you need to send HUP signal to nginx master process      HUP - changing configuration  keeping up with a changed time zone  only for FreeBSD and Linux   starting new worker processes with a new configuration  graceful shutdown of old worker processes   Check the documentation here  http   nginx org en docs control html  You can send the HUP signal to nginx master process PID like this   kill -HUP    cat  var run nginx pid     The command above reads the nginx PID from  var run nginx pid  By default nginx pid is written to  usr local nginx logs nginx pid but that can be overridden in config  Check your nginx config to see where it saves the PID

User · Answer

You can reload using  etc init d nginx reload and sudo service nginx reload  If nginx -t throws some error then it won t reload   so use  amp  amp  to run both at a same time   like      nginx -t   amp  amp   etc init d nginx reload

[ubuntu] How do I restart nginx only after the configuration test was successful on Ubuntu?

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