Bug#728015: [nginx] Don't use type=forking in systemd service file
If we turn this off, is it possible for systemd to send nginx the reload signal as opposed to a complete restart? Of course. If you look the attached service file, you can notice that the reload is fully operational. Here is a proof. # Ensure that nginx is stopped first root@complexe:~# systemctl stop nginx.service root@complexe:~# pgrep nginx # Start nginx and show actual PIDs root@complexe:~# systemctl start nginx.service root@complexe:~# systemctl status nginx.service nginx.service - A high performance web server and a reverse proxy server Loaded: loaded (/etc/systemd/system/nginx.service; enabled) […] Main PID: 12876 (nginx) CGroup: name=systemd:/system/nginx.service ├─12876 nginx: master process /usr/sbin/nginx -g daemon off; master_process on; ├─12877 nginx: worker process ├─12878 nginx: worker process ├─12879 nginx: worker process └─12880 nginx: worker process # Try with the reload command. Notice how worker PIDs change. root@complexe:~# nginx -s reload root@complexe:~# systemctl status nginx.service nginx.service - A high performance web server and a reverse proxy server […] Main PID: 12876 (nginx) CGroup: name=systemd:/system/nginx.service ├─12876 nginx: master process /usr/sbin/nginx -g daemon off; master_process on; ├─12883 nginx: worker process ├─12884 nginx: worker process ├─12885 nginx: worker process └─12886 nginx: worker process # Trying with systemctl. Notice how worker PIDs change also. root@complexe:~# systemctl reload nginx.service root@complexe:~# systemctl status nginx.service nginx.service - A high performance web server and a reverse proxy server […] Main PID: 12876 (nginx) CGroup: name=systemd:/system/nginx.service ├─12876 nginx: master process /usr/sbin/nginx -g daemon off; master_process on; ├─12892 nginx: worker process ├─12893 nginx: worker process ├─12894 nginx: worker process └─12895 nginx: worker process This is working because nginx writes its PID file anyway. Which is nice. This would also break the nginx upgrade mechanism which is used for package updates (postinst script) in order to upgrade the nginx binary without dropping connections. Using the current approach systemd understands that the pid has changed correctly, probably by monitoring the pid file and the upgrade behaves as expected. Actually there is a patch that will be included in the next release that fixes this behaviour. [1] Indeed, I've made some checks, that confirm a part of this. Type=forking can be removed, but PIDFile must be there, otherwise systemd thinks that since the main process is gone, the whole service should stop. With PIDFile, systemd reload the main PID from the file, and kill every other process if this main PID doesn't exist. So to use nginx special ability to upgrade on-the-fly, at least PIDFile must be used. This would be great if the same PIDFile mentionned in the nginx's conf is used, but I don't actually see how this could be done. And in this case, I don't have any special argument to remove the Type=forking directive, except that it's simpler. Not so convincing ;) -- To UNSUBSCRIBE, email to debian-bugs-dist-requ...@lists.debian.org with a subject of unsubscribe. Trouble? Contact listmas...@lists.debian.org
Bug#728015: [nginx] Don't use type=forking in systemd service file
On Sun, Oct 27, 2013 at 05:32:48PM +0100, Adrien CLERC wrote: Package: nginx Version: 1.4.3-2 Severity: minor --- Please enter the report below this line. --- Hi, In the systemd service file, the two following directive are used: Type=forking PIDFile=/run/nginx.pid However, when running systemd, it's easier to let systemd handle the PID stuff, and tell the program not to fork itself. Moreover, we can have a situation when the user changes the PID file location in the configuration file located at /etc/nginx/nginx.conf Thus, I recommend removing them, and disabling nginx forking with the directive daemon off. See attached unit file. It is of course opened to discussion. I tried to find any side-effect of daemon off, but the documentation doesn't mention any. This would also break the nginx upgrade mechanism which is used for package updates (postinst script) in order to upgrade the nginx binary without dropping connections. Using the current approach systemd understands that the pid has changed correctly, probably by monitoring the pid file and the upgrade behaves as expected. Actually there is a patch that will be included in the next release that fixes this behaviour. [1] [0] http://nginx.org/en/docs/control.html Upgrading Executable on the Fly Section [1] http://anonscm.debian.org/gitweb/?p=collab-maint/nginx.git;a=commitdiff;h=1e277 -- To UNSUBSCRIBE, email to debian-bugs-dist-requ...@lists.debian.org with a subject of unsubscribe. Trouble? Contact listmas...@lists.debian.org
Bug#728015: [nginx] Don't use type=forking in systemd service file
Package: nginx Version: 1.4.3-2 Severity: minor --- Please enter the report below this line. --- Hi, In the systemd service file, the two following directive are used: Type=forking PIDFile=/run/nginx.pid However, when running systemd, it's easier to let systemd handle the PID stuff, and tell the program not to fork itself. Moreover, we can have a situation when the user changes the PID file location in the configuration file located at /etc/nginx/nginx.conf Thus, I recommend removing them, and disabling nginx forking with the directive daemon off. See attached unit file. It is of course opened to discussion. I tried to find any side-effect of daemon off, but the documentation doesn't mention any. Have fun, Adrien --- System information. --- Architecture: i386 Kernel: Linux 3.11-1-686-pae Debian Release: jessie/sid 500 unstable ftp.fr.debian.org 1 experimental ftp.fr.debian.org --- Package information. --- Depends (Version) | Installed =-+-= nginx-common (= 1.4.3-2) | 1.4.3-2 libc6 (= 2.10) | 2.17-93 libpcre3 (= 8.10) | 1:8.31-2 libssl1.0.0 (= 1.0.1) | 1.0.1e-3 zlib1g (= 1:1.1.4) | 1:1.2.8.dfsg-1 Package's Recommends field is empty. Suggests (Version) | Installed =-+- nginx-doc (= 1.4.3-2) | [Unit] Description=A high performance web server and a reverse proxy server After=network.target [Service] ExecStartPre=/usr/sbin/nginx -t -q -g 'daemon off; master_process on;' ExecStart=/usr/sbin/nginx -g 'daemon off; master_process on;' ExecReload=/usr/sbin/nginx -g 'daemon off; master_process on;' -s reload ExecStop=/usr/sbin/nginx -s quit [Install] WantedBy=multi-user.target
Bug#728015: [nginx] Don't use type=forking in systemd service file
Using 'daemon off;' in nginx will likely cause issues when a user wants to run 'nginx -s reload'. The reload signal allows nginx to not drop any connections while bringing up a new config. This is one of the reasons that using supervisord is disliked so much. This is done by opening a new master process that begins taking all of the new connections while the old master is allowed to finish handling old connections. If we turn this off, is it possible for systemd to send nginx the reload signal as opposed to a complete restart? On Sun, 27 Oct 2013 17:32:48 +0100 Adrien CLERC bugs-deb...@antipoul.fr wrote: Package: nginx Version: 1.4.3-2 Severity: minor --- Please enter the report below this line. --- Hi, In the systemd service file, the two following directive are used: Type=forking PIDFile=/run/nginx.pid However, when running systemd, it's easier to let systemd handle the PID stuff, and tell the program not to fork itself. Moreover, we can have a situation when the user changes the PID file location in the configuration file located at /etc/nginx/nginx.conf Thus, I recommend removing them, and disabling nginx forking with the directive daemon off. See attached unit file. It is of course opened to discussion. I tried to find any side-effect of daemon off, but the documentation doesn't mention any. Have fun, Adrien --- System information. --- Architecture: i386 Kernel: Linux 3.11-1-686-pae Debian Release: jessie/sid 500 unstable ftp.fr.debian.org 1 experimental ftp.fr.debian.org --- Package information. --- Depends (Version) | Installed =-+-= nginx-common (= 1.4.3-2) | 1.4.3-2 libc6 (= 2.10) | 2.17-93 libpcre3 (= 8.10) | 1:8.31-2 libssl1.0.0 (= 1.0.1) | 1.0.1e-3 zlib1g (= 1:1.1.4) | 1:1.2.8.dfsg-1 Package's Recommends field is empty. Suggests (Version) | Installed =-+- nginx-doc (= 1.4.3-2) | -- Michael Lustfield -- To UNSUBSCRIBE, email to debian-bugs-dist-requ...@lists.debian.org with a subject of unsubscribe. Trouble? Contact listmas...@lists.debian.org
