How to fix the NGINX error “Failed to read PID from file”, quick and easy

Here’s a tip on how to fix the error message:

nginx.service: Failed to read PID from file /run/nginx.pid: Invalid argument

quick and easy. This fix should do it for you.

This behavior is a known bug, caused by a race condition between nginx and systemd. Systemd is expecting the PID file to be populated before nginx had the time to create it.

To fix the error, you have basically two options.

Option 1: create the PID file

To fix the error, you have to create the PID file manually.

Step 1. Create the directory /etc/systemd/system/nginx.service.d

Create a directory named nginx.service.d in /etc/systemd/system/:

mkdir /etc/systemd/system/nginx.service.d

Should the system complain that it already exists, ignore and  move on to Step 2.

Step 2. Print data to file

Execute:

printf "[Service]\nExecStartPost=/bin/sleep 0.1\n" > /etc/systemd/system/nginx.service.d/override.conf

This is a one-liner. printf will write its output into the configuration file /etc/systemd/system/nginx.service.d/override.conf.

Step 3. Reload the daemon

Reload systemd manager configuration:

systemctl daemon-reload

This will rerun all generators, reload all unit files and recreate the entire systemd dependency tree.

Step 4. Restart NGINX

This line will restart NGINX for you:

systemctl restart nginx

The error should be fixed now.

Option 2: an alternative workaround

Another workaround is removing the PIDFile option and adding the line:

ExecStopPost=/bin/rm -f /run/nginx.pid

 

You can find the full documentation of this bug at:

https://bugs.launchpad.net/ubuntu/+source/nginx/+bug/1581864

If you experience this problem, SELinux could be preventing php-fpm from accessing a port. Just a hint. Try

journalctl -xe

for guidance on your next steps.