SOP: Restart, Verify and Diagnose a LAMP + Gunicorn Box

Published August 09, 2026

The commands, in the order you actually need them, for a box running Apache in front of a Python app.

Restart and reload

sudo systemctl reload apache2      # config changes - no dropped connections
sudo systemctl restart apache2     # when reload is not enough
sudo systemctl status apache2      # is it up, and what did it last say
sudo apache2ctl configtest         # ALWAYS before restarting

Reload before restart. A reload re-reads configuration without dropping connections; a restart drops them. configtest first, always — a syntax error found by restart is a syntax error found by an outage.

For the app itself:

sudo systemctl restart aios
sudo systemctl status aios
sudo journalctl -u aios -n 100 --no-pager

Enable a module

apache2ctl -M | grep headers       # is it loaded
sudo a2enmod headers
sudo systemctl reload apache2

What is actually listening

sudo ss -tlnp

This is the answer to "is my app port exposed", and it is the only trustworthy one. Trying to reach http://your-site:8000 from a browser tab on an HTTPS page gets blocked as mixed content before the request leaves the machine — three clean-looking failures that prove nothing at all.

Read the bind address. 127.0.0.1:8000 means loopback only and Apache is the sole route in. 0.0.0.0:8000 means the internet can reach your app directly.

Where the errors are

sudo tail -n 100 /var/log/apache2/error.log
sudo tail -f /var/log/apache2/access.log

A PHP fatal lands in the Apache error log, not in the response. A 500 with an empty body almost always means the script died before it produced output — a failed require, an uncaught exception at the top of the file. The response tells you nothing; the log has the line number.

Permissions after a deploy

sudo chown -R www-data:www-data /var/www/html/some/path
sudo chmod 600 /var/www/.env

Secrets get 600 and belong above the docroot, not in it.

A deploy checklist that catches the usual failures

1. configtest before touching the service.
2. Reload, do not restart, unless you must.
3. curl -sI the site and read the headers that came back.
4. Load one real page and check the console, not just the status code.
5. Check the error log even when it looks fine.

The rule worth keeping

Everything in this list answers a question about the running system. That is why they are the commands worth memorising.

Written from Kevin's own working notes and formatted with the help of AIOS, then reviewed before publishing.

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