1. Bypassing the White Screen of Death (WSOD)
When a WordPress site crashes with an HTTP 500 Fatal Memory Exhaustion error (`Allowed memory size of 268435456 bytes exhausted`), the standard web interface becomes completely inaccessible. Diagnosing the issue via SSH and WP-CLI bypasses Apache/Nginx timeouts, allowing engineers to probe the application state directly from the server CLI.
# Bypass active theme/plugins to regain control
wp plugin deactivate --all --skip-plugins --skip-themes
# Profile loading times to identify the exact bottleneck hook
wp profile stage --all --spotlight2. Isolating Rogue Hooks via Strace
If WP-CLI itself fails due to memory exhaustion, engineers must trace the underlying PHP-FPM worker processes at the operating system level. By attaching `strace` to the active PHP process, we can observe the exact file read/write operations and system calls looping infinitely.
# Find the active PHP-FPM worker process ID
ps aux | grep php-fpm
# Attach strace to observe infinite loops or hanging file descriptors
strace -p 12345 -s 2000 -e trace=open,read,write3. Enforcing Strict Resource Governance
Once the offending plugin or theme hook is identified and neutralized, permanent stability requires enforcing strict PHP resource governance. This involves configuring aggressive PHP-FPM `request_terminate_timeout` directives and isolating heavy background cron jobs into a dedicated CLI execution pool to protect frontend traffic.