listen = 127.0.0.1:9000 its breaking-change

[Kutuzovska]

After updating the php-fpm-alpine Docker image
php-fpm started listening on 127.0.0.1:9000 instead of 0.0.0.0:9000.

As a result, nginx running in a separate container could no longer connect to php-fpm, causing 502 errors and complete service downtime.

[Kutuzovska]

Damn, I'm sorry, we figured it out deeper.

It turned out that we have had our own project for a long time. www.conf with the following contents:

[www]
user = www-data
group = www-data
listen = 127.0.0.1:9000
pm = dynamic
pm.max_children = 30
pm.start_servers = 10
...

And he makes his way into the image:

COPY ./deploy/www.conf "$PHP_INI_DIR/../php-fpm.d/www.conf"

Before fixing the build, we just didn't notice it. #1635

After the update, the configuration:

; the [www] ini section below is for backwards compatibility and will be removed in 8.6+
[www]

As a result, our www.conf it became the main source of pool settings, and php-fpm started listening only to 127.0.0.1:9000 inside the container. Because of this, it has become unavailable to external nginx running in another container.