Variables or at least better defaults for PHP pm.* settings

[t3easy]

The default values for

pm.max_children
pm.start_servers
pm.min_spare_servers
pm.max_spare_servers

are not usable in production in most Nextcloud installations.

In the new docs, there is a part that these settings should be changed depending on the available resources:
https://docs.nextcloud.com/server/26/admin_manual/installation/server_tuning.html#tune-php-fpm

Older docs had some example values:
https://docs.nextcloud.com/server/21/admin_manual/installation/server_tuning.html#tune-php-fpm

If these settings are not changed, the Nextcloud no longer responds when the load increases.

[pool www] server reached pm.max_children setting (5), consider raising it

The docker image should provide better defaults for PHP pm.* settings and environment variables to change them without building the image.

[J0WI]

Duplicate of #1969

[rugk]

I think this issue is not actually a real duplicate IMHO. Could not you e.g.:

• configure these settings to at least somewhat higher number?
• at the first start of the container automatically calculate a value that is considered to be "good" (e.g. based on the ram or whatever) likely in a shell script
• or, maybe in addition, include, if possible, a check for a good value in the Nextcloud "health/system check" admin page (would be am issue for the Nextcloud php project itself of course, however)?

[J0WI]

There is some attempt in #1766 and #1964. We can't make any assumption about the host system. This may range from a tiny SOC board to a large root server and from single purpose hosts to one that shares it's resources with many other services. There is no "good" default or at least I'm not aware of a "good" way to calculate it.

[t3easy]

@J0WI I would assume that a docker host has at least 4 GB RAM and is dedicated for the Nextcloud stack. If this parameters can be changed for larger or smaller hosts by environment variables like the PHP memory and upload limit https://github.com/nextcloud/docker/blob/master/26/fpm-alpine/Dockerfile#L81 this should be a good solution.
Otherwise you force the users to build an own image extending Nextcloud or mount a config into the container.

[t3easy]

This is what I did:

FROM nextcloud:${NEXTCLOUD_VERSION}-fpm-alpine

# ...

ENV PHP_PM_MAX_CHILDREN=5
ENV PHP_PM_START_SERVERS=2
ENV PHP_PM_MIN_SPARE_SERVERS=1
ENV PHP_PM_MAX_SPARE_SERVERS=3

RUN set -eux; \
    { \
        echo '[www]'; \
        echo 'pm.max_children = ${PHP_PM_MAX_CHILDREN}'; \
        echo 'pm.start_servers = ${PHP_PM_START_SERVERS}'; \
        echo 'pm.min_spare_servers = ${PHP_PM_MIN_SPARE_SERVERS}'; \
        echo 'pm.max_spare_servers = ${PHP_PM_MAX_SPARE_SERVERS}'; \
    } | tee "/usr/local/etc/php-fpm.d/zz-pm.conf"

The defaults are those from /usr/local/etc/php-fpm.d/www.conf so there is no change for existing installations. I cloud provide a PR if you like.

[skl256]

@t3easy Thank you very mush! My problem (freeze when rewinding video) solved!