Allow overriding php-fpm params by ansible variables

[tangrufus]

Allow overriding php-fpm params by ansible variables.

Related: https://discourse.roots.io/t/overriding-php-fpm-config-best-practice/10101

[tangrufus]

When adding this to the docs, I think we should add links to tutorials about finding these php fpm pm values. Setting them too high would raise memory issues.

[swalkinshaw]

These defaults might be better defined in roles/php/defaults/main.yml. This template already uses php_display_errors which is from there.

@fullyint do you have an opinion on this?

[fullyint]

I tend to think that these variable defaults are appropriate here in the wordpress-setup role given that the vars are used in wordpress-setup role and not in the php role. In contrast, it appears that php_display_errors is used in both roles.

Although users could intuit that roles/php/defaults/main.yml holds all the php configs, I think the real function of a role's default/main.yml is to hold defaults for variables used in the role, not to hold configs for a service generally (e.g., php generally).

For comparison, I added some nginx-related vars to roles/wordpress-setup/defaults in the past with the justification that the vars were only used in the wordpress-setup role.

[swalkinshaw]

Thanks @tangrufus 👍

[partounian]

This is very helpful as I was going to modify the values directly myself. Quick question, what is the reason we use a 3rd party PHP 7.1 repo instead of the official one?