Comment 1 for bug 1737022

As a workaround, I forked this charm and added the following to get the custom-config:

templates/my.cnf

{% if custom_config %}
{% for item in custom_config %}
{{item}}
{% endfor %}
{% endif %}

hooks/percona_hooks.py:render_config()

    if config('custom-config'):
        context['custom_config'] = config('custom-config').split(",")

config.yaml

  custom-config:
    type: string
    default:
    description: |
      Comma delineated custom config to make it to my.cnf
      E.x. `"ft_min_word_len=2,otherconfig=otherval"`