The new V3 spec let’s you create volumes backed by config maps
You can also used the “files” section to specify text files which will be created and placed at specified locations in the workload (using a config map but that’s transparent to the charm).
See Writing a Kubernetes charm - #5 by jacins
files:
- name: configurations
mountPath: /etc/mysql/conf.d
files:
custom_mysql.cnf: |
[mysqld]
skip-host-cache
skip-name-resolve
query_cache_limit = 1M
query_cache_size = %(query-cache-size)s