Concerning the first question, I tried:
- Using a remote URL
- Specifying an external (local) path e.g
/home/user_name/synonyms.txt
Both of this approaches didn't work mainly for security reasons (more details here and here)
Now I'll try to use docker volume and see hos it goes.
Update:
Yes, docker volumes solved my problem, In docker-compose.yml I mounted the directory containing synonyms files (host) to /usr/share/elasticsearch/config/synonyms inside ES docker image using the shot syntax.
Hope this helps someone else.