You don't want wait for all players to sleep, and you don't want to spend time configuring a plugin ? SimpleSleep !
- Needs simpleCore, but you don't have to worry about that (see https://github.com/telec16/simpleCore)
- Can be used with https://www.spigotmc.org/resources/actionbarapi-1-8-1-14-2.1315/
- Put the jar files in your plugin folder
- Reload the server
- Change
config.yml - Issue the
/updatecommand - Enjoy !