How to pass the command "--overwrite-conf" in ubuntu terminal?

Add option after ceph-deploy:

ceph-deploy --overwrite-conf mon create-initial 

You started ceph with the command:

ceph-deploy mon create-initial

So to pass the additional parameter --overwrite-conf, you just append it to your previous command:

ceph-deploy mon create-initial --overwrite-conf

That's all the magic. Maybe you should google for a beginner's Linux command-line tutorial.

Enter the following command to get command syntax for --overwrite-conf :

$ ceph-deploy --overwrite-conf usage: ceph-deploy [-h] [-v | -q] [--version] [--username USERNAME] [--overwrite-conf] [--ceph-conf CEPH_CONF] COMMAND ...

The response does not state this but 'COMMAND' stands

'new', 'install', 'mds', 'mgr', 'mon', 'rgw', 'gatherkeys', 'disk', 'osd', 'admin', 'config', 'repo', 'purge', 'purgedata', 'uninstall', 'calamari', 'forgetkeys', 'pkg')

Typical usage of the --overwrite-conf is to re-execute the 'ceph-deploy admin ..' command so the syntax would be:

$ ceph-deploy --overwrite-conf admin mon01 osd01 osd02 osd03

where mon01 is replaced by the hostname of your monitor node and osd01,osd02,osd03 are replaced by the hostname of your osd nodes