I am new to GIS and I am trying to deploy my own off-line map server. I have found very interesting open source tools like: geoserver. I have downloaded OpenStreetMap data from geofabrik.de
In the packages I downloaded from geofabrik we find different layers with diffrent information: landuse, natural, places, railways ... but not the base map i.e: the geographic map with country border and no other information.
My question is: How can I get (download) this base map layer in order to use it off-line?
Thanks for any help.