mkcephfs: require -k; update man page

Force users to specify keyring location; update man page accordingly.

Signed-off-by: Sage Weil <sage@newdream.net>

man/mkcephfs.8

@@ -5,6 +5,7 @@ mkcephfs \- create a ceph file system
 .B mkcephfs
 [ \fB\-a\fP ]
 [ \fB\-c\fP\fI ceph.conf\fP ]
+[ \fB\-k\fI /path/to/keyring.bin\fP ]
 [ \fB\-\-clobber_old_data\fP ]
 [ \fB\-\-mkbtrfs\fP ]
 .SH DESCRIPTION
@@ -23,6 +24,9 @@ executing commands via SSH.
 \fB\-c\fI ceph.conf\fR, \fB\-\-conf=\fIceph.conf\fR
 Use the given conf file instead of the default \fI/etc/ceph/ceph.conf\fP.
 .TP
+\fB\-k\fI /path/to/keyring.bin\fR
+Location to write the client.admin keyring, which is used to administer the cluster.  The default is \fI/etc/ceph/keyring.bin\fP, but must still be specified explicitly.
+.TP
 \fB\-\-clobber_old_data\fR
 Overwrite any existing data found in monitor or osd paths.
 .TP

src/mkcephfs.in

@@ -90,6 +90,11 @@ if [ $allhosts -eq 0 ]; then
     usage_exit
 fi
 
+if [ -z "$adminkeyring" ]; then
+    echo "mkcephfs requires '-k /path/to/admin/keyring'. default location is /etc/ceph/keyring.bin."
+    usage_exit
+fi
+
 verify_conf
 
 get_name_list "$@"