marsadm: allow --force --host= cleanup on non-joined host

docu/mars-manual.lyx

@@ -17352,6 +17352,33 @@ marsadm delete-resource --force all
 .
 \end_layout
 
+\begin_layout Standard
+\begin_inset Graphics
+	filename images/MatieresCorrosives.png
+	lyxscale 50
+	scale 17
+
+\end_inset
+
+Beware when combining this with 
+\family typewriter
+--host=somebody
+\family default
+.
+ In some very rare cases, like final destruction of a whole datacenter after
+ an earthquake, you might need a combination like 
+\family typewriter
+marsadm --host=defective delete-resource --force all
+\family default
+.
+ Don't use such combinations if you don't need them 
+\emph on
+really
+\emph default
+! You can easily shoot yourself in your head if you are not carefully operating
+ such commands!
+\end_layout
+
 \begin_layout Subsection
 Resource Creation / Deletion / Modification
 \begin_inset CommandInset label
@@ -18177,7 +18204,16 @@ leave-resource
 \family typewriter
 --force
 \family default
-, increasing the danger to maximum!
+, increasing the danger to maximum! It is even possible to combine 
+\family typewriter
+--force
+\family default
+ with an invalid resource argument and an invalid 
+\family typewriter
+--host=somebodyelse
+\family default
+ argument in order to desperately try to destroy remains of incomplete or
+ pysically damaged hardware.
 \end_layout
 
 \begin_layout Plain Layout
@@ -26855,7 +26891,19 @@ Wait until
 all
 \emph default
  nodes in the cluster have sent a message, or until timeout.
- The default timeout is 30 s (exceptionally) and may be changed by
+ The default timeout is 30 s (exceptionally) and
+\size default
+
+\begin_inset Graphics
+	filename images/MatieresCorrosives.png
+	lyxscale 50
+	scale 17
+
+\end_inset
+
+Be
+\size scriptsize
+ may be changed by
 \family typewriter
  --timeout=$seconds
 \end_layout

userspace/marsadm

@@ -373,7 +373,10 @@ sub check_id {
   ldie "identifier '$str' is too long (only 63 chars supported according to RFC 1123)" if length($str) > 63;
   if (defined($must_exist) && $must_exist) {
     my $ip_path = "$mars/ips/ip-$str";
-    ldie "host '$str' does not exist in $mars/ips/" unless get_link($ip_path, 1);
+    unless (get_link($ip_path, 1)) {
+      ldie "host '$str' does not exist in $mars/ips/\n" if !$force;
+      lwarn "host '$str' does not exist in $mars/ips/ - hopefully you know what you are doing via --force\n";
+    }
   }
 }
 
@@ -4893,8 +4896,7 @@ foreach my $arg (@ARGV) {
     $threshold = get_size($arg);
     next;
   } elsif ($arg =~ s/--host\s*=\s*([-_A-Za-z0-9]+)/$1/) {
-    check_id($arg);
-    ldie "host '$arg' does not exist in /mars/ips/ip-*\n" unless -l "/mars/ips/ip-$arg";
+    check_id($arg, 1);
     if ($arg ne $host) {
       lprint "ATTENTION: acting as if I were host '$arg'\n";
       lwarn "some commands require local knowledge not available here.\n";