ts-xen-install: Rewrite /etc/hosts to comment out 127.0.1.1 entry

Debian creates an entry such as:
127.0.1.1             lace-bug.xs.citrite.net         lace-bug

This causes local lookups of the FQDN to get 127.0.1.1, which is
unhelpful if you are looking for an address to bind to and were hoping
to get the public IP address, as libvirt does on the target host for
migration.

Here we remove (actually, comment) any 127.0.1.1 line in /etc/hosts.
This means that lookups of a hosts own name (fqdn or just dn) now rely
on DNS, which may not be ideal. However for a host which uses DHCP I'm
not aware of a way to keep /etc/hosts up to date with the actual IP
address the machine has.  In our infra the test host IP addresses are
all static, but I don't think we want to rely on at any more that we
already do.

Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
Acked-by: Ian Jackson <ian.jackson@eu.citrix.com>

diff --git a/ts-xen-install b/ts-xen-install
index 070e74ded120185f8cbe699889afbe994a4c308e..b511e2b03cfa42b28825e702ab49177b36549a84 100755 (executable)
--- a/ts-xen-install
+++ b/ts-xen-install
@@ -230,6 +230,23 @@ END
     target_cmd_root($ho, $cmd);
 }
 
+sub hosts () {
+    # Debian installer generates a line like:
+    #
+    # 127.0.1.1             lace-bug.xs.citrite.net         lace-bug
+    #
+    # Where xs.citrite.net is $c{TestHostDomain} and lace-bug is the
+    # hostname, this causes lookups of the hosts FQDN to result in
+    # 127.0.1.1 which is not useful if the reason for the lookup was
+    # to be able to bind to the externally accessible IP address.
+    target_editfile_root($ho, "/etc/hosts", "etc-hosts", sub {
+        while (<EI>) {
+           s|^\Q127.0.1.1\E\b|#$&|;
+           print EO;
+        }
+    });
+}
+
 sub nodhcp () {
     target_editfile_root($ho, "/etc/network/interfaces",
                          "etc-network-interfaces", sub {
@@ -351,4 +368,5 @@ if ($checkmode) {
     setupboot();
     setupinitd();
     nodhcp();
+    hosts();
 }