Before kinit, try to sync time with the NTP servers of the domain we are joining

When running ipa-client-install on a system whose clock is not in sync
with the master, kinit fails and enrollment is aborted. Manual checking
of current time at the master and adjusting on the client-to-be is then
needed.

The patch tries to fetch SRV records for NTP servers of the domain we aim
to join and runs ntpdate to get time synchronized. If no SRV records are
found, sync with IPA server itself.  If that fails, warn that time might
be not in sync with KDC.

https://fedorahosted.org/freeipa/ticket/1773

1 files changed, 21 insertions, 0 deletions

diff --git a/ipa-client/ipaclient/ipadiscovery.py b/ipa-client/ipaclient/ipadiscovery.py
index 3e31cad37..cd5f81bd5 100644
--- a/ipa-client/ipaclient/ipadiscovery.py
+++ b/ipa-client/ipaclient/ipadiscovery.py
@@ -316,6 +316,27 @@ class IPADiscovery:
 
         return servers
 
+    def ipadnssearchntp(self, tdomain):
+        servers = ""
+        rserver = ""
+
+        qname = "_ntp._udp."+tdomain
+        # terminate the name
+        if not qname.endswith("."):
+            qname += "."
+        results = ipapython.dnsclient.query(qname, ipapython.dnsclient.DNS_C_IN, ipapython.dnsclient.DNS_T_SRV)
+
+        for result in results:
+            if result.dns_type == ipapython.dnsclient.DNS_T_SRV:
+                rserver = result.rdata.server.rstrip(".")
+                if servers:
+                    servers += "," + rserver
+                else:
+                    servers = rserver
+                break
+
+        return servers
+
     def ipadnssearchkrb(self, tdomain):
         realm = None
         kdc = None