https://fedorahosted.org/freeipa/ticket/4551

See ticket & commit message for details.

--
PetrĀ³
From 2247f62f84ae098451b57fd274b1c87be61ff507 Mon Sep 17 00:00:00 2001
From: Petr Viktorin <pvikt...@redhat.com>
Date: Fri, 19 Sep 2014 15:57:44 +0200
Subject: [PATCH] ipa-replica-prepare: Wait for the DNS entry to be resolvable

It takes some time after the DNS record is added until it propagates
to Bind. In automated installations, it might happen that
replica-install is attempted before the hostname is resolvable;
in that case the connection check would fail.

Wait for the name to be resolvable at the end of replica-prepare.
Mention that this can be interrupted (Ctrl+C).
Provide an option to skip the wait.

In case DNS is not managed by IPA, this reminds the admin of the necessary
configuration and checks their work, but it's possible to skip (either by
interrupting it interactively, or by the option).

https://fedorahosted.org/freeipa/ticket/4551
---
 ipaserver/install/ipa_replica_prepare.py | 38 ++++++++++++++++++++++++++++++++
 1 file changed, 38 insertions(+)

diff --git a/ipaserver/install/ipa_replica_prepare.py b/ipaserver/install/ipa_replica_prepare.py
index 2e91ddd92d9eb9ccd690daa1c78d9027f1b0b965..91117b9f1c3e301c68ccd1146023d05e9998fac4 100644
--- a/ipaserver/install/ipa_replica_prepare.py
+++ b/ipaserver/install/ipa_replica_prepare.py
@@ -24,6 +24,8 @@
 from optparse import OptionGroup
 from ConfigParser import SafeConfigParser
 
+import dns.resolver
+
 from ipaserver.install import certs, installutils, bindinstance, dsinstance
 from ipaserver.install.replication import enable_replication_version_checking
 from ipaserver.plugins.ldap2 import ldap2
@@ -64,6 +66,9 @@ def add_options(cls, parser):
         parser.add_option("--ca", dest="ca_file", default=paths.CACERT_P12,
             metavar="FILE",
             help="location of CA PKCS#12 file, default /root/cacert.p12")
+        parser.add_option('--no-wait-for-dns', dest='wait_for_dns',
+            action='store_false', default=True,
+            help="do not wait until the replica is resolvable in DNS")
 
         group = OptionGroup(parser, "SSL certificate options",
             "Only used if the server was installed using custom SSL certificates")
@@ -290,6 +295,8 @@ def run(self):
         if options.ip_address:
             self.add_dns_records()
 
+        self.wait_for_dns()
+
     def copy_ds_certificate(self):
         options = self.options
 
@@ -452,6 +459,37 @@ def add_dns_records(self):
                 raise admintool.ScriptError(
                     "Could not add reverse DNS record for the replica: %s" % e)
 
+    def check_dns(self):
+        """Return true if the replica hostname is resolvable"""
+        resolver = dns.resolver.Resolver()
+        exceptions = dns.resolver.NXDOMAIN, dns.resolver.NoAnswer
+
+        try:
+            dns_answer = resolver.query(self.replica_fqdn, 'A', 'IN')
+        except exceptions:
+            try:
+                dns_answer = resolver.query(self.replica_fqdn, 'AAAA', 'IN')
+            except exceptions:
+                return False
+
+        return True
+
+    def wait_for_dns(self):
+        options = self.options
+
+        if not options.wait_for_dns or self.check_dns():
+            return
+
+        self.log.info('Waiting for hostname %s to be resolvable',
+                      self.replica_fqdn)
+        print 'This can be safely interrupted (Ctrl+C)'
+
+        try:
+            while not self.check_dns():
+                pass
+        except KeyboardInterrupt:
+            self.log.info('Interrupted')
+
     def copy_info_file(self, source, dest):
         """Copy a file into the info directory
 
-- 
1.9.3

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