Check /etc/hosts file in ipa-server-install

There may already be a record in /etc/hosts for chosen IP address
which may not be detected under some circumstances. Make sure
that /etc/hosts is checked properly.

https://fedorahosted.org/freeipa/ticket/1923

install/tools/ipa-server-install

@@ -796,11 +796,33 @@ def main():
 
         ip = options.ip_address
 
+    ip_add_to_hosts = False
     if ip is None:
         ip = read_ip_address(host_name, fstore)
         logging.debug("read ip_address: %s\n" % str(ip))
+        ip_add_to_hosts = True
+
     ip_address = str(ip)
 
+    # check /etc/hosts sanity, add a record when needed
+    hosts_record = record_in_hosts(ip_address)
+
+    if hosts_record is None:
+        if ip_add_to_hosts:
+            print "Adding ["+ip_address+" "+host_name+"] to your /etc/hosts file"
+            fstore.backup_file("/etc/hosts")
+            add_record_to_hosts(ip_address, host_name)
+    else:
+        primary_host = hosts_record[1][0]
+        if primary_host != host_name:
+            print >>sys.stderr, "Error: there is already a record in /etc/hosts for IP address %s:" \
+                    % ip_address
+            print >>sys.stderr, hosts_record[0], " ".join(hosts_record[1])
+            print >>sys.stderr, "Chosen hostname %s does not match configured canonical hostname %s" \
+                    % (host_name, primary_host)
+            print >>sys.stderr, "Please fix your /etc/hosts file and restart the installation."
+            return 1
+
     if options.reverse_zone and not bindinstance.verify_reverse_zone(options.reverse_zone, ip):
         sys.exit(1)
 

ipaserver/install/bindinstance.py

@@ -394,7 +394,7 @@ class BindInstance(service.Service):
         # get a connection to the DS
         self.ldap_connect()
 
-        if not installutils.record_in_hosts(self.ip_address, self.fqdn):
+        if installutils.record_in_hosts(self.ip_address, self.fqdn) is None:
             installutils.add_record_to_hosts(self.ip_address, self.fqdn)
 
         if not dns_container_exists(self.fqdn, self.suffix, realm=self.realm,

ipaserver/install/installutils.py

@@ -203,7 +203,18 @@ def verify_fqdn(host_name, no_host_dns=False, local_hostname=True):
     else:
         print "Warning: Hostname (%s) not found in DNS" % host_name
 
-def record_in_hosts(ip, host_name, file="/etc/hosts"):
+def record_in_hosts(ip, host_name=None, file="/etc/hosts"):
+    """
+    Search record in /etc/hosts - static table lookup for hostnames
+
+    In case of match, returns a tuple of ip address and a list of
+    hostname aliases
+    When no record is matched, None is returned
+
+    :param ip: IP address
+    :param host_name: Optional hostname to search
+    :param file: Optional path to the lookup table
+    """
     hosts = open(file, 'r').readlines()
     for line in hosts:
         line = line.rstrip('\n')
@@ -217,13 +228,17 @@ def record_in_hosts(ip, host_name, file="/etc/hosts"):
 
             if hosts_ip != ip:
                 continue
-            if host_name in names:
-                return True
+            if host_name is not None:
+                if host_name in names:
+                    return (hosts_ip, names)
+                else:
+                    return None
+            return (hosts_ip, names)
         except IndexError:
             print "Warning: Erroneous line '%s' in %s" % (line, file)
             continue
 
-    return False
+    return None
 
 def add_record_to_hosts(ip, host_name, file="/etc/hosts"):
     hosts_fd = open(file, 'r+')
@@ -242,11 +257,6 @@ def read_ip_address(host_name, fstore):
         else:
             break
 
-    ip = str(ip_parsed)
-    print "Adding ["+ip+" "+host_name+"] to your /etc/hosts file"
-    fstore.backup_file("/etc/hosts")
-    add_record_to_hosts(ip, host_name)
-
     return ip_parsed
 
 def read_dns_forwarders():