install: Call hostnamectl set-hostname only if --hostname option is used

This commit also splits hostname backup and configuration into two separate
functions. This allows us to backup hostname without setting it at the
same time.

https://fedorahosted.org/freeipa/ticket/6071

Reviewed-By: Jan Cholasta <jcholast@redhat.com>

client/ipa-client-install

@@ -2525,7 +2525,8 @@ def install(options, env, fstore, statestore):
     if options.hostname and not options.on_master:
         # skip this step when run by ipa-server-install as it always configures
         # hostname
-        tasks.backup_and_replace_hostname(fstore, statestore, options.hostname)
+        tasks.backup_hostname(fstore, statestore)
+        tasks.set_hostname(options.hostname)
 
     ntp_srv_servers = []
     if not options.on_master and options.conf_ntp:

doc/guide/guide.org

@@ -1039,14 +1039,14 @@ def restore_context_default(filepath):
 # version in platform services
 restore_context = restore_context_default
 
-# Default implementation of backup and replace hostname that does nothing
-def backup_and_replace_hostname_default(fstore, statestore, hostname):
+# Default implementation of backup hostname that does nothing
+def backup_hostname_default(fstore, statestore):
     return
 
-# Backup and replace system's hostname
-# Since many platforms have their own way how to store system's hostname, this method must be
+# Backup system's hostname
+# Since many platforms have their own way of handling system's hostname, this method must be
 # implemented in platform services
-backup_and_replace_hostname = backup_and_replace_hostname_default
+backup_hostname = backup_hostname_default
 
 from ipapython.platform.SUPPORTED_PLATFORM import *
 #+END_SRC

ipaplatform/base/tasks.py

@@ -45,14 +45,11 @@ class BaseTaskNamespace(object):
 
         raise NotImplementedError()
 
-    def backup_and_replace_hostname(self, fstore, statestore, hostname):
+    def backup_hostname(self, fstore, statestore):
         """
         Backs up the current hostname in the statestore (so that it can be
         restored by the restore_hostname platform task).
 
-        Makes sure that new hostname (passed via hostname argument) is set
-        as a new pemanent hostname for this host.
-
         No return value expected.
         """
 
@@ -109,7 +106,7 @@ class BaseTaskNamespace(object):
     def restore_hostname(self, fstore, statestore):
         """
         Restores the original hostname as backed up in the
-        backup_and_replace_hostname platform task.
+        backup_hostname platform task.
         """
 
         raise NotImplementedError()

ipaplatform/redhat/tasks.py

@@ -332,22 +332,13 @@ class RedHatTaskNamespace(BaseTaskNamespace):
 
         return result
 
-    def backup_and_replace_hostname(self, fstore, statestore, hostname):
-        old_hostname = socket.gethostname()
-        try:
-            self.set_hostname(hostname)
-        except ipautil.CalledProcessError as e:
-            root_logger.debug(traceback.format_exc())
-            root_logger.error(
-                "Failed to set this machine hostname to %s (%s).",
-                old_hostname, e
-            )
-
+    def backup_hostname(self, fstore, statestore):
         filepath = paths.ETC_HOSTNAME
         if os.path.exists(filepath):
             fstore.backup_file(filepath)
 
         # store old hostname
+        old_hostname = socket.gethostname()
         statestore.backup_state('network', 'hostname', old_hostname)
 
     def restore_hostname(self, fstore, statestore):

ipaserver/install/server/install.py

@@ -651,6 +651,7 @@ def install_check(installer):
     options.dm_password = dm_password
     options.master_password = master_password
     options.admin_password = admin_password
+    options._host_name_overridden = bool(options.host_name)
     options.host_name = host_name
     options.ip_addresses = ip_addresses
 
@@ -702,11 +703,10 @@ def install(installer):
         print("Please wait until the prompt is returned.")
         print("")
 
-    # configure /etc/sysconfig/network to contain the custom hostname
-    tasks.backup_and_replace_hostname(fstore, sstore, host_name)
-
-    # set hostname (we need both transient and static)
-    tasks.set_hostname(host_name)
+    # set hostname (transient and static) if user instructed us to do so
+    if options._host_name_overridden:
+        tasks.backup_hostname(fstore, sstore)
+        tasks.set_hostname(host_name)
 
     if installer._update_hosts_file:
         update_hosts_file(ip_addresses, host_name, fstore)