Configure affinity during server installation

Write a new krb5.conf in case any values changed finding the
right server to configure against (e.g. for CA, KRA) and
ensure the API connection is to the remote server that
will be installed against.

When finding a CA or KRA during initial replica installation
set the remote master as well. The order is:

 - existing server value in /etc/ipa/default.conf
 - the chosen CA host if the server doesn't provide one
 - the chosen KRA host if the server doesn't provide one

This is more or less heirarchical. If a server is provided
then that is considered first. If it provides all the
optional services needed (CA and/or KRA) then it will
be used. Otherwise it will fall back to a server that provides
all the required services.

In short, providing --server either at client install or
with ipa-replica-install is no guarantee that it will
define all topology. This may be unexpected behavior.

For the case of adding a CA or KRA things are effectively
unchanged. This type of install does not appear to be
impacted by affinity issues.

Fixes: https://pagure.io/freeipa/issue/9289

Signed-off-by: Rob Crittenden <rcritten@redhat.com>
Reviewed-By: Alexander Bokovoy <abokovoy@redhat.com>

ipaserver/masters.py

@@ -127,6 +127,8 @@ def find_providing_servers(svcname, conn=None, preferred_hosts=(), api=api):
             )
         else:
             servers.insert(0, host_name)
+    logger.debug("Discovery: available servers for service '%s' are %s",
+                 svcname, ', '.join(servers))
     return servers
 
 
@@ -143,8 +145,11 @@ def find_providing_server(svcname, conn=None, preferred_hosts=(), api=api):
         svcname, conn=conn, preferred_hosts=preferred_hosts, api=api
     )
     if not servers:
+        logger.debug("Discovery: no '%s' service found.", svcname)
         return None
     else:
+        logger.debug("Discovery: using %s for '%s' service",
+                     servers[0], svcname)
         return servers[0]