hostmaster-migrate fails from alpha2 to alpha8 on remote db servers

On top of marvelous problems with drush_make, I had a lot of fun making the alpha2 -> alpha8 upgrade on solaris. Everything was going well up to hostmaster-resume. I was able to salvage this part of the logfile:

Drush bootstrap phase : _drush_bootstrap_drupal_configuration()      [bootstrap]
[61.81 sec, 4.83 MB]
Drush bootstrap phase : _drush_bootstrap_drupal_database() [61.81    [bootstrap]
sec, 4.84 MB]
Successfully connected to the Drupal database. [61.81 sec, 4.84 MB]  [bootstrap]
Drush bootstrap phase : _drush_bootstrap_drupal_full() [61.81 sec,   [bootstrap]
4.84 MB]
Drush bootstrap phase : _drush_bootstrap_drupal_login() [61.81 sec,  [bootstrap]
4.84 MB]
Found command: hosting-setup (commandfile=hosting) [61.81 sec, 4.84  [bootstrap]
MB]
Warning: The command callback function hosting_setup has a deprecated   [notice]
name.  It must begin with drush_hosting_.  Skipping hook functions.
[61.81 sec, 4.84 MB]
Dispatch command could not be run. Returned:                         [error]
Could not find a Drupal settings.php file at
[error]
./sites/default/settings.php.
The drush command 'hosting-dispatch' could not be found.
         [error] [61.81 sec, 4.84 MB]
The command did not complete successfully, please fix the issues and [error]
re-run this script [61.81 sec, 4.84 MB]
Command dispatch complete [61.81 sec, 4.84 MB]                          [notice]
Peak memory usage was 11.6 MB [61.81 sec, 4.84 MB]                      [memory]
An error occurred at function : drush_hosting_hostmaster_resume      [error]
[61.81 sec, 4.84 MB]
Command dispatch complete [61.81 sec, 4.84 MB]                          [notice]
Peak memory usage was 13.49 MB [61.81 sec, 4.84 MB]                     [memory]
This command will replace your crontab for this user. continue? (y/n): y
/var/aegir/drush/drush.php hosting-dispatch --root='/var/aegir/hostmaster-HEAD' --uri='aegir.example.com'
An error occurred at function :                                      [error]
drush_provision_post_hostmaster_migrate [61.81 sec, 4.54 MB]
Command dispatch complete [61.81 sec, 4.53 MB]                          [notice]
Peak memory usage was 5 MB [61.81 sec, 4.53 MB]                         [memory]

Notice how hosting-dispatch is called with the wrong --root argument: that should be /var/aegir/hostmaster-0.4-alpha8, that's where the site was migrated to earlier.

Now it seems there's a problem with the services on the server. Running tasks fails in hosting:

# /usr/local/bin/php /var/aegir/drush/drush.php --php=/usr/local/bin/php   --root='/var/aegir/hostmaster-0.4-alpha8' --uri='http://aegir.example.com' hosting-task '582' --debug
PHP Warning:  Module 'mcrypt' already loaded in Unknown on line 0
Drush bootstrap phase : _drush_bootstrap_drupal_root() [0.21 sec,    [bootstrap]
3.45 MB]
Loading drushrc "/var/aegir/hostmaster-0.4-alpha8/drushrc.php" into  [bootstrap]
"drupal" scope. [0.21 sec, 3.45 MB]
Initialized Drupal 6.17 root directory at                               [notice]
/var/aegir/hostmaster-0.4-alpha8 [0.24 sec, 4.19 MB]
Drush bootstrap phase : _drush_bootstrap_drupal_site() [0.28 sec,    [bootstrap]
4.19 MB]
Initialized Drupal site aegir.example.com at sites/aegir.example.com    [notice]
[0.28 sec, 4.19 MB]
Loading drushrc                                                      [bootstrap]
"/var/aegir/hostmaster-0.4-alpha8/sites/aegir.example.com/drushrc.php"
into "site" scope. [0.28 sec, 4.19 MB]
Drush bootstrap phase : _drush_bootstrap_drupal_configuration() [0.32[bootstrap]
sec, 4.34 MB]
Drush bootstrap phase : _drush_bootstrap_drupal_database() [0.36 sec,[bootstrap]
4.35 MB]
Successfully connected to the Drupal database. [0.36 sec, 4.35 MB]   [bootstrap]
Drush bootstrap phase : _drush_bootstrap_drupal_full() [0.41 sec,    [bootstrap]
4.61 MB]
Found command: hosting-task (commandfile=hosting) [0.76 sec, 11.14   [bootstrap]
MB]
Initializing drush commandfile: drush_make [0.76 sec, 11.14 MB]      [bootstrap]
Initializing drush commandfile: drush_make_d_o [0.76 sec, 11.14 MB]  [bootstrap]
Initializing drush commandfile: provision [0.76 sec, 11.14 MB]       [bootstrap]
Initializing drush commandfile: provision_apache [0.76 sec, 11.14 MB][bootstrap]
Initializing drush commandfile: provision_drupal [0.76 sec, 11.14 MB][bootstrap]
Initializing drush commandfile: provision_mysql [0.76 sec, 11.14 MB] [bootstrap]
Including profiles/hostmaster/modules/hosting/task.hosting.inc [0.76 [bootstrap]
sec, 11.15 MB]
The drush command hook naming conventions have changed; the function     [error]
drush_hosting_hosting_task_validate must be renamed to
drush_hosting_task_validate.  The old function will be called, but
this will be removed shortly. [0.76 sec, 11.17 MB]
The drush command hook naming conventions have changed; the function     [error]
drush_hosting_hosting_task must be renamed to drush_hosting_task. 
The old function will be called, but this will be removed shortly.
[0.77 sec, 11.18 MB]
Drush bootstrap phase : _drush_bootstrap_drupal_login() [0.77 sec,   [bootstrap]
11.19 MB]
Task starts processing [0.79 sec, 11.48 MB]                              [queue]

Fatal error: Call to a member function options() on a non-object in /var/aegir/hostmaster-0.4-alpha8/profiles/hostmaster/modules/hosting/db_server/hosting_db_server.drush.inc on line 8

That line is:

      $server->services['db']->options($task->task_type, $task->ref->type, $task

... so I guess that those services on the main server were not setup properly during the upgrade.