How to get MaaS Regional controller IP/FQDN in preseed files via {{var}}?

temp0 · 15 October 2024 15:41

Hello
Is it possible to get REGION controller IP/FQDN via variables in preseed files?
I am able to get RACK controller used for booting during deployment {{node.boot_cluster_ip}} but unable to find the way how to get region one directly from preseed file (maas cli can’t be used).
Is it possible? Thank you!

troyanov · 16 October 2024 09:41

Hi @temp0

I wonder if server_host can be helpful?

github.com

canonical/maas/blob/7d46cdeed46e438d02318ac67baec51f61bf3240/src/maasserver/preseed.py#L945


      
          """Return the node-independent context dictionary to be used to render
          preseed templates.
          
          :param osystem: See `get_preseed_filenames`.
          :param release: See `get_preseed_filenames`.
          :param rack_controller: The rack controller used to generate the preseed.
          :return: The context dictionary.
          :rtype: dict.
          """
          region_ip = get_default_region_ip(request)
          server_host = get_maas_facing_server_host(
              rack_controller=rack_controller, default_region_ip=region_ip
          )
          server_url = request.build_absolute_uri(reverse("machines_handler"))
          configs = Config.objects.get_configs(["remote_syslog", "maas_syslog_port"])
          syslog = configs["remote_syslog"]
          http_proxy = get_apt_proxy(request, rack_controller)
          if not syslog:
              syslog_port = configs["maas_syslog_port"]
              if not syslog_port:
                  syslog_port = RSYSLOG_PORT

temp0 · 17 October 2024 17:54

Hello Anton @troyanov
Thank you for your response.
Before I created this question I checked exactly same file you provided and tried all vars which included “region” word nearby so I tried “region_ip”, “http_proxy” and other ones from this file but all of them returned empty string or that it is not defined at all:

Failed to render preseed: name 'region_ip' is not defined at line 13 column 3 in file /etc/maas/preseeds/curtin_userdata_rhel_amd64_generic

I am impressed that “server_host” and “server_url” returns non-empty string but “region_ip” fail the preseed, totally weird. I am almost sure I also tested “server_host” or definitely “default_region_ip” as it is part of it but it returned error that it is not defined.
Don’t understand region_ip can’t be used but server_host works (from the context of preseed.py file) but great there is something usable, thanks!
I need to test it in environment with non-region controllers as well to check it really returns region and not rack/boot controller as I just tested it only in env with only one region controller.
Thank you very much for tip and if someone else knows why server_host works but not others in preseed.py, it will be great (to understand what vars can be used without testing each of them randomly but get failures in most cases )

troyanov · 18 October 2024 08:36

You can access values by keys that are exposed in get_preseed_context and get_node_preseed_context functions. There is also get_node_deprecated_preseed_context but as the name says it is already deprecated and can be removed in the future releases.

temp0 · 18 October 2024 09:18

Don’t understand how is it possible I totally oversight this “return” part during search/grep/whatever
Thank you

system · 20 October 2024 09:19

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