Run nova-conductor in native threading mode

Previous patches removed direct eventlet usage from nova-conductor so
now we can run it with native threading as well. This patch documents
the possibility and switches both nova-conductor process to native
threading mode in the nova-next job.

Change-Id: If26c0c7199cbda157f24b99a419697ecb6618fa6
Signed-off-by: Balazs Gibizer <gibi@redhat.com>

.zuul.yaml

@@ -497,6 +497,8 @@
         'SYSTEMD_ENV_VARS["n-sch"]': OS_NOVA_DISABLE_EVENTLET_PATCHING=true
         'SYSTEMD_ENV_VARS["n-api"]': OS_NOVA_DISABLE_EVENTLET_PATCHING=true
         'SYSTEMD_ENV_VARS["n-api-meta"]': OS_NOVA_DISABLE_EVENTLET_PATCHING=true
+        'SYSTEMD_ENV_VARS["n-cond-cell1"]': OS_NOVA_DISABLE_EVENTLET_PATCHING=true
+        'SYSTEMD_ENV_VARS["n-super-cond"]': OS_NOVA_DISABLE_EVENTLET_PATCHING=true
       devstack_services:
         # Disable OVN services
         br-ex-tcpdump: false

doc/source/admin/concurrency.rst

@@ -27,8 +27,8 @@ threading mode at service startup via setting the environment variable
 
 .. note::
 
-   Since nova 32.0.0 (2025.2 Flamingo) the nova-scheduler, nova-metadata, and
-   nova-api can be switched to native threading mode.
+   Since nova 32.0.0 (2025.2 Flamingo) the nova-scheduler, nova-metadata,
+   nova-api, and nova-conductor can be switched to native threading mode.
 
 
 Tunables for the native threading mode

releasenotes/notes/threaded-nova-conductor-5bc7a09a7f48480d.yaml

@@ -0,0 +1,10 @@
+---
+features:
+  - |
+    The nova-conductor services now can be run in native threading
+    mode instead of with eventlet. This is an experimental feature that is
+    disabled by default. Please test the native threading mode in
+    pre-production before enabling it in production. Please read the
+    `concurrency <https://docs.openstack.org/nova/latest/admin/concurrency.html>`__
+    guide for more details.
+