Allow custom ubuntu is_reachable_timeout

Default timeout of 900 seconds which is suitable for upstream CI
is too long for downstream CI. This patch allows configuring a custom
value for ubuntu is_reachable_timeout.

Change-Id: If33991b0b932d7615f7072a4c2121fde4d5bcdc8

tobiko/openstack/nova/config.py

@@ -28,6 +28,9 @@ OPTIONS = [
     cfg.StrOpt('key_type',
                default=DEFAULT_KEY_TYPE,
                help="Default SSH key type to login to server instances"),
+    cfg.FloatOpt('ubuntu_is_reachable_timeout',
+             default=900.0,
+             help="Timeout (in seconds) till ubuntu server is reachable")
 ]
 
 

tobiko/openstack/stacks/_ubuntu.py

@@ -46,6 +46,7 @@ class UbuntuMinimalImageFixture(glance.URLGlanceImageFixture):
     password = CONF.tobiko.ubuntu.password or 'ununtu'
     connection_timeout = CONF.tobiko.ubuntu.connection_timeout or 1500.
     disabled_algorithms = CONF.tobiko.ubuntu.disabled_algorithms
+    is_reachable_timeout = CONF.tobiko.nova.ubuntu_is_reachable_timeout
 
 
 IPERF3_SERVICE_FILE = """
@@ -208,8 +209,9 @@ class UbuntuServerStackFixture(UbuntuMinimalServerStackFixture,
     #: Glance image used to create a Nova server instance
     image_fixture = tobiko.required_fixture(UbuntuImageFixture)
 
-    # I expect Ubuntu based servers to be slow to boot
-    is_reachable_timeout = 900.
+    @property
+    def is_reachable_timeout(self) -> float:
+        return self.image_fixture.is_reachable_timeout
 
     # port of running HTTP server
     @property