Not to pull the base images when building.

Add --pull/--nopull parameter for kolla-build, when --nopull is
given and the base image is already loaded, The docker-engine will
not attemp to pull a newer version of the image. This makes sense
when the registry server of base images is unreachable.

This feature is as same to setting "image_pull_policy" to
"IfNotPresent" while building images.

The reason why I create this feature is that, even if I have setted
base_distro_tag to a stable tag, e.g. "7" or "2016-12-13", docker
still have to wait much time to fetch the version, and return failure
when registry server is unreachable. This is a feature of docker
build --pull=True.

Change-Id: If1bd08763fb757b4f090a3163dd1dbfb8fc531d3
Implements: blueprint docker-build-nopull-base

kolla/common/config.py

@@ -205,6 +205,8 @@ _CLI_OPTS = [
     cfg.StrOpt('template-override',
                help='Path to template override file'),
     cfg.StrOpt('logs-dir', help='Path to logs directory'),
+    cfg.BoolOpt('pull', default=True,
+                help='Attempt to pull a newer version of the base image.'),
 ]
 
 _BASE_OPTS = [

kolla/image/build.py

@@ -401,7 +401,7 @@ class BuildTask(DockerTask):
             tar.add(plugins_path, arcname='plugins')
 
         # Pull the latest image for the base distro only
-        pull = True if image.parent is None else False
+        pull = self.conf.pull if image.parent is None else False
 
         buildargs = self.update_buildargs()
         try:

releasenotes/notes/docker-build-nopull-base-a860d046b9059cfc.yaml

@@ -0,0 +1,6 @@
+---
+features:
+  - Add --pull/--nopull parameter for kolla-build, when --nopull is given and
+    the base image is already loaded, The docker-engine will not attempt to
+    pull a newer version of the image. This makes sense when the registry
+    server of base images is unreachable.