Cleanup metadata-proxy when old versions are present

The metadata proxy service will now be cleaned up when this role is
executed if an old version of the metadata-proxy is still running.
Once the old versions of the metadata-proxy have been cleaned up
the metadata agent will respawn the correct process within 60 seconds.

This change is required to ensure upgrades are always executing the
correct code from a given release.

Change-Id: I3a0b5c5b75742f06a94e5334c749b88e54f7f43c
Signed-off-by: Kevin Carter <kevin.carter@rackspace.com>

handlers/main.yml

@@ -20,4 +20,20 @@
     pattern: "{{ item.value.service_name }}"
   with_dict: "{{ neutron_services }}"
   failed_when: false
+  notify:
+    - Run ns-metadata-proxy process cleanup
   when: item.value.service_en | bool
+
+# NOTE(cloudnull):
+# When installing or upgrading it is possible that an old metadata proxy process will not
+#  be restarted by the metadata agent when a version changes. To fix it the ns-metadata
+#  proxy pids are killed if they're not running the current tag. Once the old processeses
+#  are removed the metadata agent will respawn the missing process within 60 seconds using
+#  the correct code.
+- name: Run ns-metadata-proxy process cleanup
+  shell: |
+    for ns_pid in $(pgrep neutron-ns-meta); do
+      (echo $(readlink -f "/proc/$ns_pid/exe") | grep -qv "{{ neutron_venv_tag }}") && \
+        (echo "old metadata proxy pid found running clean up on $ns_pid"; kill -9 "$ns_pid")
+    done
+  when: neutron_services['neutron-metadata-agent'].service_en | bool

releasenotes/notes/metadata-proxy-cleanup-eed6ff482035dc83.yaml

@@ -0,0 +1,10 @@
+---
+fixes:
+  - When upgrading it is possible for an old "neutron-ns-metadata-proxy"
+    process to remain running in memory. If this happens the old version of
+    the process can cause unexpected issues in a production environment. To
+    fix this a task has been added to the os_neutron role that will execute
+    a process lookup and kill any "neutron-ns-metadata-proxy" processes that
+    are not running the current release tag. Once the old processes are
+    removed the metadata agent running will respawn everything needed within
+    60 seconds.