Switch to ZooKeeper backed NodesProvisionedEvents

This puts the NodesProvisionedEvents into ZooKeeper. With this, all
result events are now in ZooKeeper.

To make the NodesProvisionedEvent serializable, we cannot store the
whole NodeRequest object in the event anymore. Instead we are using the
request.id, job name and the buildset UUID to look up the corresponding
NodeRequest object from the buildset when the NodesProvisionedEvent is
handled.

As a result of this we have to find a way to return the NodeSet even in
case the NodeRequest or the buildset cannot be found anymore (e.g. due
to a gate reset). In this case we look up the NodeRequest directly from
ZooKeeper and provide a faked NodeSet which allows us to retrieve the
node information from Zookeeper (via the update mechanism of the
NodeRequest in the Nodepool client).

Finally, we can get rid of the local result event queue in the scheduler
as now all result events are in ZooKeeper. Together with that the
`zuul.scheduler.eventqueues.result` gauge was also removed.

Change-Id: Ib5e0f13d25a21ebad908d38f0201e92b704a1c85

1 files changed, 1 insertions, 4 deletions

diff --git a/web/src/pages/Status.jsx b/web/src/pages/Status.jsx
index 38490a923..ac3dc7840 100644
--- a/web/src/pages/Status.jsx
+++ b/web/src/pages/Status.jsx
@@ -171,10 +171,7 @@ class StatusPage extends React.Component {
         }</span> events,&nbsp;
         <span>{status.management_event_queue ?
           status.management_event_queue.length : '0'
-        }</span> management events,&nbsp;
-        <span>{status.result_event_queue ?
-          status.result_event_queue.length : '0'
-        }</span> results.
+        }</span> management events.
       </p>
     )
   }