Handle read timeouts from etcd when watching a key.

buildman/manager/ephemeral.py

@@ -7,6 +7,7 @@ import os.path
 from datetime import datetime, timedelta
 from trollius import From, coroutine, Return, async
 from concurrent.futures import ThreadPoolExecutor
+from urllib3.exceptions import ReadTimeoutError
 
 from buildman.manager.basemanager import BaseManager
 from buildman.manager.executor import PopenExecutor, EC2Executor
@@ -65,7 +66,11 @@ class EphemeralBuilderManager(BaseManager):
       # Due to lack of interest, tomorrow has been cancelled
       return
 
-    etcd_result = changed_key_future.result()
+    try:
+      etcd_result = changed_key_future.result()
+    except ReadTimeoutError:
+      return
+
     if etcd_result.action == ETCD_EXPIRE_RESULT:
       # Handle the expiration
       logger.debug('Builder expired, clean up the old build node')