diff --git a/zuul/launcher/ansiblelaunchserver.py b/zuul/launcher/ansiblelaunchserver.py
index d5dc355..61ef88e 100644
--- a/zuul/launcher/ansiblelaunchserver.py
+++ b/zuul/launcher/ansiblelaunchserver.py
@@ -847,8 +847,10 @@
         )
         (out, err) = self.ansible_proc.communicate()
         for line in out.split('\n'):
+            line = line[:1024]
             self.log.debug("Ansible stdout: %s" % line)
         for line in err.split('\n'):
+            line = line[:1024]
             self.log.debug("Ansible stderr: %s" % line)
         ret = self.ansible_proc.wait()
         self.ansible_proc = None
@@ -865,8 +867,10 @@
         )
         (out, err) = proc.communicate()
         for line in out.split('\n'):
+            line = line[:1024]
             self.log.debug("Ansible post stdout: %s" % line)
         for line in err.split('\n'):
+            line = line[:1024]
             self.log.debug("Ansible post stderr: %s" % line)
         return proc.wait() == 0