diff --git a/roles/haproxy/templates/haproxy.cfg b/roles/haproxy/templates/haproxy.cfg
index f461a776c3..222be82584 100644
--- a/roles/haproxy/templates/haproxy.cfg
+++ b/roles/haproxy/templates/haproxy.cfg
@@ -225,7 +225,10 @@ listen  openqa 0.0.0.0:10044
 listen  pdc 0.0.0.0:10045
     balance hdr(appserver)
     server  pdc-web01 pdc-web01:80 check inter 10s rise 1 fall 2
-    server  pdc-web02 pdc-web02:80 check inter 10s rise 1 fall 2
+## pdc-web02 is commented out because we don't currently know how to configure
+## mod_auth_mellon to work when distributed across more than one app node.  It
+## expects to be able to share some state between requests in-process.  Boo.
+#    server  pdc-web02 pdc-web02:80 check inter 10s rise 1 fall 2
     option  httpchk GET /rest_api/v1/
     timeout server 3600000
     timeout connect 3600000