In Zend Framework 2 Zend\Log\Writer\Syslog contains a bug where _facility gets overwritten by the current object which leads to subsequent openlog() calls to fail.

A patch to fix this can be found on https://github.com/zendframework/zf2/pull/137 and is given below:

--- a/library/Zend/Log/Writer/Syslog.php
+++ b/library/Zend/Log/Writer/Syslog.php
@@ -105,7 +105,7 @@ class Syslog extends AbstractWriter

         $runInitializeSyslog = true;
         if (isset($params['facility'])) {
-            $this->_facility = $this->setFacility($params['facility']);
+            $this->setFacility($params['facility']);
             $runInitializeSyslog = false;
         }