diff --git a/collectd/files/plugin/collectd_base.py b/collectd/files/plugin/collectd_base.py
index 4a9842a..4e6eaff 100644
--- a/collectd/files/plugin/collectd_base.py
+++ b/collectd/files/plugin/collectd_base.py
@@ -165,15 +165,12 @@
             non-zero status code (default=True).
 
         Returns:
-            A tuple containing the standard output and error strings if the
-            program execution has been successful.
+            A tuple containing the return code, the standard output and the
+            standard error if the program has been executed.
 
-            ("foobar\n", "")
+            (0, "foobar\n", "")
 
-            (None, "stderr of the command") if the command returned a
-            non-zero status code.
-
-            (None, None) if the command couldn't be executed at all.
+            (-1, None, None) if the program couldn't be executed at all.
         """
         start_time = time.time()
         try:
@@ -189,24 +186,19 @@
         except Exception as e:
             self.logger.error("Cannot execute command '%s': %s : %s" %
                               (cmd, str(e), traceback.format_exc()))
-            return (None, None)
+            return (-1, None, None)
 
         returncode = proc.returncode
 
-        if returncode != 0:
-            if log_error:
-                self.logger.error("Command '%s' failed (return code %d): %s" %
-                                  (cmd, returncode, stderr))
-            return (None, stderr)
+        if returncode != 0 and log_error:
+            self.logger.error("Command '%s' failed (return code %d): %s" %
+                              (cmd, returncode, stderr))
         if self.debug:
             elapsedtime = time.time() - start_time
             self.logger.info("Command '%s' returned %s in %0.3fs" %
                              (cmd, returncode, elapsedtime))
 
-        if not stdout and self.debug:
-            self.logger.info("Command '%s' returned no output!", cmd)
-
-        return (stdout, stderr)
+        return (returncode, stdout, stderr)
 
     def execute_to_json(self, *args, **kwargs):
         """Executes a program and decodes the output as a JSON string.
@@ -217,12 +209,12 @@
             A Python object or
             None if the execution of the program or JSON decoding fails.
         """
-        outputs = self.execute(*args, **kwargs)
-        if outputs:
+        (retcode, out, err) = self.execute(*args, **kwargs)
+        if retcode == 0:
             try:
-                return json.loads(outputs[0])
+                return json.loads(out)
             except ValueError as e:
-                self.logger.error("{}: document: '{}'".format(e, outputs[0]))
+                self.logger.error("{}: document: '{}'".format(e, out))
 
     @staticmethod
     def restore_sigchld():
diff --git a/collectd/files/plugin/collectd_glusterfs.py b/collectd/files/plugin/collectd_glusterfs.py
index 344d5b5..9b03e8f 100644
--- a/collectd/files/plugin/collectd_glusterfs.py
+++ b/collectd/files/plugin/collectd_glusterfs.py
@@ -59,9 +59,9 @@
 
     def itermetrics(self):
         # Collect peers' metrics
-        out, err = self.execute([GLUSTER_BINARY, 'peer', 'status'],
-                                shell=False)
-        if not out:
+        retcode, out, err = self.execute([GLUSTER_BINARY, 'peer', 'status'],
+                                         shell=False)
+        if retcode != 0:
             raise base.CheckException("Failed to execute 'gluster peer'")
 
         total = 0
@@ -107,8 +107,8 @@
 
         # Collect volumes' metrics
         cmd = [GLUSTER_BINARY, 'volume', 'status', 'all', 'detail']
-        out, err = self.execute(cmd, shell=False, log_error=False)
-        if not out:
+        retcode, out, err = self.execute(cmd, shell=False, log_error=False)
+        if retcode != 0:
             if err and vol_status_transaction_in_progress_re.match(err):
                 # "transaction already in progress" error, we assume volumes
                 # metrics are being collected on another glusterfs node, and
diff --git a/collectd/files/plugin/collectd_pacemaker.py b/collectd/files/plugin/collectd_pacemaker.py
index 682c100..87dc470 100644
--- a/collectd/files/plugin/collectd_pacemaker.py
+++ b/collectd/files/plugin/collectd_pacemaker.py
@@ -73,9 +73,9 @@
                 return 1
             return 0
 
-        out, err = self.execute([self.crm_mon_binary, '--as-xml', '-r', '-f'],
-                                shell=False)
-        if not out:
+        retcode, out, err = self.execute(
+            [self.crm_mon_binary, '--as-xml', '-r', '-f'], shell=False)
+        if retcode != 0:
             raise base.CheckException(
                 "Failed to execute crm_mon '{}'".format(err))