Github user dyozie commented on a diff in the pull request:
https://github.com/apache/incubator-hawq-docs/pull/97#discussion_r105239316
--- Diff: markdown/admin/ambari-admin.html.md.erb ---
@@ -368,6 +348,49 @@ All of the listed steps are mandatory. This ensures
that HAWQ service remains fu
4. Restart HAWQ service to propagate the configuration change to all
Ambari agents.
This will synchronize the password on the host machines with the
password that you specified in Ambari.
+
+## <a id="manual-cfg-norestart"></a>Updating HAWQ Configuration Without
Cluster Restart
+There may be circumstances, such as during dynamic cluster expansion, when
you must update HAWQ configuration parameters but cannot tolerate cluster
downtime in your Ambari-managed cluster. In these situations, perform the
following workaround to update and reload HAWQ configuration changes without a
complete cluster restart.
+
+**Note**: Use this procedure for setting or updating only those HAWQ
server configuration parameters with a set classification of reload.
+
+1. Use the Ambari console UI to set and save the desired HAWQ
configuration parameter(s) via the **HAWQ** service **Settings**, **Configs
>Settings**, and/or **Configs >Advanced** tabs. Make sure to note the
configuration parameter names and new values. You may need to hover the mouse
over the configuration field to identify the HAWQ parameter name.
+
+ **Note**: After updating the configuration parameters, do *not*
restart the HAWQ service.
+
+1. Use HAWQ command line utilities to update the same HAWQ configuration
parameters:
+ 1. Log in to the HAWQ master host as a HAWQ administrator and source
greenplum_path.sh:
+
+ ``` shell
+ $ ssh gpadmin@<master>
+ gpadmin@master$ source /usr/local/hawq/greenplum_path.sh
+ ```
+
+ 2. Identify the current value of the HAWQ configuration parameter:
+
+ ``` shell
+ gpadmin@master$ hawq config -s <parameter_name>
+ ```
+
+ 3. Set the configuration parameter to the new value:
+
+ ``` shell
+ gpadmin@master$ hawq config -c <parameter_name> -v <new_value>
+ ```
+
+ Perform Steps 2 and 3 for each configuration parameter you set or
updated via Ambari.
+
+3. Reload the HAWQ configuration; this operation does not restart the
cluster:
+
+ ``` shell
+ gpadmin@master$ hawq stop cluster --reload
+ ```
+
+4. Verify that each parameter was updated:
+
+ ```shell
+ gpadmin@master$ hawq config -s <parameter_name>
+ ```
--- End diff --
Seems like this section also needs a closing sentence about when the
changes refresh in Ambari?
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