Using an HTTP proxy between client browsers connecting to Greenplum Command Center, or between Command Center agents on Greenplum hosts and the Command Center backend, can cause problems updating data in the Command Center Query Monitor. This topic explains how to configure client connections and the Command Center agents to prevent this problem.
With the exception of the Query Monitor, Command Center supports browser access through an HTTP proxy. The Query Monitor, however, uses websocket connections on the front end. The websocket connection will fail if the user's browser is configured to access the Command Center server through an HTTP proxy. Command Center will be unable to update data on the Query Monitor, and the display will be empty with no reported error.
To enable the Query Monitor to work with a client browser configured through an HTTP proxy, either the Command Center hostname must be added to the proxy's exception list, or the HTTP proxy must be disabled for the Command Center browser session.
On some platforms, the proxy configuration is accessed through the browser's settings. On others, MacOS for example, the proxy is configured in the operating system network preferences. See the documentation for your web browser for help configuring the HTTP proxy.
On the backend,
ccagent agent processes running on the Greenplum master and segment hosts connect to the Command Center backend. The agents gather the data, insert it into the database and send the information to the Command Center backend through an HTTP connection. If the
ccagent process is started in a shell session that has
https_proxy environment variables set, the
ccagent connection is redirected to the specified proxy server instead of the Greenplum master host. This prevents the agent from delivering the data that updates the Query Monitor display, and the Query Monitor will be empty.
To prevent the proxy settings from interfering with Command Center backend connections, you can disable the proxy environment variables using one of these methods:
https_proxy environment variable settings from shell startup scripts on the master and all segment hosts. For example, delete commands like the following from
/home/gpadmin/.bash_profile, and any other scripts executed for the gpadmin user.
https_proxy environment variables in the
$GPCC_HOME/bin/start_agent.sh files on the master and all segment hosts.