A daemon is a process that runs in the background on Unix systems and is comparable to what Windows calls a service. To see a list of Zenoss Core daemons, navigate to Advanced | Settings | Daemons. For each daemon, we see the process ID (PID), Log File, Configuration, State, and Actions, as shown in the following screenshot:

We've been working with these daemons from the very beginning through our actions within the Zenoss UI. As we look over the list of daemons, we can speculate about what some of these processes are responsible for. For example, zensyslog processes syslogs, zenmodeler creates the model of our devices based on the plugins defined for each device, and zenping monitors device availability.

We usually turn to the daemons when we're curious or troubleshooting. Click on the view log link to display the log file for each daemon. We can also find the logs by browsing the $ZENHOME/log directory.

If we want to override the default daemon behavior, we can edit the configuration by clicking on the edit config link, and naturally, the view config link displays the current configuration. To view the available options for each daemon, open a command line environment and type the name of the daemon followed by the word help. To see zenmodeler's options, we type:

zenmodeler help

The syntax we use to enter command parameters and values via the web interface varies from the way we specify options on the command line. As an example, let's increase zenmodeler's logging level from the default INFO to a more verbose DEBUG. On the command line, we use the following command as the Zenoss User:

zenmodeler restart --logseverity=4

If we use the edit config link via the Daemons page, all the possible options, with descriptions are displayed by the interface. To, set zenmodeler to log in debug mode, find the logseverity option, and choose Debug from the drop-down list. See the following screenshot:

Don't forget to click the restart button for the zenmodeler daemon to pass the new configuration to the daemon. To view the results of our change, click on the view log link and scroll to the bottom. We see the results of our action and our logs now show debugging messages.

Each of the daemon configuration files can be found in the $ZENHOME/etc directory, and we can edit them with a text editor if we so choose.