Technical Tip: Restarting internal processes/daemons

Description

This article describes how to force-restart internal processes and daemons without restarting the whole unit.

Scope

FortiGate, FortiMail.

Solution

Some internal processes get stuck under certain conditions, or it is required to force them to reload in order to release memory and CPU resources.

On FortiMail, use the command below:

execute reload <daemon_name>

On FortiGate, the most common daemons can be restarted by using 'diagnose' command:

diagnose test application <daemon_name> 99 

When the above procedures do not show the process has restarted, then it could be necessary to kill the process.

The kill instruction should be used as a last resort before a reboot of the unit.

The format of the command to use is:

diagnose sys kill <sig_term> <pid>

The process ID (pid) could be taken from the second column of the command 'diagnose sys top'.

For example:

diagnose sys top
Run Time:  2 days, 16 hours and 48 minutes
0U, 0S, 100I; 442T, 154F, 127KF
scanunitd      519      R       4.7     3.2
ipsengine       63      S <     0.0     8.4
pyfcgid      511      S       0.0     4.9

In this example, the 'ipsengine' process has the PID '63'.

Although the <sig_term> is mostly the same as those used on Unix/Unix-like platforms, is recommended to use only SIGSEGV (11), SIGINT (2), SIGTERM(15) or SIGKILL(9) in that order.

SIGSEGV (11): is used to terminate the process and dump a crash exit into the crashlog (diag debug crashlog read). This is helpful for troubleshooting that process.

SIGINT (2): is used, for example, when the user hits 'Ctrl-C' on the keyboard to end a process.

SIGTERM (15): is a 'polite' termination signal, asking the process to close connections, files, handlers, buffers, etc. For device stability is the recommended way to end a process.

SIGKILL (9): This is a mandatory termination of the process. This signal could not be ignored by the system (except by specific conditions where the system is waiting for the process to free physical I/O resources). This kind of signal could leave sessions and files open.

In the above example, to kill process 'ipsengine', it is possible to perform the following:

diagnose sys kill 11 63

Note: Alternatively, to kill or restart all related processes at once, can be done using the following 'killall' command:

fnsysctl killall <process name> 
fnsysctl killall httpsd

fnsysctl killall httpsd <-- It will restart all httpsd processes at once.

Note: The command 'fnsysctl' requires Super Admin Privilege. Otherwise, FortiGate will return an error, as explained in Troubleshooting Tip: fnsysctl command returns Unknown action 0.

Related articles:

Technical Tip: How to list processes in FortiOS

Technical Tip:Diagnose sys top CLI command

Technical Tip: Find and restart/kill a process on a FortiGate by the process ID (PID) via pidof 

Troubleshooting Tip: fnsysctl command returns Unknown action 0