System Power and Switch Reboot

Cumulus Linux provides commands to:

• Reboot the switch
• Power off the switch
• Power cycle the switch

Switch Reboot

Cumulus Linux provides these reboot modes:

• cold restarts the system and resets all the hardware devices on the switch (including the switching ASIC). This is the default restart mode on the switch.

• fast restarts the system more efficiently with minimal impact to traffic by reloading the kernel and software stack without a hard reset of the hardware. During a fast restart, the system decouples from the network to the extent possible using existing protocol extensions before recovering to the operational mode of the system. The switch restarts the kernel and software stack without touching the forwarding entries or the switching ASIC; therefore, the data plane is not affected as the software stack restarts. Traffic outage is much lower in this mode as there is a momentary interruption after reboot, while the system reinitializes.

• warm restarts the switch with no interruption to traffic for existing route entries and without a hardware reset of the switch ASIC. While this process does not affect the data plane, the control plane is absent during restart and is unable to process routing updates. Warm reboot mode reduces all the available forwarding table entries on the switch by half to accommodate traffic forwarding during a reboot.

  When you restart the switch in warm reboot mode, BGP only performs a graceful restart if the BGP graceful restart option is set to full. To set BGP graceful restart to full, run the nv set router bgp graceful-restart mode full command, then apply the configuration with nv config apply. For more information about BGP graceful restart, refer to Optional BGP Configuration.

  In an eBGP multihop configuration with warm reboot mode, you must set the BGP graceful restart timer to 180 seconds or more.

NVIDIA recommends you use NVUE commands to configure reboot mode and reboot the system. If you prefer to use csmgrctl commands, you must stop NVUE from managing the /etc/cumulus/csmgrd.conf file before you set reboot mode.

1. Run the following NVUE commands:

   cumulus@switch:~$ nv set system config apply ignore /etc/cumulus/csmgrd.conf
   cumulus@switch:~$ nv config apply
   

2. Edit the /etc/cumulus/csmgrd.conf file and set the csmgrctl_override option to true:

   cumulus@switch:~$ sudo nano /etc/cumulus/csmgrd.conf
   csmgrctl_override=true
   ...
   

3. Save the configuration:

   cumulus@switch:~$ nv config save
   

The following commands configure the switch to restart in cold mode:

cumulus@switch:~$ nv set system reboot mode cold
cumulus@switch:~$ nv config apply

cumulus@switch:~$ nv action reboot system no-confirm

cumulus@switch:~$ sudo csmgrctl -c

cumulus@switch:~$ sudo reboot

The following command configures the switch to restart in fast mode:

cumulus@switch:~$ nv set system reboot mode fast
cumulus@switch:~$ nv config apply

cumulus@switch:~$ nv action reboot system no-confirm

cumulus@switch:~$ sudo csmgrctl -f

cumulus@switch:~$ sudo reboot

The following command configures the switch to restart in warm mode.

cumulus@switch:~$ nv set system reboot mode warm
cumulus@switch:~$ nv config apply

cumulus@switch:~$ nv action reboot system no-confirm

cumulus@switch:~$ sudo csmgrctl -w

cumulus@switch:~$ sudo reboot

Show Reboot Mode

You can confirm the current operational reboot mode active on the switch with the nv show system reboot command. The command also shows reboot information, such as the reboot date and time, and reason:

cumulus@switch:~$ nv show system reboot
           operational                       applied
---------  --------------------------------  -------
reason                                              
  reason   Unknown                                  
  gentime  2025-05-16T16:08:27.798068+00:00         
  user     system/root                              
mode       warm                               warm   
required   no

Power Off

In certain situations, you might need to power off the switch instead of rebooting. To power off the switch, run the cl-poweroff command, which shuts down the switch.

cumulus@switch:~$ sudo cl-poweroff

You can also run the Linux poweroff command, which gracefully shuts down the switch (the switch LEDs stay on). On certain switches, such as the NVIDIA SN2201, SN2010, SN2100, SN2100B, SN3420, SN3700, SN3700C, SN4410, SN4600C, SN4600, SN4700, SN5400, or SN5600, the switch reboots instead of powering off.

cumulus@switch:~$ sudo poweroff

Power Cycle

NVUE provides the nv action power-cycle system command so that you can power cycle the switch remotely to recover from certain conditions, such as a thermal ASIC shutdown due to high temperatures.

When you run the nv action power-cycle system command, the switch prompts you for confirmation before power cycling.

cumulus@switch:~$ nv action power-cycle system
The operation will Power Cycle the switch.
Type [y] to power cycle.
Type [N] to abort.

Do you want to continue? [y/N]  
Action executing ... 
Action succeeded 

To power cycle the switch without prompts for confirmation, run the nv action power-cycle system force command:

cumulus@switch:~$ nv action power-cycle system force 
Action executing ... 
Action succeeded