Smart System Manager
Use Smart System Manager, also known as ISSU, to upgrade and troubleshoot an active switch with minimal disruption to the network.
Smart System Manager includes the following modes:
- The Smart System Manager is supported on Spectrum 1, 2 and 3 ASICs only.
- The Smart System Manager NCLU commands do not require a
The Smart System Manager requires the
kexec-tools package, which is installed on the switch when you install a new Cumulus Linux image. However, upgrading the switch with
apt-get does not install the
To verify that the
kexec-tools package is installed on the switch, run the following command:
cumulus@switch:~$ net show package version
To install the
kexec-tools package, run the following commands:
cumulus@switch:~$ sudo -E apt-get update cumulus@switch:~$ sudo -E apt-get install kexec-tools
You can restart the switch in one of the following modes.
coldcompletely restarts the system and resets all the hardware devices on the switch (including the switching ASIC).
fastrestarts 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 is decoupled from the network to the extent possible using existing protocol extensions before recovering to the operational mode of the system. The forwarding entries of the switching ASIC are maintained through the restart process and the data plane is not affected. The data plane is only interrupted when
switchdresets and reconfigures the ASIC if the SDK is upgraded. Traffic outage is significantly lower in this mode.
The following command restarts the system in cold mode:
cumulus@switch:~$ net system maintenance restart cold
cumulus@switch:~$ sudo csmgrctl -c
The following command restarts the system in fast mode:
cumulus@switch:~$ net system maintenance restart fast
cumulus@switch:~$ sudo csmgrctl -f
Upgrade mode updates all the components and services on the switch to the latest Cumulus Linux release without traffic loss. After upgrade is complete, you must restart the switch with either a cold or fast restart.
Upgrade mode includes the following options:
apt-get upgradeto upgrade all the system components to the latest release without affecting traffic flow. You must restart the system after the upgrade completes with one of the restart modes.
dry-runprovides information on the components that will be upgraded.
The following command upgrades all the system components:
cumulus@switch:~$ net system maintenance upgrade all
cumulus@switch:~$ sudo csmgrctl -u
The following command provides information on the components that will be upgraded:
cumulus@switch:~$ net system maintenance upgrade dry-run
cumulus@switch:~$ sudo csmgrctl -d
Maintenance mode isolates the system from the rest of the network so that you can perform intrusive troubleshooting tasks and data collection or perform system changes, such as break out ports and replace optics or cables with minimal disruption.
Depending on your configuration and network topology, complete isolation might not be possible.
Enable Maintenance Mode
Run the following command to enable maintenance mode. When maintenance mode is enabled, Smart System Manager performs a graceful BGP shutdown, redirects traffic over the peerlink and brings down the MLAG port link.
switchd maintains full capability.
cumulus@switch:~$ net system maintenance mode enable
cumulus@switch:~$ sudo csmgrctl -m1
You can run additional commands to bring all the ports down, then up to restore the port admin state.
cumulus@switch:~$ net system maintenance ports down cumulus@switch:~$ net system maintenance ports up
cumulus@switch:~$ sudo csmgrctl -p0 cumulus@switch:~$ sudo csmgrctl -p1
Before you disable maintenance mode, be sure to bring the ports back up.
Disable Maintenance Mode
Run the following command to disable maintenance mode and restore normal operation. When maintenance mode is disabled, Smart System Manager performs a soft restart, runs a BGP graceful restart, and brings the MLAG port link back up.
switchd maintains full capability.
cumulus@switch:~$ net system maintenance mode disable
cumulus@switch:~$ sudo csmgrctl -m0
Show Maintenance Mode Status
To see if maintanance mode is enabled or disabled, run the NCLU
net system maintenance show status command or the Linux
sudo csmgrctl -s command. For example:
cumulus@switch:~$ net system maintenance show status Current System Mode: Maintenance since Tue Jan 5 00:13:37 2021 (Duration: 00:00:31) Boot Mode: reboot_cold 2 registered modules frr : Maintenance, down switchd : Maintenance, down