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Cumulus Linux

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If you are using the current version of Cumulus Linux, the content on this page may not be up to date. The current version of the documentation is available here. If you are redirected to the main page of the user guide, then this page may have been renamed; please search for it there.

Upgrading Cumulus Linux

This topic describes how to upgrade Cumulus Linux on your switch.

Consider deploying, provisioning, configuring, and upgrading switches using automation, even with small networks or test labs. During the upgrade process, you can quickly upgrade dozens of devices in a repeatable manner. Using tools like Ansible, Chef, or Puppet for configuration management greatly increases the speed and accuracy of the next major upgrade; these tools also enable the quick swap of failed switch hardware.

Before You Upgrade

Be sure to read the knowledge base article Upgrades: Network Device Worldview and Linux Host Worldview Comparison, which provides a detailed comparison between the network device and Linux host worldview of upgrade and installation.

Back up Configuration Files

Understanding the location of configuration data is required for successful upgrades, migrations, and backup. As with other Linux distributions, the /etc directory is the primary location for all configuration data in Cumulus Linux. The following list is a likely set of files that you need to back up and migrate to a new release. Make sure you examine any file that has been changed. Consider making the following files and directories part of a backup strategy.

File Name and Location Explanation Cumulus Linux Documentation Debian Documentation
/etc/network/ Network configuration files, most notably /etc/network/interfaces and /etc/network/interfaces.d/ Switch Port Attributes N/A
/etc/resolv.conf DNS resolution Not unique to Cumulus Linux: wiki.debian.org/NetworkConfiguration https://www.debian.org/doc/manuals/debian-reference/ch05.en.html
/etc/frr/ Routing application (responsible for BGP and OSPF) FRRouting Overview N/A
/etc/hostname Configuration file for the hostname of the switch Quick Start Guide https://wiki.debian.org/HowTo/ChangeHostname
/etc/hosts Configuration file for the hostname of the switch Quick Start Guide https://wiki.debian.org/HowTo/ChangeHostname
/etc/cumulus/acl/* Netfilter configuration Netfilter - ACLs N/A
/etc/cumulus/ports.conf Breakout cable configuration file Switch Port Attributes N/A; read the guide on breakout cables
/etc/cumulus/switchd.conf switchd configuration Configuring switchd N/A; read the guide on switchd configuration
File Name and Location Explanation Cumulus Linux Documentation Debian Documentation
/etc/motd Message of the day Not unique to Cumulus Linux wiki.debian.org/motd
/etc/passwd User account information Not unique to Cumulus Linux https://www.debian.org/doc/manuals/debian-reference/ch04.en.html
/etc/shadow Secure user account information Not unique to Cumulus Linux https://www.debian.org/doc/manuals/debian-reference/ch04.en.html
/etc/group Defines user groups on the switch Not unique to Cumulus Linux https://www.debian.org/doc/manuals/debian-reference/ch04.en.html
/etc/lldpd.conf Link Layer Discover Protocol (LLDP) daemon configuration Link Layer Discovery Protocol https://packages.debian.org/buster/lldpd
/etc/lldpd.d/ Configuration directory for lldpd Link Layer Discovery Protocol https://packages.debian.org/buster/lldpd
/etc/nsswitch.conf Name Service Switch (NSS) configuration file TACACS N/A
/etc/ssh/ SSH configuration files SSH for Remote Access https://wiki.debian.org/SSH
/etc/sudoers, /etc/sudoers.d Best practice is to place changes in /etc/sudoers.d/ instead of /etc/sudoers; changes in the /etc/sudoers.d/ directory are not lost during upgrade. Using sudo to Delegate Privileges
File Name and Location Explanation
/etc/bcm.d/ Per-platform hardware configuration directory, created on first boot. Do not copy.
/etc/mlx/ Per-platform hardware configuration directory, created on first boot. Do not copy.
/etc/default/clagd Created and managed by ifupdown2. Do not copy.
/etc/default/grub Grub init table. Do not modify manually.
/etc/default/hwclock Platform hardware-specific file. Created during first boot. Do not copy.
/etc/init Platform initialization files. Do not copy.
/etc/init.d/ Platform initialization files. Do not copy.
/etc/fstab Static information on filesystem. Do not copy.
/etc/image-release System version data. Do not copy.
/etc/os-release System version data. Do not copy.
/etc/lsb-release System version data. Do not copy.
/etc/lvm/archive Filesystem files. Do not copy.
/etc/lvm/backup Filesystem files. Do not copy.
/etc/modules Created during first boot. Do not copy.
/etc/modules-load.d/ Created during first boot. Do not copy.
/etc/sensors.d Platform-specific sensor data. Created during first boot. Do not copy.
/root/.ansible Ansible tmp files. Do not copy.
/home/cumulus/.ansible Ansible tmp files. Do not copy.

You can check which files have changed since the last binary install with the following commands. Be sure to back up any changed files:

  • Run the sudo dpkg --verify command to show a list of changed files.
  • Run the egrep -v '^$|^#|=""$' /etc/default/isc-dhcp-* command to see if any of the generated /etc/default/isc-* files have changed.
  • If you are using the root user account, consider including /root/.
  • If you have custom user accounts, consider including /home/<username>/.
  • Run the net show configuration files | grep -B 1 "===" command and back up the files listed in the command output.

Create a cl-support File

Before and after you upgrade the switch, run the cl-support script to create a cl-support archive file. The file is a compressed archive of useful information for troubleshooting. If you experience any issues during upgrade, you can send this archive file to the Cumulus Linux support team to investigate.

  1. Create the cl-support archive file with the cl-support command:

    cumulus@switch:~$ sudo cl-support

  2. Copy the cl-support file off the switch to a different location.

  3. After upgrade is complete, run the cl-support command again to create a new archive file:

    cumulus@switch:~$ sudo cl-support

Upgrade Cumulus Linux

To upgrade to Cumulus Linux 4.0 from Cumulus Linux 3.7, you must install a disk image of the new release using ONIE. You cannot upgrade packages with the apt-get upgrade command.

ONIE is an open source project (equivalent to PXE on servers) that enables the installation of network operating systems (NOS) on a bare metal switch.

Upgrading an MLAG pair requires additional steps. If you are using MLAG to dual connect two Cumulus Linux switches in your environment, follow the steps in Upgrading Cumulus Linux below to ensure a smooth upgrade.

Lightweight network virtualization (LNV) is deprecated in Cumulus Linux 4.0 in favor of Ethernet virtual private networks (EVPN. If your network is configured for LNV, you need to migrate your network configuration to a BGP EVPN configuration that is functionally equivalent before you upgrade to Cumulus Linux 4.0. Refer to Migrating from LNV to EVPN..

Be aware of the following when installing the disk image:

  • Installing a disk image is destructive; any configuration files on the switch are not saved; copy them to a different server before you start installation.
  • You must move configuration data to the new OS using ZTP or automation while the OS is first booted, or soon afterwards using out-of-band management.
  • Moving a configuration file might cause issues:
    • Identifying all the locations of configuration data is not always an easy task. See Before You Upgrade above.
    • Merge conflicts with configuration file changes in the new release might go undetected.
  • If configuration files are not restored correctly, you might be unable to ssh to the switch from in-band management. Out-of-band connectivity (eth0 or console) is recommended.
  • You must reinstall and reconfigure third-party applications after upgrade.

To upgrade the switch:

  1. Back up the configurations off the switch.

  2. Download the Cumulus Linux image.

  3. Install the disk image with the onie-install -a -i <image-location> command, which boots the switch into ONIE. The following example command installs the image from a web server, then reboots the switch. There are additional ways to install the disk image, such as using FTP, TFTP, a local file, or a USB drive. For more information, see Installing a New Cumulus Linux Image.

    cumulus@switch:~$ sudo onie-install -a -i http://10.0.1.251/cumulus-linux-4.0.0-mlx-amd64.bin && sudo reboot

  4. Restore the configuration files to the new release - ideally with automation.

  5. Verify correct operation with the old configurations on the new release.

  6. Reinstall third party applications and associated configurations.

Upgrade Switches in an MLAG Pair

If you are using MLAG to dual connect two switches in your environment, follow the steps below to upgrade the switches.

You must upgrade both switches in the MLAG pair to the same release of Cumulus Linux.

Only during the upgrade process does Cumulus Linux supports different software versions between MLAG peer switches. After you upgrade the first MLAG switch in the pair, run the clagctl showtimers command to monitor the init-delay timer. When the timer expires, make the upgraded MLAG switch the primary, then upgrade the peer to the same version of Cumulus Linux.

Running different versions of Cumulus Linux on MLAG peer switches outside of the upgrade time period is untested and might have unexpected results.

For networks with MLAG deployments, only upgrade to Cumulus Linux 4.0 from version 3.7.10 or later. If you are using a version of Cumulus Linux earlier than 3.7.10, you must upgrade to version 3.7.10 first, then upgrade to version 4.0. Version 3.7.10 is available on the NVIDIA Enterprise support portal.

During upgrade, MLAG bonds stay single-connected while the switches are running different major releases; for example, while leaf01 is running 3.7.12 and leaf02 is running 4.1.1.

This is due to a change in the bonding driver regarding how the actor port key is derived, which causes the port key to have a different value for links with the same speed/duplex settings across different major releases. The port key received from the LACP partner must remain consistent between all bond members in order for all bonds to be synchronized. When each MLAG switch sends LACPDUs with different port keys, only links to one MLAG switch are in sync.

  1. Verify the switch is in the secondary role:

    cumulus@switch:~$ clagctl status

  2. Shut down the core uplink layer 3 interfaces:

    cumulus@switch:~$ sudo ip link set swpX down

  3. Shut down the peer link:

    cumulus@switch:~$ sudo ip link set peerlink down

  4. To boot the switch into ONIE, run the onie-install -a -i <image-location> command. The following example command installs the image from a web server. There are additional ways to install the Cumulus Linux image, such as using FTP, a local file, or a USB drive. For more information, see Installing a New Cumulus Linux Image.

    cumulus@switch:~$ sudo onie-install -a -i http://10.0.1.251/downloads/cumulus-linux-4.1.0-mlx-amd64.bin

    To upgrade the switch with package upgrade instead of booting into ONIE, run the sudo -E apt-get update and sudo -E apt-get upgrade commands; see Package Upgrade.

  5. Reboot the switch:

    cumulus@switch:~$ sudo reboot

  6. If you installed a new image on the switch, restore the configuration files to the new release.

  7. Verify STP convergence across both switches:

    cumulus@switch:~$ mstpctl showall

  8. Verify core uplinks and peer links are UP:

    cumulus@switch:~$ net show interface

  9. Verify MLAG convergence:

    cumulus@switch:~$ clagctl status

  10. Make this secondary switch the primary:

cumulus@switch:~$ clagctl priority 2048

  1. Verify the other switch is now in the secondary role.

  2. Repeat steps 2-9 on the new secondary switch.

  3. Remove the priority 2048 and restore the priority back to 32768 on the current primary switch:

    cumulus@switch:~$ clagctl priority 32768

Roll Back a Cumulus Linux Installation

Even the most well planned and tested upgrades can result in unforeseen problems; sometimes the best solution is to roll back to the previous state. There are three main strategies; all require detailed planning and execution:

  • Flatten and rebuild: If the OS becomes unusable, you can use orchestration tools to reinstall the previous OS release from scratch and then rebuild the configuration automatically.
  • Backup and restore: Another common strategy is to restore to a previous state using a backup captured before the upgrade. See Back up and Restore.

The method you employ is specific to your deployment strategy, so providing detailed steps for each scenario is outside the scope of this document.

Third Party Packages

Third party packages in the Linux host world often use the same package system as the distribution into which it is to be installed (for example, Debian uses apt-get). Or, the package might be compiled and installed by the system administrator. Configuration and executable files generally follow the same filesystem hierarchy standards as other applications.

If you install any third party applications on a Cumulus Linux switch, configuration data is typically installed into the /etc directory, but it is not guaranteed. It is your responsibility to understand the behavior and configuration file information of any third party packages installed on the switch.

After you upgrade using a full disk image install, you need to reinstall any third party packages or any Cumulus Linux add-on packages.

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