This topic describes how to upgrade Cumulus Linux on your switches to a more recent release.

Cumulus Networks recommends that you deploy, provision, configure, and upgrade 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.

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Before You Upgrade Cumulus Linux

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

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. Cumulus Networks recommends you consider making the following files and directories part of a backup strategy.

 Network Configuration Files
File Name and LocationExplanationCumulus Linux DocumentationDebian Documentation
/etc/network/Network configuration files, most notably /etc/network/interfaces and /etc/network/interfaces.d/Switch Port AttributesN/A
/etc/resolv.confDNS resolutionNot unique to Cumulus Linux: wiki.debian.org/NetworkConfigurationwww.debian.org/doc/manuals/debian-reference/ch05.en.html
/etc/frr/Routing application (responsible for BGP and OSPF)FRRouting OverviewN/A
/etc/hostnameConfiguration file for the hostname of the switchQuick Start Guidewiki.debian.org/HowTo/ChangeHostname
/etc/cumulus/acl/*Netfilter configurationNetfilter - ACLsN/A
/etc/cumulus/ports.confBreakout cable configuration fileSwitch Port AttributesN/A; please read the guide on breakout cables
/etc/cumulus/switchd.confSwitchd configurationConfiguring switchdN/A; please read the guide on switchd configuration

If you are using the root user account, consider including /root/.

If you have custom user accounts, consider including /home/<username>/.

 Additional Commonly Used Files
File Name and LocationExplanationCumulus Linux DocumentationDebian Documentation
/etc/motdMessage of the dayNot unique to Cumulus Linuxwiki.debian.org/motd
/etc/passwdUser account informationNot unique to Cumulus Linuxwww.debian.org/doc/manuals/debian-reference/ch04.en.html
/etc/shadowSecure user account informationNot unique to Cumulus Linuxwww.debian.org/doc/manuals/debian-reference/ch04.en.html
/etc/groupDefines user groups on the switchNot unique to Cumulus Linuxwww.debian.org/doc/manuals/debian-reference/ch04.en.html
/etc/lldpd.confLink Layer Discover Protocol (LLDP) daemon configurationLink Layer Discovery Protocolpackages.debian.org/wheezy/lldpd
/etc/lldpd.d/Configuration directory for lldpdLink Layer Discovery Protocolpackages.debian.org/wheezy/lldpd
/etc/nsswitch.confName Service Switch (NSS) configuration fileTACACS PlusN/A
/etc/ssh/SSH configuration filesSSH for Remote Accesswiki.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. If you are upgrading from a release prior to 3.2 (such as 3.1.2) to a 3.2 or later release, be aware that the sudoers file changed in Cumulus Linux 3.2. Using sudo to Delegate Privileges

If you are using the root user account, consider including /root/.

If you have custom user accounts, consider including /home/<username>/.

 Files to Never Migrate between Versions or Switches
File Name and LocationExplanation
/etc/adjtimeSystem clock adjustment data. NTP manages this automatically. It is incorrect when the switch hardware is replaced. Do not copy.
/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/blkid.tabPartition table. Do not modify manually. Do not copy.
/etc/blkid.tab.oldA previous partition table. Do not modify manually. Do not copy.
/etc/cumulus/initPlatform hardware-specific files. Do not copy.
/etc/default/clagdCreated and managed by ifupdown2. Do not copy.
/etc/default/grubGrub init table. Do not modify manually.
/etc/default/hwclockPlatform hardware-specific file. Created during first boot. Do not copy.
/etc/initPlatform initialization files. Do not copy.
/etc/init.d/Platform initialization files. Do not copy.
/etc/fstabStatic info on filesystem. Do not copy.
/etc/image-releaseSystem version data. Do not copy.
/etc/os-releaseSystem version data. Do not copy.
/etc/lsb-releaseSystem version data. Do not copy.
/etc/lvm/archiveFilesystem files. Do not copy.
/etc/lvm/backupFilesystem files. Do not copy.
/etc/modulesCreated during first boot. Do not copy.
/etc/modules-load.d/Created during first boot. Do not copy.
/etc/sensors.dPlatform-specific sensor data. Created during first boot. Do not copy.
/root/.ansibleAnsible tmp files. Do not copy.
/home/cumulus/.ansibleAnsible tmp files. Do not copy.

If you are using certain forms of network virtualization, including VMware NSX-V or Midokura MidoNet, you might have updated the /usr/share/openvswitch/scripts/ovs-ctl-vtep file. This file is not marked as a configuration file; therefore, if the file contents change in a newer release of Cumulus Linux, they overwrite any changes you made to the file. Cumulus Networks recommends you back up this file before upgrading.  

Upgrade Cumulus Linux

You can upgrade Cumulus Linux in one of two ways:

  • Install a disk image of the new release, using ONIE. 
  • Upgrade only the changed packages using the sudo -E apt-get update and sudo -E apt-get upgrade command. 

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 Upgrade Switches in an MLAG Pair below to ensure a smooth upgrade.

Should I Install a Disk Image or Upgrade Packages?

The decision to upgrade Cumulus Linux by either installing a disk image or upgrading packages depends on your environment and your preferences. Here are some recommendations for each upgrade method.

Installing a disk image is recommended if you are performing a rolling upgrade in a production environment and if are using up-to-date and comprehensive automation scripts. This upgrade method enables you to choose the exact release to which you want to upgrade and is the only method available to upgrade your switch to a new release train (for example, from 2.5.6 to 3.7.0)  or from a release earlier than 3.6.2.

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 the disk image install.
  • 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 Cumulus Linux 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.

Package upgrade is recommended if you are upgrading from Cumulus Linux 3.6.2 or later, or if you use third-party applications (package upgrade does not replace or remove third-party applications, unlike disk image install).

Be aware of the following when upgrading packages:

  • You cannot upgrade the switch to a new release train. For example, you cannot upgrade the switch from 2.5.6 to 3.y.z.
  • If you are upgrading Cumulus Linux from a release earlier than 3.6.2, you might encounter certain issues due to package changes and service restarts.
  • You cannot choose the exact release that you want to run. When you upgrade, you upgrade all packages to the latest available release in the Cumulus Networks repository.
  • If you are upgrading from a release earlier than 3.6.2, certain upgrade operations terminate SSH sessions and/or routing on the in-band (front panel) ports, leaving you unable to monitor the upgrade process. (As a workaround, you can use the dtach tool.)
    • The sudo -E apt-get upgrade command might result in services being restarted or stopped as part of the upgrade process.

    • The sudo -E apt-get install command might disrupt core services by changing core service dependency packages.

  • After you upgrade, account UIDs and GIDs created by packages might be different on different switches, depending on the configuration and package installation history.

Disk Image Install (ONIE)

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.

To upgrade the switch with a new disk image using ONIE:

  1. Back up the configurations off the switch.

  2. Download the Cumulus Linux image you want to install.
  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, 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-3.7.1-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.

Package Upgrade

Cumulus Linux completely embraces the Linux and Debian upgrade workflow, where you use an installer to install a base image, then perform any upgrades within that release train with -E apt-get update and -E apt-get upgrade commands. Any packages that have been changed since the base install get upgraded in place from the repository. All switch configuration files remain untouched, or in rare cases merged (using the Debian merge function) during the package upgrade.

When you use package upgrade to upgrade your switch, configuration data stays in place while the packages are upgraded. If the new release updates a configuration file that you changed previously, you are prompted for the version you want to use or if you want to evaluate the differences.

To upgrade the switch using package upgrade:

  1. Back up the configurations from the switch.

  2. Fetch the latest update metadata from the repository.

    cumulus@switch$ sudo -E apt-get update
  3. Review potential upgrade issues (in some cases, upgrading new packages might also upgrade additional existing packages due to dependencies). Run the following command to see the additional packages that will be installed or upgraded.

    cumulus@switch$ sudo -E apt-get install --dry-run
  4. Upgrade all the packages to the latest distribution.

    cumulus@switch$ sudo -E apt-get upgrade

    If no reboot is required after the upgrade completes, the upgrade ends, restarts all upgraded services, and logs messages in the /var/log/syslog file similar to the ones shown below. In the examples below, only the frr package was upgraded.

    Policy: Service frr.service action stop postponed
    Policy: Service frr.service action start postponed
    Policy: Restarting services: frr.service
    Policy: Finished restarting services
    Policy: Removed /usr/sbin/policy-rc.d
    Policy: Upgrade is finished

    If the upgrade process encounters changed configuration files that have new versions in the release to which you are upgrading, you see a message similar to this:

    Configuration file '/etc/frr/daemons'
    ==> Modified (by you or by a script) since installation.
    ==> Package distributor has shipped an updated version.
    What would you like to do about it ? Your options are:
    Y or I : install the package maintainer's version
    N or O : keep your currently-installed version
    D : show the differences between the versions
    Z : start a shell to examine the situation
    The default action is to keep your current version.
    *** daemons (Y/I/N/O/D/Z) [default=N] ?

    - To see the differences between the currently installed version and the new version, type D.

    - To keep the currently installed version, type N. The new package version is installed with the suffix _.dpkg-dist (for example, /etc/frr/daemons.dpkg-dist). When upgrade is complete and before you reboot, merge your changes with the changes from the newly installed file.

    -To install the new version, type I. Your currently installed version is saved with the suffix .dpkg-old.

    When the upgrade is complete, you can search for the files with the sudo find / -mount -type f -name '*.dpkg-*' command.

    If you see errors for expired GPG keys that prevent you from upgrading packages, follow the steps in Upgrading Expired GPG Keys.

  5. Reboot the switch if the upgrade messages indicate that a system restart is required.

    cumulus@switch$ sudo -E apt-get upgrade
          ... upgrade messages here ...
     
    *** Caution: Service restart prior to reboot could cause unpredictable behavior
    *** System reboot required ***
    cumulus@switch$ sudo reboot
  6. Verify correct operation with the old configurations on the new version.

Upgrade Notes 

Package upgrade always updates to the latest available release in the Cumulus Linux repository. For example, if you are currently running Cumulus Linux 3.0.1 and run the sudo -E apt-get upgrade command on that switch, the packages are upgraded to the latest releases contained in the latest 3.y.z release.

Because Cumulus Linux is a collection of different Debian Linux packages, be aware of the following:

  • The /etc/os-release and /etc/lsb-release files are updated to the currently installed Cumulus Linux release when you upgrade the switch using either package upgrade or disk image install. For example, if you run sudo -E apt-get upgrade and the latest Cumulus Linux release on the repository is 3.7.1, these two files display the release as 3.7.1 after the upgrade.
  • The /etc/image-release file is updated only when you run a disk image install. Therefore, if you run a disk image install of Cumulus Linux 3.5.0, followed by a package upgrade to 3.7.1 using sudo -E apt-get upgrade, the /etc/image-release file continues to display Cumulus Linux 3.5.0, which is the originally installed base image.

Upgrade Switches in an MLAG Pair

If you are using MLAG to dual connect two switches in your environment, follow the steps below according to the version of Cumulus Linux from which you are upgrading. 

Upgrade from Cumulus Linux 3.y.z to a Later 3.y.z Release

When you upgrade Cumulus Linux from 3.y.z to a later 3.y.z release, you can either install a disk image using ONIE or use package upgrade. Both methods are included below.

To upgrade the switches:

  1. Verify the switch is in the secondary role:

    cumulus@switch:~$ clagctl status
  2. If you want to install a disk image, go to the next step. If you want to use package upgrade, update the Cumulus Linux repositories:

    cumulus@switch:~$ sudo -E apt-get update
  3. Shut down the core uplink layer 3 interfaces:

    cumulus@switch:~$ sudo ip link set swpX down
  4. Shut down the peerlink:

    cumulus@switch:~$ sudo ip link set peerlink down
  5. Perform the upgrade either by installing a disk image or upgrading packages.
    To install a disk image, run the onie-install -a -i <image-location> command to boot the switch into ONIE. The following example command installs the image from a web server. There are additional ways to install the disk 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-3.7.1-mlx-amd64.bin

    To use package upgrade, run the -E apt-get upgrade command:

    cumulus@switch:~$ sudo -E apt-get upgrade
  6. Reboot the switch:

    cumulus@switch:~$ sudo reboot
  7. If you were originally running Cumulus Linux 3.0.0 through 3.3.2, follow the steps for upgrading from Quagga to FRRouting.
  8. Verify STP convergence across both switches:

    cumulus@switch:~$ mstpctl showall
  9. Verify core uplinks and peerlinks are UP:

    cumulus@switch:~$ net show interface
  10. Verify MLAG convergence:

    cumulus@switch:~$ clagctl status
  11. Make this secondary switch the primary:

    cumulus@switch:~$ clagctl priority 2048
  12. Verify the other switch is now in the secondary role.
  13. Repeat steps 2-10 on the new secondary switch.
  14. Remove the priority 2048 and restore the priority back to 32768 on the current primary switch:

    cumulus@switch:~$ clagctl priority 32768

Upgrade from Cumulus Linux 2.y.z to 3.y.z

If you are using MLAG to dual connect two switches in your environment and those switches are still running Cumulus Linux 2.5 ESR or any other release earlier than 3.0.0, the switches are not dual-connected after you upgrade the first switch. 

To upgrade the switches, you must install a new disk image using ONIE; you cannot use package upgrade:

  1. Disable clagd in the /etc/network/interfaces file (set clagd-enable to no), then restart switchd, networking, and FRR services.

    cumulus@switch:~$ sudo systemctl restart switchd.service
    cumulus@switch:~$ sudo systemctl restart networking.service
    cumulus@switch:~$ sudo systemctl restart frr.service
  2. If you are using BGP, notify the BGP neighbors that the switch is going down:

    cumulus@switch:~$ sudo vtysh -c "config t" -c "router bgp" -c "neighbor X.X.X.X shutdown"
  3. Stop the Quagga service: 

    cumulus@switch:~$ sudo systemctl stop [quagga|frr].service 
  4. Bring down all the front panel ports:

    cumulus@switch:~$ sudo ip link set swp<#> down
  5. Run cl-img-select -fr to boot the switch in the secondary role into ONIE, then reboot the switch.
  6. Install Cumulus Linux onto the secondary switch using ONIE. At this time, all traffic goes to the switch in the primary role.
  7. After the install, copy the license file and all the configuration files you backed up, then restart the switchd, networking, and Quagga services. All traffic is still going to the primary switch.

    cumulus@switch:~$ sudo systemctl restart switchd.service
    cumulus@switch:~$ sudo systemctl restart networking.service
    cumulus@switch:~$ sudo systemctl restart quagga.service
  8. Run cl-img-select -fr to boot the switch in the primary role into ONIE, then reboot the switch. Now, all traffic is going to the switch in the secondary role that you just upgraded.
  9. Install Cumulus Linux onto the primary switch using ONIE. 
  10. After the install, copy the license file and all the configuration files you backed up.
  11. Follow the steps for upgrading from Quagga to FRRouting.
  12. Enable clagd again in the /etc/network/interfaces file (set clagd-enable to yes), then run ifreload -a.

    cumulus@switch:~$ sudo ifreload -a
  13. Bring up all the front panel ports:

    cumulus@switch:~$ sudo ip link set swp<#> up 

    The two switches are dual-connected again and traffic flows to both switches.

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:
  • Back out individual packages: If you identify the problematic package, you can downgrade the affected package directly. In rare cases, you might need to restore the configuration files from backup or edit to back out any changes made automatically by the upgrade package.
  • 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.

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, such as vxsnd or vxrd.

Related Information