Talos Linux

Requirements

You must meet the following requirements before installing Longhorn on a Talos Linux cluster.

System Extensions

Some Longhorn-dependent binary executables are not present in the default Talos root filesystem. To have access to these binaries, Talos offers system extension mechanism to extend the installation.

  • siderolabs/iscsi-tools: this extension enables iscsid daemon and iscsiadm to be available to all nodes for the Kubernetes persistent volumes operations.

  • siderolabs/util-linux-tools: this extension enables linux tool to be available to all nodes. For example, the fstrim binary is used for Longhorn volume trimming.

The most straightforward method is patching the extensions onto existing Talos Linux nodes.

customization:
  systemExtensions:
    officialExtensions:
      - siderolabs/iscsi-tools
      - siderolabs/util-linux-tools

For detailed instructions, see the Talos documentation on System Extensions and Boot Assets.

Pod Security

Longhorn requires pod security enforce: "privileged".

By default, Talos Linux applies a baseline pod security profile across namespaces, except for the kube-system namespace. This default setting restricts Longhorn’s ability to manage and access system resources. For more information, see Root and Privileged Permission.

For detailed instructions, see Pod Security Policies Disabled & Pod Security Admission Introduction and the Talos documentation on Pod Security.

Data Path Mounts

You need provide additional data path mounts to be accessible to the Kubernetes Kubelet container.

These mounts are necessary to provide access to the host directories, and attach volumes required by Longhorn components.

machine:
  kubelet:
    extraMounts:
      - destination: /var/lib/longhorn
        type: bind
        source: /var/lib/longhorn
        options:
          - bind
          - rshared
          - rw

For detailed instructions, see the Talos documentation on Editing Machine Configuration.

Limitations

  • Exclusive to v1 data volume: currently, within a Talos Linux cluster, Longhorn only supports v1 data volume. The v2 data volume isn’t currently supported in this environment.

Talos Linux Upgrades

When upgrading a Talos Linux node, always include the --preserve option in the command. This option explicitly tells Talos to keep ephemeral data intact.

Example:

talosctl upgrade --nodes 10.20.30.40 --image ghcr.io/siderolabs/installer:v1.7.6 --preserve
If you do not include the --preserve option, Talos wipes /var/lib/longhorn, destroying all replicas stored on that node.

Recovering from an Upgraded Node without Preserving Data

If you were unable to include the --preserve option in the upgrade command, perform the following steps:

  1. On the Longhorn UI, go to the Node screen.

  2. Select the upgraded node, and then select Edit node and disks in the Operation menu.

  3. On the Edit Node and Disks screen, set Scheduling to Disable, delete the disk, and then click Save.

  4. Select the upgraded node again, and then select Edit node and disks in the Operation menu.

  5. On the Edit Node and Disks screen, add a disk and configure the following settings:

    • Path: Specify /var/lib/longhorn/.

    • Storage Reserved: Specify a value that matches your requirements. The default value is 30 Gi.

    • Scheduling: Select Enable.

  6. Click Save.

Longhorn synchronizes the replicas based on the configured settings.

References