Kernel

IncusOS exposes a limited set of configuration knobs for adjusting kernel-level settings. A system reboot may be required for changes to fully take effect.

Configuration options

Configuration fields are defined in the SystemKernelConfig struct.

The following configuration options can be set:

• blacklist_modules: A list of one or more kernel modules to blacklist. Typically useful when passing through PCI devices to virtual machines.

• memory: Change sysctl values or other settings that impact the system’s memory configuration

  • persistent_hugepages: Optional; number of persistent hugepages to allocate.

  • zram_swap_size: Optional; a human-readable string such as “4GiB” that defines the size of the zram-backed swap device to create. A value of “0” will disable any existing zram-backed swap that may exist. IncusOS will attempt to immediately apply this change without requiring a reboot.

• network: Change sysctl values that impact the system’s network configuration.

  • buffer_size: Optional; configure the maximum buffer size used when setting the net.ipv4.tcp_rmem, net.ipv4.tcp_wmem, net.core.rmem_max, and net.core.wmem_max sysctl fields.

  • queuing_discipline: Optional; configure the value of the net.core.default_qdisc sysctl field.

  • tcp_congestion_algorithm: Optional; configure the TCP congestion algorithm used by the system, defaults to bbr.

• pci: Change PCI device configuration.

  • passthrough: Configure one or more PCI devices for pass-through to a virtual machine:

    • vendor_id: The PCI vendor ID

    • product_id: The PCI product ID

    • pci_address: Optional; if specified the system will attempt to unbind the given PCI device from its existing driver and configure it for passing though to a virtual machine without requiring a reboot.