# Instance configuration ## Instances ### Properties The following are direct instance properties and can't be part of a profile: - `name` - `architecture` Name is the instance name and can only be changed by renaming the instance. Valid instance names must: - Be between 1 and 63 characters long - Be made up exclusively of letters, numbers and dashes from the ASCII table - Not start with a digit or a dash - Not end with a dash This requirement is so that the instance name may properly be used in DNS records, on the filesystem, in various security profiles as well as the hostname of the instance itself. ### Key/value configuration The key/value configuration is namespaced with the following namespaces currently supported: - `boot` (boot related options, timing, dependencies, ...) - `environment` (environment variables) - `image` (copy of the image properties at time of creation) - `limits` (resource limits) - `nvidia` (NVIDIA and CUDA configuration) - `raw` (raw instance configuration overrides) - `security` (security policies) - `user` (storage for user properties, searchable) - `volatile` (used internally by LXD to store internal data specific to an instance) The currently supported keys are: ```{rst-class} dec-font-size break-col-1 min-width-1-15 ``` Key | Type | Default | Live update | Condition | Description :-- | :--- | :------ | :---------- | :---------- | :---------- boot.autostart | boolean | - | n/a | - | Always start the instance when LXD starts (if not set, restore last state) boot.autostart.delay | integer | 0 | n/a | - | Number of seconds to wait after the instance started before starting the next one boot.autostart.priority | integer | 0 | n/a | - | What order to start the instances in (starting with highest) boot.host\_shutdown\_timeout | integer | 30 | yes | - | Seconds to wait for instance to shutdown before it is force stopped boot.stop.priority | integer | 0 | n/a | - | What order to shutdown the instances (starting with highest) environment.\* | string | - | yes (exec) | - | key/value environment variables to export to the instance and set on exec limits.cpu | string | - | yes | - | Number or range of CPUs to expose to the instance (defaults to 1 CPU for VMs) limits.cpu.allowance | string | 100% | yes | container | How much of the CPU can be used. Can be a percentage (e.g. 50%) for a soft limit or hard a chunk of time (25ms/100ms) limits.cpu.priority | integer | 10 (maximum) | yes | container | CPU scheduling priority compared to other instances sharing the same CPUs (overcommit) (integer between 0 and 10) limits.disk.priority | integer | 5 (medium) | yes | - | When under load, how much priority to give to the instance's I/O requests (integer between 0 and 10) limits.hugepages.64KB | string | - | yes | container | Fixed value in bytes (various suffixes supported, see below) to limit number of 64 KB hugepages (Available hugepage sizes are architecture dependent.) limits.hugepages.1MB | string | - | yes | container | Fixed value in bytes (various suffixes supported, see below) to limit number of 1 MB hugepages (Available hugepage sizes are architecture dependent.) limits.hugepages.2MB | string | - | yes | container | Fixed value in bytes (various suffixes supported, see below) to limit number of 2 MB hugepages (Available hugepage sizes are architecture dependent.) limits.hugepages.1GB | string | - | yes | container | Fixed value in bytes (various suffixes supported, see below) to limit number of 1 GB hugepages (Available hugepage sizes are architecture dependent.) limits.kernel.\* | string | - | no | container | This limits kernel resources per instance (e.g. number of open files) limits.memory | string | - | yes | - | Percentage of the host's memory or fixed value in bytes (various suffixes supported, see below) (defaults to 1GiB for VMs) limits.memory.enforce | string | hard | yes | container | If hard, instance can't exceed its memory limit. If soft, the instance can exceed its memory limit when extra host memory is available limits.memory.hugepages | boolean | false | no | virtual-machine | Controls whether to back the instance using hugepages rather than regular system memory limits.memory.swap | boolean | true | yes | container | Controls whether to encourage/discourage swapping less used pages for this instance limits.memory.swap.priority | integer | 10 (maximum) | yes | container | The higher this is set, the least likely the instance is to be swapped to disk (integer between 0 and 10) limits.network.priority | integer | 0 (minimum) | yes | - | When under load, how much priority to give to the instance's network requests (integer between 0 and 10) limits.processes | integer | - (max) | yes | container | Maximum number of processes that can run in the instance linux.kernel\_modules | string | - | yes | container | Comma separated list of kernel modules to load before starting the instance migration.incremental.memory | boolean | false | yes | container | Incremental memory transfer of the instance's memory to reduce downtime migration.incremental.memory.goal | integer | 70 | yes | container | Percentage of memory to have in sync before stopping the instance migration.incremental.memory.iterations | integer | 10 | yes | container | Maximum number of transfer operations to go through before stopping the instance migration.stateful | boolean | false | no | virtual-machine | Allow for stateful stop/start and snapshots. This will prevent the use of some features that are incompatible with it nvidia.driver.capabilities | string | compute,utility | no | container | What driver capabilities the instance needs (sets libnvidia-container NVIDIA\_DRIVER\_CAPABILITIES) nvidia.runtime | boolean | false | no | container | Pass the host NVIDIA and CUDA runtime libraries into the instance nvidia.require.cuda | string | - | no | container | Version expression for the required CUDA version (sets libnvidia-container NVIDIA\_REQUIRE\_CUDA) nvidia.require.driver | string | - | no | container | Version expression for the required driver version (sets libnvidia-container NVIDIA\_REQUIRE\_DRIVER) raw.apparmor | blob | - | yes | - | Apparmor profile entries to be appended to the generated profile raw.idmap | blob | - | no | unprivileged container | Raw idmap configuration (e.g. "both 1000 1000") raw.lxc | blob | - | no | container | Raw LXC configuration to be appended to the generated one raw.qemu | blob | - | no | virtual-machine | Raw Qemu configuration to be appended to the generated command line raw.seccomp | blob | - | no | container | Raw Seccomp configuration security.devlxd | boolean | true | no | - | Controls the presence of /dev/lxd in the instance security.devlxd.images | boolean | false | no | container | Controls the availability of the /1.0/images API over devlxd security.idmap.base | integer | - | no | unprivileged container | The base host ID to use for the allocation (overrides auto-detection) security.idmap.isolated | boolean | false | no | unprivileged container | Use an idmap for this instance that is unique among instances with isolated set security.idmap.size | integer | - | no | unprivileged container | The size of the idmap to use security.nesting | boolean | false | yes | container | Support running lxd (nested) inside the instance security.privileged | boolean | false | no | container | Runs the instance in privileged mode security.protection.delete | boolean | false | yes | - | Prevents the instance from being deleted security.protection.shift | boolean | false | yes | container | Prevents the instance's filesystem from being uid/gid shifted on startup security.agent.metrics | boolean | true | no | virtual-machine | Controls whether the lxd-agent is queried for state information and metrics security.secureboot | boolean | true | no | virtual-machine | Controls whether UEFI secure boot is enabled with the default Microsoft keys security.syscalls.allow | string | - | no | container | A '\n' separated list of syscalls to allow (mutually exclusive with security.syscalls.deny\*) security.syscalls.deny | string | - | no | container | A '\n' separated list of syscalls to deny security.syscalls.deny\_compat | boolean | false | no | container | On x86\_64 this enables blocking of compat\_\* syscalls, it is a no-op on other arches security.syscalls.deny\_default | boolean | true | no | container | Enables the default syscall deny security.syscalls.intercept.mknod | boolean | false | no | container | Handles the `mknod` and `mknodat` system calls (allows creation of a limited subset of char/block devices) security.syscalls.intercept.mount | boolean | false | no | container | Handles the `mount` system call security.syscalls.intercept.mount.allowed | string | - | yes | container | Specify a comma-separated list of filesystems that are safe to mount for processes inside the instance security.syscalls.intercept.mount.fuse | string | - | yes | container | Whether to redirect mounts of a given filesystem to their fuse implemenation (e.g. ext4=fuse2fs) security.syscalls.intercept.mount.shift | boolean | false | yes | container | Whether to mount shiftfs on top of filesystems handled through mount syscall interception security.syscalls.intercept.setxattr | boolean | false | no | container | Handles the `setxattr` system call (allows setting a limited subset of restricted extended attributes) snapshots.schedule | string | - | no | - | Cron expression (` `), or a comma separated list of schedule aliases `<@hourly> <@daily> <@midnight> <@weekly> <@monthly> <@annually> <@yearly> <@startup>` snapshots.schedule.stopped | bool | false | no | - | Controls whether or not stopped instances are to be snapshoted automatically snapshots.pattern | string | snap%d | no | - | Pongo2 template string which represents the snapshot name (used for scheduled snapshots and unnamed snapshots) snapshots.expiry | string | - | no | - | Controls when snapshots are to be deleted (expects expression like `1M 2H 3d 4w 5m 6y`) user.\* | string | - | n/a | - | Free form user key/value storage (can be used in search) The following volatile keys are currently internally used by LXD: Key | Type | Default | Description :-- | :--- | :------ | :---------- volatile.apply\_template | string | - | The name of a template hook which should be triggered upon next startup volatile.base\_image | string | - | The hash of the image the instance was created from, if any volatile.idmap.base | integer | - | The first id in the instance's primary idmap range volatile.idmap.current | string | - | The idmap currently in use by the instance volatile.idmap.next | string | - | The idmap to use next time the instance starts volatile.last\_state.idmap | string | - | Serialized instance uid/gid map volatile.last\_state.power | string | - | Instance state as of last host shutdown volatile.vsock\_id | string | - | Instance vsock ID used as of last start volatile.uuid | string | - | Instance UUID (globally unique across all servers and projects) volatile.\.apply\_quota | string | - | Disk quota to be applied on next instance start volatile.\.ceph\_rbd | string | - | RBD device path for Ceph disk devices volatile.\.host\_name | string | - | Network device name on the host volatile.\.hwaddr | string | - | Network device MAC address (when no hwaddr property is set on the device itself) volatile.\.last\_state.created | string | - | Whether or not the network device physical device was created ("true" or "false") volatile.\.last\_state.mtu | string | - | Network device original MTU used when moving a physical device into an instance volatile.\.last\_state.hwaddr | string | - | Network device original MAC used when moving a physical device into an instance volatile.\.last\_state.vf.id | string | - | SR-IOV Virtual function ID used when moving a VF into an instance volatile.\.last\_state.vf.hwaddr | string | - | SR-IOV Virtual function original MAC used when moving a VF into an instance volatile.\.last\_state.vf.vlan | string | - | SR-IOV Virtual function original VLAN used when moving a VF into an instance volatile.\.last\_state.vf.spoofcheck | string | - | SR-IOV Virtual function original spoof check setting used when moving a VF into an instance Additionally, those user keys have become common with images (support isn't guaranteed): Key | Type | Default | Description :-- | :--- | :------ | :---------- user.meta-data | string | - | Cloud-init meta-data, content is appended to seed value user.network-config | string | DHCP on eth0 | Cloud-init network-config, content is used as seed value user.network\_mode | string | dhcp | One of "dhcp" or "link-local". Used to configure network in supported images user.user-data | string | #!cloud-config | Cloud-init user-data, content is used as seed value user.vendor-data | string | #!cloud-config | Cloud-init vendor-data, content is used as seed value Note that while a type is defined above as a convenience, all values are stored as strings and should be exported over the REST API as strings (which makes it possible to support any extra values without breaking backward compatibility). Those keys can be set using the lxc tool with: ```bash lxc config set ``` Volatile keys can't be set by the user and can only be set directly against an instance. The raw keys allow direct interaction with the backend features that LXD itself uses, setting those may very well break LXD in non-obvious ways and should whenever possible be avoided. #### CPU limits The CPU limits are implemented through a mix of the `cpuset` and `cpu` CGroup controllers. `limits.cpu` results in CPU pinning through the `cpuset` controller. A set of CPUs (e.g. `1,2,3`) or a CPU range (e.g. `0-3`) can be specified. When a number of CPUs is specified instead (e.g. `4`), LXD will do dynamic load-balancing of all instances that aren't pinned to specific CPUs, trying to spread the load on the machine. Instances will then be re-balanced every time an instance starts or stops as well as whenever a CPU is added to the system. To pin to a single CPU, you have to use the range syntax (e.g. `1-1`) to differentiate it from a number of CPUs. `limits.cpu.allowance` drives either the CFS scheduler quotas when passed a time constraint, or the generic CPU shares mechanism when passed a percentage value. The time constraint (e.g. `20ms/50ms`) is relative to one CPU worth of time, so to restrict to two CPUs worth of time, something like 100ms/50ms should be used. When using a percentage value, the limit will only be applied when under load and will be used to calculate the scheduler priority for the instance, relative to any other instance which is using the same CPU(s). `limits.cpu.priority` is another knob which is used to compute that scheduler priority score when a number of instances sharing a set of CPUs have the same percentage of CPU assigned to them. #### VM CPU topology LXD virtual machines default to having just one vCPU allocated which shows up as matching the host CPU vendor and type but has a single core and no threads. When `limits.cpu` is set to a single integer, this will cause multiple vCPUs to be allocated and exposed to the guest as full cores. Those vCPUs will not be pinned to specific physical cores on the host. When `limits.cpu` is set to a range or comma separate list of CPU IDs (as provided by `lxc info --resources`), then the vCPUs will be pinned to those physical cores. In this scenario, LXD will check whether the CPU configuration lines up with a realistic hardware topology and if it does, it will replicate that topology in the guest. This means that if the pinning configuration includes 8 threads, with each pair of thread coming from the same core and an even number of cores spread across two CPUs, LXD will have the guest show two CPUs, each with two cores and each core with two threads. The NUMA layout is similarly replicated and in this scenario, the guest would most likely end up with two NUMA nodes, one for each CPU socket. In such an environment with multiple NUMA nodes, the memory will similarly be divided across NUMA nodes and be pinned accordingly on the host and then exposed to the guest. All this allows for very high performance operations in the guest as the guest scheduler can properly reason about sockets, cores and threads as well as consider NUMA topology when sharing memory or moving processes across NUMA nodes. ## Devices configuration LXD will always provide the instance with the basic devices which are required for a standard POSIX system to work. These aren't visible in instance or profile configuration and may not be overridden. Those include: - `/dev/null` (character device) - `/dev/zero` (character device) - `/dev/full` (character device) - `/dev/console` (character device) - `/dev/tty` (character device) - `/dev/random` (character device) - `/dev/urandom` (character device) - `/dev/net/tun` (character device) - `/dev/fuse` (character device) - `lo` (network interface) Anything else has to be defined in the instance configuration or in one of its profiles. The default profile will typically contain a network interface to become `eth0` in the instance. To add extra devices to an instance, device entries can be added directly to an instance, or to a profile. Devices may be added or removed while the instance is running. Every device entry is identified by a unique name. If the same name is used in a subsequent profile or in the instance's own configuration, the whole entry is overridden by the new definition. Device entries are added to an instance through: ```bash lxc config device add [key=value]... ``` or to a profile with: ```bash lxc profile device add [key=value]... ``` ### Device types LXD supports the following device types: ID (database) | Name | Condition | Description :-- | :-- | :-- | :-- 0 | [none](#type-none) | - | Inheritance blocker 1 | [nic](#type-nic) | - | Network interface 2 | [disk](#type-disk) | - | Mountpoint inside the instance 3 | [unix-char](#type-unix-char) | container | Unix character device 4 | [unix-block](#type-unix-block) | container | Unix block device 5 | [usb](#type-usb) | - | USB device 6 | [gpu](#type-gpu) | - | GPU device 7 | [infiniband](#type-infiniband) | container | Infiniband device 8 | [proxy](#type-proxy) | container | Proxy device 9 | [unix-hotplug](#type-unix-hotplug) | container | Unix hotplug device #### Type: none Supported instance types: container, VM A none type device doesn't have any property and doesn't create anything inside the instance. It's only purpose it to stop inheritance of devices coming from profiles. To do so, just add a none type device with the same name of the one you wish to skip inheriting. It can be added in a profile being applied after the profile it originated from or directly on the instance. #### Type: nic LXD supports several different kinds of network devices (referred to as Network Interface Controller or NIC). When adding a network device to an instance, there are two ways to specify the type of device you want to add; either by specifying the `nictype` property or using the `network` property. ##### Specifying a NIC using the `network` property When specifying the `network` property, the NIC is linked to an existing managed network and the `nictype` is automatically detected based on the network's type. Some of the NICs properties are inherited from the network rather than being customisable for each NIC. These are detailed in the "Managed" column in the NIC specific sections below. ##### NICs Available: See the NIC's settings below for details about which properties are available. The following NICs can be specified using the `nictype` or `network` properties: - [bridged](#nic-bridged): Uses an existing bridge on the host and creates a virtual device pair to connect the host bridge to the instance. The following NICs can be specified using only the `nictype` property: - [macvlan](#nic-macvlan): Sets up a new network device based on an existing one but using a different MAC address. - [sriov](#nic-sriov): Passes a virtual function of an SR-IOV enabled physical network device into the instance. - [physical](#nic-physical): Straight physical device passthrough from the host. The targeted device will vanish from the host and appear in the instance. - [ipvlan](#nic-ipvlan): Sets up a new network device based on an existing one using the same MAC address but a different IP. - [p2p](#nic-p2p): Creates a virtual device pair, putting one side in the instance and leaving the other side on the host. - [routed](#nic-routed): Creates a virtual device pair to connect the host to the instance and sets up static routes and proxy ARP/NDP entries to allow the instance to join the network of a designated parent interface. ##### nic: bridged Supported instance types: container, VM Selected using: `nictype`, `network` Uses an existing bridge on the host and creates a virtual device pair to connect the host bridge to the instance. Device configuration properties: Key | Type | Default | Required | Managed | Description :-- | :-- | :-- | :-- | :-- | :-- parent | string | - | yes | yes | The name of the host device network | string | - | yes | no | The LXD network to link device to (instead of parent) name | string | kernel assigned | no | no | The name of the interface inside the instance mtu | integer | parent MTU | no | yes | The MTU of the new interface hwaddr | string | randomly assigned | no | no | The MAC address of the new interface host\_name | string | randomly assigned | no | no | The name of the interface inside the host limits.ingress | string | - | no | no | I/O limit in bit/s for incoming traffic (various suffixes supported, see below) limits.egress | string | - | no | no | I/O limit in bit/s for outgoing traffic (various suffixes supported, see below) limits.max | string | - | no | no | Same as modifying both limits.ingress and limits.egress ipv4.address | string | - | no | no | An IPv4 address to assign to the instance through DHCP ipv6.address | string | - | no | no | An IPv6 address to assign to the instance through DHCP ipv4.routes | string | - | no | no | Comma delimited list of IPv4 static routes to add on host to NIC ipv6.routes | string | - | no | no | Comma delimited list of IPv6 static routes to add on host to NIC security.mac\_filtering | boolean | false | no | no | Prevent the instance from spoofing another's MAC address security.ipv4\_filtering | boolean | false | no | no | Prevent the instance from spoofing another's IPv4 address (enables mac\_filtering) security.ipv6\_filtering | boolean | false | no | no | Prevent the instance from spoofing another's IPv6 address (enables mac\_filtering) maas.subnet.ipv4 | string | - | no | yes | MAAS IPv4 subnet to register the instance in maas.subnet.ipv6 | string | - | no | yes | MAAS IPv6 subnet to register the instance in boot.priority | integer | - | no | no | Boot priority for VMs (higher boots first) ##### nic: macvlan Supported instance types: container, VM Selected using: `nictype` Sets up a new network device based on an existing one but using a different MAC address. Device configuration properties: Key | Type | Default | Required | Description :-- | :-- | :-- | :-- | :-- parent | string | - | yes | The name of the host device name | string | kernel assigned | no | The name of the interface inside the instance mtu | integer | parent MTU | no | The MTU of the new interface hwaddr | string | randomly assigned | no | The MAC address of the new interface vlan | integer | - | no | The VLAN ID to attach to maas.subnet.ipv4 | string | - | no | MAAS IPv4 subnet to register the instance in maas.subnet.ipv6 | string | - | no | MAAS IPv6 subnet to register the instance in boot.priority | integer | - | no | Boot priority for VMs (higher boots first) ##### nic: sriov Supported instance types: container, VM Selected using: `nictype` Passes a virtual function of an SR-IOV enabled physical network device into the instance. Device configuration properties: Key | Type | Default | Required | Description :-- | :-- | :-- | :-- | :-- parent | string | - | yes | The name of the host device name | string | kernel assigned | no | The name of the interface inside the instance mtu | integer | kernel assigned | no | The MTU of the new interface hwaddr | string | randomly assigned | no | The MAC address of the new interface security.mac\_filtering | boolean | false | no | Prevent the instance from spoofing another's MAC address vlan | integer | - | no | The VLAN ID to attach to maas.subnet.ipv4 | string | - | no | MAAS IPv4 subnet to register the instance in maas.subnet.ipv6 | string | - | no | MAAS IPv6 subnet to register the instance in boot.priority | integer | - | no | Boot priority for VMs (higher boots first) ##### nic: physical Supported instance types: container, VM Selected using: `nictype` Straight physical device passthrough from the host. The targeted device will vanish from the host and appear in the instance. Device configuration properties: Key | Type | Default | Required | Description :-- | :-- | :-- | :-- | :-- parent | string | - | yes | The name of the host device name | string | kernel assigned | no | The name of the interface inside the instance mtu | integer | parent MTU | no | The MTU of the new interface hwaddr | string | randomly assigned | no | The MAC address of the new interface vlan | integer | - | no | The VLAN ID to attach to maas.subnet.ipv4 | string | - | no | MAAS IPv4 subnet to register the instance in maas.subnet.ipv6 | string | - | no | MAAS IPv6 subnet to register the instance in boot.priority | integer | - | no | Boot priority for VMs (higher boots first) ##### nic: ipvlan Supported instance types: container Selected using: `nictype` Sets up a new network device based on an existing one using the same MAC address but a different IP. LXD currently supports IPVLAN in L2 and L3S mode. In this mode, the gateway is automatically set by LXD, however IP addresses must be manually specified using either one or both of `ipv4.address` and `ipv6.address` settings before instance is started. For DNS, the nameservers need to be configured inside the instance, as these will not automatically be set. It requires the following sysctls to be set: If using IPv4 addresses: ``` net.ipv4.conf..forwarding=1 ``` If using IPv6 addresses: ``` net.ipv6.conf..forwarding=1 net.ipv6.conf..proxy_ndp=1 ``` Device configuration properties: Key | Type | Default | Required | Description :-- | :-- | :-- | :-- | :-- parent | string | - | yes | The name of the host device name | string | kernel assigned | no | The name of the interface inside the instance mtu | integer | parent MTU | no | The MTU of the new interface hwaddr | string | randomly assigned | no | The MAC address of the new interface ipv4.address | string | - | no | Comma delimited list of IPv4 static addresses to add to the instance ipv4.gateway | string | auto | no | Whether to add an automatic default IPv4 gateway, can be "auto" or "none" ipv6.address | string | - | no | Comma delimited list of IPv6 static addresses to add to the instance ipv6.gateway | string | auto | no | Whether to add an automatic default IPv6 gateway, can be "auto" or "none" vlan | integer | - | no | The VLAN ID to attach to ##### nic: p2p Supported instance types: container, VM Selected using: `nictype` Creates a virtual device pair, putting one side in the instance and leaving the other side on the host. Device configuration properties: Key | Type | Default | Required | Description :-- | :-- | :-- | :-- | :-- name | string | kernel assigned | no | The name of the interface inside the instance mtu | integer | kernel assigned | no | The MTU of the new interface hwaddr | string | randomly assigned | no | The MAC address of the new interface host\_name | string | randomly assigned | no | The name of the interface inside the host limits.ingress | string | - | no | I/O limit in bit/s for incoming traffic (various suffixes supported, see below) limits.egress | string | - | no | I/O limit in bit/s for outgoing traffic (various suffixes supported, see below) limits.max | string | - | no | Same as modifying both limits.ingress and limits.egress ipv4.routes | string | - | no | Comma delimited list of IPv4 static routes to add on host to NIC ipv6.routes | string | - | no | Comma delimited list of IPv6 static routes to add on host to NIC boot.priority | integer | - | no | Boot priority for VMs (higher boots first) ##### nic: routed Supported instance types: container, VM Selected using: `nictype` This NIC type is similar in operation to IPVLAN, in that it allows an instance to join an external network without needing to configure a bridge and shares the host's MAC address. However it differs from IPVLAN because it does not need IPVLAN support in the kernel and the host and instance can communicate with each other. It will also respect netfilter rules on the host and will use the host's routing table to route packets which can be useful if the host is connected to multiple networks. IP addresses must be manually specified using either one or both of `ipv4.address` and `ipv6.address` settings before the instance is started. For containers it uses a veth pair, and for VMs it uses a TAP device. It then configures the following link-local gateway IPs on the host end which are then set as the default gateways in the instance: 169.254.0.1 fe80::1 For containers these are automatically set as default gateways on the instance NIC interface. But for VMs the IP addresses and gateways will need to be configured manually or via a mechanism like cloud-init. Note also that if your container image is configured to perform DHCP on the interface it will likely remove the automatically added configuration, and will need to be configured manually or via a mechanism like cloud-init. It then configures static routes on the host pointing to the instance's veth interface for all of the instance's IPs. This nic can operate with and without a `parent` network interface set. With the `parent` network interface set proxy ARP/NDP entries of the instance's IPs are added to the parent interface allowing the instance to join the parent interface's network at layer 2. For DNS, the nameservers need to be configured inside the instance, as these will not automatically be set. It requires the following sysctls to be set: If using IPv4 addresses: ``` net.ipv4.conf..forwarding=1 ``` If using IPv6 addresses: ``` net.ipv6.conf.all.forwarding=1 net.ipv6.conf..forwarding=1 net.ipv6.conf.all.proxy_ndp=1 net.ipv6.conf..proxy_ndp=1 ``` Each NIC device can have multiple IP addresses added to them. However it may be desirable to utilise multiple `routed` NIC interfaces. In these cases one should set the `ipv4.gateway` and `ipv6.gateway` values to "none" on any subsequent interfaces to avoid default gateway conflicts. It may also be useful to specify a different host-side address for these subsequent interfaces using `ipv4.host_address` and `ipv6.host_address` respectively. Device configuration properties: Key | Type | Default | Required | Description :-- | :-- | :-- | :-- | :-- parent | string | - | no | The name of the host device to join the instance to name | string | kernel assigned | no | The name of the interface inside the instance host\_name | string | randomly assigned | no | The name of the interface inside the host mtu | integer | parent MTU | no | The MTU of the new interface hwaddr | string | randomly assigned | no | The MAC address of the new interface limits.ingress | string | - | no | I/O limit in bit/s for incoming traffic (various suffixes supported, see below) limits.egress | string | - | no | I/O limit in bit/s for outgoing traffic (various suffixes supported, see below) limits.max | string | - | no | Same as modifying both limits.ingress and limits.egress ipv4.address | string | - | no | Comma delimited list of IPv4 static addresses to add to the instance ipv4.gateway | string | auto | no | Whether to add an automatic default IPv4 gateway, can be "auto" or "none" ipv4.host\_address | string | 169.254.0.1 | no | The IPv4 address to add to the host-side veth interface ipv4.host\_table | integer | - | no | The custom policy routing table ID to add IPv4 static routes to (in addition to main routing table) ipv6.address | string | - | no | Comma delimited list of IPv6 static addresses to add to the instance ipv6.gateway | string | auto | no | Whether to add an automatic default IPv6 gateway, can be "auto" or "none" ipv6.host\_address | string | fe80::1 | no | The IPv6 address to add to the host-side veth interface ipv6.host\_table | integer | - | no | The custom policy routing table ID to add IPv6 static routes to (in addition to main routing table) vlan | integer | - | no | The VLAN ID to attach to ##### bridged, macvlan or ipvlan for connection to physical network The `bridged`, `macvlan` and `ipvlan` interface types can be used to connect to an existing physical network. `macvlan` effectively lets you fork your physical NIC, getting a second interface that's then used by the instance. This saves you from creating a bridge device and veth pairs and usually offers better performance than a bridge. The downside to this is that macvlan devices while able to communicate between themselves and to the outside, aren't able to talk to their parent device. This means that you can't use macvlan if you ever need your instances to talk to the host itself. In such case, a bridge is preferable. A bridge will also let you use mac filtering and I/O limits which cannot be applied to a macvlan device. `ipvlan` is similar to `macvlan`, with the difference being that the forked device has IPs statically assigned to it and inherits the parent's MAC address on the network. ##### SR-IOV The `sriov` interface type supports SR-IOV enabled network devices. These devices associate a set of virtual functions (VFs) with the single physical function (PF) of the network device. PFs are standard PCIe functions. VFs on the other hand are very lightweight PCIe functions that are optimized for data movement. They come with a limited set of configuration capabilities to prevent changing properties of the PF. Given that VFs appear as regular PCIe devices to the system they can be passed to instances just like a regular physical device. The `sriov` interface type expects to be passed the name of an SR-IOV enabled network device on the system via the `parent` property. LXD will then check for any available VFs on the system. By default LXD will allocate the first free VF it finds. If it detects that either none are enabled or all currently enabled VFs are in use it will bump the number of supported VFs to the maximum value and use the first free VF. If all possible VFs are in use or the kernel or card doesn't support incrementing the number of VFs LXD will return an error. To create a `sriov` network device use: ``` lxc config device add nic nictype=sriov parent= ``` To tell LXD to use a specific unused VF add the `host_name` property and pass it the name of the enabled VF. ##### MAAS integration If you're using MAAS to manage the physical network under your LXD host and want to attach your instances directly to a MAAS managed network, LXD can be configured to interact with MAAS so that it can track your instances. At the daemon level, you must configure `maas.api.url` and `maas.api.key`, then set the `maas.subnet.ipv4` and/or `maas.subnet.ipv6` keys on the instance or profile's `nic` entry. This will have LXD register all your instances with MAAS, giving them proper DHCP leases and DNS records. If you set the `ipv4.address` or `ipv6.address` keys on the nic, then those will be registered as static assignments in MAAS too. #### Type: infiniband Supported instance types: container LXD supports two different kind of network types for infiniband devices: - `physical`: Straight physical device passthrough from the host. The targeted device will vanish from the host and appear in the instance. - `sriov`: Passes a virtual function of an SR-IOV enabled physical network device into the instance. Different network interface types have different additional properties, the current list is: Key | Type | Default | Required | Used by | Description :-- | :-- | :-- | :-- | :-- | :-- nictype | string | - | yes | all | The device type, one of "physical", or "sriov" name | string | kernel assigned | no | all | The name of the interface inside the instance hwaddr | string | randomly assigned | no | all | The MAC address of the new interface. Can be either full 20 byte variant or short 8 byte variant (which will only modify the last 8 bytes of the parent device) mtu | integer | parent MTU | no | all | The MTU of the new interface parent | string | - | yes | physical, sriov | The name of the host device or bridge To create a `physical` `infiniband` device use: ``` lxc config device add infiniband nictype=physical parent= ``` ##### SR-IOV with infiniband devices Infiniband devices do support SR-IOV but in contrast to other SR-IOV enabled devices infiniband does not support dynamic device creation in SR-IOV mode. This means users need to pre-configure the number of virtual functions by configuring the corresponding kernel module. To create a `sriov` `infiniband` device use: ``` lxc config device add infiniband nictype=sriov parent= ``` #### Type: disk Supported instance types: container, VM Disk entries are essentially mountpoints inside the instance. They can either be a bind-mount of an existing file or directory on the host, or if the source is a block device, a regular mount. LXD supports the following additional source types: - Ceph-rbd: Mount from existing ceph RBD device that is externally managed. LXD can use ceph to manage an internal file system for the instance, but in the event that a user has a previously existing ceph RBD that they would like use for this instance, they can use this command. Example command ``` lxc config device add ceph-rbd1 disk source=ceph:/ ceph.user_name= ceph.cluster_name= path=/ceph ``` - Ceph-fs: Mount from existing ceph FS device that is externally managed. LXD can use ceph to manage an internal file system for the instance, but in the event that a user has a previously existing ceph file sys that they would like use for this instancer, they can use this command. Example command. ``` lxc config device add ceph-fs1 disk source=cephfs:/ ceph.user_name= ceph.cluster_name= path=/cephfs ``` - VM cloud-init: Generate a cloud-init config ISO from the user.vendor-data, user.user-data and user.meta-data config keys and attach to the VM so that cloud-init running inside the VM guest will detect the drive on boot and apply the config. Only applicable to virtual-machine instances. Example command. ``` lxc config device add config disk source=cloud-init:config ``` Currently only the root disk (path=/) and config drive (source=cloud-init:config) are supported with virtual machines. The following properties exist: Key | Type | Default | Required | Description :-- | :-- | :-- | :-- | :-- limits.read | string | - | no | I/O limit in byte/s (various suffixes supported, see below) or in iops (must be suffixed with "iops") limits.write | string | - | no | I/O limit in byte/s (various suffixes supported, see below) or in iops (must be suffixed with "iops") limits.max | string | - | no | Same as modifying both limits.read and limits.write path | string | - | yes | Path inside the instance where the disk will be mounted (only for containers). source | string | - | yes | Path on the host, either to a file/directory or to a block device required | boolean | true | no | Controls whether to fail if the source doesn't exist readonly | boolean | false | no | Controls whether to make the mount read-only size | string | - | no | Disk size in bytes (various suffixes supported, see below). This is only supported for the rootfs (/) size.state | string | - | no | Same as size above but applies to the filesystem volume used for saving runtime state in virtual machines. recursive | boolean | false | no | Whether or not to recursively mount the source path pool | string | - | no | The storage pool the disk device belongs to. This is only applicable for storage volumes managed by LXD propagation | string | - | no | Controls how a bind-mount is shared between the instance and the host. (Can be one of `private`, the default, or `shared`, `slave`, `unbindable`, `rshared`, `rslave`, `runbindable`, `rprivate`. Please see the Linux Kernel [shared subtree](https://www.kernel.org/doc/Documentation/filesystems/sharedsubtree.txt) documentation for a full explanation) shift | boolean | false | no | Setup a shifting overlay to translate the source uid/gid to match the instance (only for containers) raw.mount.options | string | - | no | Filesystem specific mount options ceph.user\_name | string | admin | no | If source is ceph or cephfs then ceph user\_name must be specified by user for proper mount ceph.cluster\_name | string | ceph | no | If source is ceph or cephfs then ceph cluster\_name must be specified by user for proper mount boot.priority | integer | - | no | Boot priority for VMs (higher boots first) #### Type: unix-char Supported instance types: container Unix character device entries simply make the requested character device appear in the instance's `/dev` and allow read/write operations to it. The following properties exist: Key | Type | Default | Required | Description :-- | :-- | :-- | :-- | :-- source | string | - | no | Path on the host path | string | - | no | Path inside the instance (one of "source" and "path" must be set) major | int | device on host | no | Device major number minor | int | device on host | no | Device minor number uid | int | 0 | no | UID of the device owner in the instance gid | int | 0 | no | GID of the device owner in the instance mode | int | 0660 | no | Mode of the device in the instance required | boolean | true | no | Whether or not this device is required to start the instance #### Type: unix-block Supported instance types: container Unix block device entries simply make the requested block device appear in the instance's `/dev` and allow read/write operations to it. The following properties exist: Key | Type | Default | Required | Description :-- | :-- | :-- | :-- | :-- source | string | - | no | Path on the host path | string | - | no | Path inside the instance (one of "source" and "path" must be set) major | int | device on host | no | Device major number minor | int | device on host | no | Device minor number uid | int | 0 | no | UID of the device owner in the instance gid | int | 0 | no | GID of the device owner in the instance mode | int | 0660 | no | Mode of the device in the instance required | boolean | true | no | Whether or not this device is required to start the instance #### Type: usb Supported instance types: container, VM USB device entries simply make the requested USB device appear in the instance. The following properties exist: Key | Type | Default | Required | Description :-- | :-- | :-- | :-- | :-- vendorid | string | - | no | The vendor id of the USB device productid | string | - | no | The product id of the USB device uid | int | 0 | no | UID of the device owner in the instance gid | int | 0 | no | GID of the device owner in the instance mode | int | 0660 | no | Mode of the device in the instance required | boolean | false | no | Whether or not this device is required to start the instance. (The default is false, and all devices are hot-pluggable) #### Type: gpu GPU device entries simply make the requested gpu device appear in the instance. ```{note} Container devices may match multiple GPUs at once. However, for virtual machines a device can only match a single GPU. ``` ##### GPUs Available: The following GPUs can be specified using the `gputype` property: - [physical](#gpu-physical) Passes through an entire GPU. This is the default if `gputype` is unspecified. - [mdev](#gpu-mdev) Creates and passes through a virtual GPU into the instance. - [mig](#gpu-mig) Creates and passes through a MIG (Multi-Instance GPU) device into the instance. - [sriov](#gpu-sriov) Passes a virtual function of an SR-IOV enabled GPU into the instance. ##### gpu: physical Supported instance types: container, VM Passes through an entire GPU. The following properties exist: Key | Type | Default | Required | Description :-- | :-- | :-- | :-- | :-- vendorid | string | - | no | The vendor id of the GPU device productid | string | - | no | The product id of the GPU device id | string | - | no | The card id of the GPU device pci | string | - | no | The pci address of the GPU device uid | int | 0 | no | UID of the device owner in the instance (container only) gid | int | 0 | no | GID of the device owner in the instance (container only) mode | int | 0660 | no | Mode of the device in the instance (container only) ##### gpu: mdev Supported instance types: VM Creates and passes through a virtual GPU into the instance. A list of available mdev profiles can be found by running `lxc info --resources`. The following properties exist: Key | Type | Default | Required | Description :-- | :-- | :-- | :-- | :-- vendorid | string | - | no | The vendor id of the GPU device productid | string | - | no | The product id of the GPU device id | string | - | no | The card id of the GPU device pci | string | - | no | The pci address of the GPU device mdev | string | - | yes | The mdev profile to use (e.g. i915-GVTg\_V5\_4) ##### gpu: mig Supported instance types: container Creates and passes through a MIG compute instance. This currently requires NVIDIA MIG instances to be pre-created. The following properties exist: Key | Type | Default | Required | Description :-- | :-- | :-- | :-- | :-- vendorid | string | - | no | The vendor id of the GPU device productid | string | - | no | The product id of the GPU device id | string | - | no | The card id of the GPU device pci | string | - | no | The pci address of the GPU device mig.ci | int | - | no | Existing MIG compute instance ID mig.gi | int | - | no | Existing MIG GPU instance ID mig.uuid | string | - | no | Existing MIG device UUID ("MIG-" prefix can be omitted) Note: Either "mig.uuid" (Nvidia drivers 470+) or both "mig.ci" and "mig.gi" (old Nvidia drivers) must be set. ##### gpu: sriov Supported instance types: VM Passes a virtual function of an SR-IOV enabled GPU into the instance. The following properties exist: Key | Type | Default | Required | Description :-- | :-- | :-- | :-- | :-- vendorid | string | - | no | The vendor id of the parent GPU device productid | string | - | no | The product id of the parent GPU device id | string | - | no | The card id of the parent GPU device pci | string | - | no | The pci address of the parent GPU device #### Type: proxy Supported instance types: container (`nat` and non-`nat` modes), VM (`nat` mode only) Proxy devices allow forwarding network connections between host and instance. This makes it possible to forward traffic hitting one of the host's addresses to an address inside the instance or to do the reverse and have an address in the instance connect through the host. The supported connection types are: * `tcp <-> tcp` * `udp <-> udp` * `unix <-> unix` * `tcp <-> unix` * `unix <-> tcp` * `udp <-> tcp` * `tcp <-> udp` * `udp <-> unix` * `unix <-> udp` The proxy device also supports a `nat` mode where packets are forwarded using NAT rather than being proxied through a separate connection. This has benefit that the client address is maintained without the need for the target destination to support the `PROXY` protocol (which is the only way to pass the client address through when using the proxy device in non-nat mode). When configuring a proxy device with `nat=true`, you will need to ensure that the target instance has a static IP configured in LXD on its NIC device. E.g. ``` lxc config device set ipv4.address= ipv6.address= ``` In order to define a static IPv6 address, the parent managed network needs to have `ipv6.dhcp.stateful` enabled. In NAT mode the supported connection types are: * `tcp <-> tcp` * `udp <-> udp` When defining IPv6 addresses use square bracket notation, e.g. ``` connect=tcp:[2001:db8::1]:80 ``` You can specify that the connect address should be the IP of the instance by setting the connect IP to the wildcard address (`0.0.0.0` for IPv4 and `[::]` for IPv6). The listen address can also use wildcard addresses when using non-NAT mode. However when using `nat` mode you must specify an IP address on the LXD host. Key | Type | Default | Required | Description :-- | :-- | :-- | :-- | :-- listen | string | - | yes | The address and port to bind and listen (`::[-][,]`) connect | string | - | yes | The address and port to connect to (`::[-][,]`) bind | string | host | no | Which side to bind on (host/instance) uid | int | 0 | no | UID of the owner of the listening Unix socket gid | int | 0 | no | GID of the owner of the listening Unix socket mode | int | 0644 | no | Mode for the listening Unix socket nat | bool | false | no | Whether to optimize proxying via NAT (requires instance NIC has static IP address) proxy\_protocol | bool | false | no | Whether to use the HAProxy PROXY protocol to transmit sender information security.uid | int | 0 | no | What UID to drop privilege to security.gid | int | 0 | no | What GID to drop privilege to ``` lxc config device add proxy listen=::[-][,] connect=:: bind= ``` #### Type: unix-hotplug Supported instance types: container Unix hotplug device entries make the requested unix device appear in the instance's `/dev` and allow read/write operations to it if the device exists on the host system. Implementation depends on systemd-udev to be run on the host. The following properties exist: Key | Type | Default | Required | Description :-- | :-- | :-- | :-- | :-- vendorid | string | - | no | The vendor id of the unix device productid | string | - | no | The product id of the unix device uid | int | 0 | no | UID of the device owner in the instance gid | int | 0 | no | GID of the device owner in the instance mode | int | 0660 | no | Mode of the device in the instance required | boolean | false | no | Whether or not this device is required to start the instance. (The default is false, and all devices are hot-pluggable) ### Units for storage and network limits Any value representing bytes or bits can make use of a number of useful suffixes to make it easier to understand what a particular limit is. Both decimal and binary (kibi) units are supported with the latter mostly making sense for storage limits. The full list of bit suffixes currently supported is: - bit (1) - kbit (1000) - Mbit (1000^2) - Gbit (1000^3) - Tbit (1000^4) - Pbit (1000^5) - Ebit (1000^6) - Kibit (1024) - Mibit (1024^2) - Gibit (1024^3) - Tibit (1024^4) - Pibit (1024^5) - Eibit (1024^6) The full list of byte suffixes currently supported is: - B or bytes (1) - kB (1000) - MB (1000^2) - GB (1000^3) - TB (1000^4) - PB (1000^5) - EB (1000^6) - KiB (1024) - MiB (1024^2) - GiB (1024^3) - TiB (1024^4) - PiB (1024^5) - EiB (1024^6) ### Instance types LXD supports simple instance types. Those are represented as a string which can be passed at instance creation time. There are three allowed syntaxes: - `` - `:` - `c-m` For example, those 3 are equivalent: - t2.micro - aws:t2.micro - c1-m1 On the command line, this is passed like this: ```bash lxc launch ubuntu:20.04 my-instance -t t2.micro ``` The list of supported clouds and instance types can be found here: https://github.com/dustinkirkland/instance-type ### Hugepage limits via `limits.hugepages.[size]` LXD allows to limit the number of hugepages available to a container through the `limits.hugepage.[size]` key. Limiting hugepages is done through the hugetlb cgroup controller. This means the host system needs to expose the hugetlb controller in the legacy or unified cgroup hierarchy for these limits to apply. Note that architectures often expose multiple hugepage sizes. In addition, architectures may expose different hugepage sizes than other architectures. Limiting hugepages is especially useful when LXD is configured to intercept the mount syscall for the `hugetlbfs` filesystem in unprivileged containers. When LXD intercepts a `hugetlbfs` mount syscall, it will mount the `hugetlbfs` filesystem for a container with correct `uid` and `gid` values as mount options. This makes it possible to use hugepages from unprivileged containers. However, it is recommended to limit the number of hugepages available to the container through `limits.hugepages.[size]` to stop the container from being able to exhaust the hugepages available to the host. ### Resource limits via `limits.kernel.[limit name]` LXD exposes a generic namespaced key `limits.kernel.*` which can be used to set resource limits for a given instance. It is generic in the sense that LXD will not perform any validation on the resource that is specified following the `limits.kernel.*` prefix. LXD cannot know about all the possible resources that a given kernel supports. Instead, LXD will simply pass down the corresponding resource key after the `limits.kernel.*` prefix and its value to the kernel. The kernel will do the appropriate validation. This allows users to specify any supported limit on their system. Some common limits are: Key | Resource | Description :-- | :--- | :---------- limits.kernel.as | RLIMIT\_AS | Maximum size of the process's virtual memory limits.kernel.core | RLIMIT\_CORE | Maximum size of the process's coredump file limits.kernel.cpu | RLIMIT\_CPU | Limit in seconds on the amount of cpu time the process can consume limits.kernel.data | RLIMIT\_DATA | Maximum size of the process's data segment limits.kernel.fsize | RLIMIT\_FSIZE | Maximum size of files the process may create limits.kernel.locks | RLIMIT\_LOCKS | Limit on the number of file locks that this process may establish limits.kernel.memlock | RLIMIT\_MEMLOCK | Limit on the number of bytes of memory that the process may lock in RAM limits.kernel.nice | RLIMIT\_NICE | Maximum value to which the process's nice value can be raised limits.kernel.nofile | RLIMIT\_NOFILE | Maximum number of open files for the process limits.kernel.nproc | RLIMIT\_NPROC | Maximum number of processes that can be created for the user of the calling process limits.kernel.rtprio | RLIMIT\_RTPRIO | Maximum value on the real-time-priority that maybe set for this process limits.kernel.sigpending | RLIMIT\_SIGPENDING | Maximum number of signals that maybe queued for the user of the calling process A full list of all available limits can be found in the manpages for the `getrlimit(2)`/`setrlimit(2)` system calls. To specify a limit within the `limits.kernel.*` namespace use the resource name in lowercase without the `RLIMIT_` prefix, e.g. `RLIMIT_NOFILE` should be specified as `nofile`. A limit is specified as two colon separated values which are either numeric or the word `unlimited` (e.g. `limits.kernel.nofile=1000:2000`). A single value can be used as a shortcut to set both soft and hard limit (e.g. `limits.kernel.nofile=3000`) to the same value. A resource with no explicitly configured limitation will be inherited from the process starting up the instance. Note that this inheritance is not enforced by LXD but by the kernel. ### Snapshot scheduling and configuration LXD supports scheduled snapshots which can be created at most once every minute. There are three configuration options: - `snapshots.schedule` takes a shortened cron expression: ` `. If this is empty (default), no snapshots will be created. - `snapshots.schedule.stopped` controls whether or not stopped instance are to be automatically snapshotted. It defaults to `false`. - `snapshots.pattern` takes a pongo2 template string to format the snapshot name. To name snapshots with time stamps, the pongo2 context variable `creation_date` can be used. Be aware that you should format the date (e.g. use `{{ creation_date|date:"2006-01-02_15-04-05" }}`) in your template string to avoid forbidden characters in the snapshot name. Another way to avoid name collisions is to use the placeholder `%d`. If a snapshot with the same name (excluding the placeholder) already exists, all existing snapshot names will be taken into account to find the highest number at the placeholders position. This number will be incremented by one for the new name. The starting number if no snapshot exists will be `0`. The default behavior of `snapshots.pattern` is equivalent to a format string of `snap%d`. Example of using pongo2 syntax to format snapshot names with timestamps: ```bash lxc config set INSTANCE snapshots.pattern "{{ creation_date|date:'2006-01-02_15-04-05' }}" ``` This results in snapshots named `{date/time of creation}` down to the precision of a second.