Project configuration#

LXD supports projects as a way to split your LXD server. Each project holds its own set of instances and may also have its own images and profiles.

What a project contains is defined through the features configuration keys. When a feature is disabled, the project inherits from the default project.

By default all new projects get the entire feature set, on upgrade, existing projects do not get new features enabled.

The key/value configuration is namespaced with the following namespaces currently supported:

  • features (What part of the project featureset is in use)

  • limits (Resource limits applied on containers and VMs belonging to the project)

  • user (free form key/value for user metadata)

Key

Type

Condition

Default

Description

backups.compression_algorithm

string

-

-

Compression algorithm to use for backups (bzip2, gzip, lzma, xz or none) in the project

features.images

boolean

-

true

Separate set of images and image aliases for the project

features.networks

boolean

-

false

Separate set of networks for the project

features.profiles

boolean

-

true

Separate set of profiles for the project

features.storage.volumes

boolean

-

true

Separate set of storage volumes for the project

images.auto_update_cached

boolean

-

-

Whether to automatically update any image that LXD caches

images.auto_update_interval

integer

-

-

Interval in hours at which to look for update to cached images (0 disables it)

images.compression_algorithm

string

-

-

Compression algorithm to use for images (bzip2, gzip, lzma, xz or none) in the project

images.default_architecture

string

-

-

Default architecture which should be used in mixed architecture cluster

images.remote_cache_expiry

integer

-

-

Number of days after which an unused cached remote image will be flushed in the project

limits.containers

integer

-

-

Maximum number of containers that can be created in the project

limits.cpu

integer

-

-

Maximum value for the sum of individual “limits.cpu” configs set on the instances of the project

limits.disk

string

-

-

Maximum value of aggregate disk space used by all instances volumes, custom volumes and images of the project

limits.instances

integer

-

-

Maximum number of total instances that can be created in the project

limits.memory

string

-

-

Maximum value for the sum of individual “limits.memory” configs set on the instances of the project

limits.networks

integer

-

-

Maximum value for the number of networks this project can have

limits.processes

integer

-

-

Maximum value for the sum of individual “limits.processes” configs set on the instances of the project

limits.virtual-machines

integer

-

-

Maximum number of VMs that can be created in the project

restricted

boolean

-

false

Block access to security-sensitive features (this must be enabled to allow the restricted.* keys to take effect, this is so it can be tempoarily disabled if needed without having to clear the related keys)

restricted.backups

string

-

block

Prevents the creation of any instance or volume backups.

restricted.cluster.groups

string

-

-

Prevents targeting cluster groups other than the provided ones.

restricted.cluster.target

string

-

block

Prevents direct targeting of cluster members when creating or moving instances.

restricted.containers.lowlevel

string

-

block

Prevents use of low-level container options like raw.lxc, raw.idmap, volatile, etc.

restricted.containers.nesting

string

-

block

Prevents setting security.nesting=true.

restricted.containers.privilege

string

-

unpriviliged

If “unpriviliged”, prevents setting security.privileged=true. If “isolated”, prevents setting security.privileged=true and also security.idmap.isolated=true. If “allow”, no restriction apply.

restricted.containers.interception

string

-

block

Prevents use for system call interception options. When set to allow usually safe interception options will be allowed (filesystem mounting will remain blocked).

restricted.devices.disk

string

-

managed

If “block” prevent use of disk devices except the root one. If “managed” allow use of disk devices only if “pool=” is set. If “allow”, no restrictions apply.

restricted.devices.disk.paths

string

-

-

If restricted.devices.disk is set to allow, this sets a comma-separated list of path prefixes that restrict the source setting on disk devices. If empty then all paths are allowed.

restricted.devices.gpu

string

-

block

Prevents use of devices of type “gpu”

restricted.devices.infiniband

string

-

block

Prevents use of devices of type “infiniband”

restricted.devices.nic

string

-

managed

If “block” prevent use of all network devices. If “managed” allow use of network devices only if “network=” is set. If “allow”, no restrictions apply.

restricted.devices.pci

string

-

block

Prevents use of devices of type “pci”

restricted.devices.proxy

string

-

block

Prevents use of devices of type “proxy”

restricted.devices.unix-block

string

-

block

Prevents use of devices of type “unix-block”

restricted.devices.unix-char

string

-

block

Prevents use of devices of type “unix-char”

restricted.devices.unix-hotplug

string

-

block

Prevents use of devices of type “unix-hotplug”

restricted.devices.usb

string

-

block

Prevents use of devices of type “usb”

restricted.idmap.uid

string

-

-

Specifies the allowed host UID ranges allowed in the instance raw.idmap setting.

restricted.idmap.gid

string

-

-

Specifies the allowed host GID ranges allowed in the instance raw.idmap setting.

restricted.networks.subnets

string

-

block

Comma delimited list of network subnets from the uplink networks (in the form <uplink>:<subnet>) that are allocated for use in this project

restricted.networks.uplinks

string

-

block

Comma delimited list of network names that can be used as uplinks for networks in this project

restricted.networks.zones

string

-

block

Comma delimited list of network zones that can be used (or something under them) in this project

restricted.snapshots

string

-

block

Prevents the creation of any instance or volume snapshots.

restricted.virtual-machines.lowlevel

string

-

block

Prevents use of low-level virtual-machine options like raw.qemu, volatile, etc.

Those keys can be set using the lxc tool with:

lxc project set <project> <key> <value>

Project limits#

Note that to be able to set one of the limits.* config keys, all instances in the project must have that same config key defined, either directly or via a profile.

In addition to that:

  • The limits.cpu config key also requires that CPU pinning is not used.

  • The limits.memory config key must be set to an absolute value, not a percentage.

The limits.* config keys defined on a project act as a hard upper bound for the aggregate value of the individual limits.* config keys defined on the project’s instances, either directly or via profiles.

For example, setting the project’s limits.memory config key to 50GB means that the sum of the individual values of all limits.memory config keys defined on the project’s instances will be kept under 50GB. Trying to create or modify an instance assigning it a limits.memory value that would make the total sum exceed 50GB, will result in an error.

Similarly, setting the project’s limits.cpu config key to 100, means that the sum of individual limits.cpu values will be kept below 100.

Project restrictions#

If the restricted config key is set to true, then the instances of the project won’t be able to access security-sensitive features, such as container nesting, raw LXC configuration, etc.

The exact set of features that the restricted config key blocks may grow across LXD releases, as more features are added that are considered security-sensitive.

Using the various restricted.* sub-keys, it’s possible to pick individual features which would be normally blocked by restricted and allow them, so they can be used by instances of the project.

For example:

lxc project set <project> restricted=true
lxc project set <project> restricted.containers.nesting=allow

will block all security-sensitive features except container nesting.

Each security-sensitive feature has an associated restricted.* project config sub-key whose default value needs to be explicitly changed if you want for that feature to be allowed it in the project.

Note that changing the value of a specific restricted.* config key has an effect only if the top-level restricted key itself is currently set to true. If restricted is set to false, changing a restricted.* sub-key is effectively a no-op.

Most 'restricted.* config keys are binary switches that can be set to either block (the default) or allow. However some of them support other values for more fine-grained control.

Setting all restricted.* keys to allow is effectively equivalent to setting restricted itself to false.