Server configuration

The server configuration is a simple set of key and values.

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

  • backups (backups configuration)
  • candid (External user authentication through Candid)
  • cluster (cluster configuration)
  • core (core daemon configuration)
  • images (image configuration)
  • maas (MAAS integration)
  • rbac (Role Based Access Control through external Candid + Canonical RBAC)
Key Type Scope Default API extension Description
backups.compression_algorithm string global gzip backup_compression Compression algorithm to use for new images (bzip2, gzip, lzma, xz or none)
candid.api.key string global - candid_config_key Public key of the candid server (required for HTTP-only servers)
candid.api.url string global - candid_authentication URL of the the external authentication endpoint using Candid
candid.expiry integer global 3600 candid_config Candid macaroon expiry in seconds string global - candid_config Comma-separated list of allowed Candid domains (empty string means all domains are valid)
cluster.https_address string local - clustering_server_address Address the server should using for clustering traffic
cluster.offline_threshold integer global 20 clustering Number of seconds after which an unresponsive node is considered offline
cluster.images_minimal_replica integer global 3 clustering_image_replication Minimal numbers of cluster members with a copy of a particular image (set 1 for no replication, -1 for all members)
cluster.max_voters integer global 3 clustering_sizing Maximum number of cluster members that will be assigned the database voter role
cluster.max_standby integer global 2 clustering_sizing Maximum number of cluster members that will be assigned the database stand-by role
core.debug_address string local - pprof_http Address to bind the pprof debug server to (HTTP)
core.https_address string local - - Address to bind for the remote API (HTTPS)
core.https_allowed_credentials boolean global - - Whether to set Access-Control-Allow-Credentials http header value to "true"
core.https_allowed_headers string global - - Access-Control-Allow-Headers http header value
core.https_allowed_methods string global - - Access-Control-Allow-Methods http header value
core.https_allowed_origin string global - - Access-Control-Allow-Origin http header value
core.proxy_https string global - - https proxy to use, if any (falls back to HTTPS_PROXY environment variable)
core.proxy_http string global - - http proxy to use, if any (falls back to HTTP_PROXY environment variable)
core.proxy_ignore_hosts string global - - hosts which don't need the proxy for use (similar format to NO_PROXY, e.g.,, falls back to NO_PROXY environment variable)
core.trust_ca_certificates boolean global - - Whether to automatically trust clients signed by the CA
core.trust_password string global - - Password to be provided by clients to setup a trust
images.auto_update_cached boolean global true - Whether to automatically update any image that LXD caches
images.auto_update_interval integer global 6 - Interval in hours at which to look for update to cached images (0 disables it)
images.compression_algorithm string global gzip - Compression algorithm to use for new images (bzip2, gzip, lzma, xz or none)
images.remote_cache_expiry integer global 10 - Number of days after which an unused cached remote image will be flushed
maas.api.key string global - maas_network API key to manage MAAS
maas.api.url string global - maas_network URL of the MAAS server
maas.machine string local hostname maas_network Name of this LXD host in MAAS
rbac.agent.url string global - rbac The Candid agent url as provided during RBAC registration
rbac.agent.username string global - rbac The Candid agent username as provided during RBAC registration
rbac.agent.public_key string global - rbac The Candid agent public key as provided during RBAC registration
rbac.agent.private_key string global - rbac The Candid agent private key as provided during RBAC registration
rbac.api.expiry integer global - rbac RBAC macaroon expiry in seconds
rbac.api.key string global - rbac Public key of the RBAC server (required for HTTP-only servers)
rbac.api.url string global - rbac URL of the external RBAC server
storage.backups_volume string local - daemon_storage Volume to use to store the backup tarballs (syntax is POOL/VOLUME)
storage.images_volume string local - daemon_storage Volume to use to store the image tarballs (syntax is POOL/VOLUME)

Those keys can be set using the lxc tool with:

lxc config set <key> <value>

When operating as part of a cluster, the keys marked with a global scope will immediately be applied to all the cluster members. Those keys with a local scope must be set on a per member basis using the --target option of the command line tool.

Exposing LXD to the network

By default, LXD can only be used by local users through a UNIX socket.

To expose LXD to the network, you'll need to set core.https_address. All remote clients can then connect to LXD and access any image which was marked for public use.

Trusted clients can be manually added to the trust store on the server with lxc config trust add or the core.trust_password key can be set allowing for clients to self-enroll into the trust store at connection time by providing the confgiured password.

More details about authentication can be found here.

External authentication

LXD when accessed over the network can be configured to use external authentication through Candid.

Setting the candid.* configuration keys above to the values matching your Candid deployment will allow users to authenticate through their web browsers and then get trusted by LXD.

For those that have a Canonical RBAC server in front of their Candid server, they can instead set the rbac.* configuration keys which are a superset of the candid.* ones and allow for LXD to integrate with the RBAC service.

When integrated with RBAC, individual users and groups can be granted various level of access on a per-project basis. All of this is driven externally through the RBAC service.

More details about authentication can be found here.