# Cluster link configuration Each cluster link has its own key/value configuration with the following supported namespaces: - [Miscellaneous options](#ref-cluster-link-config-misc) - [Volatile internal data](#ref-cluster-link-config-volatile) ## Miscellaneous options The following keys are currently supported: `user.*` Free form user key/value storage [](#cluster-link-conf:user.*) | **Key:** | `user.*` | |-------------|------------| | **Type:** | string | User keys can be used in search. ## Volatile internal data #### WARNING The `volatile.*` keys cannot be manipulated by the user. Do not attempt to modify these keys in any way. LXD modifies these keys, and attempting to manipulate them yourself might break LXD in non-obvious ways. The following volatile keys are currently used internally by LXD to store internal data specific to a cluster link: `volatile.addresses` Cluster link member addresses. [](#cluster-link-volatile-conf:volatile.addresses) | **Key:** | `volatile.addresses` | |-------------|------------------------| | **Type:** | string | | **Scope:** | global | A comma-separated list of cluster link member addresses. `volatile.pending_address` Pending public cluster link address. [](#cluster-link-volatile-conf:volatile.pending_address) | **Key:** | `volatile.pending_address` | |-------------|------------------------------| | **Type:** | string | | **Scope:** | global | The address that was contacted and verified for a pending public cluster link, awaiting confirmation. `volatile.pending_certificate` Pending public cluster link certificate. [](#cluster-link-volatile-conf:volatile.pending_certificate) | **Key:** | `volatile.pending_certificate` | |-------------|----------------------------------| | **Type:** | string | | **Scope:** | global | The PEM-encoded certificate fetched for a pending public cluster link, awaiting confirmation. `volatile.uuid` Linked cluster UUID. [](#cluster-link-volatile-conf:volatile.uuid) | **Key:** | `volatile.uuid` | |-------------|-------------------| | **Type:** | string | | **Scope:** | global | The UUID of the linked cluster. ## Related topics How-to guides: - [Clustering](https://canonical.com/lxd/docs/latest/clustering/index.html.md#clustering) Explanation: - [Clusters](https://canonical.com/lxd/docs/latest/explanation/clusters/index.html.md#exp-clusters)