介紹

A LXD cluster consists of one bootstrap server and at least two further cluster members.

It stores its state in a dqlite

dqlite = distributed SQLite(https://dqlite.io/)

When you create the cluster, the Dqlite database runs on only the bootstrap server

until a third member joins the cluster.

Then both the second and the third server receive a replica of the database.

At each time, there is an elected cluster leader that monitors the health of the other members.

Each member that replicates the database has either the role of a voter or of a stand-by.

Role: database-leader, database, database-standby, event-hub, ovn-chassis

The default number of voter members (cluster.max_voters) is 3

The default number of stand-by members (cluster.max_standby) is 2

Cluster certificate

In a LXD cluster, the API on all servers responds with the same shared certificate

/var/snap/lxd/common/lxd/cluster.crt

lxc cluster update-certificate