| Project | LXD |
| Status | Implemented |
| Author(s) | @monstermunchkin |
| Approver(s) | @stgraber |
| Release | 4.21 |
| Internal ID | LX010 |
Abstract
This adds support for grouping cluster members.
Rationale
LXD currently doesn’t support grouping cluster members. Adding this feature will allow targeting groups instead of single members. This will also add project restrictions for groups and members.
Specification
Design
Initially, there will be an undeletable default group which all members will belong to. Cluster groups can be created using lxc cluster group create. There will also be delete, edit, and show commands for groups .
Cluster members can change their groups by editing their groups config option. They always need to be in at least one group.
The existing scheduler.instance config option will gain a new group value. This allows targeting of the server when either selected directly or selected by one of its groups. If the value is all, targeting using the @ prefix will work as well.
When using a group as a target, it needs to be prefixed with @. Example:
lxc launch images:ubuntu/20.04 c1 --target=@foobar
This will create a new container on one of the cluster members in the foobar group.
Since group targeting will use the @ prefix, cluster member names will no longer be able to start with @.
There will also be a new project restriction restricted.cluster.groups which when set will restrict the user to targeting those group of cluster members (either by group name or cluster member name that’s part of those groups).
API changes
Create and edit a cluster group
POST /1.0/cluster/groups
POST /1.0/cluster/groups/<name>
PUT /1.0/cluster/groups/<name>
PATCH /1.0/cluster/groups/<name>
Using the following new API structures respectively:
type ClusterGroupsPost struct {
// The name of the cluster group
// Example: group1
GroupName string `json:"group_name" yaml:"group_name"`
}
type ClusterGroupPost struct {
// The new name of the cluster group
// Example: group1
GroupName string `json:"group_name" yaml:"group_name"`
}
type ClusterGroupPut struct {
// The description of the cluster group
// Example: amd64 servers
Description string `json:"description" yaml:"description"`
// List of members in this group
// Example: ["node1", "node3"]
Members []string `json:"members" yaml:"members"`
}
Delete a cluster group
DELETE /1.0/cluster/groups/<name>
List cluster groups
GET /1.0/cluster/groups
GET /1.0/cluster/groups/<name>
Returns a list or single record (respectively) of this new ClusterGroup structure:
type ClusterGroup struct {
ClusterGroupPut `yaml:",inline"`
ClusterGroupPost `yaml:",inline"`
}
If GET /1.0/cluster/groups is used with recursion=1, the entire records are listed. If recursion=0 (default), only the cluster group names are listed.
Other
The ClusterMemberPut struct will gain a new Groups fields:
type ClusterMemberPut struct {
// ...
// List of cluster groups this member belongs to
// Example: ["group1", "group2"]
Groups []string `json:"groups" yaml:"groups"`
}
CLI changes
The CLI will gain the following new commands:
- Create new group:
lxc cluster group create <group_name> - Delete existing group:
lxc cluster group delete <group_name> - Show information on group:
lxc cluster group show <group_name> - Change group fields and members:
lxc cluster group edit <group_name> - Assign member to group:
lxc cluster group assign <member_name> <group_name> - Remove member from group:
lxc cluster group remove <member_name> <group_name> - Rename group:
lxc cluster group rename <old_name> <new_name> - List groups:
lxc cluster group list
Database changes
There will be two new tables added called cluster_groups and nodes_cluster_groups.
CREATE TABLE "cluster_groups" (
id INTEGER PRIMARY KEY AUTOINCREMENT NOT NULL,
name TEXT NOT NULL,
description TEXT,
UNIQUE (name),
);
CREATE TABLE nodes_cluster_groups (
node_id INTEGER NOT NULL,
group_id INTEGER NOT NULL,
FOREIGN KEY (node_id) REFERENCES nodes (id) ON DELETE CASCADE,
FOREIGN KEY (group_id) REFERENCES cluster_groups (id) ON DELETE CASCADE,
UNIQUE (node_id, group_id)
);
Upgrade handling
For clusters, all existing cluster members will be placed in the default cluster group.