Horizontal Scaling

Experimental

Horizontal scaling is an experimental feature. Test thoroughly in a non-production environment before using it in production.

Horizontal scaling clones containers when group-level resource usage exceeds thresholds, and removes clones when usage drops.

Configuration

HORIZONTAL_SCALING_GROUP_1:
  base_snapshot_name: "101"
  min_instances: 2
  max_instances: 5
  starting_clone_id: 99000
  clone_network_type: "static"   # "static" or "dhcp"
  static_ip_range:
    - "192.168.100.195"
    - "192.168.100.200"
  horiz_cpu_upper_threshold: 95
  horiz_memory_upper_threshold: 95
  horiz_cpu_lower_threshold: 30
  horiz_memory_lower_threshold: 30
  scale_out_grace_period: 300    # seconds between scale-out actions
  scale_in_grace_period: 600     # seconds between scale-in actions
  lxc_containers:
    - "101"

How it works

1. Metrics — Average CPU and memory usage are calculated across all containers in the group.
2. Scale out — If averages exceed the upper thresholds, a new container is cloned from the base snapshot.
3. Scale in — If averages drop below the lower thresholds and the group has more than min_containers, the last clone is stopped.
4. Grace periods — Scale-out and scale-in actions are throttled by configurable grace periods.

Parameters

Parameter	Description
base_snapshot_name	Container ID to use as the clone source.
min_instances	Minimum number of containers in the group.
max_instances	Maximum number of containers (clones stop here).
starting_clone_id	First container ID for new clones.
clone_network_type	"dhcp" or "static".
static_ip_range	List of IPs for static assignment. Leave [] for DHCP.
horiz_cpu_upper_threshold	Group avg CPU % to trigger scale-out.
horiz_memory_upper_threshold	Group avg memory % to trigger scale-out.
horiz_cpu_lower_threshold	Group avg CPU % to trigger scale-in.
horiz_memory_lower_threshold	Group avg memory % to trigger scale-in.
scale_out_grace_period	Minimum seconds between scale-out actions.
scale_in_grace_period	Minimum seconds between scale-in actions.

Use case

A web server container group that experiences traffic spikes: when average CPU exceeds 95%, a clone is created and started automatically. When traffic drops, excess clones are stopped.