Server Groups API Reference

Reference · Updated Sep 2026

Coming from another cloud?

▸AWS·Placement Groups

Placement Groupshigh

Policies: cluster/partition/spread vs affinity/anti-affinity.
AZ-scoped, no instance moves/merges.
Specified at launch via PlacementGroupName.
Max 7 partitions per AZ for partition type.

AWS docs ↗

▸Azure·Availability sets

Availability setshigh

Uses fault/update domains (max 3/20) for HA, fixed at creation, vs flexible OpenStack server group policies (affinity/anti-affinity).
ARM resource (Microsoft.Compute/availabilitySets), VMs assigned at create, no dynamic move.
No extra cost, but requires 2+ VMs for SLA; prefers zones/scale sets.
Lower latency between VMs in set vs zones, hardware-specific isolation.

Azure docs ↗

▸DigitalOcean·API

DigitalOcean APIhigh

Uses REST API over HTTPS with Bearer token authentication via personal access tokens, not OpenStack's Keystone token-based auth.
Base URL https://api.digitalocean.com/v2, incompatible with OpenStack APIs like Nova/Neutron.
Scoped permissions tied to granular API scopes based on team roles, unlike OpenStack role/project assignments.
Rate limits: 5000/hour, 250/minute.

DigitalOcean docs ↗

▸Google Cloud·Sole-Tenant Nodes / Instance Groups

Sole-Tenant Nodes / Instance Groupshigh

MIGs offer autoscaling, autohealing, rolling updates via templates; OpenStack only scheduling policies (affinity etc.).
Zonal/regional with HA/load balancing integration; no management in OpenStack groups.
App health checks trigger recreation; requires external orchestration in OpenStack.

Google Cloud docs ↗

▸Hetzner·Cloud API

Cloud APIhigh

Proprietary REST API over HTTPS with Bearer token auth, not OpenStack Identity API (keystone) endpoints or mechanisms.
Base URL https://api.hetzner.cloud/v1/ with resource-specific endpoints (e.g., /servers) vs OpenStack service endpoints (nova, cinder).
No multi-project handling in single auth; separate per-project tokens vs keystone scopes/projects.
Missing identity/catalog endpoints; no service discovery via API.

Hetzner docs ↗

Server groups API reference

In these methods, \{server_group_id\} is a placeholder for the ID of the server group; replace it with the actual ID. The API lists existing server groups, shows details of a specific server group, creates a new server group with a specified policy, and deletes a server group. The policy in the request body determines how the scheduler places instances in the group relative to each other on the compute hosts.

List server groups#

bash

GET /os-server-groups

Show server group details#

bash

GET /os-server-groups/{server_group_id}

Create a server group#

bash

POST /os-server-groups

The request body shape depends on the Nova microversion you send. See Microversions for how to set the header.

Request body (default microversion 2.1, through 2.63):

JSON

{
  "server_group": {
    "name": "SERVER_GROUP_NAME",
    "policies": ["affinity"]
  }
}

policies: Single-element array. On the default microversion, the endpoint accepts only affinity and anti-affinity. To use soft-affinity or soft-anti-affinity, send the header OpenStack-API-Version: compute 2.15 (or X-OpenStack-Nova-API-Version: 2.15) or later.

Request body (microversion 2.64 or later):

JSON

{
  "server_group": {
    "name": "SERVER_GROUP_NAME",
    "policy": "anti-affinity",
    "rules": {}
  }
}

policy: Single string. From microversion 2.64, this string field replaces the policies array.
rules: Optional object of scheduler rules for the policy, for example max_server_per_host with the soft policies.

Delete a server group#

bash

DELETE /os-server-groups/{server_group_id}

Was this page helpful?

Server Groups API Reference

Server groups API reference

List server groups#

Show server group details#

Create a server group#

Delete a server group#

See Also