Creating an instance without a public IP

By default a new instance gets two addresses: one on your project’s private network and a public floating IP. For anything that should not be reachable from the internet — a database, a worker, an internal service — you can skip the public one at creation.

Verified on production: the request below was run for real, and the instance came up with only its private address.

The request

Add "skip_floating_ip": true to a normal create. Everything else is the same as creating any instance, including the eight required fields:

curl -X POST https://console.cloudlogics.com/api/v1/vm/create \
  -H "Authorization: Bearer $CL_KEY" \
  -H "Content-Type: application/json" \
  -d '{
        "name": "my-private-vm",
        "flavor_id": "bx1aL",
        "image_id": "232f283d-672b-4aee-a2dc-71bebdb535df",
        "size": "1",
        "region": "us-ftw-1",
        "id": "42",
        "owner": "your-username",
        "project": "my-project-a1b2",
        "skip_floating_ip": true
      }'

Returns 202:

{ "data": "server provisioning" }

As with any create, the instance does not exist yet and the response carries no instance id. Provisioning takes about a minute.

What you get

Once it is up, GET /vm shows the instance with only the private-network address — there is no public entry at all:

"addresses": { "my-project-a1b2_private_network": ["172.26.8.197"] }

Compare an instance created without the flag, which lists both a private address and a public one.

Reaching it

The instance can talk to, and be reached from, other instances on the same private network. To administer it, go through an instance that does have a public IP — for example, SSH to a public instance and from there to the private one.

Security group rules still apply. A rule with remote_ip set to your private network’s range (for example 172.26.8.0/24) lets other instances in the project reach it while nothing else can.

Things to know

• The decision is made at creation. There is currently no API operation to attach a public IP to a running instance. If you later need one, create a new instance without the flag.
• Leaving the flag out, or setting it to false, gives the instance a public IP — the default behaviour, also verified on production.
• size is still required, and still leaves a data volume behind when the instance is deleted. See deleting an instance.