Document full OpenStack server create command with flavor, image, network

deploy/README.md

@@ -22,10 +22,32 @@ Other distributions will need manual adaptation.
 Customize `cloud-init.yml` — replace the SSH public key and optionally the hostname/timezone. Then use it during VM creation:
 
 - **Proxmox**: attach as cloud-init user-data
-- **OpenStack**: `openstack server create --user-data cloud-init.yml ...`
+- **OpenStack**: pass via `--user-data` flag (see full example below)
 - **AWS/DigitalOcean/etc**: paste into the "user data" field
 
-The VM boots with Docker installed, firewall configured, and your SSH key authorized. Log in as the `devbox` user.
+#### Full OpenStack example
+
+Cloud-init only handles guest configuration — flavor, image, network, and security group must be specified explicitly at creation time:
+
+```bash
+# List available flavors to choose appropriate sizing
+openstack flavor list
+
+# Create the security group first (one-time, see below)
+./setup-openstack-secgroup.sh
+
+# Create the VM
+openstack server create \
+  --flavor m1.medium \
+  --image debian-13-trixie \
+  --network my-network \
+  --security-group opencode-devbox \
+  --key-name my-ssh-key \
+  --user-data cloud-init.yml \
+  devbox-vm
+```
+
+The VM boots with Docker installed, firewall configured (or skipped on OpenStack), and your SSH key authorized. Log in as the `devbox` user.
 
 ### Option 2: Post-install script (manual)