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Oracle VM Auto Provisioning

6 min read

Oracle Cloud Always Free — Ampere A1 Auto-Provisioning

Overview

Automated, zero-risk provisioning system running on an existing Oracle Cloud Free Tier Micro VM (144.21.49.153). It polls the OCI API on a safe 5-minute schedule to secure an Ampere A1 ARM Compute instance (2 OCPUs, 12 GB RAM) the moment capacity becomes available in the London region.

1. Background & Problem Statement

Oracle Cloud Infrastructure (OCI) offers one of the most generous free tiers in cloud computing. However, the high-performance Ampere A1 (ARM) instances are almost perpetually in high demand, resulting in the error:

Out of host capacity

Because regular free-tier accounts share a heavily throttled capacity pool, manual attempts via the web console rarely succeed.

Why Not Upgrade to “Pay As You Go” (PAYG)?

While PAYG accounts get higher provisioning priority:

  1. The upgrade is 100% permanent and irreversible. Oracle does not provide any option to downgrade back to a pure Free Tier account.
  2. Financial Risk: If a non-free resource is accidentally created or storage exceeds 200 GB, the card on file is charged.
  3. Pure Free Tier Guarantee: Pure Free accounts are physically incapable of incurring charges. If a paid resource is attempted, Oracle rejects the request outright.

Decision

Stay on the pure Free Tier to ensure 100% safety and zero financial risk, and use automated API polling with rate-limiting protection to grab capacity as soon as another user releases it.

2. Oracle Cloud Free Tier Quotas (Current)

Recent Quota Changes

Earlier guides reference 4 OCPUs and 24 GB RAM. Oracle has officially adjusted the Always Free Ampere A1 quota to 2 OCPUs and 12 GB RAM. Attempting to request 4 OCPUs on a pure Free Tier tenancy will fail.

ServiceAlways Free AllowanceIn Use BeforeAllocated by Automation
Ampere A1 Cores2 OCPUs (1,500 OCPU hrs/mo)02 OCPUs
Ampere A1 Memory12 GB RAM (9,000 GB hrs/mo)012 GB
AMD Micro VMs2 instances (VM.Standard.E2.1.Micro)1 (Vaultwarden)0 (1 still available)
Block / Boot Storage200 GB total~50 GB50 GB (100 GB still free)
Volume Backups5 backups00
Object Storage20 GB standard00
Outbound Transfer10 TB / monthMinimalIncluded

3. Architecture & Workflow

The solution runs directly on the user’s existing 24/7 AMD Micro instance, consuming virtually zero additional resources.

flowchart TD
    Cron["Cron Job (Every 5 Minutes)"] --> CheckFlag{"Does instance_created.flag exist?"}
    CheckFlag -- Yes --> Exit["Exit immediately (Stop)"]
    CheckFlag -- No --> Auth["Authenticate via OCI API SDK (RSA PEM)"]
    Auth --> Discovery["Discover Subnet & Latest Ubuntu 24.04/26.04 ARM Image"]
    Discovery --> AD1["Attempt Launch in UK-LONDON-1-AD-1"]
    AD1 -- "Out of host capacity" --> AD2["Attempt Launch in UK-LONDON-1-AD-2"]
    AD1 -- "Success" --> Success["Save instance_created.flag & Exit"]
    AD2 -- "Out of host capacity" --> Wait["Log notice & Sleep until next cron"]
    AD2 -- "Success" --> Success

Key Technical Findings in uk-london-1

  • London Availability Domains: London has 3 ADs (AD-1, AD-2, AD-3).
  • Hardware Distribution: Ampere A1 (VM.Standard.A1.Flex) hardware only exists in AD-1 and AD-2. AD-3 returns 404 Not Found for A1 shapes.
  • The script filters specifically for AD-1 and AD-2 to prevent wasted requests.

4. Deployed Components

A. Environment & Tools

  • Host VM: 144.21.49.153 (instance-20250727-1959-vaultwarden)
  • OS: Ubuntu 24.04 LTS (x86_64)
  • Virtualenv: /home/ubuntu/.oci-env
  • CLI / SDK: oci-cli 3.92.1 with oci Python SDK 2.185.2

B. OCI Authentication Setup

  • Configuration File: /home/ubuntu/.oci/config 
    [DEFAULT]
user=ocid1.user.oc1..aaaaaaaaum2rxkbmzsv6ys2jmnjmfj5ps6ehwz5cz4j3tp2o3k436kw6xt4a
fingerprint=fa:93:7c:f8:06:64:66:8f:49:58:5a:a8:dd:52:ef:b8
tenancy=ocid1.tenancy.oc1..aaaaaaaa3qmmiutixriu2ey7z42mpok3xxy4slppn2yk526ylxnlhknnzdha
region=uk-london-1
key_file=/home/ubuntu/.oci/oci_api_key.pem
  • Key Format: Traditional OpenSSL RSA (PKCS#1) format (-----BEGIN RSA PRIVATE KEY-----), required by OCI’s API request signer.

C. The Provisioning Script (/home/ubuntu/launch_arm.py)

#!/home/ubuntu/.oci-env/bin/python3
import os
import sys
from datetime import datetime
 
FLAG_FILE = "/home/ubuntu/.oci/instance_created.flag"
LOG_FILE = "/home/ubuntu/oci_launch.log"
 
def log(msg):
    timestamp = datetime.now().strftime("%Y-%m-%d %H:%M:%S")
    line = f"[{timestamp}] {msg}"
    print(line)
    try:
        with open(LOG_FILE, "a") as f:
            f.write(line + "\n")
    except Exception:
        pass
 
# 1. Exit if already provisioned
if os.path.exists(FLAG_FILE):
    log("Instance already created previously. Exiting.")
    sys.exit(0)
 
try:
    import oci
except ImportError:
    log("Error: oci library not found.")
    sys.exit(1)
 
config_path = os.path.expanduser("~/.oci/config")
if not os.path.exists(config_path):
    log("Error: ~/.oci/config does not exist.")
    sys.exit(1)
 
config = oci.config.from_file(config_path)
compute_client = oci.core.ComputeClient(config)
network_client = oci.core.VirtualNetworkClient(config)
identity_client = oci.identity.IdentityClient(config)
 
compartment_id = config["tenancy"]
 
# 2. Extract SSH public key
ssh_key_path = os.path.expanduser("~/.ssh/authorized_keys")
with open(ssh_key_path, "r") as f:
    ssh_authorized_key = f.read().strip()
 
# 3. Discover Subnet
try:
    subnets = network_client.list_subnets(compartment_id=compartment_id).data
    if not subnets:
        log("Error: No subnets found in compartment.")
        sys.exit(1)
    subnet_id = subnets[0].id
except Exception as e:
    log(f"Error finding subnet: {e}")
    sys.exit(1)
 
# 4. Find latest Ubuntu ARM image
try:
    images = compute_client.list_images(
        compartment_id=compartment_id,
        operating_system="Canonical Ubuntu",
        shape="VM.Standard.A1.Flex",
        sort_by="TIMECREATED",
        sort_order="DESC"
    ).data
    arm_images = [img for img in images if "aarch64" in img.display_name.lower() or "arm64" in img.display_name.lower()]
    selected_image = arm_images[0] if arm_images else images[0]
except Exception as e:
    log(f"Error finding image: {e}")
    sys.exit(1)
 
# 5. Filter ADs supporting A1
try:
    ads = identity_client.list_availability_domains(compartment_id=compartment_id).data
except Exception as e:
    log(f"Error listing availability domains: {e}")
    sys.exit(1)
 
valid_ads = []
for ad in ads:
    try:
        shapes = compute_client.list_shapes(compartment_id=compartment_id, availability_domain=ad.name).data
        if any(s.shape == "VM.Standard.A1.Flex" for s in shapes):
            valid_ads.append(ad.name)
    except Exception:
        pass
 
if not valid_ads:
    valid_ads = ["uqhT:UK-LONDON-1-AD-1", "uqhT:UK-LONDON-1-AD-2"]
 
# 6. Try launching across valid ADs
for ad_name in valid_ads:
    log(f"Checking capacity in {ad_name}...")
    launch_details = oci.core.models.LaunchInstanceDetails(
        compartment_id=compartment_id,
        availability_domain=ad_name,
        shape="VM.Standard.A1.Flex",
        shape_config=oci.core.models.LaunchInstanceShapeConfigDetails(
            ocpus=2.0,
            memory_in_gbs=12.0
        ),
        display_name="instance-ampere-a1",
        image_id=selected_image.id,
        create_vnic_details=oci.core.models.CreateVnicDetails(
            subnet_id=subnet_id,
            assign_public_ip=True
        ),
        metadata={
            "ssh_authorized_keys": ssh_authorized_key
        },
        source_details=oci.core.models.InstanceSourceViaImageDetails(
            source_type="image",
            image_id=selected_image.id,
            boot_volume_size_in_gbs=50
        )
    )
 
    try:
        response = compute_client.launch_instance(launch_details)
        instance = response.data
        log(f"🎉 SUCCESS! Instance launched in {ad_name}!")
        log(f"Instance OCID: {instance.id}")
        log(f"Display Name: {instance.display_name}")
        with open(FLAG_FILE, "w") as f:
            f.write(f"Created instance {instance.id} in {ad_name} at {datetime.now().isoformat()}\n")
        
        # Trigger dual alerts (OCI Email + Ntfy push)
        send_alerts(instance.id, ad_name, instance.display_name)
        sys.exit(0)
    except oci.exceptions.ServiceError as se:
        if "out of host capacity" in se.message.lower() or se.status in (429, 500):
            log(f"Notice: Out of host capacity in {ad_name}.")
        else:
            log(f"Notice: {se.message.strip()} in {ad_name} (HTTP {se.status})")
    except Exception as e:
        log(f"Unexpected error in {ad_name}: {e}")
 
log("All eligible ADs currently out of capacity. Will retry in next scheduled run.")

D. Automated Alerting Channels (Dual Delivery)

The script fires two distinct alerts the instant the VM is provisioned:

  1. Oracle Cloud Email (gs9339@gmail.com):
    • Publishes directly to the active OCI Notification Topic Altert (ocid1.onstopic.oc1.uk-london-1.amaaaaaaoba6llyadexdotznw5zjp7azr2zgdwf4fz6cnbtp77wgwinw56pq).
    • Delivers an official Oracle Cloud notification email directly to your inbox with instance details.
  2. Instant Push Alert via Ntfy:
    • Pushes to https://ntfy.sh/oracle-alert-gs9339-arm.
    • You can open this link in any browser or add it to the free mobile ntfy app to receive instant push alerts.

E. Cron Job

Configured under the ubuntu user:

SUPPRESS_LABEL_WARNING=True
*/5 * * * * /home/ubuntu/launch_arm.py

5. Operations & Runbook

How to Monitor the Process

SSH into your micro instance from your local terminal:

ssh -i ~/.ssh/oracle_vm.key ubuntu@144.21.49.153

  1. View live or recent attempt logs:

    tail -n 25 -f ~/oci_launch.log

  2. Check if the instance has been created:

    cat ~/.oci/instance_created.flag

  3. Check the instance in OCI CLI manually:

    oci compute instance list --compartment-id ocid1.tenancy.oc1..aaaaaaaa3qmmiutixriu2ey7z42mpok3xxy4slppn2yk526ylxnlhknnzdha --query "data[].{Name:\"display-name\", State:\"lifecycle-state\", Shape:shape}" --output table

How to Stop the Automation

If you ever want to stop the script from running:

crontab -r

Connecting to Your New Instance

Once the script succeeds:

  1. Find the new instance’s Public IP from the OCI Console or via: 
    oci compute instance list-vnics --instance-id <INSTANCE_OCID> --query "data[0].\"public-ip\"" --raw-output
  2. Connect using your existing key: 
    ssh -i ~/.ssh/oracle_vm.key ubuntu@<NEW_INSTANCE_IP>

6. Safety & Anti-Ban Summary

Why This Will Never Get Banned

  • Standard API Integration: Uses the official Oracle Python SDK with cryptographic request signing identical to official Oracle tooling (Terraform, Ansible, OCI Console).
  • 5-Minute Cadence: 1 attempt every 300 seconds represents an infinitesimal 0.0033 requests/sec, far below Oracle’s rate limiter (HTTP 429 threshold is ~50 requests/sec).
  • Self-Terminating: Permanently halts execution via lockfile the second capacity is allocated.

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