avnm-pool-cidr
Pick the next free CIDR prefix from an Azure Virtual Network Manager (AVNM)
IPAM pool — without manually scrolling through the Azure portal or writing yet
another ipaddress-and-az-CLI bash one-liner.
Why
AVNM IPAM is the right way to centralize CIDR allocation across an Azure tenant,
but the day-to-day operator workflow ("give me a free /24 from prod-pool") is
not yet a first-class CLI verb in az. This tool fills the gap with three
focused commands.
Install
pipx install avnm-pool-cidr
You need az on your PATH and a current Azure login (az login). Auth is
delegated entirely to the Azure CLI — this tool does not embed credentials.
Usage
All commands take the same three locator options (each also reads from an environment variable):
| Option | Env var | Description |
|---|---|---|
--subscription/-s |
AZURE_SUBSCRIPTION_ID |
Subscription containing the VNM |
--resource-group/-g |
AZURE_RESOURCE_GROUP |
RG containing the network manager |
--network-manager/-n |
AZURE_NETWORK_MANAGER |
Name of the network manager |
# 1. Find the next free /24 in prod-pool
apc next-prefix prod-pool --size 24 \
-s 11111111-1111-1111-1111-111111111111 \
-g rg-network -n vnm-prod
# -> 10.0.5.0/24
# 2. List every resource that has reserved space from prod-pool
apc list prod-pool -s ... -g rg-network -n vnm-prod
# 3. Show address-level utilization (per parent prefix)
apc usage prod-pool -s ... -g rg-network -n vnm-prod
The short alias apc is installed alongside avnm-pool-cidr.
How it works
avnm-pool-cidr shells out to az network manager ipam-pool for the
authoritative pool/reservation data, then does the CIDR math in pure Python
(ipaddress stdlib). Splitting it this way keeps the math trivial to unit-test
and means the tool inherits whatever auth, proxy, and ARM endpoint settings your
az install already has.
Companion tool
This is the second tool in a series of small Azure operator CLIs. The first is
azkv-ssh-fetch — for fetching
SSH private keys from Key Vault and connecting through Azure Bastion in one step.
Development
python -m venv .venv && source .venv/bin/activate
pip install -e ".[dev]"
pre-commit install
ruff check . && ruff format --check .
mypy src
pytest --cov
Test layers
| Layer | What it covers | Where |
|---|---|---|
| Unit | Pure CIDR math (tests/test_cidr.py) and inline-mocked az calls (tests/test_ipam.py, tests/test_cli.py) |
Every CI run, no network |
| Snapshot | Full CLI run against scrubbed JSON fixtures of real az network manager ipam-pool ... output (tests/test_cli_with_fixtures.py) |
Every CI run, no network |
| Smoke | Operator-run live check against a personal Azure subscription | Pre-tag, manual |
Snapshot fixtures live in tests/fixtures/. Re-record with
scripts/record-fixtures.sh (refuses to run against Microsoft-internal tenants;
scrubs subscription/RG/VNM names and all GUIDs before writing).
License
MIT © 2026 Naeem Hossain
1 maintainer
Metadata
1 maintainer
Release files for avnm-pool-cidr 0.1.0
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| File | Size | Uploaded | |
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| avnm_pool_cidr-0.1.0-py3-none-any.whl | Python 3 | none | any | Details |
Total release size: 24.0 kB
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