github.com/metal-stack/go-ipam

go-ipam

go-ipam is a module to handle IP address management. It can operate on networks, prefixes and IPs.

It also comes as a ready to go microservice which offers a grpc api.

IP

Most obvious this library is all about IP management. The main purpose is to acquire and release an IP, or a bunch of IP's from prefixes.

Prefix

A prefix is a network with IP and mask, typically in the form of 192.168.0.0/24. To be able to manage IPs you have to create a prefix first.

Library Example usage:

package main

import (
    "context"
    "fmt"
    "time"

    goipam "github.com/metal-stack/go-ipam"
)

func main() {
    // The background context
    bgCtx := context.Background()

    // Create a ipamer with in memory storage
    ipam := goipam.New(bgCtx)

    // Optionally, we can pass around a context for a given namespace
    namespace := "tenant-a"
    err := ipam.CreateNamespace(bgCtx, namespace)
    if err != nil {
        panic(err)
    }
    ctx := goipam.NewContextWithNamespace(bgCtx, namespace)
    ctx, cancel := context.WithTimeout(ctx, 5*time.Second)
    defer cancel()

    // Create a prefix to manage some IPs
    prefix, err := ipam.NewPrefix(ctx, "192.168.0.0/24")
    if err != nil {
        panic(err)
    }

    // Acquire and release an IP with this prefix
    ip, err := ipam.AcquireIP(ctx, prefix.Cidr)
    if err != nil {
        panic(err)
    }
    fmt.Printf("got IP: %s\n", ip.IP)

    prefix, err = ipam.ReleaseIP(ctx, ip)
    if err != nil {
        panic(err)
    }
    fmt.Printf("IP: %s released.\n", ip.IP)

    // Now a IPv6 Super Prefix with Child Prefixes
    prefix, err = ipam.NewPrefix(ctx, "2001:aabb::/48")
    if err != nil {
        panic(err)
    }

    cp1, err := ipam.AcquireChildPrefix(ctx, prefix.Cidr, 64)
    if err != nil {
        panic(err)
    }
    fmt.Printf("got Prefix: %s\n", cp1)

    cp2, err := ipam.AcquireChildPrefix(ctx, prefix.Cidr, 72)
    if err != nil {
        panic(err)
    }
    fmt.Printf("got Prefix: %s\n", cp2)
    ip21, err := ipam.AcquireIP(ctx, cp2.Cidr)
    if err != nil {
        panic(err)
    }
    fmt.Printf("got IP: %s\n", ip21.IP)
}

GRPC Service

First start the go-ipam container with the database backend of your choice already up and running. For example if you have a postgres database for storing the ipam data, you could run the grpc service like so:

docker run -it --rm ghcr.io/metal-stack/go-ipam postgres

From a client perspective you can now talk to this service via grpc.

GRPC Example usage:

package main

import (
    "http"

    "github.com/bufbuild/connect-go"
    v1 "github.com/metal-stack/go-ipam/api/v1"
    "github.com/metal-stack/go-ipam/api/v1/apiv1connect"
)
func main() {

    c := apiv1connect.NewIpamServiceClient(
            http.DefaultClient,
            "http://localhost:9090",
            connect.WithGRPC(),
    )

    bgCtx := context.Background()

    // Optional with Namespace
    ctx := goipam.NewContextWithNamespace(bgCtx, "tenant-a")

    result, err := c.CreatePrefix(ctx, connect.NewRequest(&v1.CreatePrefixRequest{Cidr: "192.168.0.0/16",}))
    if err != nil {
        panic(err)
    }
    fmt.Println("Prefix:%q created", result.Msg.GetPrefix().GetCidr())
}

GRPC client

There is also a cli provided in the container which can be used to make calls to the grpc endpoint manually:

docker run -it --rm --entrypoint /cli ghcr.io/metal-stack/go-ipam

Metrics

http://localhost:2112/metrics

pprof

go tool pprof -http :8080 localhost:2113/debug/pprof/heap
go tool pprof -http :8080 localhost:2113/debug/pprof/goroutine

Docker Compose example

Ensure you have docker with compose support installed. Then execute the following command:

docker compose up -d

# check if up and running
docker compose ps

NAME                 IMAGE             COMMAND                  SERVICE    CREATED          STATUS                    PORTS
go-ipam-ipam-1       go-ipam           "/server postgres"       ipam       14 seconds ago   Up 13 seconds (healthy)   0.0.0.0:9090->9090/tcp, :::9090->9090/tcp
go-ipam-postgres-1   postgres:alpine   "docker-entrypoint.s…"   postgres   8 minutes ago    Up 13 seconds             5432/tcp


# Then execute the cli to create prefixes and acquire ips

docker compose exec ipam /cli prefix create --cidr 192.168.0.0/16
prefix:"192.168.0.0/16" created

docker compose exec ipam /cli ip acquire --prefix  192.168.0.0/16
ip:"192.168.0.1" acquired

# Queries can also made against the Rest api like so:

curl -v -X POST -d '{}' -H 'Content-Type: application/json' localhost:9090/api.v1.IpamService/ListPrefixes

Supported Databases & Performance

Database	Acquire Child Prefix	Acquire IP	New Prefix	Prefix Overlap	Production-Ready	Geo-Redundant
In-Memory	106,861/sec	196,687/sec	330,578/sec	248/sec	N	N
File					N	N
KeyDB	777/sec	975/sec	2,271/sec		Y	Y
Redis	773/sec	958/sec	2,349/sec		Y	N
MongoDB	415/sec	682/sec	772/sec		Y	Y
Etcd	258/sec	368/sec	533/sec		Y	N
Postgres	203/sec	331/sec	472/sec		Y	N
CockroachDB	170/sec	300/sec	470/sec		Y	Y

The benchmarks above were performed using:

• cpu: Intel(R) Xeon(R) Platinum 8370C CPU @ 2.80GHz
• postgres:17-alpine
• cockroach:v24.1.0
• redis:7.4-alpine
• keydb:alpine_x86_64_v6.3.1
• etcd:v3.5.15
• mongodb:7

Database Version Compatibility

Database	Details
KeyDB
Redis
MongoDB	mongodb-go compatibility
Etcd
Postgres
CockroachDB

Testing individual Backends

It is possible to test a individual backend only to speed up development roundtrip.

backend can be one of Memory, Postgres, Cockroach, Etcd, Redis, and MongoDB.

BACKEND=backend make test