Building a Hybrid Docker Orchestrator in Go: The Journey from Single VM to Multi-Node Cluster

A developer built Gubernator, a lightweight container orchestrator in Go that combines Docker Compose simplicity with Nomad-like decentralized targeting. The project evolved from a single-node API to a multi-node VM cluster with autonomous DNS resolution and local ingress routing, co-authored with Google DeepMind's Antigravity AI pair programmer. Gubernator uses SQLite, CoreDNS, and Caddy to provide a fast, decentralized alternative to Kubernetes for small-to-medium deployments.

What if you could combine the native simplicity of Docker Compose with the decentralized targeting and reliability of HashiCorp Nomad ? Meet Gubernator or gbnt , a "Goldilocks" container orchestrator written in Go. In this post, I want to share how I took Gubernator from a single-node API to a fully decentralized, multi-node VM cluster with autonomous DNS resolution and local ingress routing—all co-authored alongside Antigravity , Google DeepMind's agentic AI pair programmer. Kubernetes is the undisputed king of container orchestration, but for small-to-medium projects, homelabs, or edge deployments, it represents massive operational overhead. Docker Swarm is simple but lacks fine-grained task scheduling constraints. Gubernator is designed to fill that sweet spot: gbnt binary acts as the Central Manager holding the centralized SQLite state and the Worker Agents.To test the orchestrator realistically, we provisioned three Multipass Ubuntu VMs: gbnt-manager 192.168.252.8 gbnt-worker1 192.168.252.9 gbnt-worker2 192.168.252.10 php graph TD Host Mac/Laptop Host OS -- |Resolves .gbnt via local resolver| CoreDNS Manager subgraph Manager VM gbnt-manager: 192.168.252.8 CoreDNS Manager gbnt-coredns Mgr gbnt-manager API & DB Caddy Mgr gbnt-caddy end subgraph Worker 1 VM gbnt-worker1: 192.168.252.9 Agent1 gbnt Agent Caddy1 gbnt-caddy CoreDNS1 gbnt-coredns Cont1 App Containers end subgraph Worker 2 VM gbnt-worker2: 192.168.252.10 Agent2 gbnt Agent Caddy2 gbnt-caddy CoreDNS2 gbnt-coredns Cont2 App Containers end Mgr -- |Orchestrates| Agent1 & Agent2 CoreDNS Manager -- |Synchronizes Records| CoreDNS1 & CoreDNS2 Caddy1 -- |Routes to local| Cont1 Caddy2 -- |Routes to local| Cont2 One of the biggest challenges in multi-host networking is how to route web traffic to containers without overloading the Manager. Instead of routing all external traffic through a single ingress proxy on the Manager, we built a fully decentralized routing scheme: hello-app.gbnt pointing directly to the IP of the Worker VM hosting the container.This means if hello-app.gbnt is deployed on gbnt-worker2 192.168.252.10 : 192.168.252.10 . gbnt-worker2 on port 80. 172.17.0.2:80 .What makes this project unique is that 100% of the Go code, GORM integrations, Flutter dashboard widgets, and cluster setups were co-authored with Antigravity , Google DeepMind's agentic AI coding assistant. Unlike simple autocomplete or chat windows, Antigravity acts as a pair programmer with agentic capabilities: bridge and gbnt-monitor-net had their IPs concatenated e.g., 172.17.0.2172.19.0.7 . Antigravity traced the container IP extraction logic, proposed a fix, and validated the parser.Observability is built-in. By running gbnt monitor init , the Manager spins up a complete telemetry stack connected via a dedicated network gbnt-monitor-net : Gubernator proves that you don't need a heavy orchestrator like Kubernetes to manage multi-host Docker deployments. By combining Go, SQLite, CoreDNS, and Caddy, we created a lightning-fast, decentralized orchestrator. Pair-programming with an agentic coder like Antigravity allowed me to focus on high-level architecture while the AI handled refactoring, cross-compilation, VM deployment, and frontend updates. If you are interested in building lightweight orchestration systems, check out the Gubernator repository https://github.com/mario-ezquerro/gubernator and start building Have you built or used lightweight orchestrators? Let me know in the comments below devops docker golang ai pairprogramming antigravity