# HashiCorp Nomad — Flexible Workload Orchestrator

> Nomad is an easy-to-use, flexible, and performant workload orchestrator that can deploy containers, VMs, Java apps, and binaries on bare metal. Smaller and simpler than Kubernetes with native Consul and Vault integration.

## Install

Save as a script file and run:

## Quick Use

```bash
# Install
brew install hashicorp/tap/nomad            # macOS
# Or download binary from https://www.nomadproject.io/downloads

# Dev mode (single-node)
nomad agent -dev

# Check
nomad node status
nomad server members
```

Simple job `web.nomad.hcl`:
```hcl
job "web" {
  datacenters = ["dc1"]
  type        = "service"

  group "webs" {
    count = 3

    network {
      port "http" { to = 80 }
    }

    service {
      name = "web"
      port = "http"
      check {
        type     = "http"
        path     = "/"
        interval = "10s"
        timeout  = "2s"
      }
    }

    task "nginx" {
      driver = "docker"

      config {
        image = "nginx:alpine"
        ports = ["http"]
      }

      resources {
        cpu    = 200
        memory = 128
      }
    }
  }
}
```

```bash
nomad job plan web.nomad.hcl
nomad job run web.nomad.hcl
nomad job status web
```

## Intro

HashiCorp Nomad is an easy-to-use, flexible, and performant workload orchestrator. Unlike Kubernetes (which targets containers), Nomad schedules any workload: Docker, Podman, raw binaries, Java JARs, Windows services, QEMU VMs. Smaller and simpler than K8s with native Consul service discovery and Vault secrets integration.

- **Repo**: https://github.com/hashicorp/nomad
- **Stars**: 16K+
- **Language**: Go
- **License**: BUSL 1.1 (source-available)

## What Nomad Does

- **Multi-workload** — Docker, raw exec, Java, Windows, QEMU
- **Service discovery** — Consul integration or native
- **Secrets** — Vault integration
- **Bin packing** — optimal placement algorithm
- **Blue-green / canary** — deploy strategies built in
- **Rolling updates** — with health checks
- **Batch jobs** — periodic, batch, system types
- **Spread / affinity** — placement constraints
- **ACLs** — fine-grained access control
- **Federation** — multi-region clusters

## Architecture

Servers form a Raft-consensus cluster for scheduling decisions. Clients run on each node to execute tasks. Schedulers (service, batch, system, sysbatch) place workloads based on constraints and resources. Nomad is a single Go binary per role.

## Self-Hosting

```hcl
# server.hcl
data_dir = "/opt/nomad/data"
server {
  enabled = true
  bootstrap_expect = 3
}
```

```hcl
# client.hcl
data_dir = "/opt/nomad/data"
client {
  enabled = true
  servers = ["nomad-server-1:4647"]
}
```

## Key Features

- Multi-workload orchestration
- Single Go binary
- Simpler than Kubernetes
- Native Consul + Vault integration
- Rolling deploys, canary, blue-green
- Multi-region federation
- ACL system
- Spread and affinity placement
- CSI volume support

## Comparison

| Orchestrator | Workloads | Complexity | Ecosystem |
|---|---|---|---|
| Nomad | Docker, VM, bare | Low | Smaller |
| Kubernetes | Containers | High | Huge |
| Docker Swarm | Docker | Very low | Declining |
| HashiCorp Waypoint | Containers | Low | Newer |
| Mesos + Marathon | Anything | Very high | Declining |

## 常见问题 FAQ

**Q: Nomad vs Kubernetes？**
A: K8s 功能完备但复杂、学习曲线陡；Nomad 单 binary、简单、能跑非容器负载。中小团队 Nomad 够用且运维便宜；大团队生态选 K8s。

**Q: BUSL 是什么？**
A: Business Source License 1.1 — 4 年转 MPL 2.0 开源、中间版本禁止与 Nomad 竞争的商用。自用、非竞品商用完全 OK。

**Q: 需要 Consul 吗？**
A: 不强制。Nomad v1.3+ 有原生 service discovery。但要高级功能（service mesh、KV、分布式锁）还是建议 Consul。

## 来源与致谢 Sources

- Docs: https://www.nomadproject.io/docs
- GitHub: https://github.com/hashicorp/nomad
- License: BUSL 1.1

---
Source: https://tokrepo.com/en/workflows/a2aa9c27-35f3-11f1-9bc6-00163e2b0d79
Author: Script Depot