Nomad Translator

The translator converts an InfraSpec into Nomad job specifications. There are three translation functions for three job types.

Translate — Service Jobs

Translate(spec, imageTag, env) creates a Nomad service job. Each non-scheduled process in the infraspec becomes a TaskGroup within the job.

Process → TaskGroup Mapping

InfraSpec.Processes
├── web (port: 8080)      → TaskGroup "web"     [service job]
├── worker (no port)      → TaskGroup "worker"   [service job]
├── cleanup (schedule)    → SKIPPED (separate periodic job)
└── resize (function)     → SKIPPED (on-demand batch job)

Scheduled processes and functions are excluded from the main service job — they get their own jobs via TranslatePeriodic and TranslateBatch.

Docker Task Config

Each TaskGroup contains a single Docker task:

task "web" {
  driver = "docker"
  config {
    image   = "ghcr.io/user/myapp:abc1234"
    command = "/bin/sh"
    args    = ["-c", "./server"]
    ports   = ["web-http"]
  }
}

• image — the built and pushed Docker image tag
• command / args — only set if the process defines a command (overrides Docker CMD)
• ports — label format: {processName}-http

Port Handling

Scenario	Port Type	Nomad Config
Process has port + app has endpoints	Static	ReservedPorts: [{Label, Value}]
Process has port, no endpoints	Dynamic	DynamicPorts: [{Label, To}]
Process has no port	None	No network resource

Static ports are used when endpoints are defined because cloudflared needs a predictable address for routing.

Consul Service Registration

Processes with a port are registered as Consul services:

service {
  name      = "myapp-web"
  port      = "web-http"
  provider  = "consul"

  check {
    type     = "http"
    path     = "/health"
    interval = "10s"
    timeout  = "5s"
  }
}

Health checks are added when the process defines a health block.

Environment Variables

Environment variables are merged from two sources:

1. spec.Env — static variables from the infraspec
2. env parameter — secrets and runtime variables injected by the pipeline

The env parameter takes precedence on conflicts.

Resources

Field	Default	Override
CPU	100 MHz	process.resources.cpu
Memory	128 MB	process.resources.memory

Volume Mounts

Volumes declared in the infraspec are mapped to Nomad host volumes:

volume "signal-data" {
  type   = "host"
  source = "signal-data"
}

volume_mount {
  volume      = "signal-data"
  destination = "/var/lib/signal-cli"
  read_only   = false
}

Update Strategy

All service TaskGroups use this update strategy:

Setting	Value	Purpose
MaxParallel	1	Roll one allocation at a time
MinHealthyTime	30s	Must be healthy for 30 seconds before continuing
AutoRevert	true	Automatically revert to last stable version on failure

Restart Policy

Setting	Value
Attempts	3
Interval	5 minutes
Delay	15 seconds
Mode	delay

TranslatePeriodic — Cron Jobs

TranslatePeriodic(spec, procName, proc, imageTag, env) creates a Nomad periodic batch job for a process with a schedule.

• Job ID: {appName}-{processName}
• Periodic config uses the cron spec type
• Same environment, resource, and volume handling as service jobs
• No health checks or Consul registration

# infraspec
processes:
  cleanup:
    schedule: "0 3 * * *"
    command: ./cleanup

Translates to:

job "myapp-cleanup" {
  type = "batch"
  periodic {
    cron     = "0 3 * * *"
    enabled  = true
  }
  # ...
}

TranslateBatch — Function Jobs

TranslateBatch(spec, procName, proc, imageTag, env, jobID) creates a one-shot Nomad batch job for function invocations.

• Job ID: caller-supplied (includes execution ID for uniqueness)
• No retries: restart policy is attempts: 0, mode: fail
• function.memory overrides resources.memory if set
• Same environment and volume handling as other job types