Nomad

Nomad is a simple and flexible scheduler and workload orchestrator to deploy and manage containers and non-containerized applications across on-prem and clouds at scale.

Quick Start

Start dev environment

1. Start Docker Desktop

2. Start Nomad

   nomad agent -dev -bind 0.0.0.0 -network-interface=en0
   

3. If you get IPv6 issues on macOS check MacOS Docker Desktop Tricks

For more information, see Dev Environment

Deploy a job

1. Create a redis.nomad.hcl file with the following contents

   redis.nomad.hcl

   job "redis" {
     group "redis" {
       network {
         port "redis" {
           static = 6379
           to     = 6379
         }
       }
   
       task "redis" {
         driver = "docker"
         config {
           image = "redis:alpine"
           ports = ["redis"]
         }
       }
     }
   }
   

2. Deploy it via the CLI

   nomad job run redis.nomad.hcl
   

For more information, see Jobs

Pages

• Dev Environment
• Concepts
  • Overview
  • Filesystem
  • Glossary
• Jobs
• Networking
• Data and Volumes
• HCL2
• Task Drivers
  • Docker
  • Raw Exec
• Resources

CLI Commands

Run a Job

nomad job run job.nomad

Open Web UI

nomad ui

Directories

• Config File (Fedora): /etc/nomad.d/nomad.hcl
• Data Directory (Fedora): /opt/nomad/data

Tips

Docker images failing to pull due to timeouts

• Increase the image_pull_timeout in the config
  • image_pull_timeout docs

Permission denied after mounting host volume into Docker container

• Github Issue - Cannot use volume and volume_mount when SELinux is set to enforcing

Set the user to root

task "prometheus" {
  driver = "docker"
  user = "root"

  config {
    image = "prom/prometheus:latest"
  }
}

Debugging failed allocations

Set the entrypoint to prevent the container from crashing so it can be exec’d into

task "grafana" {
  driver = "docker"
  config {
    image = "grafana/grafana-oss:latest"
    ports = ["grafana-ui"]

    entrypoint = ["/bin/sh", "-c", "while true; do sleep 500; done"]
  }
}

Debugging Environment Variables

Exec into a container a run printenv or env

Extending the Garbage Collection threshold for a Job

By default old Jobs are removed after 4 hours, after that time passes all data related to the Job is removed (including logs).

It can be useful to increase this, for example to see logs of failed Jobs in the UI.

• job_gc_threshold docs

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Last update: August 12, 2023
Created: May 27, 2023