Nomad to deploy a container with a file

Question

I'm quite new to Nomad and i'm looking to deploy a docker container which contains a specific file. I know Nomad has a docker driver built in, so would this be the correct action to take: 1. create a dockerfile which copies the file I want 2. use the image built from that dockerfile to use in the Nomad (in the config{} block?

Or, From looking at similar questions e.g. here, I would put in the args variable the docker cp file.yml commands to copy the file into the container

I'd also like to know where to actually see the container if it were successfully deployed along with the file? Would I just type in docker container list?

Answer 1

Here is an exemple i took from nomad website on monitoring section :

1- in this exemple i try to install prometheus with a docker image prom/prometheus:latest and copy file webserver_alert.yml in docker image

2- copy paste the code below in visual studio code to see the ligne

3- At line 20 we created file webserver_alert.yml in the nomad file system

4-from line 22 to 91 the content of yml file

5- we ask nomad to mount local/webserver_alert.yml in the docker file system /etc/prometheus/webserver_alert.yml at startup of docker

job "prometheus" {
  datacenters = ["dc1"]
  type = "service"

  group "monitoring" {
    count = 1
    restart {
      attempts = 2
      interval = "30m"
      delay = "15s"
      mode = "fail"
    }
    ephemeral_disk {
      size = 300
    }

    task "prometheus" {
      template {
        change_mode = "noop"
        destination = "local/webserver_alert.yml"
        data = <<EOH
---
groups:
- name: prometheus_alerts
  rules:
  - alert: Webserver down
    expr: absent(up{job="webserver"})
    for: 10s
    labels:
      severity: critical
    annotations:
      description: "Our webserver is down."

EOH
      }

      template {
        change_mode = "noop"
        destination = "local/prometheus.yml"
        data = <<EOH
---
global:
  scrape_interval:     5s
  evaluation_interval: 5s

alerting:
  alertmanagers:
  - consul_sd_configs:
    - server: '{{ env "NOMAD_IP_prometheus_ui" }}:8500'
      services: ['alertmanager']

rule_files:
  - "webserver_alert.yml"

scrape_configs:

  - job_name: 'alertmanager'

    consul_sd_configs:
    - server: '{{ env "NOMAD_IP_prometheus_ui" }}:8500'
      services: ['alertmanager']

  - job_name: 'nomad_metrics'

    consul_sd_configs:
    - server: '{{ env "NOMAD_IP_prometheus_ui" }}:8500'
      services: ['nomad-client', 'nomad']

    relabel_configs:
    - source_labels: ['__meta_consul_tags']
      regex: '(.*)http(.*)'
      action: keep

    scrape_interval: 5s
    metrics_path: /v1/metrics
    params:
      format: ['prometheus']

  - job_name: 'webserver'

    consul_sd_configs:
    - server: '{{ env "NOMAD_IP_prometheus_ui" }}:8500'
      services: ['webserver']

    metrics_path: /metrics

  - job_name: 'node_exporter'
    static_configs:
      - targets: ['167.86.106.9:9100','167.86.106.9:9107']

EOH
      }
      driver = "docker"
      config {
        image = "prom/prometheus:latest"
        volumes = [
          "local/webserver_alert.yml:/etc/prometheus/webserver_alert.yml",
          "local/prometheus.yml:/etc/prometheus/prometheus.yml"
        ]
        port_map {
          prometheus_ui = 9090
        }
      }
      resources {
        network {
          mbits = 10
          port "prometheus_ui" {}
        }
      }
      service {
        name = "prometheus"
        tags = ["urlprefix-/"]
        port = "prometheus_ui"
        check {
          name     = "prometheus_ui port alive"
          type     = "http"
          path     = "/-/healthy"
          interval = "10s"
          timeout  = "2s"
        }
      }
    }
  }
}

if other people have #nomad - #consul - #vault or hashistack issue tag me stackoverflow

Answer 2

Just an addition to the answer above, jinja2 templating can also work, so rather than hardcoding in the file by copy and paste, you can use jinja to include the file

      template {
        data = <<EOF
{% include "path/to/template" %}
EOF
        destination = "path/you/want"
      }