tent

Tent

A simple tool to manage builds and deployments when using Nomad and Docker. (Although docker is optional!)

1. Features
2. Configuration
   1. Reference
   2. Examples
3. Nomad
4. Commands
   1. Build
   2. Deploy
   3. Destroy
5. Upcomming Features

Features

• Simple YAML configuration
  • Environment variable interpolation within config
  • Sensible defaults assumed for nearly all config properties
• Concurrent processing
  • Run up to 5 build tasks at once
  • Run up to 5 deployment tasks at once
• Build Docker images ready for deployment
  • Tagging of images
  • Pushing built images to custom registries
• Run custom build scripts instead of docker
• Deploy the build Docker images
  • Docker images can be injected into a *.nomad file using Tent variables
• Supports multiple environments (eg, staging/production)
• Handles cases where the nomad file and group counts within may be out of sync with the running job

Configuration

Configuration is done in a tent.yaml file within the root of your project.

Reference

Most config variables support environment variable interpolation. This can be done using the following format:

// Outputs the value of $MY_VARIABLE or an empty string
${MY_VARIABLE}

Defaults are also supported using the following format:

// Outputs "default-value"
${MY_VARIABLE:-default_value}

Any config values that support environment variable interpolation are marked below.

# (Required) Specify the name of your service.
# - Must only contain lowercase alpha characters (a-z) and hyphens (-)
# - Available as `[!name!]` within a nomad file.
# - Supports environment variable interpolation.
name: my-service

# Enable running multiple builds/deployments/destructions at the same time.
concurrent: true

# Setup specific config for different environments.
# These environments can be specified when passing in the -env flag to the
# deploy or destroy commands.
#
# Has no effect in build.
environments:

  # Repeat enviroment config as many times as desired.
  staging:

    # (Required) The URL to the nomad server to use.
    # - Supports environment variable interpolation.
    nomad_url: https://example.com/

    # (Optional) Any variables to make available when parsing the nomad file.
    # Default: 
    variables:

      # A variable that can be used within a nomad file.
      # The below variable would be available as so: `[!env_my_variable!]`
      # - Supports environment variable interpolation.
      my_variable: test

  production:

    # (Required) The URL to the nomad server to use.
    # - Supports environment variable interpolation.
    nomad_url: https://example.com/

# Configure the deployments to be run.
#
# Minimal config:
# deployments:
#   my-app:
#     nomad_file: example.nomad
#
# Minimal config with builds:
# deployments:
#   my-app:
#     nomad_file: example.nomad
#     builds:
#       my-build:
#         name: image_name
#         tags:
#           - my-tag
#         push: true
#         deploy_tag: my-tag
deployments:

  # The name of the deployment.
  # Available as `[!deployment_name!]` within a nomad file.
  app:

    # Builds for this deployment.
    builds:

      # The name of the build.
      web:

        # (Optional) The docker context to use.
        # Default: .
        context: .

        # (Optional) The path to the dockerfile to use.
        # Default: Dockerfile
        file: example.Dockerfile

        # (Optional) The docker registry url to use.
        # - Supports environment variable interpolation.
        # - Should NOT include the protocol.
        # Default: <none>
        registry_url: example.com

        # The name of the docker image.
        # - Supports environment variable interpolation.
        name: tent

        # (Optional) Any tags to apply to the image. (Should NOT contain the image name or registry!)
        # - Supports environment variable interpolation.
        # Default: [latest]
        tags:
          - my-tag
          - latest

        # (Optional) Should the tags be pushed to the registry?
        # Default: false
        push: true

        # (Optional) The dockerfile multi-stage target.
        # - Supports environment variable interpolation.
        # Default: <none>
        target: production
        
        # (Optional) The dockerfile build arguments.
        # - Supports environment variable interpolation.
        # Default: <none>
        build_args:
          arg: value

        # The tag to use when generating the image url/name to use in the nomad file.
        # The generated/built image (eg, 240422614719.dkr.ecr.eu-west-1.amazonaws.com/tent:my-tag)
        # is available as `[!image_{build_name}!]` within a nomad file, where {build_name}
        # is the name of the build.
        #
        # In this example, {build_name} would be web, giving `[!image_web!]` as the variable.
        #
        # - Supports environment variable interpolation.
        # Default: latest
        deploy_tag: my-tag

    # (Optional) The path to the nomad file to use.
    # - Supports environment variable interpolation.
    # Default: Defaults to the `name` property from the root of this configuration concatenated with the name of the deployment.
    # In this example. The default would be `my-service-web.nomad`
    nomad_file: my-service.nomad

    # (Optional) The number of instances to start if no currently running job is found.
    # Default: 2
    start_instances: 2

    # (Optional) Only to be used if the job name is hard coded within the nomad file. (job "my-name-here" { ... })
    # - Supports environment variable interpolation.
    # Default: <none>
    service_name: my-service

    # (Optional) Any variables to make available when parsing the nomad file.
    # Default: <none>
    variables:
      # A variable that can be used within a nomad file.
      # The below variable would be available as so: `[!var_some_variable!]`
      # - Supports environment variable interpolation.
      some_variable: example

Examples

Minimal Configuration (With Builds)

name: test

environments:

  production:
    nomad_url: http://example.com/

deployments:

  web:
    builds:
      app:
        push: true
    

Minimal Configuration (Without Builds)

name: test

  environments:

    production:
      nomad_url: http://example.com/

  deployments:
  
    web:

Nomad

Tent is built to work seamlessly with Nomad and the way Nomad handles deployments.

Out of the box, Tent will deploy a *.nomad file to nomad and monitor the deployment until success or failure.

Nomad File Variables

Tent will replace certain variables found within a nomad file with their computed value.

Any variables that can not be found will be replaced with an empty string!

Available Variables:

• [!name!]
  • This is the name property from the yaml config.
• [!deployment_name!]
  • This is the name of the currently running deployment from the yaml config.
• [!job_name!]
  • This is either the service_name property from the yaml config for the running deployment, or the combination of the name property and the currently running deployment name from the yaml config.
• [!image_{build_name}!]
  • This is the generated docker image name, where {bulild_name} is replaced with the name of the build within the currently running deployment.
• [!group_{task_group}_size!]
  • This is the current size of the Task Group if the job is already running in nomad. This will be the same as the group name in your .nomad file. If you use the [!deployment_name!] variable for your nomad group you may use [!group_size!] to retrieve the value.
  • If there is no job running, this will be replaced with 2.
• [!env_{var_name}!]
  • You can use any variable defined within the variables map of an environment configuration using this syntax.
• [!var_{var_name}!]
  • You can use any variable defined within the variables map of a deployment using this syntax.

Commands

Usage: tent [-version] [-help] [-verbose] [-autocomplete-(un)install] <command> [args]

Common commands:
    build        Build the project according to the config.
    deploy       Deploy the project according to the config.
    destroy      Destroy the project according to the config.

The -verbose option may be provided to ANY command.

Build

The build command is responsible for running the build configuration for each configured deployment.

If concurrent is set to true, up to 5 builds will be run at once.

Usage: tent build

    Build is used to build the project ready for deployment.

General Options:

    -verbose
        Enables verbose logging.

Deploy

The deploy command is responsible for deploying the configured setup and .nomad file to Nomad, and monitoring the deploment until completion.

If concurrent is set to true, up to 5 deployments will be run at once.

Usage: tent deploy [-env=]

    Deploy is used to build the project ready for deployment.

    -env=
        Specify the environment configuration to use.

General Options:

    -verbose
        Enables verbose logging.

Destroy

The deploy command is responsible for bringing down any currently running deployments.

If concurrent is set to true, up to 5 destructions will be run at once.

Usage: tent destroy [-env=] [-purge] [-force]

    Destroy is used to build the project ready for deployment.

    -purge
        Forces garbage collection of the job within nomad.
    -env=
        Specify the environment configuration to use.

General Options:

    -verbose
        Enables verbose logging.

Upcomming Features

The following features will be added in later releases, in no particular order.

• A rollback command to rollback to the last (or a given) nomad version.
• Ability to automatically rollback all defined deployments on a single deployment failure.
• Enable generation of a nomad file.
• Allow configuration of max concurrent jobs in yaml config file.