Pool File

Overview

By default when using AWS the runner does not need a pool file. It can use environment variables to set up a simple pool in memory. However if you want a more complex configuration or multiple pools follow the below quide.

The pool file sets up the build pools that instantiates hot instances (builds do not wait for an instance to spin up). You can have multiple pools, each with a different configuration or that even use different cloud drivers.

  • pool.yml is the default file name.
  • Each pool only has one instance type.
  • There can be multiple pools. Different pipelines can use the same pool
  • You can specify the minimum size of the pool.
  • You can specify the maximum size of the pool.
  • A pool can only be in one region.
  • Changing the pool configuration will mean removing the existing images and restarting the daemon.
  • If the pool is empty, it will trigger an adhoc instance.
  • For Microsoft Windows pools it is important to set platform. As seen in the windows example below.

Pool file sections

Root section

It is recommended when you are naming your pool to use alphanumeric characters and start with a letter. This is to avoid issues with naming on amazon/anka/digitalocean/google.

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  name          string   # name of the pool, used by pipelines to select the pool
  default       bool     # default pool
  type          string   # amazon, anka, digitalocean, google
  pool          int      # total number of warm instances in the pool at all times
  limit         int      # limit the total number of running servers. If exceeded block or error.
  platform      Platform # explained in section below
  spec          Spec     # explained in section below

Platform

is (this is the same as plaform in other runners) NB windows support is implemented:

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  os      string
  arch    string
  variant string
  version string
  os_name string # currently only used for amazon-linux

Spec

This is where we configure the cloud drivers specific configuration. There are a number of different drivers.

Using a pool file

Below is an example of using a pool file with the docker command. We can use a config folder that contains the necessary configuration files.

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ls  /path/on/host/config/
.drone_pool.yml
.env

The below command creates a container and starts the runner.

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docker run -d \
  --volume=/path/on/host/config:/config/ \
  --publish=3000:3000 \
  --restart always \
  --name runner \
  drone/drone-runner-aws /config/.env /config/pool.yml