Dude Scale My Runners

Stephen Jones
Aws
March 10, 2023

Table of Contents

In our github Enterprise Instance, we use the super-linter to keep all our users honest and lint everything.

While some find it tedious, linting is a valuable tool for improving the quality and reliability of your code and can save time and effort in the long run.

Actions Lint to the rescue

With our use of the super-linter, we were notified when performing a regular pull request of the following issue.

https://github.blog/changelog/2022-10-11-github-actions-deprecating-save-state-and-set-output-commands/

This is picked up by actionlint under the depreciated command rule as follows:-

on: push

jobs:
  test:
    runs-on: ubuntu-latest
    steps:
      # ERROR: 'set-output' workflow command was deprecated
      - run: echo '::set-output name=foo::bar'
      # OK: Use this instead
      - run: echo "foo=bar" >> "$GITHUB_OUTPUT"
      # OK: 'debug' command is not deprecated
      - run: echo "::debug::Set the Octocat variable"

test.yaml:8:14: workflow command "set-output" was deprecated. use `echo "{name}={value}" >> $GITHUB_OUTPUT` instead: https://docs.github.com/en/actions/using-workflows/workflow-commands-for-github-actions [deprecated-commands]
  |
8 |       - run: echo '::set-output name=foo::bar'
  |              ^~~~

This depreciation was released in November, but we picked it up thanks to our linting over the Christmas break.

Rolling the fix

Now what I wanted to share with the background above - Scaling Self-Hosted runners when we pushed out a fix for this across all our Terraform module repositories 100+.

As described here, we run our Self-Hosted runners in AWS using the fabulous Philips labs solution built with Terraform.

We have a CloudWatch dashboard to give us an overview of what jobs are ticking over and the number of SPOT instances created.

Here it is on a typical week of usage. We hit about 1200 SPOT instances.