> (I always wondered who started it with YAML and why everyone copied that, if anyone knows I'd love to read about it).
I know this isn't a definite answer to your question, but it was still super interesting to me and hopefully it will inspire someone else to dig into
finding the actual answer
- I was shocked that GitHub existed in 2008 https://web.archive.org/web/20081230235955/http://github.com... with an especial nod to no longer a pain in the ass and Not only is Git the new hotness, it's a fast, efficient, distributed version control system ideal for the collaborative development of software but this was just "for funsies" link since they were very, very late to the CI/CD game
- cloud-init had yaml in 2010 https://github.com/openstack-archive/cloud-init/blob/0.7.0/d... so that's a plausible "it started here" since they were yaml declarations of steps to perform upon machine boot (and still, unquestionably, my favorite user-init thing)
I know this isn't a definite answer to your question, but it was still super interesting to me and hopefully it will inspire someone else to dig into finding the actual answer
The best guess I have as far as CI/CD specifically appears to be <https://en.wikipedia.org/wiki/Travis_CI#:~:text=travis%20ci%...> which launched in 2011 offering free CI and I found a reference to their .travis.yml in GitLab's repo in 2011, too
- CruiseControl (2004) was "ant as a service," so it was XML https://web.archive.org/web/20040812214609/http://confluence...
- Hudson (2007) https://web.archive.org/web/20140701020639/https://www.java.... was also XML, and was by that point driving Maven 2 builds (also XML)
- I was shocked that GitHub existed in 2008 https://web.archive.org/web/20081230235955/http://github.com... with an especial nod to no longer a pain in the ass and Not only is Git the new hotness, it's a fast, efficient, distributed version control system ideal for the collaborative development of software but this was just "for funsies" link since they were very, very late to the CI/CD game
- I was surprised but k8s 1.0.0 still had references to .json PodSpec files in 2010 https://github.com/kubernetes/kubernetes/blob/v1.0.0/example...
- cloud-init had yaml in 2010 https://github.com/openstack-archive/cloud-init/blob/0.7.0/d... so that's a plausible "it started here" since they were yaml declarations of steps to perform upon machine boot (and still, unquestionably, my favorite user-init thing)
- just for giggles, GitLab 1.0.2 (2011) didn't even have CI/CD https://gitlab.com/gitlab-org/gitlab/-/tree/v1.0.2 -- however, while digging into that I found .travis.yml in v2.0.0 (also 2011) so that's a very plausible citation <https://gitlab.com/gitlab-org/gitlab/-/blob/v2.0.0/.travis.y...>
- Ansible 1.0 in 2012 was also "execution in yaml" https://github.com/ansible/ansible/blob/v1.0/examples/playbo...