August 2008, Agile Conference, Toronto. andrew-clay-shafer posted a Birds of a Feather session titled "Agile Infrastructure." One person attended: patrick-debois. Shafer had nearly not shown up himself.
The session's near-failure is part of the story. The Agile community of 2008 was largely uninterested in infrastructure — the manifesto and its ecosystem were focused on development practices, and operations was someone else's problem. Shafer's attempt to bring Agile thinking to infrastructure found no audience except for a Belgian consultant who had been independently frustrated by the same gap from the operations side.
Shafer was then at Puppet Labs (one of the earliest infrastructure automation companies, building on the infrastructure-as-code lineage from mark-burgess's CFEngine). Debois was working in systems administration and had been running test environments, managing the gap between how developers worked and how operations worked. They recognized each other's frustration immediately.
The conversation that started in that empty session room led directly to the organization of first-devopsdays-ghent-2009 a year later. Debois had the network, the motivation, and now the conceptual vocabulary from Shafer to organize a conference at the intersection of Agile and operations.
Significance. This event illustrates how movements often begin in near-failure and small rooms. The Agile community's indifference to infrastructure in 2008 was itself diagnostic — it was the gap that DevOps would fill. The accident of Shafer posting the session and Debois finding it meant that two people who needed to meet each other did.
The date is approximate (August 2008); the Agile Conference that year was held in Toronto in early August.