Wikimedia Release Engineering Team/Pretrain/Progress reports/2026-06-19

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Pretrain progress reports week ending 2026-06-19

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Report on activities in the Pretrain project for the week ending 2026-06-19.

[WE6.7.2] Routing test

Tracked in Phabricator
Task T427659

If we create the Pretrain deployment environment using existing production MediaWiki container images and begin routing testwiki traffic to it, we will develop confidence that our routing design is sufficiently complete to support the full Pretrain MVP (e.g., all testwiki traffic is reliably served by the Pretrain environment and container).

Progress update

• Stage: Engineering/Development
• This week, we were able to resolve open questions around how Pretrain will be able to coexist with the experimental Wikifunctions Single-Version Ingress routing configuration, as now reflected in T427668. Separately, we have now also started the Pretrain k8s services turnup (in the new "mw-pretrain" namespace).
• (Joint with WE6.7.3) In parallel, we also focused on defining a clear model for how MediaWiki deployments and supervision can become "scope aware" in a way that will support our needs. See [[phab:T428971#12030988|]] for a sketch of what this may look like, which builds on ideas from Deployment and supervision scoping for Pretrain (google doc content not yet available on wiki).

Any new metrics related to the hypothesis

• None

Any emerging blockers or risks

• Not yet

Any unresolved dependencies - do you depend on another team that hasn’t already given you what you need? Are you on the hook to give another team something you aren’t able to give right now?

• No

Have there been any new lessons from the hypothesis?

• Not yet

Have there been any changes to the hypothesis scope or timeline?

• No

[WE6.7.3] Automated supervision

Tracked in Phabricator
Task T427968

If we implement an initial set of automated supervision strategies and enable automated deployment to the Pretrain environment for the routing test, we will develop confidence that automated supervision is ready to serve as our primary risk mitigation for the full Pretrain MVP (e.g., false positives are understood, and we have identified a path to mitigate them).

Progress update

• Stage: Design
• Met to clarify implementation of T428971: Allow configuration of canary and production checks based on deployment target
  • Scott French provided a mock configuration on that task that would allow Ahmon to build against.
  • We will start work on adding this configuration to scap next week.
• Affirmed direction on T428972: Configure additional httpbb checks to perform during a deployment
  • Met with members of Quality Services this week to talk about the work to be done for creating additional production checks and traffic, and discussed far future possibilities.
  • Built confidence in this direction and scope: it can be completed, the scope seems reasonable, initially, and it will help us build confidence in our deploys.

Any new metrics related to the hypothesis

• None

Any emerging blockers or risks

• Not yet

Any unresolved dependencies - do you depend on another team that hasn’t already given you what you need? Are you on the hook to give another team something you aren’t able to give right now?

• No

Have there been any new lessons from the hypothesis?

• Not yet

Have there been any changes to the hypothesis scope or timeline?

• No