Pre-load runners with common base images
Description
Downloading large Docker images at the beginning of a build takes a long time, even with the image proxy caching some of them. We should consider pre-downloading certain images to every shared runner, and then telling people about this so they can choose efficient base images.
Proposal
- Pre-fetch
alpine:latest
andubuntu:16.04
- Document and blog about these "preferred" images
Links
Notes
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This was @ayufan's idea.
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I'm not sure whether this is a better tactic than investing in the caching common images, but it could be better if we help converge people on specific images. It will also help set expectations that if you follow the "preferred" images, then your build will be fast. If you need to diverge, then it will be slower.
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For single-tenant installations, admins could decide to pre-load their companies' own preferred images. (EE feature?)
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I know this could go on the runner issue tracker, but I'd like to discuss it broadly in the context of CI, not about specific implementation.