Use dnsutils image for DNS debugging #18001
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/assign @BenTheElder @bowei |
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/assign @zparnold |
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Deploy preview for kubernetes-io-master-staging ready! Built with commit 9831193 https://deploy-preview-18001--kubernetes-io-master-staging.netlify.com |
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Deploy preview for kubernetes-io-master-staging ready! Built with commit 6debada https://deploy-preview-18001--kubernetes-io-master-staging.netlify.com |
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Not sure it is a good thing to test a feature using an image customized for it. If the DNS resolving feature works well, why we cannot use busybox or other images? |
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@tengqm this is the context of this issue https://kubernetes.slack.com/archives/C09QYUH5W/p1575667447086200 As you can see in current documentation the busybox version has to be pinned to 1.28 because later versions don't work with kubernetes docker-library/busybox#48 Also, you can see that there are already some known issues https://kubernetes.io/docs/tasks/administer-cluster/dns-debugging-resolution/#known-issues , unfortunately, DNS is a complex topic with many moving parts. Having an image that is being tested daily guarantees that the docs will be up to date, using a generic image it may break in the future without anybody noticing. |
the set of tools is the only thing customized, not any details about how it behaves. most common images lack DNS utilities. the busybox tools are not a great choice, they are known to behave badly on kubernetes. we are observing the search paths not being respected. this could certainly happen with other real tools, but they should respect this. |
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/lgtm |
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Okay. That is a convincing. /lgtm |
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@aojea Can I suggest leaving the existing example in place? It might be linked to from elsewhere.
After a while it might be OK to tidy up. If you agree about leaving it in place, how about logging an instantly-frozen issue to track that future work?
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DNS debugging documentation is using a busybox image as example. This image has different known issues with the way it resolves the DNS names in k8s, creating confusion with users that try to follow the docs. The e2e tests use a custom small image ~4.3MB for DNS testing with all the necessary tools. Also, the fact that this image is being used for the k8s e2e testing guarantees it's compatibility.
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/assign @zparnold |
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gentle poke 🙃 |
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/lgtm |
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[APPROVALNOTIFIER] This PR is APPROVED This pull-request has been approved by: bowei, sftim The full list of commands accepted by this bot can be found here. The pull request process is described here
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DNS debugging documentation is using a busybox image as example. This image has different known issues with the way it resolves the DNS names in k8s, creating confusion with users that try to follow the docs. The e2e tests use a custom small image ~4.3MB for DNS testing with all the necessary tools. Also, the fact that this image is being used for the k8s e2e testing guarantees it's compatibility.
DNS debugging documentation is using a busybox image as example.
This image has different known issues with the way it resolves
the DNS names in k8s that create confusion with users following the
docs.
The e2e tests use a custom small image ~4.3MB for DNS testing
with all the tools necessary. Also, the fact that this image is
being used for the k8s e2e testing guarantees it's compatibility.