docs: improve NodePort collision section with example and reference #51228
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To complement the existing explanation of static and dynamic NodePort bands, add the default range breakdown and a link to a related blog post. This provides users with a clearer understanding and the key information they'd otherwise need to search for separately.
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We should be wary to link to https://kubernetes.io/blog/2023/05/11/nodeport-dynamic-and-static-allocation/ unless we're going to mark that page evergreen. Otherwise, people will follow the link and see:
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I see your point, thanks for bringing it up. If you feel it's better to leave the link out, I'm happy to drop it. I just thought it might help reduce the need for readers to search elsewhere. That said, the original documentation does feel a bit abstract, so I think the concrete example could be still helpful for readers. Of course, including specific details always carries the risk of reducing the long-term accuracy if those details change over time (though that seems unlikely in this case). Do you think it would still be reasonable to include the default range example, and perhaps the port range calculation formula, given that trade-off? |
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By the way, the code for port range calculation can be found here: https://github.com/kubernetes/kubernetes/blob/089849ac22f4d67ac0a8651d1a8e5fda9d7752e4/pkg/registry/core/service/portallocator/allocator.go#L259-L285 |
| When using the default NodePort range 30000-32767, the bands are partitioned as follows: | ||
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| - Static band: 30000-30085 | ||
| - Dynamic band: 30086-32767 |
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I might actually put this in https://kubernetes.io/docs/reference/networking/virtual-ips/ anbd link there. Maybe also the information about bands.
Not sure.
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I assume you're referring to placing it near the IP address ranges for Service virtual IP addresses section. That sounds reasonable to me; happy to give it a try and see how it looks.
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Hmm... it turns out it's a bit tricky to find a good place for this change in Virtual IPs and Service Proxies. As the title suggests, that page appears to focus more on how kube-proxy handles internal packet distribution using the virtual IP mechanism through iptables, IPVS, or similar components. Personally, I feel this change is slightly off-topic for that page, since it's specific to the NodePort Service type. That said, I don't have a strong opinion.
It might be helpful to get input from other reviewers. Could you take a look, @nate-double-u @shannonxtreme? (Cc @lmktfy)
Description
Changes:
To complement the existing explanation of static and dynamic NodePort bands, add the default range breakdown and a link to the related blog post. This provides users with a clearer understanding and the key information they'd otherwise need to search for separately.
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