Add a flag to customize kubeReleaseBucketURL

[yxxhero]

Add a flag to customize kubeReleaseBucketURL

https://dl.k8s.io is not stable in china. so we can add a flag to customize kubeReleaseBucketURL.

[yxxhero]

/cc @pacoxu

[yxxhero]

/cc @neolit123

[yxxhero]

/assign

[neolit123]

what is the blocker here? if it fails, it ends up using the local version, correct?

new configuration options should go in the api and not flags:
#3160

my initial reaction is -1, https://dl.k8s.io/ is a stable default, same to registry.k8s.io.
but registry.k8s.io is configurable.

by making this configurable are you supposed to deploy a fake service that emulates what dl.k8s.io does?
that sounds very hacky.

[yxxhero]

@neolit123 thanks for your comments.
Due to network issues, there may be instability in address access in China, so it would be better to add a configuration option that can cover this scenario in the settings.

[neolit123]

if there is a custom url, how would one set it up the service?

it has some custom version markers and it falls back to binary version on network failure. it is used to fetch latest patch version, but the user can just pass --kubernetes-version instead.

cc @SataQiu @carlory @HirazawaUi for opinion.

[yxxhero]

@neolit123 user can mirror https://dl.k8s.io.

[HirazawaUi]

LOL, Chinese people active on github are really good at tunneling through the internet, so I've never run into this issue.

In fact, there are plenty of guides on the Chinese internet about using kubeadm offline, and they’ve never been troubled by this problem, so I’m quite skeptical about the necessity of adding this parameter. Could you describe the issue you encountered in more detail?

edit:
I tried turning off my VPN and accessing https://dl.k8s.io/ in my browser, and it seems this website isn’t blocked by the GFW.

[HirazawaUi]

Upon revisiting this issue, I think the vast majority of users wouldn’t do this (even in a restricted network environment). Setting up a mirror for https://dl.k8s.io/ is far more troublesome than simply specifying kubernetes version (at the very least, there’s no reliable documentation telling users how to set up such a mirror). Unless there’s a more compelling reason, my stance also -1.

[carlory]

Unless there’s a more compelling reason, my stance also -1.

Agreed.

[yxxhero]

make sense. thanks you all