virtualbox: Make DNS settings configurable

[cvila84]

Closes #3720

add --dns-proxy and --host-dns-resolver flags to start command for controlling virtualbox dns settings

[k8s-ci-robot]

Hi @cvila84. Thanks for your PR.

I'm waiting for a kubernetes member to verify that this patch is reasonable to test. If it is, they should reply with /ok-to-test on its own line. Until that is done, I will not automatically test new commits in this PR, but the usual testing commands by org members will still work. Regular contributors should join the org to skip this step.

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[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is NOT APPROVED

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[minikube-bot]

Can one of the admins verify this patch?

[medyagh]

Thank you for the PR, could you tell me an example where this setting would be useful ? or how I could test this ?

[cvila84]

Hello @medyagh,

These settings would allow people to disable the usage of Virtualbox NAT DNS proxy which can be quite unstable (see [https://www.virtualbox.org/ticket/13899?cversion=0&cnum_hist=3]).

To test it, when --dns-proxy and --host-dns-resolver are set to false, the /etc/resolv.conf of the minikube VM shall contain the same DNS IP as the host. If any of the settings are true, the /etc/resolv.conf of the minikube shall be the default DNS proxy IP which is 10.2.0.3

[medyagh]

ok thank you for the explain. does this have any relation with proxy or vpn ?

@minikube-bot OK to test

[cvila84]

@medyagh i don't see any relation with proxy. the only relation i see with VPN is related to host network switching (office <-> VPN home) while minikube VM is running. when DNS proxy is deactivated, it won't reflect the new host DNS IP into /etc/resolv.conf but this is an acceptable constraint as sometimes the silent crash of Virtualbox DNS proxy prevents any communication to be done from the VM to the external world (because of DNS resolve timeout)

i see the label needs-ok-to-test is still set. it seems you need to write /ok-to-test on its own line

[medyagh]

/retest this please