add pdb to coredns

[lobiyedKarim1]

What type of PR is this?

/kind feature

What this PR does / why we need it:
This PR introduces changes to enhance CoreDNS. The following modifications have been made:

• Introduced the coredns_pod_disruption_budget variable to enable/disable PodDisruptionBudget for CoreDNS.
• Set the default value of coredns_pod_disruption_budget to false.
• Added the coredns_pod_disruption_budget_max_unavailable variable to specify the maximum number of unavailable pods during disruptions. The default value is set to 1.
• Created a new template coredns-poddisruptionbudget.yml.j2 to generate the corresponding PodDisruptionBudget YAML file with configurable options.

These changes provide users with more control over CoreDNS's behavior during disruptions and enable fine-grained tuning of the PodDisruptionBudget settings.

Which issue(s) this PR fixes:
NONE

Special notes for your reviewer:
NONE

Does this PR introduce a user-facing change?:

Add pdb to coredns

[k8s-ci-robot]

Hi @lobiyedKarim1. Thanks for your PR.

I'm waiting for a kubernetes-sigs 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.

Once the patch is verified, the new status will be reflected by the ok-to-test label.

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[yankay]

HI @lobiyedKarim1

Thanks to the PR.

The default config should not be changed :-)
Is it ok to use a variable to to config. like:
like the https://github.com/coredns/helm/blob/master/charts/coredns/templates/poddisruptionbudget.yaml

And the maxUnavailable can also be a variable.

/ok-to-test

[VannTen]

Does that really belong in Kubespray ? From #6400 I had the impression that one of the long-term goals was to somehow reduce the scope, and this looks like it could easily enough be in an standalone manifest applied after kubespray.

[VannTen]

By the way, you're only applying your pdb to the second instance of coredns (when using coredns_dual). It should be applied on both.

[lobiyedKarim1]

By the way, you're only applying your pdb to the second instance of coredns (when using coredns_dual). It should be applied on both.

[lobiyedKarim1]

By the way, you're only applying your pdb to the second instance of coredns (when using coredns_dual). It should be applied on both.

[VannTen]

I don't know if it's weird but it's already used in kubespray https://github.com/kubernetes-sigs/kubespray/blob/master/roles/network_plugin/cilium/tasks/install.yml#L63

Mmmh. I guess. Don't like that, but looks like there isn't a simpler way.

[VannTen]

Last thing and we're good.

[VannTen]

/lgtm
Thanks (for putting up with me 👍 )
/assign @yankay @mzaian
(approval)

[mzaian]

Thanks @lobiyedKarim1

/lgtm

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: lobiyedKarim1, mzaian

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