Assert that IP range is enough for the nodes

[eakyildirim]

What type of PR is this?

/kind feature

What this PR does / why we need it:

• We would like to have a safeguard against adding way too many nodes. Currently, there is a task for checking the maximum pod count, but we couldn't find a checking mechanism for the node count.

Which issue(s) this PR fixes:

• Fixes Assert that IP range is enough for the nodes #8719

Special notes for your reviewer:

• We might need to subtract one from the result to consider the reserved IPs.

Does this PR introduce a user-facing change?:

Assert that IP range is enough for the nodes

[linux-foundation-easycla]

The committers listed above are authorized under a signed CLA.

• ✅ login: eakyildirim / name: Elif Akyıldırım (fb1e793)

[k8s-ci-robot]

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[liupeng0518]

fatal: [instance-1]: FAILED! => {"msg": "The conditional check '2 ** ( kube_network_node_prefix - kube_pods_subnet | ipaddr('prefix' ) >= groups['k8s_cluster'] | length' failed. The error was: template error while templating string: unexpected '}', expected ')'. String: {% if 2 ** ( kube_network_node_prefix - kube_pods_subnet | ipaddr('prefix' ) >= groups['k8s_cluster'] | length %} True {% else %} False {% endif %}"}

@eakyildirim

[cristicalin]

I'm guessing you are missing a parentheses.

Suggested change

	- 2 ** ( kube_network_node_prefix - kube_pods_subnet | ipaddr('prefix' ) >= groups['k8s_cluster'] | length
	- 2 ** ( kube_network_node_prefix - kube_pods_subnet | ipaddr('prefix' ) >= groups['k8s_cluster'] | length )

[eakyildirim]

Hello, thank you for your review! Basic mistakes for the first start🥲

[cristicalin]

@eakyildirim since the following commits are fixes please squash them into a single commit.

[cristicalin]

/ok-to-test

[oomichi]

Please check @cristicalin comment to make this pull request simple.

/approve

[oomichi]

The additional check follows the samples of

kubespray/roles/kubespray-defaults/defaults/main.yaml

Lines 192 to 202 in 937e64d

	# Example:
	# Up to 64 nodes and up to 254 or kubelet_max_pods (the lowest of the two) pods per node:
	# - kube_pods_subnet: 10.233.64.0/18
	# - kube_network_node_prefix: 24
	# - kubelet_max_pods: 110
	#
	# Example:
	# Up to 128 nodes and up to 126 or kubelet_max_pods (the lowest of the two) pods per node:
	# - kube_pods_subnet: 10.233.64.0/18
	# - kube_network_node_prefix: 25
	# - kubelet_max_pods: 110

That seems good for me.

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: eakyildirim, oomichi

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[cristicalin]

Since this is a first time contribution we can dispense with the squash commits requirement.
/lgtm