[WIP][improvement] : allow auto-allocation of NB backend ips

[rahulait]

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2. Have you added tests?
3. Are you addressing a single feature in this PR?
4. Are your commits atomic, addressing one change per commit?
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[codecov]

Codecov Report

Attention: Patch coverage is 82.02247% with 16 lines in your changes missing coverage. Please review.

Project coverage is 74.54%. Comparing base (8d08bde) to head (1dff45a).

Files with missing lines	Patch %	Lines
cloud/linode/loadbalancers.go	86.95%	6 Missing and 3 partials ⚠️
cloud/linode/vpc.go	71.42%	3 Missing and 1 partial ⚠️
cloud/linode/cloud.go	50.00%	2 Missing and 1 partial ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #391      +/-   ##
==========================================
+ Coverage   74.41%   74.54%   +0.12%     
==========================================
  Files          16       16              
  Lines        2865     2942      +77     
==========================================
+ Hits         2132     2193      +61     
- Misses        550      561      +11     
- Partials      183      188       +5     

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[Copilot]

Pull Request Overview

This PR adds support for auto-allocation of NodeBalancer backend IPs. Key changes include:

• Adding new command-line flags for specifying the backend IPv4 subnet ID and name.
• Updating e2e tests to incorporate VPC configuration retrieval and subnet ID auto-allocation.
• Enhancing chart templates and cloud configuration logic to enforce mutual exclusion of subnet flags and annotations.

Reviewed Changes

Copilot reviewed 12 out of 13 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
main.go	Added CLI flags for NodeBalancer backend IPv4 subnet allocation.
e2e/test/lb-updated-with-nb-id/chainsaw-test.yaml	Updated test script to retrieve and use the existing NB backend subnet.
e2e/test/lb-preserve-annotation-new-nb-specified/chainsaw-test.yaml	Updated test script to support annotation-based subnet selection.
deploy/chart/values.yaml	Documented new chart configuration options.
deploy/chart/templates/daemonset.yaml	Added validation to prevent both subnet name and ID from being set.
cloud/linode/vpc.go	Introduced getNodeBalancerBackendIPv4SubnetID to retrieve the subnet id from a name.
cloud/linode/loadbalancers_test.go	Updated tests with consistent default subnet naming and new NB creation scenarios.
cloud/linode/loadbalancers.go	Updated NB creation logic to leverage VPC create options based on flags/annotations.
cloud/linode/cloud.go	Enforced mutual exclusion for subnet flags and set the backend subnet ID based on a provided name.
cloud/annotations/annotations.go	Added constant for backend subnet ID annotation.

Files not reviewed (1)

• go.mod: Language not supported

Comments suppressed due to low confidence (1)

deploy/chart/templates/daemonset.yaml:88

• [nitpick] Consider using a consistent naming convention for template variables (e.g. use $nodeBalancerBackendIpv4SubnetName and $nodeBalancerBackendIpv4SubnetID) to align with the rest of the codebase.

{{- if and $nbvpcBackendIpv4SubnetName $nbvpcBackendIpv4SubnetID }}

[Copilot]

The function getNodeBalancerBackendIPv4SubnetID logs errors and returns 0 instead of propagating the error. Consider returning the error to enable better diagnostics and failure handling.

Suggested change

	func getNodeBalancerBackendIPv4SubnetID(client client.Client) int {
	vpcName := strings.Split(Options.VPCNames, ",")[0]
	// Get the VPC ID from the name
	vpcID, err := GetVPCID(context.TODO(), client, vpcName)
	if err != nil {
	klog.Errorf("failed to get vpc id for %s: %v", vpcName, err)
	return 0
	}
	// Get the subnet ID from the name
	subnetID, err := GetSubnetID(context.TODO(), client, vpcID, Options.NodeBalancerBackendIPv4SubnetName)
	if err != nil {
	klog.Errorf("failed to get subnet id for %s: %v", Options.NodeBalancerBackendIPv4SubnetName, err)
	return 0
	}
	return subnetID
	func getNodeBalancerBackendIPv4SubnetID(client client.Client) (int, error) {
	vpcName := strings.Split(Options.VPCNames, ",")[0]
	// Get the VPC ID from the name
	vpcID, err := GetVPCID(context.TODO(), client, vpcName)
	if err != nil {
	return 0, fmt.Errorf("failed to get vpc id for %s: %w", vpcName, err)
	}
	// Get the subnet ID from the name
	subnetID, err := GetSubnetID(context.TODO(), client, vpcID, Options.NodeBalancerBackendIPv4SubnetName)
	if err != nil {
	return 0, fmt.Errorf("failed to get subnet id for %s: %w", Options.NodeBalancerBackendIPv4SubnetName, err)
	}
	return subnetID, nil

[Copilot]

[nitpick] The nested conditions in getVPCCreateOptions make the flow somewhat complex; consider refactoring to simplify the control flow for improved clarity and maintainability.