Bootstrap with pre-defined identities

[gman0]

Summary

This PR adds a way to inject identities from a file while performing phase0 bootstrapping, making it possible to override core identities with pre-defined ones.

The file is expected to by YAML-formatted, passed via --core-identities-file kcp command line flag; its structure is rather simple, see the linked issue for reference.

What Type of PR Is This?

/kind feature

Related Issue(s)

Fixes #3320

Release Notes

Adds a new --core-identities-file kcp flag

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pull-kcp-test-e2e-shared	d343e91	link	true	/test pull-kcp-test-e2e-shared

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[ntnn]

Suggested change

	var coreIdentities coreIdentitiesFile
	bs, err := os.ReadFile(identitiesFilename)
	if err != nil {
	return fmt.Errorf("failed to read core identities file %s: %v", identitiesFilename, err)
	}
	if err = yaml.UnmarshalStrict(bs, &coreIdentities); err != nil {
	return fmt.Errorf("failed to parse YAML file %s: %v", identitiesFilename, err)
	}
	bs, err := os.ReadFile(identitiesFilename)
	if err != nil {
	return fmt.Errorf("failed to read core identities file %s: %v", identitiesFilename, err)
	}
	var coreIdentities coreIdentitiesFile
	if err := yaml.UnmarshalStrict(bs, &coreIdentities); err != nil {
	return fmt.Errorf("failed to parse YAML file %s: %v", identitiesFilename, err)
	}

[ntnn]

E.g. here the file is read pkg/server and then the contents are handed off:

kcp/pkg/server/config.go

Lines 369 to 389 in e2ba960

	if opts.Extra.ShardClientCertFile != "" && opts.Extra.ShardClientKeyFile != "" && opts.Extra.ShardVirtualWorkspaceCAFile != "" {
	caCert, err := os.ReadFile(opts.Extra.ShardVirtualWorkspaceCAFile)
	if err != nil {
	return nil, fmt.Errorf("failed to read CA file %q: %w", opts.Extra.ShardVirtualWorkspaceCAFile, err)
	}
	caCertPool := x509.NewCertPool()
	caCertPool.AppendCertsFromPEM(caCert)
	cert, err := tls.LoadX509KeyPair(opts.Extra.ShardClientCertFile, opts.Extra.ShardClientKeyFile)
	if err != nil {
	return nil, fmt.Errorf("failed to load client certificate %q or key %q: %w", opts.Extra.ShardClientCertFile, opts.Extra.ShardClientKeyFile, err)
	}
	transport := http.DefaultTransport.(*http.Transport).Clone()
	transport.TLSClientConfig = &tls.Config{
	Certificates: []tls.Certificate{cert},
	RootCAs: caCertPool,
	}
	virtualWorkspaceServerProxyTransport = transport
	}

Might also make it easier to test config without having to write the contents out to a file rather than just passing the bytes.

[sttts]

the format must be documented. In the docs, and If it's super simple, then here too.

[sttts]

Maybe you mean that in the description. Maybe `.... with a map where keys are X and values are Y. What are the keys? What is a identity secret? Are these write 1:1 to the secret of the same name? Try to be clear and precise.

[sttts]

Also it must be very clear what happens if the secrets are pre-existing.

[sttts]

Suggested change

	fs.StringVar(&o.Extra.CoreIdentitiesFile, "core-identities-file", "", "Path to a YAML file with APIExport - Identity secret Identity key pairs. Defaults to empty, i.e. all identities are generated.")
	fs.StringVar(&o.Extra.CoreIdentitiesFile, "core-identities-file", "", "Path to a YAML file with APIExport - identity secret identity key pairs. Defaults to empty, i.e. all identities are generated.")

[sttts]

2025