Persist TLS certificate and key of antrea-controller #5955

tnqn · 2024-02-01T14:30:14Z

In clusters where upgrade is performed with rolling update of Nodes and images of new versions are only available on new Nodes, the deployment strategy of antrea-controller is set to RollingUpdate to prevent antrea-controller Pod from being deleted immediately when the deployment is updated, leading to a period in which no antrea-controller is running. However, it also causes two instances of antrea-controller to run simultaneously in a short time, making it possible that the old instance overrides the CA bundle stored in antrea-ca ConfigMap, APIServices, and Webhooks, while the new instance won't update them again.

The commit makes two changes to fix the problem:

CACertController will periodically sync the CA cert to improve the robustness.
Self-signed TLS certificate and key of antrea-controller will be stored in a Secret and will be reused after restarting controller. This makes running multiple antrea-controller instances simultaneously possible and makes restart of antrea-controller smoother as antrea-agents don't need to retrieve a new CA bundle most of the time.

Besides, the change is helpful for implementing high-availability of antrea-controller in the future.

antoninbas · 2024-02-02T18:09:53Z

pkg/apiserver/certificate/selfsignedcert_provider.go

+	}
+	remainingDuration := certs[0].NotAfter.Sub(p.clock.Now())
+	if remainingDuration < p.caConfig.MinValidationDuration {
+		klog.InfoS("The remaining duration of the TLS certificate and key is less than max rotate duration", "remaining", remainingDuration, "max", p.caConfig.MinValidationDuration)


is the log message still appropriate after replacing MaxRotateDuration with MinValidationDuration (same for the "max" log key)?

thanks for reminding, forgot updating this one

antoninbas · 2024-02-02T18:18:23Z

pkg/apiserver/certificate/config.go

-	ServiceName       string
-	PairName          string
+	// MinValidationDuration is the minimal remaining validation duration for the self-signed certificate. It must be
+	// rotated once shorter than the duration.


Suggested change

// rotated once shorter than the duration.

// rotated once the time until the certificate expires becomes shorter than this duration.

antoninbas · 2024-02-02T18:19:15Z

multicluster/cmd/multicluster-controller/controller.go

@@ -113,7 +113,7 @@ func getCaConfig(isLeader bool, controllerNs string) *certificate.CAConfig {
 		MutationWebhookSelector:   getWebhookLabel(isLeader, controllerNs),
 		ValidatingWebhookSelector: getWebhookLabel(isLeader, controllerNs),
 		CertReadyTimeout:          2 * time.Minute,
-		MaxRotateDuration:         time.Hour * (24 * 365),
+		MinValidationDuration:     time.Hour * 24 * 90, // Rotate the certificate 90 days in advance.


nit: I feel like MinValidDuration would be a more "correct" name

agree, I was thinking valid but somehow wrote validation.

antoninbas · 2024-02-02T18:22:27Z

pkg/apiserver/certificate/selfsignedcert_provider.go

+	secureServing.ServerCert.CertKey.CertFile = path.Join(caConfig.SelfSignedCertDir, caConfig.PairName+".crt")
+	secureServing.ServerCert.CertKey.KeyFile = path.Join(caConfig.SelfSignedCertDir, caConfig.PairName+".key")


maybe the path/filepath package should be used here instead of path, given that these are actual filepaths AFAIK

antoninbas · 2024-02-02T18:25:49Z

pkg/apiserver/certificate/selfsignedcert_provider_test.go

+	caConfig := &CAConfig{
+		TLSSecretName:         tlsSecretName,
+		SelfSignedCertDir:     t.TempDir(),
+		MinValidationDuration: maxRotateDuration,


you're using the maxRotateDuration term here still, yet you use the parameter value to initialize MinValidationDuration. But the 2 mean different things right?

fixed, forgot to update after renaming it

antoninbas · 2024-02-02T18:28:42Z

pkg/apiserver/certificate/selfsignedcert_provider.go

+		provider.secretInformer.AddEventHandler(cache.ResourceEventHandlerFuncs{
+			AddFunc:    func(obj interface{}) { provider.enqueue() },
+			UpdateFunc: func(_, _ interface{}) { provider.enqueue() },
+			DeleteFunc: func(obj interface{}) { provider.enqueue() },
+		})


just to check my understanding: normally there is no reason for the secret to be modified and for these handlers to be invoked, as the Controller should be the only entity modifying the secret?

This is for the corner case that the certificate needs rotation when upgrading. With the handling, regardless of which instance updates the secret first, the other one will switch to it and stop generating a new one.
In the future when HA is implemented, we should only let the active instance rotate the certificate, and the standby instances should refresh its certificate immediately, so the even handlers are also needed for that case.

maybe a comment would be a good idea?

antoninbas · 2024-02-02T18:38:09Z

test/e2e/security_test.go

+	secretBeforeRestart, err := data.clientset.CoreV1().Secrets(tlsSecretNamespace).Get(context.TODO(), tlsSecretName, metav1.GetOptions{})
+	require.NoError(t, err)
+
+	testCert(t, data, string(secretBeforeRestart.Data[certificate.TLSCertFile]), true)


so in the self-signed certificate case, the published CA bundle (published to the ConfigMap) is equal to the certificate itself (stored in the Secret)?

Yes, self-signed certificate util always include both CA cert and signed cert in server cert. We can choose to only publish CA cert for server authentication, but never made the change. We discussed this before in #5135 (comment)

antoninbas · 2024-02-02T18:39:52Z

@tnqn

However, it also causes two instances of antrea-controller to run simultaneously in a short time, making it possible that the old instance overrides the CA bundle stored in antrea-ca ConfigMap, APIServices, and Webhooks, while the new instance won't update them again.

Should we backport this then? It seems that there is no automatic recovery in this case, until the Controller is manually restarted. Could this explain some issues we saw over the years, with APIServices / Webhooks not working because of TLS issues?

luolanzone · 2024-02-04T03:38:19Z

pkg/apiserver/certificate/cacert_controller.go

@@ -171,6 +169,7 @@ func (c *CACertController) syncConversionWebhooks(caCert []byte) error {
 			crdDef.Spec.Conversion.Webhook.ClientConfig.CABundle = caCert
 		}
 		if updated {
+			klog.InfoS("Syncing CA certificate with CRD that have conversion webhooks", "name", crdDef.Name)


Suggested change

klog.InfoS("Syncing CA certificate with CRD that have conversion webhooks", "name", crdDef.Name)

klog.InfoS("Syncing CA certificate with CRD that have conversion webhook", "name", crdDef.Name)

a CRD can have multiple conversion webhooks.

luolanzone · 2024-02-04T03:53:24Z

pkg/apiserver/certificate/selfsignedcert_provider.go

+}
+
+func (p *selfSignedCertProvider) enqueue() {
+	// The key can be anything as we only have single item.


Suggested change

// The key can be anything as we only have single item.

// The key can be anything as we only have a single item.

luolanzone · 2024-02-04T03:59:53Z

pkg/apiserver/certificate/selfsignedcert_provider.go

+	var err error
+	var secret *corev1.Secret
+	// If Secret is specified, we should prioritize it.
+	if p.caConfig.TLSSecretName != "" {


Maybe define a new variable hasTLSSecretName=p.caConfig.TLSSecretName != "" which can be used in following codes.

I feel they are equivalently readable and there are only two such checks. It seems a bit verbose to me to define a variable.

luolanzone · 2024-02-04T05:52:45Z

pkg/apiserver/certificate/selfsignedcert_provider.go

+	if p.shouldRotateCertificate(cert) {
+		klog.InfoS("Generating self signed cert")
+		if cert, key, err = generateSelfSignedCertKey(p.caConfig.ServiceName, loopbackAddresses, GetAntreaServerNames(p.caConfig.ServiceName)); err != nil {
+			return fmt.Errorf("unable to generate self signed cert: %v", err)


I think "self-signed cert" is a more common one. Probably replace the self signed with self-signed.

luolanzone · 2024-02-04T05:53:15Z

pkg/apiserver/certificate/selfsignedcert_provider.go

+	if bytes.Equal(cert, p.cert) && bytes.Equal(key, p.key) {
+		return nil
+	}
+	klog.InfoS("Writing certificate and key to cert directory")


Suggested change

klog.InfoS("Writing certificate and key to cert directory")

klog.InfoS("Writing certificate and key to the cert directory")

luolanzone · 2024-02-04T06:08:13Z

pkg/apiserver/certificate/selfsignedcert_provider_test.go

+}
+
+func TestSelfSignedCertProviderRun(t *testing.T) {
+	secretNamespace := env.GetAntreaNamespace()


I suppose we can simply set this as "kube-system" considering it's for testing?

Then the correctness of this test would be subject to the value of defaultAntreaNamespace.
I would prefer not to introduce obsecure dependency unnecessarily. The provider is implemented to not assume the Pod must run in "kube-system", the test code shouldn't assume that too. To make it more clear, I have changed the code to set the env var in the beginning of the test.

tnqn · 2024-02-04T10:20:51Z

However, it also causes two instances of antrea-controller to run simultaneously in a short time, making it possible that the old instance overrides the CA bundle stored in antrea-ca ConfigMap, APIServices, and Webhooks, while the new instance won't update them again.

Should we backport this then? It seems that there is no automatic recovery in this case, until the Controller is manually restarted. Could this explain some issues we saw over the years, with APIServices / Webhooks not working because of TLS issues?

There was a time the certificate was overridden by the deployment tool kapp when it's used. I don't know what was the cause for other occurrences. Even for the latest report, we only know there was an old controller overwriting the CA bundle with its own one generated two days ago, but this shouldn't happen as overwriting the ConfigMap is one-time job and an old instance will only do it again after 1/2 of the valid duration (half a year) or it never succeeded to update all resources' CA bundle in the last two days.

The change is compatible when upgrading from an old controller to patched controller, as well as patched controller to patched controller. However, it may cause issue if upgrading from patch controller to unpatched controller. For example, if we release 1.14.3 with the patch, and users upgrade 1.14.3 to 1.15.0, there would be an issue. Not sure if we can assume users will always upgrade to latest patch version of a minor release. But it's pretty sure this only happens when the deployment strategy is changed to RollingUpdate.

antoninbas · 2024-02-05T18:19:35Z

But it's pretty sure this only happens when the deployment strategy is changed to RollingUpdate.

Thanks, I missed that earlier. Didn't realize it could only happen for custom installations.

antoninbas

LGTM

antoninbas · 2024-02-05T18:21:06Z

pkg/apiserver/certificate/selfsignedcert_provider.go

+		provider.secretInformer.AddEventHandler(cache.ResourceEventHandlerFuncs{
+			AddFunc:    func(obj interface{}) { provider.enqueue() },
+			UpdateFunc: func(_, _ interface{}) { provider.enqueue() },
+			DeleteFunc: func(obj interface{}) { provider.enqueue() },
+		})


maybe a comment would be a good idea?

antoninbas · 2024-02-05T18:23:54Z

pkg/apiserver/certificate/selfsignedcert_provider.go

+}
+
+func newVerifyOptions(caBundle []byte) *x509.VerifyOptions {
+	// We don't really use the CA bundle to verify clients, this is just to follow DynamicFileCAContent.


just to double-check: with this, you mean that the generated cert is never used for client-side auth, only server-side auth?

The generated cert is used for client-side server authentication. The server, antrea-controller, doesn't validate clients' TLS using this cert and it can't use it because none of the client cert is signed by it. It uses token to validate clients.

I added the comment because it sets the key usage to "ExtKeyUsageClientAuth" which might be confusing for people who wonders how can this CA bundle be used for server-side client authentication as we never generate any client cert. It's to follow DynamicFileCAContent's implementation.The verify option will never be used actually.

only server-side auth

That was poor phrasing on my part. I indeed meant server authentication on the client-side...

pkg/apiserver/certificate/selfsignedcert_provider_test.go

In clusters where upgrade is performed with rolling update of Nodes and images of new versions are only available on new Nodes, the deployment strategy of antrea-controller is set to RollingUpdate to prevent antrea-controller Pod from being deleted immediately when the deployment is updated, leading to a period in which no antrea-controller is running. However, it also causes two instances of antrea-controller to run simultaneously in a short time, making it possible that the old instance overrides the CA bundle stored in antrea-ca ConfigMap, APIServices, and Webhooks, while the new instance won't update them again. The commit makes two changes to fix the problem: 1. CACertController will periodically sync the CA cert to improve the robustness. 2. Self-signed TLS certificate and key of antrea-controller will be stored in a Secret and will be reused after restarting controller. This makes running multiple antrea-controller instances simultaneously possible and makes restart of antrea-controller smoother as antrea-agents don't need to retrieve a new CA bundle most of the time. Besides, the change is helpful for implementing high-availability of antrea-controller in the future. Signed-off-by: Quan Tian <[email protected]>

tnqn · 2024-02-07T06:05:07Z

/test-all

In clusters where upgrade is performed with rolling update of Nodes and images of new versions are only available on new Nodes, the deployment strategy of antrea-controller is set to RollingUpdate to prevent antrea-controller Pod from being deleted immediately when the deployment is updated, leading to a period in which no antrea-controller is running. However, it also causes two instances of antrea-controller to run simultaneously in a short time, making it possible that the old instance overrides the CA bundle stored in antrea-ca ConfigMap, APIServices, and Webhooks, while the new instance won't update them again. The commit makes two changes to fix the problem: 1. CACertController will periodically sync the CA cert to improve the robustness. 2. Self-signed TLS certificate and key of antrea-controller will be stored in a Secret and will be reused after restarting controller. This makes running multiple antrea-controller instances simultaneously possible and makes restart of antrea-controller smoother as antrea-agents don't need to retrieve a new CA bundle most of the time. Besides, the change is helpful for implementing high-availability of antrea-controller in the future. Signed-off-by: Quan Tian <[email protected]>

tnqn added the action/release-note Indicates a PR that should be included in release notes. label Feb 1, 2024

tnqn force-pushed the tolerate-ephemeral-multi-controllers branch 7 times, most recently from d003e37 to a34f717 Compare February 2, 2024 16:22

tnqn marked this pull request as ready for review February 2, 2024 16:27

tnqn requested review from antoninbas, luolanzone and jianjuns February 2, 2024 16:27

antoninbas reviewed Feb 2, 2024

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luolanzone reviewed Feb 4, 2024

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tnqn force-pushed the tolerate-ephemeral-multi-controllers branch from a34f717 to c2bbf66 Compare February 4, 2024 10:04

tnqn force-pushed the tolerate-ephemeral-multi-controllers branch from c2bbf66 to af8b178 Compare February 5, 2024 15:31

antoninbas previously approved these changes Feb 5, 2024

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tnqn dismissed antoninbas’s stale review via 94cd0cd February 6, 2024 04:24

tnqn force-pushed the tolerate-ephemeral-multi-controllers branch from af8b178 to 94cd0cd Compare February 6, 2024 04:24

antoninbas approved these changes Feb 6, 2024

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tnqn merged commit f877806 into antrea-io:main Feb 7, 2024
51 of 54 checks passed

tnqn deleted the tolerate-ephemeral-multi-controllers branch February 7, 2024 13:33

antoninbas mentioned this pull request Feb 9, 2024

Flaky test antrea.io/antrea/pkg/apiserver/certificate.TestSelfSignedCertProviderRun #5977

Closed

tnqn mentioned this pull request Mar 6, 2024

Automated cherry pick of #5955: Persist TLS certificate and key of antrea-controller (#5955) #6004: Fix race condition in pkg/apiserver/certificate unit tests #6068

Merged

tnqn mentioned this pull request Mar 7, 2024

Automated cherry pick of #5955: Persist TLS certificate and key of antrea-controller (#5955) #6004: Fix race condition in pkg/apiserver/certificate unit tests #6079

Merged

tnqn mentioned this pull request Mar 7, 2024

Automated cherry pick of #5955: Persist TLS certificate and key of antrea-controller (#5955) #6004: Fix race condition in pkg/apiserver/certificate unit tests #6080

Merged

tnqn added the kind/bug Categorizes issue or PR as related to a bug. label Jul 16, 2024

	// rotated once shorter than the duration.
	// rotated once the time until the certificate expires becomes shorter than this duration.

		secureServing.ServerCert.CertKey.CertFile = path.Join(caConfig.SelfSignedCertDir, caConfig.PairName+".crt")
		secureServing.ServerCert.CertKey.KeyFile = path.Join(caConfig.SelfSignedCertDir, caConfig.PairName+".key")

	klog.InfoS("Syncing CA certificate with CRD that have conversion webhooks", "name", crdDef.Name)
	klog.InfoS("Syncing CA certificate with CRD that have conversion webhook", "name", crdDef.Name)

	// The key can be anything as we only have single item.
	// The key can be anything as we only have a single item.

	klog.InfoS("Writing certificate and key to cert directory")
	klog.InfoS("Writing certificate and key to the cert directory")

Persist TLS certificate and key of antrea-controller #5955

Persist TLS certificate and key of antrea-controller #5955

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tnqn commented Feb 1, 2024 • edited Loading

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antoninbas commented Feb 2, 2024

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tnqn commented Feb 4, 2024

antoninbas commented Feb 5, 2024

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tnqn commented Feb 7, 2024

tnqn commented Feb 1, 2024 •

edited

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