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OCPBUGS-76530: Fix intermittent etcd peer communication failures #8479

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1ccc561
fix(cpo/pki): add etcd-client SANs to peer certificate
vsolanki12 May 11, 2026
2511ea2
fix(cpo/etcd): switch etcd-client to ClusterIP service
vsolanki12 May 29, 2026
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5 changes: 5 additions & 0 deletions control-plane-operator/controllers/hostedcontrolplane/pki/etcd.go
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Original file line number Diff line number Diff line change
Expand Up @@ -45,6 +45,11 @@ func ReconcileEtcdPeerSecret(secret, ca *corev1.Secret, ownerRef config.OwnerRef
dnsNames := []string{
fmt.Sprintf("*.etcd-discovery.%s.svc", secret.Namespace),
fmt.Sprintf("*.etcd-discovery.%s.svc.cluster.local", secret.Namespace),
// etcd-client headless service shares pod IPs with etcd-discovery; reverse DNS may resolve
// to etcd-client, so peer certs must include both service SANs to pass TLS verification.
fmt.Sprintf("*.etcd-client.%s.svc", secret.Namespace),
fmt.Sprintf("*.etcd-client.%s.svc.cluster.local", secret.Namespace),

@enxebre enxebre May 15, 2026

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can we please add a // comment on the reasoning why this is needed so it's clear for humans/agents landing here without needing to trace back the PR desc?

@vsolanki12 vsolanki12 May 15, 2026

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thank you @enxebre , I have added the comment as per the suggestion

// TODO(OCPBUGS-86648): move IPs to the ips parameter of reconcileSignedCertWithKeysAndAddresses.
"127.0.0.1",
"::1",
}
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82 changes: 82 additions & 0 deletions control-plane-operator/controllers/hostedcontrolplane/pki/etcd_test.go
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Original file line number Diff line number Diff line change
@@ -0,0 +1,82 @@
package pki

import (
"crypto/x509"
"crypto/x509/pkix"
"testing"

. "github.com/onsi/gomega"

"github.com/openshift/hypershift/support/certs"
"github.com/openshift/hypershift/support/config"

corev1 "k8s.io/api/core/v1"
metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
)

func TestReconcileEtcdPeerSecret(t *testing.T) {
t.Parallel()

caCfg := certs.CertCfg{
IsCA: true,
Subject: pkix.Name{CommonName: "etcd-signer", OrganizationalUnit: []string{"openshift"}},
}
caKey, caCert, err := certs.GenerateSelfSignedCertificate(&caCfg)
if err != nil {
t.Fatalf("failed to generate CA: %v", err)
}
caSecret := &corev1.Secret{
Data: map[string][]byte{
certs.CASignerCertMapKey: certs.CertToPem(caCert),
certs.CASignerKeyMapKey: certs.PrivateKeyToPem(caKey),
},
}

t.Run("When reconciling etcd peer secret it should include both etcd-discovery and etcd-client SANs", func(t *testing.T) {
g := NewWithT(t)
secret := &corev1.Secret{
ObjectMeta: metav1.ObjectMeta{
Namespace: "clusters-test",
},
}

err := ReconcileEtcdPeerSecret(secret, caSecret, config.OwnerRef{})
g.Expect(err).ToNot(HaveOccurred())

certData := secret.Data[EtcdPeerCrtKey]
g.Expect(certData).ToNot(BeEmpty())

cert, err := certs.PemToCertificate(certData)
g.Expect(err).ToNot(HaveOccurred())

g.Expect(cert.DNSNames).To(ContainElements(
"*.etcd-discovery.clusters-test.svc",
"*.etcd-discovery.clusters-test.svc.cluster.local",
"*.etcd-client.clusters-test.svc",
"*.etcd-client.clusters-test.svc.cluster.local",
// TODO(OCPBUGS-86648): assert on cert.IPAddresses instead once IPs are moved out of dnsNames.
"127.0.0.1",
"::1",
Comment on lines +58 to +59

@coderabbitai coderabbitai Bot May 12, 2026

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⚠️ Potential issue | 🔴 Critical | ⚡ Quick win

🧩 Analysis chain

🏁 Script executed:

#!/bin/bash
# Description: Check how ReconcileEtcdPeerSecret handles IP addresses in certificate generation

# Search for the implementation of ReconcileEtcdPeerSecret
ast-grep --pattern $'func ReconcileEtcdPeerSecret($$$) $$$'

# Search for certificate generation calls that might include IPs
rg -A 10 -B 5 "127\.0\.0\.1|::1" --type go --glob '**/pki/etcd.go'

# Look for DNSNames and IPAddresses field assignments
rg -A 5 "DNSNames|IPAddresses" --type go --glob '**/pki/etcd.go'

Repository: openshift/hypershift

Length of output: 2726

🏁 Script executed:

# Find the reconcileSignedCertWithKeysAndAddresses function implementation
ast-grep --pattern $'func reconcileSignedCertWithKeysAndAddresses($$$) $$$'

# Also search for where DNSNames is actually set in the certificate
rg -B 5 -A 15 "DNSNames\s*=" --type go --glob '**/pki/*.go' | head -100

# Look for IPAddresses assignment in certificate generation
rg -B 5 -A 5 "IPAddresses\s*=" --type go --glob '**/pki/*.go'

Repository: openshift/hypershift

Length of output: 1123

🏁 Script executed:

# Find where certs.ReconcileSignedCert is imported from
rg "import.*certs" --type go --glob '**/pki/cert.go' -A 20 | head -40

# Find the certs package and ReconcileSignedCert implementation
find . -name "*.go" -type f -exec grep -l "func ReconcileSignedCert" {} \;

# Search for how it populates certificate fields
rg -B 5 -A 20 "func ReconcileSignedCert" --type go

Repository: openshift/hypershift

Length of output: 1324

🏁 Script executed:

# Get the full ReconcileSignedCert implementation
sed -n '1,300p' support/certs/tls.go | tail -200

Repository: openshift/hypershift

Length of output: 6056

🏁 Script executed:

# Find where the CSR is generated with dnsNames and ips in ReconcileSignedCert
sed -n '/^func ReconcileSignedCert/,/^func [A-Z]/p' support/certs/tls.go | head -100

Repository: openshift/hypershift

Length of output: 2748

🏁 Script executed:

# Get the test file context around lines 57-58
sed -n '35,75p' control-plane-operator/controllers/hostedcontrolplane/pki/etcd_test.go

Repository: openshift/hypershift

Length of output: 1305

Fix IP address handling in etcd peer certificate generation.

Lines 50–51 in etcd.go incorrectly add IP addresses ("127.0.0.1", "::1") to the dnsNames list. Per X.509 standards, IP addresses must be in the IPAddresses field, not DNSNames. The function signature supports a separate ips parameter for this purpose.

Fix the implementation by passing IPs via the dedicated parameter:

return reconcileSignedCertWithKeysAndAddresses(secret, ca, ownerRef, "etcd-discovery", []string{"kubernetes"}, X509UsageClientServerAuth, EtcdPeerCrtKey, EtcdPeerKeyKey, "", dnsNames, []string{"127.0.0.1", "::1"}, "")

Then update the test assertion to check the correct certificate field:

g.Expect(cert.IPAddresses).To(ContainElements(
    net.ParseIP("127.0.0.1"),
    net.ParseIP("::1"),
))
🤖 Prompt for AI Agents 
Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

In `@control-plane-operator/controllers/hostedcontrolplane/pki/etcd_test.go`
around lines 57 - 58, The etcd peer cert is currently placing "127.0.0.1" and
"::1" into DNSNames; move those into the IPAddresses parameter when calling
reconcileSignedCertWithKeysAndAddresses by removing them from dnsNames and
passing them as the ips argument (use []string{"127.0.0.1", "::1"}) in the
reconcileSignedCertWithKeysAndAddresses call for "etcd-discovery"; then adjust
the test in etcd_test.go to assert on cert.IPAddresses (using net.ParseIP for
each IP) instead of cert.DNSNames so the test verifies IPs are present in the
certificate's IPAddresses field.

@sdminonne sdminonne May 27, 2026

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This is encoding the behavior that should be fixed. Mind after creating the JIRA card reference it here in a comment with a TODO

@vsolanki12 vsolanki12 May 28, 2026

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Hi @sdminonne ,
I have added the TODO comment and raised the JIRA card(OCPBUGS-86648) as per the suggestion.

))
})

t.Run("When reconciling etcd peer secret it should have client and server auth usage", func(t *testing.T) {
g := NewWithT(t)
secret := &corev1.Secret{
ObjectMeta: metav1.ObjectMeta{
Namespace: "clusters-test",
},
}

err := ReconcileEtcdPeerSecret(secret, caSecret, config.OwnerRef{})
g.Expect(err).ToNot(HaveOccurred())

cert, err := certs.PemToCertificate(secret.Data[EtcdPeerCrtKey])
g.Expect(err).ToNot(HaveOccurred())

g.Expect(cert.ExtKeyUsage).To(ContainElements(
x509.ExtKeyUsageClientAuth,
x509.ExtKeyUsageServerAuth,
))
})
}
1 change: 0 additions & 1 deletion ...ane/testdata/etcd/AROSwift/zz_fixture_TestControlPlaneComponents_etcd_client_service.yaml
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1 change: 0 additions & 1 deletion ...rolplane/testdata/etcd/GCP/zz_fixture_TestControlPlaneComponents_etcd_client_service.yaml
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1 change: 0 additions & 1 deletion ...ane/testdata/etcd/IBMCloud/zz_fixture_TestControlPlaneComponents_etcd_client_service.yaml
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1 change: 0 additions & 1 deletion .../etcd/TechPreviewNoUpgrade/zz_fixture_TestControlPlaneComponents_etcd_client_service.yaml
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1 change: 0 additions & 1 deletion ...controlplane/testdata/etcd/zz_fixture_TestControlPlaneComponents_etcd_client_service.yaml
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1 change: 0 additions & 1 deletion control-plane-operator/controllers/hostedcontrolplane/v2/assets/etcd/service.yaml
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Original file line number Diff line number Diff line change
Expand Up @@ -5,7 +5,6 @@ metadata:
app: etcd
name: etcd-client
spec:
clusterIP: None
ports:
- name: etcd-client
port: 2379
Expand Down