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Renew etcd certificates generated by custom etcd CA #7796

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40 changes: 33 additions & 7 deletions inttest/customca/customca_test.go
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Original file line number Diff line number Diff line change
Expand Up @@ -17,28 +17,43 @@ type CustomCASuite struct {
common.BootlooseSuite
}

func (s *CustomCASuite) initCA(ssh *common.SSHConnection, dir, cn string) string {
err := ssh.Exec(s.Context(), "sh -e", common.SSHStreams{
//nolint:dupword // this is a script
In: strings.NewReader(strings.NewReplacer("{dir}", dir, "{cn}", cn).Replace(`
mkdir -p {dir}
command -v openssl || apk add openssl
openssl genrsa -out {dir}/ca.key 4096
openssl req -x509 -new -nodes -key {dir}/ca.key -sha256 -days 365 -out {dir}/ca.crt -subj "/CN={cn}"
`)),
})
s.Require().NoError(err)

cert, err := ssh.ExecWithOutput(s.Context(), fmt.Sprintf("cat %s/ca.crt", dir))
s.Require().NoError(err)

return cert
}

func (s *CustomCASuite) TestK0sGetsUp() {
// Create an custom certificate to prove that k0s manage to work with it
ssh, err := s.SSH(s.Context(), s.ControllerNode(0))
s.Require().NoError(err)
defer ssh.Disconnect()

cert := s.initCA(ssh, "/var/lib/k0s/pki", "Test CA")
etcdCert := s.initCA(ssh, "/var/lib/k0s/pki/etcd", "Test Etcd CA")

err = ssh.Exec(s.Context(), "sh -e", common.SSHStreams{
//nolint:dupword // this is a script
In: strings.NewReader(fmt.Sprintf(`
K0S_PATH=%q
IP_ADDRESS=%q
mkdir -p /var/lib/k0s/pki /var/lib/k0s/manifests/test
apk add openssl
openssl genrsa -out /var/lib/k0s/pki/ca.key 4096
openssl req -x509 -new -nodes -key /var/lib/k0s/pki/ca.key -sha256 -days 365 -out /var/lib/k0s/pki/ca.crt -subj "/CN=Test CA"
mkdir -p /var/lib/k0s/manifests/test
"$K0S_PATH" token pre-shared --cert /var/lib/k0s/pki/ca.crt --url https://"$IP_ADDRESS":6443/ --out /var/lib/k0s/manifests/test
`, s.K0sFullPath, s.GetControllerIPAddress(0))),
})
s.Require().NoError(err)

cert, err := ssh.ExecWithOutput(s.Context(), "cat /var/lib/k0s/pki/ca.crt")
s.Require().NoError(err)
token, err := ssh.ExecWithOutput(s.Context(), "cat /var/lib/k0s/manifests/test/token_* && rm /var/lib/k0s/manifests/test/token_*")
s.Require().NoError(err)

Expand All @@ -58,9 +73,17 @@ func (s *CustomCASuite) TestK0sGetsUp() {
s.Require().NoError(err)
s.Equal(cert, newCert)

newEtcdCert, err := ssh.ExecWithOutput(s.Context(), "cat /var/lib/k0s/pki/etcd/ca.crt")
s.Require().NoError(err)
s.Equal(etcdCert, newEtcdCert)

// Validate that k0s renews certificates with custom CA
k0sAPICert, err := ssh.ExecWithOutput(s.Context(), "cat /var/lib/k0s/pki/k0s-api.crt")
s.Require().NoError(err, "Failed to obtain k0s-api certificate")

etcdServerCert, err := ssh.ExecWithOutput(s.Context(), "cat /var/lib/k0s/pki/etcd/server.crt")
s.Require().NoError(err, "Failed to obtain etcd server certificate")

s.Require().NoError(s.StopController(s.ControllerNode(0)))
s.Require().NoError(s.StartController(s.ControllerNode(0)))

Expand All @@ -69,6 +92,9 @@ func (s *CustomCASuite) TestK0sGetsUp() {
s.Require().NoError(err, "Failed to obtain new k0s certificate")
s.Require().NotEqual(k0sAPICert, newK0sAPICert, "k0s-api certificate was not renewed")

newEtcdServerCert, err := ssh.ExecWithOutput(s.Context(), "cat /var/lib/k0s/pki/etcd/server.crt")
s.Require().NoError(err, "Failed to obtain new etcd server certificate")
s.Require().NotEqual(etcdServerCert, newEtcdServerCert, "etcd server certificate was not renewed")
}

func TestCustomCASuite(t *testing.T) {
Expand Down
14 changes: 14 additions & 0 deletions pkg/certificate/manager.go
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Original file line number Diff line number Diff line change
Expand Up @@ -223,6 +223,14 @@ func (m *Manager) isManagedByK0s(cert *certinfo.Certificate) (bool, error) {
return false, fmt.Errorf("unable to parse ca certificate: %w", err)
}

etcdCA, err := certinfo.ParseCertificateFile(filepath.Join(m.K0sVars.EtcdCertDir, "ca.crt"))
if err != nil {
// etcd CA is created separately from the cluster CA
// and may not available right away on the first start,
// this is expected and should not result in an error
logrus.Warnf("unable to parse etcd ca certificate: %v ", err)
}

switch cert.Issuer.CommonName {
case "kubernetes-ca":
return true, nil
Expand All @@ -236,6 +244,12 @@ func (m *Manager) isManagedByK0s(cert *certinfo.Certificate) (bool, error) {
}
logrus.Warnf("certificate issued by %q, but no ca.key found, not renewing the certificate %q", ca.Subject.CommonName, cert.Subject.CommonName)
return false, nil
case etcdCA.Subject.CommonName:
if file.Exists(filepath.Join(m.K0sVars.EtcdCertDir, "ca.key")) {
return true, nil
}
logrus.Warnf("certificate issued by %q, but no ca.key found, not renewing the certificate %q", etcdCA.Subject.CommonName, cert.Subject.CommonName)
return false, nil
}

return false, nil
Expand Down
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