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Merge pull request #98305 from aojea/holdports

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kube-proxy has to clear NodePort stale UDP entries
This commit is contained in:
Kubernetes Prow Robot 2021-02-10 23:36:16 -08:00 committed by GitHub
commit 659b4dc4a8
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3 changed files with 109 additions and 17 deletions
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1
pkg/proxy/iptables/BUILD
View File

@ -25,6 +25,7 @@ go_library(
"//staging/src/k8s.io/api/core/v1:go_default_library",
"//staging/src/k8s.io/api/discovery/v1beta1:go_default_library",
"//staging/src/k8s.io/apimachinery/pkg/types:go_default_library",
"//staging/src/k8s.io/apimachinery/pkg/util/sets:go_default_library",
"//staging/src/k8s.io/apimachinery/pkg/util/wait:go_default_library",
"//staging/src/k8s.io/apiserver/pkg/util/feature:go_default_library",
"//staging/src/k8s.io/client-go/tools/record:go_default_library",

38
pkg/proxy/iptables/proxier.go
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@ -36,6 +36,7 @@ import (
v1 "k8s.io/api/core/v1"
discovery "k8s.io/api/discovery/v1beta1"
"k8s.io/apimachinery/pkg/types"
"k8s.io/apimachinery/pkg/util/sets"
"k8s.io/apimachinery/pkg/util/wait"
utilfeature "k8s.io/apiserver/pkg/util/feature"
"k8s.io/client-go/tools/record"
@ -835,14 +836,23 @@ func (proxier *Proxier) syncProxyRules() {
serviceUpdateResult := proxier.serviceMap.Update(proxier.serviceChanges)
endpointUpdateResult := proxier.endpointsMap.Update(proxier.endpointsChanges)
staleServices := serviceUpdateResult.UDPStaleClusterIP
// We need to detect stale connections to UDP Services so we
// can clean dangling conntrack entries that can blackhole traffic.
conntrackCleanupServiceIPs := serviceUpdateResult.UDPStaleClusterIP
conntrackCleanupServiceNodePorts := sets.NewInt()
// merge stale services gathered from updateEndpointsMap
// an UDP service that changes from 0 to non-0 endpoints is considered stale.
for _, svcPortName := range endpointUpdateResult.StaleServiceNames {
if svcInfo, ok := proxier.serviceMap[svcPortName]; ok && svcInfo != nil && conntrack.IsClearConntrackNeeded(svcInfo.Protocol()) {
klog.V(2).InfoS("Stale service", "protocol", strings.ToLower(string(svcInfo.Protocol())), "svcPortName", svcPortName.String(), "clusterIP", svcInfo.ClusterIP().String())
staleServices.Insert(svcInfo.ClusterIP().String())
conntrackCleanupServiceIPs.Insert(svcInfo.ClusterIP().String())
for _, extIP := range svcInfo.ExternalIPStrings() {
staleServices.Insert(extIP)
conntrackCleanupServiceIPs.Insert(extIP)
}
nodePort := svcInfo.NodePort()
if svcInfo.Protocol() == v1.ProtocolUDP && nodePort != 0 {
klog.V(2).Infof("Stale %s service NodePort %v -> %d", strings.ToLower(string(svcInfo.Protocol())), svcPortName, nodePort)
conntrackCleanupServiceNodePorts.Insert(nodePort)
}
}
}
@ -1278,16 +1288,6 @@ func (proxier *Proxier) syncProxyRules() {
klog.ErrorS(err, "can't open port, skipping this nodePort", "port", lp.String())
continue
}
if lp.Protocol == "udp" {
// TODO: We might have multiple services using the same port, and this will clear conntrack for all of them.
// This is very low impact. The NodePort range is intentionally obscure, and unlikely to actually collide with real Services.
// This only affects UDP connections, which are not common.
// See issue: https://github.com/kubernetes/kubernetes/issues/49881
err := conntrack.ClearEntriesForPort(proxier.exec, lp.Port, isIPv6, v1.ProtocolUDP)
if err != nil {
klog.ErrorS(err, "Failed to clear udp conntrack", "port", lp.Port)
}
}
replacementPortsMap[lp] = socket
}
}
@ -1646,13 +1646,21 @@ func (proxier *Proxier) syncProxyRules() {
}
// Finish housekeeping.
// Clear stale conntrack entries for UDP Services, this has to be done AFTER the iptables rules are programmed.
// TODO: these could be made more consistent.
klog.V(4).InfoS("Deleting stale services", "ips", staleServices.UnsortedList())
for _, svcIP := range staleServices.UnsortedList() {
klog.V(4).InfoS("Deleting conntrack stale entries for Services", "ips", conntrackCleanupServiceIPs.UnsortedList())
for _, svcIP := range conntrackCleanupServiceIPs.UnsortedList() {
if err := conntrack.ClearEntriesForIP(proxier.exec, svcIP, v1.ProtocolUDP); err != nil {
klog.ErrorS(err, "Failed to delete stale service connections", "ip", svcIP)
}
}
klog.V(4).InfoS("Deleting conntrack stale entries for Services", "nodeports", conntrackCleanupServiceNodePorts.UnsortedList())
for _, nodePort := range conntrackCleanupServiceNodePorts.UnsortedList() {
err := conntrack.ClearEntriesForPort(proxier.exec, nodePort, isIPv6, v1.ProtocolUDP)
if err != nil {
klog.ErrorS(err, "Failed to clear udp conntrack", "port", nodePort)
}
}
klog.V(4).InfoS("Deleting stale endpoint connections", "endpoints", endpointUpdateResult.StaleEndpoints)
proxier.deleteEndpointConnections(endpointUpdateResult.StaleEndpoints)
}

87
pkg/proxy/iptables/proxier_test.go
View File

@ -26,14 +26,13 @@ import (
"testing"
"time"
"k8s.io/klog/v2"
"github.com/stretchr/testify/assert"
v1 "k8s.io/api/core/v1"
discovery "k8s.io/api/discovery/v1beta1"
metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
"k8s.io/apimachinery/pkg/types"
"k8s.io/apimachinery/pkg/util/intstr"
"k8s.io/klog/v2"
"k8s.io/kubernetes/pkg/proxy"
"k8s.io/kubernetes/pkg/proxy/healthcheck"
utilproxy "k8s.io/kubernetes/pkg/proxy/util"
@ -2848,4 +2847,88 @@ COMMIT
assert.NotEqual(t, expectedIPTables, fp.iptablesData.String())
}
func TestProxierDeleteNodePortStaleUDP(t *testing.T) {
fcmd := fakeexec.FakeCmd{}
fexec := fakeexec.FakeExec{
LookPathFunc: func(cmd string) (string, error) { return cmd, nil },
}
execFunc := func(cmd string, args ...string) exec.Cmd {
return fakeexec.InitFakeCmd(&fcmd, cmd, args...)
}
cmdOutput := "1 flow entries have been deleted"
cmdFunc := func() ([]byte, []byte, error) { return []byte(cmdOutput), nil, nil }
// Delete ClusterIP entries
fcmd.CombinedOutputScript = append(fcmd.CombinedOutputScript, cmdFunc)
fexec.CommandScript = append(fexec.CommandScript, execFunc)
// Delete NodePort entries
fcmd.CombinedOutputScript = append(fcmd.CombinedOutputScript, cmdFunc)
fexec.CommandScript = append(fexec.CommandScript, execFunc)
ipt := iptablestest.NewFake()
fp := NewFakeProxier(ipt, false)
fp.exec = &fexec
svcIP := "10.20.30.41"
svcPort := 80
nodePort := 31201
svcPortName := proxy.ServicePortName{
NamespacedName: makeNSN("ns1", "svc1"),
Port: "p80",
Protocol: v1.ProtocolUDP,
}
makeServiceMap(fp,
makeTestService(svcPortName.Namespace, svcPortName.Name, func(svc *v1.Service) {
svc.Spec.ClusterIP = svcIP
svc.Spec.Ports = []v1.ServicePort{{
Name: svcPortName.Port,
Port: int32(svcPort),
Protocol: v1.ProtocolUDP,
NodePort: int32(nodePort),
}}
}),
)
makeEndpointsMap(fp)
fp.syncProxyRules()
if fexec.CommandCalls != 0 {
t.Fatalf("Created service without endpoints must not clear conntrack entries")
}
epIP := "10.180.0.1"
makeEndpointsMap(fp,
makeTestEndpoints(svcPortName.Namespace, svcPortName.Name, func(ept *v1.Endpoints) {
ept.Subsets = []v1.EndpointSubset{{
Addresses: []v1.EndpointAddress{{
IP: epIP,
}},
Ports: []v1.EndpointPort{{
Name: svcPortName.Port,
Port: int32(svcPort),
Protocol: v1.ProtocolUDP,
}},
}}
}),
)
fp.syncProxyRules()
if fexec.CommandCalls != 2 {
t.Fatalf("Updated UDP service with new endpoints must clear UDP entries")
}
// Delete ClusterIP Conntrack entries
expectCommand := fmt.Sprintf("conntrack -D --orig-dst %s -p %s", svcIP, strings.ToLower(string((v1.ProtocolUDP))))
actualCommand := strings.Join(fcmd.CombinedOutputLog[0], " ")
if actualCommand != expectCommand {
t.Errorf("Expected command: %s, but executed %s", expectCommand, actualCommand)
}
// Delete NodePort Conntrack entrie
expectCommand = fmt.Sprintf("conntrack -D -p %s --dport %d", strings.ToLower(string((v1.ProtocolUDP))), nodePort)
actualCommand = strings.Join(fcmd.CombinedOutputLog[1], " ")
if actualCommand != expectCommand {
t.Errorf("Expected command: %s, but executed %s", expectCommand, actualCommand)
}
}
// TODO(thockin): add *more* tests for syncProxyRules() or break it down further and test the pieces.