forked from openshift/origin
-
Notifications
You must be signed in to change notification settings - Fork 1
/
unidlersocket.go
385 lines (325 loc) · 11.8 KB
/
unidlersocket.go
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
package unidler
import (
"fmt"
"net"
"strconv"
"strings"
"time"
"github.com/golang/glog"
utilruntime "k8s.io/apimachinery/pkg/util/runtime"
"k8s.io/kubernetes/pkg/api"
"k8s.io/kubernetes/pkg/proxy"
"k8s.io/kubernetes/pkg/proxy/userspace"
)
const (
UDPBufferSize = 4096 // 4KiB should be enough for most whole-packets
NeedPodsReason = "NeedPods"
)
var endpointDialTimeout = []time.Duration{250 * time.Millisecond, 500 * time.Millisecond, 1 * time.Second, 2 * time.Second}
type connectionList struct {
conns []heldConn
maxSize int
tickSize time.Duration
timeSinceStart time.Duration
timeout time.Duration
svcName string
}
type heldConn struct {
net.Conn
connectedAt time.Duration
}
func newConnectionList(maxSize int, tickSize time.Duration, timeout time.Duration, svcName string) *connectionList {
return &connectionList{
conns: []heldConn{},
maxSize: maxSize,
tickSize: tickSize,
timeSinceStart: 0,
timeout: timeout,
svcName: svcName,
}
}
func (l *connectionList) Add(conn net.Conn) {
if len(l.conns) >= l.maxSize {
// TODO: look for closed connections
utilruntime.HandleError(fmt.Errorf("max connections exceeded while waiting for idled service %s to awaken, dropping oldest", l.svcName))
var oldConn net.Conn
oldConn, l.conns = l.conns[0], l.conns[1:]
oldConn.Close()
}
l.conns = append(l.conns, heldConn{conn, l.timeSinceStart})
}
func (l *connectionList) Tick() {
l.timeSinceStart += l.tickSize
l.cleanOldConnections()
}
func (l *connectionList) cleanOldConnections() {
cleanInd := -1
for i, conn := range l.conns {
if l.timeSinceStart-conn.connectedAt < l.timeout {
cleanInd = i
break
}
}
if cleanInd > 0 {
oldConns := l.conns[:cleanInd]
l.conns = l.conns[cleanInd:]
utilruntime.HandleError(fmt.Errorf("timed out %v connections while waiting for idled service %s to awaken.", len(oldConns), l.svcName))
for _, conn := range oldConns {
conn.Close()
}
}
}
func (l *connectionList) GetConns() []net.Conn {
conns := make([]net.Conn, len(l.conns))
for i, conn := range l.conns {
conns[i] = conn.Conn
}
return conns
}
func (l *connectionList) Len() int {
return len(l.conns)
}
func (l *connectionList) Clear() {
for _, conn := range l.conns {
conn.Close()
}
l.conns = []heldConn{}
}
var (
// MaxHeldConnections is the maximum number of TCP connections per service that
// will be held by the unidler at once (new connections will cause older ones
// to be dropped after the limit is reached)
MaxHeldConnections = 16
needPodsWaitTimeout = 120 * time.Second
needPodsTickLen = 5 * time.Second
)
func newUnidlerSocket(protocol api.Protocol, ip net.IP, port int, signaler NeedPodsSignaler) (userspace.ProxySocket, error) {
host := ""
if ip != nil {
host = ip.String()
}
switch strings.ToUpper(string(protocol)) {
case "TCP":
listener, err := net.Listen("tcp", net.JoinHostPort(host, strconv.Itoa(port)))
if err != nil {
return nil, err
}
return &tcpUnidlerSocket{Listener: listener, port: port, signaler: signaler}, nil
case "UDP":
addr, err := net.ResolveUDPAddr("udp", net.JoinHostPort(host, strconv.Itoa(port)))
if err != nil {
return nil, err
}
conn, err := net.ListenUDP("udp", addr)
if err != nil {
return nil, err
}
return &udpUnidlerSocket{UDPConn: conn, port: port, signaler: signaler}, nil
}
return nil, fmt.Errorf("unknown protocol %q", protocol)
}
// tcpUnidlerSocket implements proxySocket. Close() is implemented by net.Listener. When Close() is called,
// no new connections are allowed but existing connections are left untouched.
type tcpUnidlerSocket struct {
net.Listener
port int
signaler NeedPodsSignaler
}
func (tcp *tcpUnidlerSocket) ListenPort() int {
return tcp.port
}
func (tcp *tcpUnidlerSocket) waitForEndpoints(ch chan<- interface{}, service proxy.ServicePortName, loadBalancer userspace.LoadBalancer) {
defer close(ch)
for {
if loadBalancer.ServiceHasEndpoints(service) {
// we have endpoints now, so we're finished
return
}
// otherwise, wait a bit before checking for endpoints again
time.Sleep(endpointDialTimeout[0])
}
}
func (tcp *tcpUnidlerSocket) acceptConns(ch chan<- net.Conn, svcInfo *userspace.ServiceInfo) {
defer close(ch)
// Block until a connection is made.
for {
inConn, err := tcp.Accept()
if err != nil {
if isTooManyFDsError(err) {
panic("Accept failed: " + err.Error())
}
// TODO: indicate errors here?
if isClosedError(err) {
return
}
if !svcInfo.IsAlive() {
// Then the service port was just closed so the accept failure is to be expected.
return
}
utilruntime.HandleError(fmt.Errorf("Accept failed: %v", err))
continue
}
ch <- inConn
}
}
// awaitAwakening collects new connections and signals once that pods are needed to fulfill them. The function
// will return when the listening socket is closed, which indicates that endpoints have successfully appeared
// (and thus the hybrid proxy has switched this service over to using the normal proxy). Connections will
// be gradually timed out and dropped off the list of connections on a per-connection basis. The list of current
// connections is returned, in addition to whether or not we should retry this method.
func (tcp *tcpUnidlerSocket) awaitAwakening(service proxy.ServicePortName, loadBalancer userspace.LoadBalancer, inConns <-chan net.Conn, endpointsAvail chan<- interface{}) (*connectionList, bool) {
// collect connections and wait for endpoints to be available
sent_need_pods := false
timeout_started := false
ticker := time.NewTicker(needPodsTickLen)
defer ticker.Stop()
svcName := fmt.Sprintf("%s/%s:%s", service.Namespace, service.Name, service.Port)
allConns := newConnectionList(MaxHeldConnections, needPodsTickLen, needPodsWaitTimeout, svcName)
for {
select {
case inConn, ok := <-inConns:
if !ok {
// the listen socket has been closed, so we're finished accepting connections
return allConns, false
}
if !sent_need_pods && !loadBalancer.ServiceHasEndpoints(service) {
glog.V(4).Infof("unidling TCP proxy sent unidle event to wake up service %s/%s:%s", service.Namespace, service.Name, service.Port)
tcp.signaler.NeedPods(service.NamespacedName, service.Port)
// only send NeedPods once
sent_need_pods = true
timeout_started = true
}
if allConns.Len() == 0 {
if !loadBalancer.ServiceHasEndpoints(service) {
// notify us when endpoints are available
go tcp.waitForEndpoints(endpointsAvail, service, loadBalancer)
}
}
allConns.Add(inConn)
glog.V(4).Infof("unidling TCP proxy has accumulated %v connections while waiting for service %s/%s:%s to unidle", allConns.Len(), service.Namespace, service.Name, service.Port)
case <-ticker.C:
if !timeout_started {
continue
}
// TODO: timeout each connection (or group of connections) separately
// timed out, close all waiting connections and reset the state
allConns.Tick()
}
}
}
func (tcp *tcpUnidlerSocket) ProxyLoop(service proxy.ServicePortName, svcInfo *userspace.ServiceInfo, loadBalancer userspace.LoadBalancer) {
if !svcInfo.IsAlive() {
// The service port was closed or replaced.
return
}
// accept connections asynchronously
inConns := make(chan net.Conn)
go tcp.acceptConns(inConns, svcInfo)
endpointsAvail := make(chan interface{})
var allConns *connectionList
for {
glog.V(4).Infof("unidling TCP proxy start/reset for service %s/%s:%s", service.Namespace, service.Name, service.Port)
var cont bool
if allConns, cont = tcp.awaitAwakening(service, loadBalancer, inConns, endpointsAvail); !cont {
break
}
}
glog.V(4).Infof("unidling TCP proxy waiting for endpoints for service %s/%s:%s to become available with %v accumulated connections", service.Namespace, service.Name, service.Port, allConns.Len())
// block until we have endpoints available
select {
case _, ok := <-endpointsAvail:
if ok {
close(endpointsAvail)
// this shouldn't happen (ok should always be false)
}
case <-time.NewTimer(needPodsWaitTimeout).C:
if allConns.Len() > 0 {
utilruntime.HandleError(fmt.Errorf("timed out %v TCP connections while waiting for idled service %s/%s:%s to awaken.", allConns.Len(), service.Namespace, service.Name, service.Port))
allConns.Clear()
}
return
}
glog.V(4).Infof("unidling TCP proxy got endpoints for service %s/%s:%s, connecting %v accumulated connections", service.Namespace, service.Name, service.Port, allConns.Len())
for _, inConn := range allConns.GetConns() {
glog.V(3).Infof("Accepted TCP connection from %v to %v", inConn.RemoteAddr(), inConn.LocalAddr())
outConn, err := userspace.TryConnectEndpoints(service, inConn.(*net.TCPConn).RemoteAddr(), "tcp", loadBalancer)
if err != nil {
utilruntime.HandleError(fmt.Errorf("Failed to connect to balancer: %v", err))
inConn.Close()
continue
}
// Spin up an async copy loop.
go userspace.ProxyTCP(inConn.(*net.TCPConn), outConn.(*net.TCPConn))
}
}
// udpUnidlerSocket implements proxySocket. Close() is implemented by net.UDPConn. When Close() is called,
// no new connections are allowed and existing connections are broken.
// TODO: We could lame-duck this ourselves, if it becomes important.
type udpUnidlerSocket struct {
*net.UDPConn
port int
signaler NeedPodsSignaler
}
func (udp *udpUnidlerSocket) ListenPort() int {
return udp.port
}
func (udp *udpUnidlerSocket) Addr() net.Addr {
return udp.LocalAddr()
}
// readFromSock tries to read from a socket, returning true if we should continue trying
// to read again, or false if no further reads should be made.
func (udp *udpUnidlerSocket) readFromSock(buffer []byte, svcInfo *userspace.ServiceInfo) bool {
if !svcInfo.IsAlive() {
// The service port was closed or replaced.
return false
}
// Block until data arrives.
// TODO: Accumulate a histogram of n or something, to fine tune the buffer size.
_, _, err := udp.ReadFrom(buffer)
if err != nil {
if e, ok := err.(net.Error); ok {
if e.Temporary() {
glog.V(1).Infof("ReadFrom had a temporary failure: %v", err)
return true
}
}
utilruntime.HandleError(fmt.Errorf("ReadFrom failed, exiting ProxyLoop: %v", err))
return false
}
return true
}
func (udp *udpUnidlerSocket) sendWakeup(svcPortName proxy.ServicePortName, svcInfo *userspace.ServiceInfo) *time.Timer {
timeoutTimer := time.NewTimer(needPodsWaitTimeout)
glog.V(4).Infof("unidling proxy sent unidle event to wake up service %s/%s:%s", svcPortName.Namespace, svcPortName.Name, svcPortName.Port)
udp.signaler.NeedPods(svcPortName.NamespacedName, svcPortName.Port)
return timeoutTimer
}
func (udp *udpUnidlerSocket) ProxyLoop(svcPortName proxy.ServicePortName, svcInfo *userspace.ServiceInfo, loadBalancer userspace.LoadBalancer) {
// just drop the packets on the floor until we have endpoints
var buffer [UDPBufferSize]byte
glog.V(4).Infof("unidling proxy UDP proxy waiting for data for service %s/%s:%s", svcPortName.Namespace, svcPortName.Name, svcPortName.Port)
if !udp.readFromSock(buffer[0:], svcInfo) {
return
}
wakeupTimeoutTimer := udp.sendWakeup(svcPortName, svcInfo)
for {
if !udp.readFromSock(buffer[0:], svcInfo) {
break
}
// reset the timer whenever we receive data, and only signal if we've
// the timer had timed out when we reset it (so only send one even for
// each "burst" of data we get).
if active := wakeupTimeoutTimer.Reset(needPodsWaitTimeout); !active {
wakeupTimeoutTimer = udp.sendWakeup(svcPortName, svcInfo)
}
}
}
func isTooManyFDsError(err error) bool {
return strings.Contains(err.Error(), "too many open files")
}
func isClosedError(err error) bool {
// A brief discussion about handling closed error here:
// https://code.google.com/p/go/issues/detail?id=4373#c14
// TODO: maybe create a stoppable TCP listener that returns a StoppedError
return strings.HasSuffix(err.Error(), "use of closed network connection")
}