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Bug fix. Incoming UDP packets not reach newly deployed services #32561

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merged 1 commit into from
Dec 2, 2016
Merged

Bug fix. Incoming UDP packets not reach newly deployed services #32561

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21 changes: 21 additions & 0 deletions pkg/proxy/iptables/proxier.go
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Original file line number Diff line number Diff line change
Expand Up @@ -1105,6 +1105,9 @@ func (proxier *Proxier) syncProxyRules() {
glog.Errorf("can't open %s, skipping this nodePort: %v", lp.String(), err)
continue
}
if lp.protocol == "udp" {
proxier.clearUdpConntrackForPort(lp.port)
}
replacementPortsMap[lp] = socket
} // We're holding the port, so it's OK to install iptables rules.

Expand Down Expand Up @@ -1323,6 +1326,24 @@ func (proxier *Proxier) syncProxyRules() {
proxier.portsMap = replacementPortsMap
}

// Clear UDP conntrack for port or all conntrack entries when port equal zero.
// When a packet arrives, it will not go through NAT table again, because it is not "the first" packet.
// The solution is clearing the conntrack. Known issus:
// https://github.com/docker/docker/issues/8795
// https://github.com/kubernetes/kubernetes/issues/31983
func (proxier *Proxier) clearUdpConntrackForPort(port int) {
var err error = nil
glog.V(2).Infof("Deleting conntrack entries for udp connections")
if port > 0 {
err = proxier.execConntrackTool("-D", "-p", "udp", "--dport", strconv.Itoa(port))
if err != nil && !strings.Contains(err.Error(), noConnectionToDelete) {
glog.Errorf("conntrack return with error: %v", err)
}
} else {
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We don't really need this fallback path any more - would be safer to just log.

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Done

glog.Errorf("Wrong port number. The port number must be greater than zero")
}
}

// Join all words with spaces, terminate with newline and write to buf.
func writeLine(buf *bytes.Buffer, words ...string) {
buf.WriteString(strings.Join(words, " ") + "\n")
Expand Down