aboutsummaryrefslogtreecommitdiff
path: root/middleware/kubernetes/setup.go
blob: 8b367e1a264964c9d30a0352d8ec31c7fcf79210 (plain) (blame)
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
package kubernetes

import (
	"errors"
	"fmt"
	"log"
	"net"
	"strings"
	"time"

	"github.com/coredns/coredns/core/dnsserver"
	"github.com/coredns/coredns/middleware"
	"github.com/coredns/coredns/middleware/pkg/dnsutil"
	"github.com/coredns/coredns/middleware/proxy"
	"github.com/miekg/dns"

	"github.com/mholt/caddy"
	unversionedapi "k8s.io/client-go/1.5/pkg/api/unversioned"
)

func init() {
	caddy.RegisterPlugin("kubernetes", caddy.Plugin{
		ServerType: "dns",
		Action:     setup,
	})
}

func setup(c *caddy.Controller) error {
	kubernetes, err := kubernetesParse(c)
	if err != nil {
		return middleware.Error("kubernetes", err)
	}

	err = kubernetes.InitKubeCache()
	if err != nil {
		return middleware.Error("kubernetes", err)
	}

	// Register KubeCache start and stop functions with Caddy
	c.OnStartup(func() error {
		go kubernetes.APIConn.Run()
		if kubernetes.APIProxy != nil {
			go kubernetes.APIProxy.Run()
		}
		return nil
	})

	c.OnShutdown(func() error {
		if kubernetes.APIProxy != nil {
			kubernetes.APIProxy.Stop()
		}
		return kubernetes.APIConn.Stop()
	})

	dnsserver.GetConfig(c).AddMiddleware(func(next middleware.Handler) middleware.Handler {
		kubernetes.Next = next
		return kubernetes
	})

	// Also register kubernetes for use in autopath.
	dnsserver.GetConfig(c).RegisterHandler(kubernetes)

	return nil
}

func kubernetesParse(c *caddy.Controller) (*Kubernetes, error) {
	k8s := &Kubernetes{
		ResyncPeriod:       defaultResyncPeriod,
		interfaceAddrsFunc: localPodIP,
		PodMode:            PodModeDisabled,
		Proxy:              proxy.Proxy{},
	}

	k8s.autoPathSearch = searchFromResolvConf()

	for c.Next() {
		if c.Val() == "kubernetes" {
			zones := c.RemainingArgs()

			if len(zones) != 0 {
				k8s.Zones = zones
				middleware.Zones(k8s.Zones).Normalize()
			} else {
				k8s.Zones = make([]string, len(c.ServerBlockKeys))
				for i := 0; i < len(c.ServerBlockKeys); i++ {
					k8s.Zones[i] = middleware.Host(c.ServerBlockKeys[i]).Normalize()
				}
			}

			k8s.primaryZone = -1
			for i, z := range k8s.Zones {
				if strings.HasSuffix(z, "in-addr.arpa.") || strings.HasSuffix(z, "ip6.arpa.") {
					continue
				}
				k8s.primaryZone = i
				break
			}

			if k8s.primaryZone == -1 {
				return nil, errors.New("non-reverse zone name must be given for Kubernetes")
			}

			for c.NextBlock() {
				switch c.Val() {
				case "cidrs":

					// DEPRECATION WARNING
					log.Printf("[WARNING] \"cidrs\" will be removed for CoreDNS soon. See https://coredns.io/2017/07/23/corefile-explained#reverse-zones for the replacement")

					args := c.RemainingArgs()
					if len(args) > 0 {
						for _, cidrStr := range args {
							_, cidr, err := net.ParseCIDR(cidrStr)
							if err != nil {
								return nil, fmt.Errorf("invalid cidr: %s", cidrStr)
							}
							k8s.ReverseCidrs = append(k8s.ReverseCidrs, *cidr)

						}
						continue
					}
					return nil, c.ArgErr()
				case "pods":
					args := c.RemainingArgs()
					if len(args) == 1 {
						switch args[0] {
						case PodModeDisabled, PodModeInsecure, PodModeVerified:
							k8s.PodMode = args[0]
						default:
							return nil, fmt.Errorf("wrong value for pods: %s,  must be one of: disabled, verified, insecure", args[0])
						}
						continue
					}
					return nil, c.ArgErr()
				case "namespaces":
					args := c.RemainingArgs()
					if len(args) > 0 {
						k8s.Namespaces = append(k8s.Namespaces, args...)
						continue
					}
					return nil, c.ArgErr()
				case "endpoint":
					args := c.RemainingArgs()
					if len(args) > 0 {
						for _, endpoint := range strings.Split(args[0], ",") {
							k8s.APIServerList = append(k8s.APIServerList, strings.TrimSpace(endpoint))
						}
						continue
					}
					return nil, c.ArgErr()
				case "tls": // cert key cacertfile
					args := c.RemainingArgs()
					if len(args) == 3 {
						k8s.APIClientCert, k8s.APIClientKey, k8s.APICertAuth = args[0], args[1], args[2]
						continue
					}
					return nil, c.ArgErr()
				case "resyncperiod":
					args := c.RemainingArgs()
					if len(args) > 0 {
						rp, err := time.ParseDuration(args[0])
						if err != nil {
							return nil, fmt.Errorf("unable to parse resync duration value: '%v': %v", args[0], err)
						}
						k8s.ResyncPeriod = rp
						continue
					}
					return nil, c.ArgErr()
				case "labels":
					args := c.RemainingArgs()
					if len(args) > 0 {
						labelSelectorString := strings.Join(args, " ")
						ls, err := unversionedapi.ParseToLabelSelector(labelSelectorString)
						if err != nil {
							return nil, fmt.Errorf("unable to parse label selector value: '%v': %v", labelSelectorString, err)
						}
						k8s.LabelSelector = ls
						continue
					}
					return nil, c.ArgErr()
				case "fallthrough":
					args := c.RemainingArgs()
					if len(args) == 0 {
						k8s.Fallthrough = true
						continue
					}
					return nil, c.ArgErr()
				case "upstream":
					args := c.RemainingArgs()
					if len(args) == 0 {
						return nil, c.ArgErr()
					}
					ups, err := dnsutil.ParseHostPortOrFile(args...)
					if err != nil {
						return nil, err
					}
					k8s.Proxy = proxy.NewLookup(ups)
				case "federation": // name zone
					args := c.RemainingArgs()
					if len(args) == 2 {
						k8s.Federations = append(k8s.Federations, Federation{
							name: args[0],
							zone: args[1],
						})
						continue
					}
					return nil, fmt.Errorf("incorrect number of arguments for federation, got %v, expected 2", len(args))
				}
			}
			return k8s, nil
		}
	}
	return nil, errors.New("kubernetes setup called without keyword 'kubernetes' in Corefile")
}

func searchFromResolvConf() []string {
	rc, err := dns.ClientConfigFromFile("/etc/resolv.conf")
	if err != nil {
		return nil
	}
	middleware.Zones(rc.Search).Normalize()
	return rc.Search
}

const (
	defaultResyncPeriod = 5 * time.Minute
	defautNdots         = 0
	defaultOnNXDOMAIN   = dns.RcodeSuccess
)