kubernetes Addon之 kubedns 1.6.7 安装

2017年07月10日 14894点热度 0人点赞 4条评论

前言

kubernetes 1.6.7已经废弃kube2sky的dns模式. 本测试使用官方的yaml文件创建。下图描述了kube-dns的组件结构：

（exechealthz-->sidecar)

kubedns 接管了以前的skydns，并使用一个树状结构保存从k8s API获取到的信息。 dnsmasq为dns pod提供解析接入服务，并作为一个dns cache保护kubedns。

sidecar执行域名检查监控kubedns和 dnsmasq是否正常提供解析：

- --probe=kubedns,127.0.0.1:10053,kubernetes.default.svc.cluster.local.,5,A

- --probe=dnsmasq,127.0.0.1:53,kubernetes.default.svc.cluster.local.,5,A

- --probe=kubedns,127.0.0.1:10053,kubernetes.default.svc.cluster.local.,5,A

- --probe=dnsmasq,127.0.0.1:53,kubernetes.default.svc.cluster.local.,5,A

yaml文件准备

进入之前下载并解压的1.6.7压缩包的 kubernetes/cluster/addons/dns/目录下

[root@docker1 dns]# pwd
/root/kubernetes/cluster/addons/dns

[root@docker1 dns]# ll
total 64
-rw-r-----. 1 root root  731 Jul  6 01:05 kubedns-cm.yaml
-rw-r-----. 1 root root 5372 Jul  6 01:05 kubedns-controller.yaml.base
-rw-r-----. 1 root root 5459 Jul  6 01:05 kubedns-controller.yaml.in
-rw-r-----. 1 root root 5352 Jul  6 01:05 kubedns-controller.yaml.sed
-rw-r-----. 1 root root  187 Jul  6 01:05 kubedns-sa.yaml
-rw-r-----. 1 root root 1037 Jul  6 01:05 kubedns-svc.yaml.base
-rw-r-----. 1 root root 1106 Jul  6 01:05 kubedns-svc.yaml.in
-rw-r-----. 1 root root 1094 Jul  6 01:05 kubedns-svc.yaml.sed
-rw-r-----. 1 root root 1138 Jul  6 01:05 Makefile
-rw-r-----. 1 root root   56 Jul  6 01:05 OWNERS
-rw-r-----. 1 root root 2106 Jul  6 01:05 README.md
-rw-r-----. 1 root root  318 Jul  6 01:05 transforms2salt.sed
-rw-r-----. 1 root root  251 Jul  6 01:05 transforms2sed.sed

[root@docker1 dns]# pwd

/root/kubernetes/cluster/addons/dns

[root@docker1 dns]# ll

total 64

-rw-r-----. 1 root root 731 Jul 6 01:05 kubedns-cm.yaml

-rw-r-----. 1 root root 5372 Jul 6 01:05 kubedns-controller.yaml.base

-rw-r-----. 1 root root 5459 Jul 6 01:05 kubedns-controller.yaml.in

-rw-r-----. 1 root root 5352 Jul 6 01:05 kubedns-controller.yaml.sed

-rw-r-----. 1 root root 187 Jul 6 01:05 kubedns-sa.yaml

-rw-r-----. 1 root root 1037 Jul 6 01:05 kubedns-svc.yaml.base

-rw-r-----. 1 root root 1106 Jul 6 01:05 kubedns-svc.yaml.in

-rw-r-----. 1 root root 1094 Jul 6 01:05 kubedns-svc.yaml.sed

-rw-r-----. 1 root root 1138 Jul 6 01:05 Makefile

-rw-r-----. 1 root root 56 Jul 6 01:05 OWNERS

-rw-r-----. 1 root root 2106 Jul 6 01:05 README.md

-rw-r-----. 1 root root 318 Jul 6 01:05 transforms2salt.sed

-rw-r-----. 1 root root 251 Jul 6 01:05 transforms2sed.sed

将kubedns-cm.yaml, kubedns-sa.yaml,kubedns-controller.yaml.in,kubedns-svc.yaml.in 四个文件拷贝/root/kubedns目录下，并按如下重命名：

[root@docker1 dns]# cd /root/kubedns
[root@docker1 kubedns]# ll
total 20
-rw-r-----. 1 root root  731 Jul  9 22:50 kubedns-cm.yaml
-rw-r-----. 1 root root 5411 Jul  9 23:05 kubedns-controller.yaml
-rw-r-----. 1 root root  187 Jul  9 22:50 kubedns-sa.yaml
-rw-r-----. 1 root root 1092 Jul  9 23:06 kubedns-svc.yaml

[root@docker1 dns]# cd /root/kubedns

[root@docker1 kubedns]# ll

total 20

-rw-r-----. 1 root root 731 Jul 9 22:50 kubedns-cm.yaml

-rw-r-----. 1 root root 5411 Jul 9 23:05 kubedns-controller.yaml

-rw-r-----. 1 root root 187 Jul 9 22:50 kubedns-sa.yaml

-rw-r-----. 1 root root 1092 Jul 9 23:06 kubedns-svc.yaml

配置文件修改

修改kubedns-controller.yaml这个 deployment类型配置文件，主要是将pillar['dns_domain'] 替换为cluster.local，以及如何连接到master，具体可以比较以下已经修改好的文件：

[root@docker1 kubedns]# cat kubedns-controller.yaml 
# Copyright 2016 The Kubernetes Authors.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#     http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.

# Should keep target in cluster/addons/dns-horizontal-autoscaler/dns-horizontal-autoscaler.yaml
# in sync with this file.

# Warning: This is a file generated from the base underscore template file: kubedns-controller.yaml.base

apiVersion: extensions/v1beta1
kind: Deployment
metadata:
  name: kube-dns
  namespace: kube-system
  labels:
    k8s-app: kube-dns
    kubernetes.io/cluster-service: "true"
    addonmanager.kubernetes.io/mode: Reconcile
spec:
  # replicas: not specified here:
  # 1. In order to make Addon Manager do not reconcile this replicas parameter.
  # 2. Default is 1.
  # 3. Will be tuned in real time if DNS horizontal auto-scaling is turned on.
  strategy:
    rollingUpdate:
      maxSurge: 10%
      maxUnavailable: 0
  selector:
    matchLabels:
      k8s-app: kube-dns
  template:
    metadata:
      labels:
        k8s-app: kube-dns
      annotations:
        scheduler.alpha.kubernetes.io/critical-pod: ''
    spec:
      tolerations:
      - key: "CriticalAddonsOnly"
        operator: "Exists"
      volumes:
      - name: kube-dns-config
        configMap:
          name: kube-dns
          optional: true
      containers:
      - name: kubedns
        image: gcr.io/google_containers/k8s-dns-kube-dns-amd64:1.14.4
        resources:
          # TODO: Set memory limits when we've profiled the container for large
          # clusters, then set request = limit to keep this container in
          # guaranteed class. Currently, this container falls into the
          # "burstable" category so the kubelet doesn't backoff from restarting it.
          limits:
            memory: 170Mi
          requests:
            cpu: 100m
            memory: 70Mi
        livenessProbe:
          httpGet:
            path: /healthcheck/kubedns
            port: 10054
            scheme: HTTP
          initialDelaySeconds: 60
          timeoutSeconds: 5
          successThreshold: 1
          failureThreshold: 5
        readinessProbe:
          httpGet:
            path: /readiness
            port: 8081
            scheme: HTTP
          # we poll on pod startup for the Kubernetes master service and
          # only setup the /readiness HTTP server once that's available.
          initialDelaySeconds: 3
          timeoutSeconds: 5
        args:
        - --domain=cluster.local.
        - --dns-port=10053
        - --config-dir=/kube-dns-config
        - --v=2
        #{{ pillar['federations_domain_map'] }}
        - --kube-master-url=http://172.16.199.17:8080
        env:
        - name: PROMETHEUS_PORT
          value: "10055"
        ports:
        - containerPort: 10053
          name: dns-local
          protocol: UDP
        - containerPort: 10053
          name: dns-tcp-local
          protocol: TCP
        - containerPort: 10055
          name: metrics
          protocol: TCP
        volumeMounts:
        - name: kube-dns-config
          mountPath: /kube-dns-config
      - name: dnsmasq
        image: gcr.io/google_containers/k8s-dns-dnsmasq-nanny-amd64:1.14.4
        livenessProbe:
          httpGet:
            path: /healthcheck/dnsmasq
            port: 10054
            scheme: HTTP
          initialDelaySeconds: 60
          timeoutSeconds: 5
          successThreshold: 1
          failureThreshold: 5
        args:
        - -v=2
        - -logtostderr
        - -configDir=/etc/k8s/dns/dnsmasq-nanny
        - -restartDnsmasq=true
        - --
        - -k
        - --cache-size=1000
        - --log-facility=-
        - --server=/cluster.local./127.0.0.1#10053
        - --server=/in-addr.arpa/127.0.0.1#10053
        - --server=/ip6.arpa/127.0.0.1#10053
        ports:
        - containerPort: 53
          name: dns
          protocol: UDP
        - containerPort: 53
          name: dns-tcp
          protocol: TCP
        # see: https://github.com/kubernetes/kubernetes/issues/29055 for details
        resources:
          requests:
            cpu: 150m
            memory: 20Mi
        volumeMounts:
        - name: kube-dns-config
          mountPath: /etc/k8s/dns/dnsmasq-nanny
      - name: sidecar
        image: gcr.io/google_containers/k8s-dns-sidecar-amd64:1.14.4
        livenessProbe:
          httpGet:
            path: /metrics
            port: 10054
            scheme: HTTP
          initialDelaySeconds: 60
          timeoutSeconds: 5
          successThreshold: 1
          failureThreshold: 5
        args:
        - --v=2
        - --logtostderr
        - --probe=kubedns,127.0.0.1:10053,kubernetes.default.svc.cluster.local.,5,A
        - --probe=dnsmasq,127.0.0.1:53,kubernetes.default.svc.cluster.local.,5,A
        ports:
        - containerPort: 10054
          name: metrics
          protocol: TCP
        resources:
          requests:
            memory: 20Mi
            cpu: 10m
      dnsPolicy: Default  # Don't use cluster DNS.
      serviceAccountName: kube-dns

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[root@docker1 kubedns]# cat kubedns-controller.yaml

# Licensed under the Apache License, Version 2.0 (the "License");

# you may not use this file except in compliance with the License.

# You may obtain a copy of the License at

# http://www.apache.org/licenses/LICENSE-2.0

# Unless required by applicable law or agreed to in writing, software

# distributed under the License is distributed on an "AS IS" BASIS,

# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

# See the License for the specific language governing permissions and

# limitations under the License.

# Should keep target in cluster/addons/dns-horizontal-autoscaler/dns-horizontal-autoscaler.yaml

# in sync with this file.

# Warning: This is a file generated from the base underscore template file: kubedns-controller.yaml.base

apiVersion: extensions/v1beta1

kind: Deployment

metadata:

namespace: kube-system

labels:

k8s-app: kube-dns

kubernetes.io/cluster-service: "true"

addonmanager.kubernetes.io/mode: Reconcile

spec:

# replicas: not specified here:

# 1. In order to make Addon Manager do not reconcile this replicas parameter.

# 2. Default is 1.

# 3. Will be tuned in real time if DNS horizontal auto-scaling is turned on.

strategy:

rollingUpdate:

maxSurge: 10%

maxUnavailable: 0

selector:

matchLabels:

k8s-app: kube-dns

template:

metadata:

labels:

k8s-app: kube-dns

annotations:

scheduler.alpha.kubernetes.io/critical-pod: ''

spec:

tolerations:

- key: "CriticalAddonsOnly"

operator: "Exists"

volumes:

- name: kube-dns-config

configMap:

optional: true

containers:

- name: kubedns

image: gcr.io/google_containers/k8s-dns-kube-dns-amd64:1.14.4

resources:

# TODO: Set memory limits when we've profiled the container for large

# clusters, then set request = limit to keep this container in

# guaranteed class. Currently, this container falls into the

# "burstable" category so the kubelet doesn't backoff from restarting it.

limits:

memory: 170Mi

requests:

cpu: 100m

memory: 70Mi

livenessProbe:

httpGet:

path: /healthcheck/kubedns

port: 10054

scheme: HTTP

initialDelaySeconds: 60

timeoutSeconds: 5

successThreshold: 1

failureThreshold: 5

readinessProbe:

httpGet:

path: /readiness

port: 8081

scheme: HTTP

# we poll on pod startup for the Kubernetes master service and

# only setup the /readiness HTTP server once that's available.

initialDelaySeconds: 3

timeoutSeconds: 5

args:

- --domain=cluster.local.

- --dns-port=10053

- --config-dir=/kube-dns-config

- --v=2

#{{ pillar['federations_domain_map'] }}

- --kube-master-url=http://172.16.199.17:8080

env:

- name: PROMETHEUS_PORT

value: "10055"

ports:

- containerPort: 10053

protocol: UDP

- containerPort: 10053

protocol: TCP

- containerPort: 10055

protocol: TCP

volumeMounts:

- name: kube-dns-config

mountPath: /kube-dns-config

- name: dnsmasq

image: gcr.io/google_containers/k8s-dns-dnsmasq-nanny-amd64:1.14.4

livenessProbe:

httpGet:

path: /healthcheck/dnsmasq

port: 10054

scheme: HTTP

initialDelaySeconds: 60

timeoutSeconds: 5

successThreshold: 1

failureThreshold: 5

args:

- -v=2

- -logtostderr

- -configDir=/etc/k8s/dns/dnsmasq-nanny

- -restartDnsmasq=true

- --

- -k

- --cache-size=1000

- --log-facility=-

- --server=/cluster.local./127.0.0.1#10053

- --server=/in-addr.arpa/127.0.0.1#10053

- --server=/ip6.arpa/127.0.0.1#10053

ports:

- containerPort: 53

protocol: UDP

- containerPort: 53

protocol: TCP

# see: https://github.com/kubernetes/kubernetes/issues/29055 for details

resources:

requests:

cpu: 150m

memory: 20Mi

volumeMounts:

- name: kube-dns-config

mountPath: /etc/k8s/dns/dnsmasq-nanny

- name: sidecar

image: gcr.io/google_containers/k8s-dns-sidecar-amd64:1.14.4

livenessProbe:

httpGet:

path: /metrics

port: 10054

scheme: HTTP

initialDelaySeconds: 60

timeoutSeconds: 5

successThreshold: 1

failureThreshold: 5

args:

- --v=2

- --logtostderr

- --probe=kubedns,127.0.0.1:10053,kubernetes.default.svc.cluster.local.,5,A

- --probe=dnsmasq,127.0.0.1:53,kubernetes.default.svc.cluster.local.,5,A

ports:

- containerPort: 10054

protocol: TCP

resources:

requests:

memory: 20Mi

cpu: 10m

dnsPolicy: Default # Don't use cluster DNS.

serviceAccountName: kube-dns

修改service yaml文件，主要修改clusterIP为kubelet服务启动时候所指定的dns IP

[root@docker1 kubedns]# cat kubedns-svc.yaml 
# Copyright 2016 The Kubernetes Authors.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#     http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.

# Warning: This is a file generated from the base underscore template file: kubedns-svc.yaml.base

apiVersion: v1
kind: Service
metadata:
  name: kube-dns
  namespace: kube-system
  labels:
    k8s-app: kube-dns
    kubernetes.io/cluster-service: "true"
    addonmanager.kubernetes.io/mode: Reconcile
    kubernetes.io/name: "KubeDNS"
spec:
  selector:
    k8s-app: kube-dns
  clusterIP: 169.169.0.53
  ports:
  - name: dns
    port: 53
    protocol: UDP
  - name: dns-tcp
    port: 53
    protocol: TCP

[root@docker1 kubedns]# cat kubedns-svc.yaml

# Licensed under the Apache License, Version 2.0 (the "License");

# you may not use this file except in compliance with the License.

# You may obtain a copy of the License at

# http://www.apache.org/licenses/LICENSE-2.0

# Unless required by applicable law or agreed to in writing, software

# distributed under the License is distributed on an "AS IS" BASIS,

# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

# See the License for the specific language governing permissions and

# limitations under the License.

# Warning: This is a file generated from the base underscore template file: kubedns-svc.yaml.base

apiVersion: v1

kind: Service

metadata:

namespace: kube-system

labels:

k8s-app: kube-dns

kubernetes.io/cluster-service: "true"

addonmanager.kubernetes.io/mode: Reconcile

kubernetes.io/name: "KubeDNS"

spec:

selector:

k8s-app: kube-dns

clusterIP: 169.169.0.53

ports:

- name: dns

port: 53

protocol: UDP

- name: dns-tcp

port: 53

protocol: TCP

docker镜像pull

由于上述配置文件里的镜像pull地址是google的服务器地址，中国访问，你懂得，因此需要先人工从其他镜像站点拉取。我已经将三个所要的镜像build到了docker hub里，直接拉取后重新tag即可，注意下面的命令需要在所有node上执行：

docker pull myf5/k8s-dns-kube-dns-amd64:1.14.4
docker pull myf5/k8s-dns-dnsmasq-nanny-amd64:1.14.4
docker pull myf5/k8s-dns-sidecar-amd64:1.14.4
docker pull myf5/pause-amd64:3.0

docker pull myf5/k8s-dns-kube-dns-amd64:1.14.4

docker pull myf5/k8s-dns-dnsmasq-nanny-amd64:1.14.4

docker pull myf5/k8s-dns-sidecar-amd64:1.14.4

docker pull myf5/pause-amd64:3.0

docker tag myf5/k8s-dns-kube-dns-amd64:1.14.4 gcr.io/google_containers/k8s-dns-kube-dns-amd64:1.14.4
docker tag myf5/k8s-dns-dnsmasq-nanny-amd64:1.14.4 gcr.io/google_containers/k8s-dns-dnsmasq-nanny-amd64:1.14.4
docker tag myf5/k8s-dns-sidecar-amd64:1.14.4  gcr.io/google_containers/k8s-dns-sidecar-amd64:1.14.4
docker tag myf5/pause-amd64:3.0 gcr.io/google_containers/pause-amd64:3.0

docker tag myf5/k8s-dns-kube-dns-amd64:1.14.4 gcr.io/google_containers/k8s-dns-kube-dns-amd64:1.14.4

docker tag myf5/k8s-dns-dnsmasq-nanny-amd64:1.14.4 gcr.io/google_containers/k8s-dns-dnsmasq-nanny-amd64:1.14.4

docker tag myf5/k8s-dns-sidecar-amd64:1.14.4 gcr.io/google_containers/k8s-dns-sidecar-amd64:1.14.4

docker tag myf5/pause-amd64:3.0 gcr.io/google_containers/pause-amd64:3.0

执行上述定义的yaml文件

cd /root/kubedns
kubectl create -f .

1 2	cd /root/kubedns kubectl create -f .

检验

[root@docker1 kubedns]# kubectl get pod -n kube-system -o wide
NAME                        READY     STATUS    RESTARTS   AGE       IP          NODE
kube-dns-1099564669-hv1pj   3/3       Running   0          1m        10.2.39.2   172.16.199.37ontainers/k8s-dns-dnsmasq-nanny-amd64:1.14.4,gcr.io/google_containers/k8s-dns-sidecar-amd64:1.14.4   k8s-app=kube-dns,pod-template-hash=1099564669

[root@docker1 kubedns]# kubectl get pod -n kube-system -o wide

NAME READY STATUS RESTARTS AGE IP NODE

kube-dns-1099564669-hv1pj 3/3 Running 0 1m 10.2.39.2 172.16.199.37ontainers/k8s-dns-dnsmasq-nanny-amd64:1.14.4,gcr.io/google_containers/k8s-dns-sidecar-amd64:1.14.4 k8s-app=kube-dns,pod-template-hash=1099564669

以下输出可以看到在弄的172.16.199.37上，pod获得了一个flannel网络分配的IP地址10.2.39.2

[root@docker1 kubedns]# kubectl get all -n kube-system -o wide
NAME                           READY     STATUS    RESTARTS   AGE       IP          NODE
po/kube-dns-1099564669-hv1pj   3/3       Running   0          1m        10.2.39.2   172.16.199.37

NAME           CLUSTER-IP     EXTERNAL-IP   PORT(S)         AGE       SELECTOR
svc/kube-dns   169.169.0.53   <none>        53/UDP,53/TCP   2h        k8s-app=kube-dns

NAME              DESIRED   CURRENT   UP-TO-DATE   AVAILABLE   AGE       CONTAINER(S)              IMAGE(S)                                                                                                                                                                   SELECTOR
deploy/kube-dns   1         1         1            1           1m        kubedns,dnsmasq,sidecar   gcr.io/google_containers/k8s-dns-kube-dns-amd64:1.14.4,gcr.io/google_containers/k8s-dns-dnsmasq-nanny-amd64:1.14.4,gcr.io/google_containers/k8s-dns-sidecar-amd64:1.14.4   k8s-app=kube-dns

NAME                     DESIRED   CURRENT   READY     AGE       CONTAINER(S)              IMAGE(S)                                                                                                                                                                   SELECTOR
rs/kube-dns-1099564669   1         1         1         1m        kubedns,dnsmasq,sidecar   gcr.io/google_containers/k8s-dns-kube-dns-amd64:1.14.4,gcr.io/google_containers/k8s-dns-dnsmasq-nanny-amd64:1.14.4,gcr.io/google_containers/k8s-dns-sidecar-amd64:1.14.4   k8s-app=kube-dns,pod-template-hash=1099564669

[root@docker1 kubedns]# kubectl get all -n kube-system -o wide

NAME READY STATUS RESTARTS AGE IP NODE

po/kube-dns-1099564669-hv1pj 3/3 Running 0 1m 10.2.39.2 172.16.199.37

NAME CLUSTER-IP EXTERNAL-IP PORT(S) AGE SELECTOR

svc/kube-dns 169.169.0.53 <none> 53/UDP,53/TCP 2h k8s-app=kube-dns

NAME DESIRED CURRENT UP-TO-DATE AVAILABLE AGE CONTAINER(S) IMAGE(S) SELECTOR

deploy/kube-dns 1 1 1 1 1m kubedns,dnsmasq,sidecar gcr.io/google_containers/k8s-dns-kube-dns-amd64:1.14.4,gcr.io/google_containers/k8s-dns-dnsmasq-nanny-amd64:1.14.4,gcr.io/google_containers/k8s-dns-sidecar-amd64:1.14.4 k8s-app=kube-dns

NAME DESIRED CURRENT READY AGE CONTAINER(S) IMAGE(S) SELECTOR

rs/kube-dns-1099564669 1 1 1 1m kubedns,dnsmasq,sidecar gcr.io/google_containers/k8s-dns-kube-dns-amd64:1.14.4,gcr.io/google_containers/k8s-dns-dnsmasq-nanny-amd64:1.14.4,gcr.io/google_containers/k8s-dns-sidecar-amd64:1.14.4 k8s-app=kube-dns,pod-template-hash=1099564669

相关节点上的docker ps

[root@docker3 ~]# docker ps
CONTAINER ID        IMAGE                                      COMMAND                  CREATED             STATUS              PORTS               NAMES
692db72631b3        myf5/k8s-dns-kube-dns-amd64                "/kube-dns --domai..."   4 minutes ago       Up 4 minutes                            k8s_kubedns_kube-dns-1099564669-hv1pj_kube-system_07a6d751-64cd-11e7-ae06-000c29420d98_0
f4f3cd1b8ac4        myf5/k8s-dns-sidecar-amd64                 "/sidecar --v=2 --..."   4 minutes ago       Up 4 minutes                            k8s_sidecar_kube-dns-1099564669-hv1pj_kube-system_07a6d751-64cd-11e7-ae06-000c29420d98_0
2085fa64a5f0        myf5/k8s-dns-dnsmasq-nanny-amd64           "/dnsmasq-nanny -v..."   4 minutes ago       Up 4 minutes                            k8s_dnsmasq_kube-dns-1099564669-hv1pj_kube-system_07a6d751-64cd-11e7-ae06-000c29420d98_0
a77f03e6ab19        gcr.io/google_containers/pause-amd64:3.0   "/pause"                 4 minutes ago       Up 4 minutes                            k8s_POD_kube-dns-1099564669-hv1pj_kube-system_07a6d751-64cd-11e7-ae06-000c29420d98_0

[root@docker3 ~]# docker ps

CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES

692db72631b3 myf5/k8s-dns-kube-dns-amd64 "/kube-dns --domai..." 4 minutes ago Up 4 minutes k8s_kubedns_kube-dns-1099564669-hv1pj_kube-system_07a6d751-64cd-11e7-ae06-000c29420d98_0

f4f3cd1b8ac4 myf5/k8s-dns-sidecar-amd64 "/sidecar --v=2 --..." 4 minutes ago Up 4 minutes k8s_sidecar_kube-dns-1099564669-hv1pj_kube-system_07a6d751-64cd-11e7-ae06-000c29420d98_0

2085fa64a5f0 myf5/k8s-dns-dnsmasq-nanny-amd64 "/dnsmasq-nanny -v..." 4 minutes ago Up 4 minutes k8s_dnsmasq_kube-dns-1099564669-hv1pj_kube-system_07a6d751-64cd-11e7-ae06-000c29420d98_0

a77f03e6ab19 gcr.io/google_containers/pause-amd64:3.0 "/pause" 4 minutes ago Up 4 minutes k8s_POD_kube-dns-1099564669-hv1pj_kube-system_07a6d751-64cd-11e7-ae06-000c29420d98_0

快速验证pod是否正常提供dns服务：

[root@docker1 kubedns]# dig @10.2.39.2 cluster.local. SOA

; <<>> DiG 9.9.4-RedHat-9.9.4-38.el7_3.3 <<>> @10.2.39.2 cluster.local. SOA
; (1 server found)
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 1762
;; flags: qr aa rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 0

;; QUESTION SECTION:
;cluster.local.                 IN      SOA

;; ANSWER SECTION:
cluster.local.          3600    IN      SOA     ns.dns.cluster.local. hostmaster.cluster.local. 1499619600 28800 7200 604800 60

;; Query time: 1 msec
;; SERVER: 10.2.39.2#53(10.2.39.2)
;; WHEN: Mon Jul 10 01:55:15 CST 2017
;; MSG SIZE  rcvd: 85

[root@docker1 kubedns]# dig @10.2.39.2 cluster.local. SOA

; <<>> DiG 9.9.4-RedHat-9.9.4-38.el7_3.3 <<>> @10.2.39.2 cluster.local. SOA

; (1 server found)

;; global options: +cmd

;; Got answer:

;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 1762

;; flags: qr aa rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 0

;; QUESTION SECTION:

;cluster.local. IN SOA

;; ANSWER SECTION:

cluster.local. 3600 IN SOA ns.dns.cluster.local. hostmaster.cluster.local. 1499619600 28800 7200 604800 60

;; Query time: 1 msec

;; SERVER: 10.2.39.2#53(10.2.39.2)

;; WHEN: Mon Jul 10 01:55:15 CST 2017

;; MSG SIZE rcvd: 85

pod输出：

[root@docker1 ~]# kubectl get pods -n kube-system -o yaml
apiVersion: v1
items:
- apiVersion: v1
  kind: Pod
  metadata:
    annotations:
      kubernetes.io/created-by: |
        {"kind":"SerializedReference","apiVersion":"v1","reference":{"kind":"ReplicaSet","namespace":"kube-system","name":"kube-dns-1099564669","uid":"07a5d7d9-64cd-11e7-ae06-000c29420d98","apiVersion":"extensions","resourceVersion":"8433"}}
      scheduler.alpha.kubernetes.io/critical-pod: ""
    creationTimestamp: 2017-07-09T17:35:41Z
    generateName: kube-dns-1099564669-
    labels:
      k8s-app: kube-dns
      pod-template-hash: "1099564669"
    name: kube-dns-1099564669-hv1pj
    namespace: kube-system
    ownerReferences:
    - apiVersion: extensions/v1beta1
      blockOwnerDeletion: true
      controller: true
      kind: ReplicaSet
      name: kube-dns-1099564669
      uid: 07a5d7d9-64cd-11e7-ae06-000c29420d98
    resourceVersion: "8461"
    selfLink: /api/v1/namespaces/kube-system/pods/kube-dns-1099564669-hv1pj
    uid: 07a6d751-64cd-11e7-ae06-000c29420d98
  spec:
    containers:
    - args:
      - --domain=cluster.local.
      - --dns-port=10053
      - --config-dir=/kube-dns-config
      - --v=2
      - --kube-master-url=http://172.16.199.17:8080
      env:
      - name: PROMETHEUS_PORT
        value: "10055"
      image: gcr.io/google_containers/k8s-dns-kube-dns-amd64:1.14.4
      imagePullPolicy: IfNotPresent
      livenessProbe:
        failureThreshold: 5
        httpGet:
          path: /healthcheck/kubedns
          port: 10054
          scheme: HTTP
        initialDelaySeconds: 60
        periodSeconds: 10
        successThreshold: 1
        timeoutSeconds: 5
      name: kubedns
      ports:
      - containerPort: 10053
        name: dns-local
        protocol: UDP
      - containerPort: 10053
        name: dns-tcp-local
        protocol: TCP
      - containerPort: 10055
        name: metrics
        protocol: TCP
      readinessProbe:
        failureThreshold: 3
        httpGet:
          path: /readiness
          port: 8081
          scheme: HTTP
        initialDelaySeconds: 3
        periodSeconds: 10
        successThreshold: 1
        timeoutSeconds: 5
      resources:
        limits:
          memory: 170Mi
        requests:
          cpu: 100m
          memory: 70Mi
      terminationMessagePath: /dev/termination-log
      terminationMessagePolicy: File
      volumeMounts:
      - mountPath: /kube-dns-config
        name: kube-dns-config
    - args:
      - -v=2
      - -logtostderr
      - -configDir=/etc/k8s/dns/dnsmasq-nanny
      - -restartDnsmasq=true
      - --
      - -k
      - --cache-size=1000
      - --log-facility=-
      - --server=/cluster.local./127.0.0.1#10053
      - --server=/in-addr.arpa/127.0.0.1#10053
      - --server=/ip6.arpa/127.0.0.1#10053
      image: gcr.io/google_containers/k8s-dns-dnsmasq-nanny-amd64:1.14.4
      imagePullPolicy: IfNotPresent
      livenessProbe:
        failureThreshold: 5
        httpGet:
          path: /healthcheck/dnsmasq
          port: 10054
          scheme: HTTP
        initialDelaySeconds: 60
        periodSeconds: 10
        successThreshold: 1
        timeoutSeconds: 5
      name: dnsmasq
      ports:
      - containerPort: 53
        name: dns
        protocol: UDP
      - containerPort: 53
        name: dns-tcp
        protocol: TCP
      resources:
        requests:
          cpu: 150m
          memory: 20Mi
      terminationMessagePath: /dev/termination-log
      terminationMessagePolicy: File
      volumeMounts:
      - mountPath: /etc/k8s/dns/dnsmasq-nanny
        name: kube-dns-config
    - args:
      - --v=2
      - --logtostderr
      - --probe=kubedns,127.0.0.1:10053,kubernetes.default.svc.cluster.local.,5,A
      - --probe=dnsmasq,127.0.0.1:53,kubernetes.default.svc.cluster.local.,5,A
      image: gcr.io/google_containers/k8s-dns-sidecar-amd64:1.14.4
      imagePullPolicy: IfNotPresent
      livenessProbe:
        failureThreshold: 5
        httpGet:
          path: /metrics
          port: 10054
          scheme: HTTP
        initialDelaySeconds: 60
        periodSeconds: 10
        successThreshold: 1
        timeoutSeconds: 5
      name: sidecar
      ports:
      - containerPort: 10054
        name: metrics
        protocol: TCP
      resources:
        requests:
          cpu: 10m
          memory: 20Mi
      terminationMessagePath: /dev/termination-log
      terminationMessagePolicy: File
    dnsPolicy: Default
    nodeName: 172.16.199.37
    restartPolicy: Always
    schedulerName: default-scheduler
    securityContext: {}
    serviceAccount: kube-dns
    serviceAccountName: kube-dns
    terminationGracePeriodSeconds: 30
    tolerations:
    - key: CriticalAddonsOnly
      operator: Exists
    volumes:
    - configMap:
        defaultMode: 420
        name: kube-dns
        optional: true
      name: kube-dns-config
  status:
    conditions:
    - lastProbeTime: null
      lastTransitionTime: 2017-07-09T17:35:41Z
      status: "True"
      type: Initialized
    - lastProbeTime: null
      lastTransitionTime: 2017-07-09T17:35:48Z
      status: "True"
      type: Ready
    - lastProbeTime: null
      lastTransitionTime: 2017-07-09T17:35:41Z
      status: "True"
      type: PodScheduled
    containerStatuses:
    - containerID: docker://2085fa64a5f04d401584e3d759236a68e472f211fc2b42060f02f045627fc621
      image: myf5/k8s-dns-dnsmasq-nanny-amd64:1.14.4
      imageID: docker-pullable://myf5/k8s-dns-dnsmasq-nanny-amd64@sha256:8e7a9752871ad5cef8b9a6f40c9227ec802d397930fdad0468733bdd70da6357
      lastState: {}
      name: dnsmasq
      ready: true
      restartCount: 0
      state:
        running:
          startedAt: 2017-07-09T17:35:43Z
    - containerID: docker://692db72631b3a1640a04165b16700f5611327e541600745e5e1eef7b53ca7a75
      image: myf5/k8s-dns-kube-dns-amd64:1.14.4
      imageID: docker-pullable://myf5/k8s-dns-kube-dns-amd64@sha256:93e31e20aa1feeed54d592c0f071b3d056ab834e676bb9fde54fd72918508796
      lastState: {}
      name: kubedns
      ready: true
      restartCount: 0
      state:
        running:
          startedAt: 2017-07-09T17:35:44Z
    - containerID: docker://f4f3cd1b8ac47c3b6ad4b8eed72491562a6c167831b1e92f2f866f69f395ee76
      image: myf5/k8s-dns-sidecar-amd64:1.14.4
      imageID: docker-pullable://myf5/k8s-dns-sidecar-amd64@sha256:975026e333c87138221a07312f35b943a244545cc7b746fb32d066297a91b41c
      lastState: {}
      name: sidecar
      ready: true
      restartCount: 0
      state:
        running:
          startedAt: 2017-07-09T17:35:43Z
    hostIP: 172.16.199.37
    phase: Running
    podIP: 10.2.39.2
    qosClass: Burstable
    startTime: 2017-07-09T17:35:41Z
kind: List
metadata: {}
resourceVersion: ""
selfLink: ""

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[root@docker1 ~]# kubectl get pods -n kube-system -o yaml

apiVersion: v1

items:

- apiVersion: v1

kind: Pod

metadata:

annotations:

kubernetes.io/created-by: |

{"kind":"SerializedReference","apiVersion":"v1","reference":{"kind":"ReplicaSet","namespace":"kube-system","name":"kube-dns-1099564669","uid":"07a5d7d9-64cd-11e7-ae06-000c29420d98","apiVersion":"extensions","resourceVersion":"8433"}}

scheduler.alpha.kubernetes.io/critical-pod: ""

creationTimestamp: 2017-07-09T17:35:41Z

generateName: kube-dns-1099564669-

labels:

k8s-app: kube-dns

pod-template-hash: "1099564669"

namespace: kube-system

ownerReferences:

- apiVersion: extensions/v1beta1

blockOwnerDeletion: true

controller: true

kind: ReplicaSet

uid: 07a5d7d9-64cd-11e7-ae06-000c29420d98

resourceVersion: "8461"

selfLink: /api/v1/namespaces/kube-system/pods/kube-dns-1099564669-hv1pj

uid: 07a6d751-64cd-11e7-ae06-000c29420d98

spec:

containers:

- args:

- --domain=cluster.local.

- --dns-port=10053

- --config-dir=/kube-dns-config

- --v=2

- --kube-master-url=http://172.16.199.17:8080

env:

- name: PROMETHEUS_PORT

value: "10055"

image: gcr.io/google_containers/k8s-dns-kube-dns-amd64:1.14.4

imagePullPolicy: IfNotPresent

livenessProbe:

failureThreshold: 5

httpGet:

path: /healthcheck/kubedns

port: 10054

scheme: HTTP

initialDelaySeconds: 60

periodSeconds: 10

successThreshold: 1

timeoutSeconds: 5

ports:

- containerPort: 10053

protocol: UDP

- containerPort: 10053

protocol: TCP

- containerPort: 10055

protocol: TCP

readinessProbe:

failureThreshold: 3

httpGet:

path: /readiness

port: 8081

scheme: HTTP

initialDelaySeconds: 3

periodSeconds: 10

successThreshold: 1

timeoutSeconds: 5

resources:

limits:

memory: 170Mi

requests:

cpu: 100m

memory: 70Mi

terminationMessagePath: /dev/termination-log

terminationMessagePolicy: File

volumeMounts:

- mountPath: /kube-dns-config

- args:

- -v=2

- -logtostderr

- -configDir=/etc/k8s/dns/dnsmasq-nanny

- -restartDnsmasq=true

- --

- -k

- --cache-size=1000

- --log-facility=-

- --server=/cluster.local./127.0.0.1#10053

- --server=/in-addr.arpa/127.0.0.1#10053

- --server=/ip6.arpa/127.0.0.1#10053

image: gcr.io/google_containers/k8s-dns-dnsmasq-nanny-amd64:1.14.4

imagePullPolicy: IfNotPresent

livenessProbe:

failureThreshold: 5

httpGet:

path: /healthcheck/dnsmasq

port: 10054

scheme: HTTP

initialDelaySeconds: 60

periodSeconds: 10

successThreshold: 1

timeoutSeconds: 5

ports:

- containerPort: 53

protocol: UDP

- containerPort: 53

protocol: TCP

resources:

requests:

cpu: 150m

memory: 20Mi

terminationMessagePath: /dev/termination-log

terminationMessagePolicy: File

volumeMounts:

- mountPath: /etc/k8s/dns/dnsmasq-nanny

- args:

- --v=2

- --logtostderr

- --probe=kubedns,127.0.0.1:10053,kubernetes.default.svc.cluster.local.,5,A

- --probe=dnsmasq,127.0.0.1:53,kubernetes.default.svc.cluster.local.,5,A

image: gcr.io/google_containers/k8s-dns-sidecar-amd64:1.14.4

imagePullPolicy: IfNotPresent

livenessProbe:

failureThreshold: 5

httpGet:

path: /metrics

port: 10054

scheme: HTTP

initialDelaySeconds: 60

periodSeconds: 10

successThreshold: 1

timeoutSeconds: 5

ports:

- containerPort: 10054

protocol: TCP

resources:

requests:

cpu: 10m

memory: 20Mi

terminationMessagePath: /dev/termination-log

terminationMessagePolicy: File

dnsPolicy: Default

nodeName: 172.16.199.37

restartPolicy: Always

schedulerName: default-scheduler

securityContext: {}

serviceAccount: kube-dns

serviceAccountName: kube-dns

terminationGracePeriodSeconds: 30

tolerations:

- key: CriticalAddonsOnly

operator: Exists

volumes:

- configMap:

defaultMode: 420

optional: true

status:

conditions:

- lastProbeTime: null

lastTransitionTime: 2017-07-09T17:35:41Z

status: "True"

type: Initialized

- lastProbeTime: null

lastTransitionTime: 2017-07-09T17:35:48Z

status: "True"

type: Ready

- lastProbeTime: null

lastTransitionTime: 2017-07-09T17:35:41Z

status: "True"

type: PodScheduled

containerStatuses:

- containerID: docker://2085fa64a5f04d401584e3d759236a68e472f211fc2b42060f02f045627fc621

image: myf5/k8s-dns-dnsmasq-nanny-amd64:1.14.4

imageID: docker-pullable://myf5/k8s-dns-dnsmasq-nanny-amd64@sha256:8e7a9752871ad5cef8b9a6f40c9227ec802d397930fdad0468733bdd70da6357

lastState: {}

ready: true

restartCount: 0

state:

running:

startedAt: 2017-07-09T17:35:43Z

- containerID: docker://692db72631b3a1640a04165b16700f5611327e541600745e5e1eef7b53ca7a75

image: myf5/k8s-dns-kube-dns-amd64:1.14.4

imageID: docker-pullable://myf5/k8s-dns-kube-dns-amd64@sha256:93e31e20aa1feeed54d592c0f071b3d056ab834e676bb9fde54fd72918508796

lastState: {}

ready: true

restartCount: 0

state:

running:

startedAt: 2017-07-09T17:35:44Z

- containerID: docker://f4f3cd1b8ac47c3b6ad4b8eed72491562a6c167831b1e92f2f866f69f395ee76

image: myf5/k8s-dns-sidecar-amd64:1.14.4

imageID: docker-pullable://myf5/k8s-dns-sidecar-amd64@sha256:975026e333c87138221a07312f35b943a244545cc7b746fb32d066297a91b41c

lastState: {}

ready: true

restartCount: 0

state:

running:

startedAt: 2017-07-09T17:35:43Z

hostIP: 172.16.199.37

phase: Running

podIP: 10.2.39.2

qosClass: Burstable

startTime: 2017-07-09T17:35:41Z

kind: List

metadata: {}

resourceVersion: ""

selfLink: ""

附录排错：

由于忘记拉去pause镜像到本地，导致pod无法起来了，总是现在 containercreating状态：

[root@docker1 kubernetes]# kubectl get all -n kube-system  -o wide
NAME                           READY     STATUS              RESTARTS   AGE       IP        NODE
po/kube-dns-2139945439-kp1v7   0/3       ContainerCreating   0          24m       <none>    172.16.199.37

NAME           CLUSTER-IP     EXTERNAL-IP   PORT(S)         AGE       SELECTOR
svc/kube-dns   169.169.0.53   <none>        53/UDP,53/TCP   1h        k8s-app=kube-dns

NAME              DESIRED   CURRENT   UP-TO-DATE   AVAILABLE   AGE       CONTAINER(S)              IMAGE(S)                                                                                                                                                                   SELECTOR
deploy/kube-dns   1         1         1            0           24m       kubedns,dnsmasq,sidecar   gcr.io/google_containers/k8s-dns-kube-dns-amd64:1.14.4,gcr.io/google_containers/k8s-dns-dnsmasq-nanny-amd64:1.14.4,gcr.io/google_containers/k8s-dns-sidecar-amd64:1.14.4   k8s-app=kube-dns

NAME                     DESIRED   CURRENT   READY     AGE       CONTAINER(S)              IMAGE(S)                                                                                                                                                                   SELECTOR
rs/kube-dns-2139945439   1         1         0         24m       kubedns,dnsmasq,sidecar   gcr.io/google_containers/k8s-dns-kube-dns-amd64:1.14.4,gcr.io/google_containers/k8s-dns-dnsmasq-nanny-amd64:1.14.4,gcr.io/google_containers/k8s-dns-sidecar-amd64:1.14.4   k8s-app=kube-dns,pod-template-hash=2139945439

[root@docker1 kubernetes]# kubectl get all -n kube-system -o wide

NAME READY STATUS RESTARTS AGE IP NODE

po/kube-dns-2139945439-kp1v7 0/3 ContainerCreating 0 24m <none> 172.16.199.37

NAME CLUSTER-IP EXTERNAL-IP PORT(S) AGE SELECTOR

svc/kube-dns 169.169.0.53 <none> 53/UDP,53/TCP 1h k8s-app=kube-dns

NAME DESIRED CURRENT UP-TO-DATE AVAILABLE AGE CONTAINER(S) IMAGE(S) SELECTOR

deploy/kube-dns 1 1 1 0 24m kubedns,dnsmasq,sidecar gcr.io/google_containers/k8s-dns-kube-dns-amd64:1.14.4,gcr.io/google_containers/k8s-dns-dnsmasq-nanny-amd64:1.14.4,gcr.io/google_containers/k8s-dns-sidecar-amd64:1.14.4 k8s-app=kube-dns

NAME DESIRED CURRENT READY AGE CONTAINER(S) IMAGE(S) SELECTOR

rs/kube-dns-2139945439 1 1 0 24m kubedns,dnsmasq,sidecar gcr.io/google_containers/k8s-dns-kube-dns-amd64:1.14.4,gcr.io/google_containers/k8s-dns-dnsmasq-nanny-amd64:1.14.4,gcr.io/google_containers/k8s-dns-sidecar-amd64:1.14.4 k8s-app=kube-dns,pod-template-hash=2139945439

此时，kubectl get events -n kube-system显示了原因：

[root@docker1 kubernetes]# kubectl get events -n kube-system  
LASTSEEN   FIRSTSEEN   COUNT     NAME                        KIND      SUBOBJECT   TYPE      REASON       SOURCE                   MESSAGE
33m        1h          173       kube-dns-2139945439-6zqt3   Pod                   Warning   FailedSync   kubelet, 172.16.199.37   Error syncing pod, skipping: failed to "CreatePodSandbox" for "kube-dns-2139945439-6zqt3_kube-system(7a27e066-64b8-11e7-ae06-000c29420d98)" with CreatePodSandboxError: "CreatePodSandbox for pod \"kube-dns-2139945439-6zqt3_kube-system(7a27e066-64b8-11e7-ae06-000c29420d98)\" failed: rpc error: code = 2 desc = unable to pull sandbox image \"gcr.io/google_containers/pause-amd64:3.0\": Error response from daemon: {\"message\":\"Get https://gcr.io/v2/: net/http: request canceled while waiting for connection (Client.Timeout exceeded while awaiting headers)\"}"

25m       25m       1         kube-dns-2139945439-bg2fk   Pod                 Normal    Scheduled    default-scheduler        Successfully assigned kube-dns-2139945439-bg2fk to 172.16.199.27
23m       24m       2         kube-dns-2139945439-bg2fk   Pod                 Warning   FailedSync   kubelet, 172.16.199.27   Error syncing pod, skipping: failed to "CreatePodSandbox" for "kube-dns-2139945439-bg2fk_kube-system(1ff21307-64c5-11e7-ae06-000c29420d98)" with CreatePodSandboxError: "CreatePodSandbox for pod \"kube-dns-2139945439-bg2fk_kube-system(1ff21307-64c5-11e7-ae06-000c29420d98)\" failed: rpc error: code = 2 desc = unable to pull sandbox image \"gcr.io/google_containers/pause-amd64:3.0\": Error response from daemon: {\"message\":\"Get https://gcr.io/v1/_ping: dial tcp 108.177.97.82:443: i/o timeout\"}"

22m       22m       1         kube-dns-2139945439-kp1v7   Pod                 Normal    Scheduled    default-scheduler        Successfully assigned kube-dns-2139945439-kp1v7 to 172.16.199.37
12s       22m       48        kube-dns-2139945439-kp1v7   Pod                 Warning   FailedSync   kubelet, 172.16.199.37   Error syncing pod, skipping: failed to "CreatePodSandbox" for "kube-dns-2139945439-kp1v7_kube-system(752d819e-64c5-11e7-ae06-000c29420d98)" with CreatePodSandboxError: "CreatePodSandbox for pod \"kube-dns-2139945439-kp1v7_kube-system(752d819e-64c5-11e7-ae06-000c29420d98)\" failed: rpc error: code = 2 desc = unable to pull sandbox image \"gcr.io/google_containers/pause-amd64:3.0\": Error response from daemon: {\"message\":\"Get https://gcr.io/v2/: net/http: request canceled while waiting for connection (Client.Timeout exceeded while awaiting headers)\"}"

33m       33m       1         kube-dns-2139945439   ReplicaSet             Normal    SuccessfulDelete    replicaset-controller   Deleted pod: kube-dns-2139945439-6zqt3
25m       25m       1         kube-dns-2139945439   ReplicaSet             Normal    SuccessfulCreate    replicaset-controller   Created pod: kube-dns-2139945439-bg2fk
23m       23m       1         kube-dns-2139945439   ReplicaSet             Normal    SuccessfulDelete    replicaset-controller   Deleted pod: kube-dns-2139945439-bg2fk
22m       22m       1         kube-dns-2139945439   ReplicaSet             Normal    SuccessfulCreate    replicaset-controller   Created pod: kube-dns-2139945439-kp1v7
33m       33m       1         kube-dns              Deployment             Normal    ScalingReplicaSet   deployment-controller   Scaled down replica set kube-dns-2139945439 to 0
25m       25m       1         kube-dns              Deployment             Normal    ScalingReplicaSet   deployment-controller   Scaled up replica set kube-dns-2139945439 to 1
23m       23m       1         kube-dns              Deployment             Normal    ScalingReplicaSet   deployment-controller   Scaled down replica set kube-dns-2139945439 to 0
22m       22m       1         kube-dns              Deployment             Normal    ScalingReplicaSet   deployment-controller   Scaled up replica set kube-dns-2139945439 to 1

[root@docker1 kubernetes]# kubectl get events -n kube-system

LASTSEEN FIRSTSEEN COUNT NAME KIND SUBOBJECT TYPE REASON SOURCE MESSAGE

33m 1h 173 kube-dns-2139945439-6zqt3 Pod Warning FailedSync kubelet, 172.16.199.37 Error syncing pod, skipping: failed to "CreatePodSandbox" for "kube-dns-2139945439-6zqt3_kube-system(7a27e066-64b8-11e7-ae06-000c29420d98)" with CreatePodSandboxError: "CreatePodSandbox for pod \"kube-dns-2139945439-6zqt3_kube-system(7a27e066-64b8-11e7-ae06-000c29420d98)\" failed: rpc error: code = 2 desc = unable to pull sandbox image \"gcr.io/google_containers/pause-amd64:3.0\": Error response from daemon: {\"message\":\"Get https://gcr.io/v2/: net/http: request canceled while waiting for connection (Client.Timeout exceeded while awaiting headers)\"}"

25m 25m 1 kube-dns-2139945439-bg2fk Pod Normal Scheduled default-scheduler Successfully assigned kube-dns-2139945439-bg2fk to 172.16.199.27

23m 24m 2 kube-dns-2139945439-bg2fk Pod Warning FailedSync kubelet, 172.16.199.27 Error syncing pod, skipping: failed to "CreatePodSandbox" for "kube-dns-2139945439-bg2fk_kube-system(1ff21307-64c5-11e7-ae06-000c29420d98)" with CreatePodSandboxError: "CreatePodSandbox for pod \"kube-dns-2139945439-bg2fk_kube-system(1ff21307-64c5-11e7-ae06-000c29420d98)\" failed: rpc error: code = 2 desc = unable to pull sandbox image \"gcr.io/google_containers/pause-amd64:3.0\": Error response from daemon: {\"message\":\"Get https://gcr.io/v1/_ping: dial tcp 108.177.97.82:443: i/o timeout\"}"

22m 22m 1 kube-dns-2139945439-kp1v7 Pod Normal Scheduled default-scheduler Successfully assigned kube-dns-2139945439-kp1v7 to 172.16.199.37

12s 22m 48 kube-dns-2139945439-kp1v7 Pod Warning FailedSync kubelet, 172.16.199.37 Error syncing pod, skipping: failed to "CreatePodSandbox" for "kube-dns-2139945439-kp1v7_kube-system(752d819e-64c5-11e7-ae06-000c29420d98)" with CreatePodSandboxError: "CreatePodSandbox for pod \"kube-dns-2139945439-kp1v7_kube-system(752d819e-64c5-11e7-ae06-000c29420d98)\" failed: rpc error: code = 2 desc = unable to pull sandbox image \"gcr.io/google_containers/pause-amd64:3.0\": Error response from daemon: {\"message\":\"Get https://gcr.io/v2/: net/http: request canceled while waiting for connection (Client.Timeout exceeded while awaiting headers)\"}"

33m 33m 1 kube-dns-2139945439 ReplicaSet Normal SuccessfulDelete replicaset-controller Deleted pod: kube-dns-2139945439-6zqt3

25m 25m 1 kube-dns-2139945439 ReplicaSet Normal SuccessfulCreate replicaset-controller Created pod: kube-dns-2139945439-bg2fk

23m 23m 1 kube-dns-2139945439 ReplicaSet Normal SuccessfulDelete replicaset-controller Deleted pod: kube-dns-2139945439-bg2fk

22m 22m 1 kube-dns-2139945439 ReplicaSet Normal SuccessfulCreate replicaset-controller Created pod: kube-dns-2139945439-kp1v7

33m 33m 1 kube-dns Deployment Normal ScalingReplicaSet deployment-controller Scaled down replica set kube-dns-2139945439 to 0

25m 25m 1 kube-dns Deployment Normal ScalingReplicaSet deployment-controller Scaled up replica set kube-dns-2139945439 to 1

23m 23m 1 kube-dns Deployment Normal ScalingReplicaSet deployment-controller Scaled down replica set kube-dns-2139945439 to 0

22m 22m 1 kube-dns Deployment Normal ScalingReplicaSet deployment-controller Scaled up replica set kube-dns-2139945439 to 1

解决上述问题后，由于上述deployment文件里没有配置master url地址，导致kube dns 镜像无法启动，导致dnsmasq镜像总是liveness探测失败，修改配置后问题解决，当时的事件输出包含类似错误：

16m       17m       7         kube-dns-2139945439-tlnt0   Pod                                  Warning   FailedSync   kubelet, 172.16.199.27   Error syncing pod, skipping: failed to "StartContainer" for "kubedns" with CrashLoopBackOff: "Back-off 1m20s restarting failed container=kubedns pod=kube-dns-2139945439-tlnt0_kube-system(5ae8de0b-64ca-11e7-ae06-000c29420d98)"

17m       17m       1         kube-dns-2139945439-tlnt0   Pod       spec.containers{dnsmasq}   Normal    Killing      kubelet, 172.16.199.27   Killing container with id docker://63aa8d879e66500e1be7c13426cdf2090cac34254df03822a76f97a36b256802:pod "kube-dns-2139945439-tlnt0_kube-system(5ae8de0b-64ca-11e7-ae06-000c29420d98)" container "dnsmasq" is unhealthy, it will be killed and re-created.

16m 17m 7 kube-dns-2139945439-tlnt0 Pod Warning FailedSync kubelet, 172.16.199.27 Error syncing pod, skipping: failed to "StartContainer" for "kubedns" with CrashLoopBackOff: "Back-off 1m20s restarting failed container=kubedns pod=kube-dns-2139945439-tlnt0_kube-system(5ae8de0b-64ca-11e7-ae06-000c29420d98)"

17m 17m 1 kube-dns-2139945439-tlnt0 Pod spec.containers{dnsmasq} Normal Killing kubelet, 172.16.199.27 Killing container with id docker://63aa8d879e66500e1be7c13426cdf2090cac34254df03822a76f97a36b256802:pod "kube-dns-2139945439-tlnt0_kube-system(5ae8de0b-64ca-11e7-ae06-000c29420d98)" container "dnsmasq" is unhealthy, it will be killed and re-created.

本作品采用知识共享署名-非商业性使用 4.0 国际许可协议进行许可

文章评论

渡河人

配置dns需要配置ssl吗

2017年08月28日

纳米

@渡河人不需要

2017年08月28日

回复

我用的是github上的yaml文件，但是运行controller文件时报错： Killing container with id docker://c57ee12790fe565365b13833177c14046373e169da19935fd0d40206862c6870:pod "kube-dns-1631782461-3dqvx_kube-system(78458c79-8bce-11e7-a72c-000c29e37283)" container "dnsmasq" is unhealthy, it will be killed and re-created

纳米

@渡河人看上去 dnsmasq 的容器 liveness 探测失败。可以跟踪下event事件信息以及容器本身。
livenessProbe:
httpGet:
path: /healthcheck/dnsmasq
port: 10054
scheme: HTTP
initialDelaySeconds: 60
timeoutSeconds: 5
successThreshold: 1
failureThreshold: 5

2017年08月28日

回复

kubernetes Addon之 kubedns 1.6.7 安装

前言

yaml文件准备

配置文件修改

docker镜像pull

执行上述定义的yaml文件

检验

附录排错：

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