最近准备系统地学习一下 k8s，所以第一件事就是搭建环境，本篇文章就来记录一下自己在 CentOS 系统上搭建 k8s 环境的经历。
环境准备
虚拟机信息：
- 本地系统：win10
- 虚拟机软件：VirtualBox
- Linux 系统：CentOS7
- 虚拟机节点（至少2U2G）：k8s-master(192.168.31.44)、k8s-node01、k8s-node02
k8s 相关信息：
- docker 版本：docker-ce 18.09.9
- k8s 版本：v1.16.0
- 准备国内镜像源
安装 docker-ce（所有机器）
给所有的虚拟机都安装 docker-ce，选择的版本为 18.09.9，这里我使用了我之前写的安装 docker 的文章里面使用的命令，直接写成了脚本 install_docker.sh，内容如下：
#/bin/bash
# 使用root用户安装docker
DOCKER_VERSION=docker-ce-18.09.9-3.el7
DOCKER_REGISTRY=https://registry.docker-cn.com
YUN_REPO=http://mirrors.aliyun.com/docker-ce/linux/centos/docker-ce.repo
# 卸载原有的 docker
yum remove docker \
docker-ce \
docker-client \
docker-client-latest \
docker-common \
docker-latest \
docker-latest-logrotate \
docker-logrotate \
docker-engine
# 清理残留目录
rm -rf /var/lib/docker
rm -rf /var/run/docker
# 添加阿里yum源，并更新yum索引
yum install -y yum-utils
yum-config-manager --add-repo ${YUN_REPO}
yum makecache fast
# 安装docker-ce,可以自定义版本
yum install -y ${DOCKER_VERSION}
# 设置为系统服务并启动docker
systemctl enable docker && systemctl start docker
# 设置镜像仓库源
cat <<EOF >/etc/docker/daemon.json
{
"registry-mirrors": ["${DOCKER_REGISTRY}"],
"exec-opts": ["native.cgroupdriver=systemd"]
}
EOF
# 重启docker
systemctl daemon-reload
systemctl restart docker
k8s 环境配置（所有机器）
安装 docker-ce 之后，需要给虚拟机执行一些命令准备好环境，这些步骤我写到脚本 k8s_env.sh 里面了，内容如下：
#/bin/bash
# 关闭防火墙
systemctl disable firewalld
systemctl stop firewalld
# 关闭selinux
# 临时禁用selinux
setenforce 0
# 永久关闭 修改/etc/sysconfig/selinux文件设置
sed -i 's/SELINUX=permissive/SELINUX=disabled/' /etc/sysconfig/selinux
sed -i "s/SELINUX=enforcing/SELINUX=disabled/g" /etc/selinux/config
# 禁用交换分区
swapoff -a
# 永久禁用，打开/etc/fstab注释掉swap那一行。
sed -i 's/.*swap.*/#&/' /etc/fstab
# 修改内核参数
cat <<EOF >/etc/sysctl.d/k8s.conf
net.bridge.bridge-nf-call-ip6tables = 1
net.bridge.bridge-nf-call-iptables = 1
EOF
sysctl --system
安装k8s v1.16.0 （master节点）
安装完 docker 并执行了 k8s 准备条件之后，需要在 k8s 主节点上面执行下面命令安装 k8s，版本为 v1.16.0，我将所有命令写到脚本 k8s_install_master.sh 里面了，这个脚本需要传入一个参数，也就是主节点的IP地址，内容如下：
#/bin/bash
# 脚本执行必须传入一个参数，就是k8s主节点IP地址
master_ip=$1
if [ "$master_ip" == "" ]; then
echo "Error: please set master ip." &
exit 210
else
echo "master ip is $master_ip"
fi
K8S_BASEURL=https://mirrors.aliyun.com/kubernetes/yum/repos/kubernetes-el7-x86_64/
K8S_GPGKEY="https://mirrors.aliyun.com/kubernetes/yum/doc/yum-key.gpg https://mirrors.aliyun.com/kubernetes/yum/doc/rpm-package-key.gpg"
POD_NETWORD=10.244.0.0
# 执行配置k8s阿里云源
cat <<EOF >/etc/yum.repos.d/kubernetes.repo
[kubernetes]
name=Kubernetes
baseurl=${K8S_BASEURL}
enabled=1
gpgcheck=1
repo_gpgcheck=1
gpgkey=${K8S_GPGKEY}
EOF
# 安装kubeadm、kubectl、kubelet
yum install -y kubectl-1.16.0-0 kubeadm-1.16.0-0 kubelet-1.16.0-0
# 启动kubelet服务
systemctl enable kubelet && systemctl start kubelet
# 安装初始化镜像，参数详解查看文档 https://kubernetes.io/zh/docs/reference/setup-tools/kubeadm/kubeadm-init/
kubeadm init --image-repository registry.aliyuncs.com/google_containers --kubernetes-version v1.16.0 --apiserver-advertise-address ${master_ip} --pod-network-cidr=${POD_NETWORD}/16 --token-ttl 0
# kubeadm init 执行完成之后需要执行的操作
mkdir -p $HOME/.kube
sudo cp -i /etc/kubernetes/admin.conf $HOME/.kube/config
sudo chown $(id -u):$(id -g) $HOME/.kube/config
主节点安装完成后，可以看到如下输出，最后一句就是给了一条命令，在 node 节点执行该命令就可以加入 k8s 集群中，以后也可以通过在主节点执行命令来查询 kubeadm token create --print-join-command。
Your Kubernetes control-plane has initialized successfully!
To start using your cluster, you need to run the following as a regular user:
mkdir -p $HOME/.kube
sudo cp -i /etc/kubernetes/admin.conf $HOME/.kube/config
sudo chown $(id -u):$(id -g) $HOME/.kube/config
You should now deploy a pod network to the cluster.
Run "kubectl apply -f [podnetwork].yaml" with one of the options listed at:
https://kubernetes.io/docs/concepts/cluster-administration/addons/
Then you can join any number of worker nodes by running the following on each as root:
kubeadm join 192.168.31.44:6443 --token i0nitb.9dx9gqqmjc25cl4v \
--discovery-token-ca-cert-hash sha256:c7deb13d6544fe360e70fdc7b1c3140d2d5c1f98fc0e5d4c8deccadd91adf726
安装k8s v1.16.0 （node 节点）
node 节点安装 k8s 比主节点的内容稍微少一点，但是版本信息一样，我写成了脚本 k8s_install_node.sh，内容如下：
#/bin/bash
K8S_BASEURL=https://mirrors.aliyun.com/kubernetes/yum/repos/kubernetes-el7-x86_64/
K8S_GPGKEY="https://mirrors.aliyun.com/kubernetes/yum/doc/yum-key.gpg https://mirrors.aliyun.com/kubernetes/yum/doc/rpm-package-key.gpg"
cat <<EOF >/etc/yum.repos.d/kubernetes.repo
[kubernetes]
name=Kubernetes
baseurl=${K8S_BASEURL}
enabled=1
gpgcheck=1
repo_gpgcheck=1
gpgkey=${K8S_GPGKEY}
EOF
# 安装kubeadm、kubectl、kubelet
yum install -y kubeadm-1.16.0-0 kubelet-1.16.0-0
# 启动kubelet服务
systemctl enable kubelet && systemctl start kubelet
# 加入集群，如果这里不知道加入集群的命令，可以登录master节点，使用kubeadm token create --print-join-command 来获取
#kubeadm join 192.168.31.213:6443 --token 7172cu.ouhrkxvv1wj5gdfr --discovery-token-ca-cert-hash sha256:b3613871b6812b09351f7501517149e48562927efc3a2f7b70f7bff29bfc697c
node 节点安装完 k8s 之后，需要在主节点上执行命令 kubeadm token create --print-join-command 查询出加入 k8s 集群的命令，在 node 上面执行该命令即可加入到集群中，如：
[root@k8s-master alex]# kubeadm token create --print-join-command
kubeadm join 192.168.31.44:6443 --token dbyk42.jt15226b6xd4rfvo --discovery-token-ca-cert-hash sha256:c7deb13d6544fe360e70fdc7b1c3140d2d5c1f98fc0e5d4c8deccadd91adf726
到这里，主节点和 node 节点都已经安装好 k8s 了，这个时候在主节点执行命令 kubectl get nodes 即可查看到集群的节点信息：
[root@k8s-master alex]# kubectl get nodes
NAME STATUS ROLES AGE VERSION
k8s-master NotReady master 13m v1.16.0
k8s-node01 NotReady <none> 97s v1.16.0
k8s-node02 NotReady <none> 7s v1.16.0
这里可以看到，1个主节点，两个 node 节点，正是我这里搭建的 k8s 集群，但是这里三个节点的状态都是 NotReady，所以，很显然，环境还没有完全搭建好。
安装 flannel（master节点）
k8s 安装完之后状态是 NotReady 这个可以当做一个问题去网上搜索解决方案，我这里写的也只是我看到的解决方案之一，也就是通过安装 flannel 来解决。
其实就是需要一个 yaml 文件，官方地址是
---
apiVersion: policy/v1beta1
kind: PodSecurityPolicy
metadata:
name: psp.flannel.unprivileged
annotations:
seccomp.security.alpha.kubernetes.io/allowedProfileNames: docker/default
seccomp.security.alpha.kubernetes.io/defaultProfileName: docker/default
apparmor.security.beta.kubernetes.io/allowedProfileNames: runtime/default
apparmor.security.beta.kubernetes.io/defaultProfileName: runtime/default
spec:
privileged: false
volumes:
- configMap
- secret
- emptyDir
- hostPath
allowedHostPaths:
- pathPrefix: "/etc/cni/net.d"
- pathPrefix: "/etc/kube-flannel"
- pathPrefix: "/run/flannel"
readOnlyRootFilesystem: false
# Users and groups
runAsUser:
rule: RunAsAny
supplementalGroups:
rule: RunAsAny
fsGroup:
rule: RunAsAny
# Privilege Escalation
allowPrivilegeEscalation: false
defaultAllowPrivilegeEscalation: false
# Capabilities
allowedCapabilities: [ 'NET_ADMIN' ]
defaultAddCapabilities: [ ]
requiredDropCapabilities: [ ]
# Host namespaces
hostPID: false
hostIPC: false
hostNetwork: true
hostPorts:
- min: 0
max: 65535
# SELinux
seLinux:
# SELinux is unused in CaaSP
rule: 'RunAsAny'
---
kind: ClusterRole
apiVersion: rbac.authorization.k8s.io/v1beta1
metadata:
name: flannel
rules:
- apiGroups: [ 'extensions' ]
resources: [ 'podsecuritypolicies' ]
verbs: [ 'use' ]
resourceNames: [ 'psp.flannel.unprivileged' ]
- apiGroups:
- ""
resources:
- pods
verbs:
- get
- apiGroups:
- ""
resources:
- nodes
verbs:
- list
- watch
- apiGroups:
- ""
resources:
- nodes/status
verbs:
- patch
---
kind: ClusterRoleBinding
apiVersion: rbac.authorization.k8s.io/v1beta1
metadata:
name: flannel
roleRef:
apiGroup: rbac.authorization.k8s.io
kind: ClusterRole
name: flannel
subjects:
- kind: ServiceAccount
name: flannel
namespace: kube-system
---
apiVersion: v1
kind: ServiceAccount
metadata:
name: flannel
namespace: kube-system
---
kind: ConfigMap
apiVersion: v1
metadata:
name: kube-flannel-cfg
namespace: kube-system
labels:
tier: node
app: flannel
data:
cni-conf.json: |
{
"name": "cbr0",
"cniVersion": "0.3.1",
"plugins": [
{
"type": "flannel",
"delegate": {
"hairpinMode": true,
"isDefaultGateway": true
}
},
{
"type": "portmap",
"capabilities": {
"portMappings": true
}
}
]
}
net-conf.json: |
{
"Network": "10.244.0.0/16",
"Backend": {
"Type": "vxlan"
}
}
---
apiVersion: apps/v1
kind: DaemonSet
metadata:
name: kube-flannel-ds-amd64
namespace: kube-system
labels:
tier: node
app: flannel
spec:
selector:
matchLabels:
app: flannel
template:
metadata:
labels:
tier: node
app: flannel
spec:
affinity:
nodeAffinity:
requiredDuringSchedulingIgnoredDuringExecution:
nodeSelectorTerms:
- matchExpressions:
- key: beta.kubernetes.io/os
operator: In
values:
- linux
- key: beta.kubernetes.io/arch
operator: In
values:
- amd64
hostNetwork: true
tolerations:
- operator: Exists
effect: NoSchedule
serviceAccountName: flannel
initContainers:
- name: install-cni
image: quay.io/coreos/flannel:v0.11.0-amd64
command:
- cp
args:
- -f
- /etc/kube-flannel/cni-conf.json
- /etc/cni/net.d/10-flannel.conflist
volumeMounts:
- name: cni
mountPath: /etc/cni/net.d
- name: flannel-cfg
mountPath: /etc/kube-flannel/
containers:
- name: kube-flannel
image: quay.io/coreos/flannel:v0.11.0-amd64
command:
- /opt/bin/flanneld
args:
- --ip-masq
- --kube-subnet-mgr
resources:
requests:
cpu: "100m"
memory: "50Mi"
limits:
cpu: "100m"
memory: "50Mi"
securityContext:
privileged: false
capabilities:
add: [ "NET_ADMIN" ]
env:
- name: POD_NAME
valueFrom:
fieldRef:
fieldPath: metadata.name
- name: POD_NAMESPACE
valueFrom:
fieldRef:
fieldPath: metadata.namespace
volumeMounts:
- name: run
mountPath: /run/flannel
- name: flannel-cfg
mountPath: /etc/kube-flannel/
volumes:
- name: run
hostPath:
path: /run/flannel
- name: cni
hostPath:
path: /etc/cni/net.d
- name: flannel-cfg
configMap:
name: kube-flannel-cfg
---
apiVersion: apps/v1
kind: DaemonSet
metadata:
name: kube-flannel-ds-arm64
namespace: kube-system
labels:
tier: node
app: flannel
spec:
selector:
matchLabels:
app: flannel
template:
metadata:
labels:
tier: node
app: flannel
spec:
affinity:
nodeAffinity:
requiredDuringSchedulingIgnoredDuringExecution:
nodeSelectorTerms:
- matchExpressions:
- key: beta.kubernetes.io/os
operator: In
values:
- linux
- key: beta.kubernetes.io/arch
operator: In
values:
- arm64
hostNetwork: true
tolerations:
- operator: Exists
effect: NoSchedule
serviceAccountName: flannel
initContainers:
- name: install-cni
image: quay.io/coreos/flannel:v0.11.0-arm64
command:
- cp
args:
- -f
- /etc/kube-flannel/cni-conf.json
- /etc/cni/net.d/10-flannel.conflist
volumeMounts:
- name: cni
mountPath: /etc/cni/net.d
- name: flannel-cfg
mountPath: /etc/kube-flannel/
containers:
- name: kube-flannel
image: quay.io/coreos/flannel:v0.11.0-arm64
command:
- /opt/bin/flanneld
args:
- --ip-masq
- --kube-subnet-mgr
resources:
requests:
cpu: "100m"
memory: "50Mi"
limits:
cpu: "100m"
memory: "50Mi"
securityContext:
privileged: false
capabilities:
add: [ "NET_ADMIN" ]
env:
- name: POD_NAME
valueFrom:
fieldRef:
fieldPath: metadata.name
- name: POD_NAMESPACE
valueFrom:
fieldRef:
fieldPath: metadata.namespace
volumeMounts:
- name: run
mountPath: /run/flannel
- name: flannel-cfg
mountPath: /etc/kube-flannel/
volumes:
- name: run
hostPath:
path: /run/flannel
- name: cni
hostPath:
path: /etc/cni/net.d
- name: flannel-cfg
configMap:
name: kube-flannel-cfg
---
apiVersion: apps/v1
kind: DaemonSet
metadata:
name: kube-flannel-ds-arm
namespace: kube-system
labels:
tier: node
app: flannel
spec:
selector:
matchLabels:
app: flannel
template:
metadata:
labels:
tier: node
app: flannel
spec:
affinity:
nodeAffinity:
requiredDuringSchedulingIgnoredDuringExecution:
nodeSelectorTerms:
- matchExpressions:
- key: beta.kubernetes.io/os
operator: In
values:
- linux
- key: beta.kubernetes.io/arch
operator: In
values:
- arm
hostNetwork: true
tolerations:
- operator: Exists
effect: NoSchedule
serviceAccountName: flannel
initContainers:
- name: install-cni
image: quay.io/coreos/flannel:v0.11.0-arm
command:
- cp
args:
- -f
- /etc/kube-flannel/cni-conf.json
- /etc/cni/net.d/10-flannel.conflist
volumeMounts:
- name: cni
mountPath: /etc/cni/net.d
- name: flannel-cfg
mountPath: /etc/kube-flannel/
containers:
- name: kube-flannel
image: quay.io/coreos/flannel:v0.11.0-arm
command:
- /opt/bin/flanneld
args:
- --ip-masq
- --kube-subnet-mgr
resources:
requests:
cpu: "100m"
memory: "50Mi"
limits:
cpu: "100m"
memory: "50Mi"
securityContext:
privileged: false
capabilities:
add: [ "NET_ADMIN" ]
env:
- name: POD_NAME
valueFrom:
fieldRef:
fieldPath: metadata.name
- name: POD_NAMESPACE
valueFrom:
fieldRef:
fieldPath: metadata.namespace
volumeMounts:
- name: run
mountPath: /run/flannel
- name: flannel-cfg
mountPath: /etc/kube-flannel/
volumes:
- name: run
hostPath:
path: /run/flannel
- name: cni
hostPath:
path: /etc/cni/net.d
- name: flannel-cfg
configMap:
name: kube-flannel-cfg
---
apiVersion: apps/v1
kind: DaemonSet
metadata:
name: kube-flannel-ds-ppc64le
namespace: kube-system
labels:
tier: node
app: flannel
spec:
selector:
matchLabels:
app: flannel
template:
metadata:
labels:
tier: node
app: flannel
spec:
affinity:
nodeAffinity:
requiredDuringSchedulingIgnoredDuringExecution:
nodeSelectorTerms:
- matchExpressions:
- key: beta.kubernetes.io/os
operator: In
values:
- linux
- key: beta.kubernetes.io/arch
operator: In
values:
- ppc64le
hostNetwork: true
tolerations:
- operator: Exists
effect: NoSchedule
serviceAccountName: flannel
initContainers:
- name: install-cni
image: quay.io/coreos/flannel:v0.11.0-ppc64le
command:
- cp
args:
- -f
- /etc/kube-flannel/cni-conf.json
- /etc/cni/net.d/10-flannel.conflist
volumeMounts:
- name: cni
mountPath: /etc/cni/net.d
- name: flannel-cfg
mountPath: /etc/kube-flannel/
containers:
- name: kube-flannel
image: quay.io/coreos/flannel:v0.11.0-ppc64le
command:
- /opt/bin/flanneld
args:
- --ip-masq
- --kube-subnet-mgr
resources:
requests:
cpu: "100m"
memory: "50Mi"
limits:
cpu: "100m"
memory: "50Mi"
securityContext:
privileged: false
capabilities:
add: [ "NET_ADMIN" ]
env:
- name: POD_NAME
valueFrom:
fieldRef:
fieldPath: metadata.name
- name: POD_NAMESPACE
valueFrom:
fieldRef:
fieldPath: metadata.namespace
volumeMounts:
- name: run
mountPath: /run/flannel
- name: flannel-cfg
mountPath: /etc/kube-flannel/
volumes:
- name: run
hostPath:
path: /run/flannel
- name: cni
hostPath:
path: /etc/cni/net.d
- name: flannel-cfg
configMap:
name: kube-flannel-cfg
---
apiVersion: apps/v1
kind: DaemonSet
metadata:
name: kube-flannel-ds-s390x
namespace: kube-system
labels:
tier: node
app: flannel
spec:
selector:
matchLabels:
app: flannel
template:
metadata:
labels:
tier: node
app: flannel
spec:
affinity:
nodeAffinity:
requiredDuringSchedulingIgnoredDuringExecution:
nodeSelectorTerms:
- matchExpressions:
- key: beta.kubernetes.io/os
operator: In
values:
- linux
- key: beta.kubernetes.io/arch
operator: In
values:
- s390x
hostNetwork: true
tolerations:
- operator: Exists
effect: NoSchedule
serviceAccountName: flannel
initContainers:
- name: install-cni
image: quay.io/coreos/flannel:v0.11.0-s390x
command:
- cp
args:
- -f
- /etc/kube-flannel/cni-conf.json
- /etc/cni/net.d/10-flannel.conflist
volumeMounts:
- name: cni
mountPath: /etc/cni/net.d
- name: flannel-cfg
mountPath: /etc/kube-flannel/
containers:
- name: kube-flannel
image: quay.io/coreos/flannel:v0.11.0-s390x
command:
- /opt/bin/flanneld
args:
- --ip-masq
- --kube-subnet-mgr
resources:
requests:
cpu: "100m"
memory: "50Mi"
limits:
cpu: "100m"
memory: "50Mi"
securityContext:
privileged: false
capabilities:
add: [ "NET_ADMIN" ]
env:
- name: POD_NAME
valueFrom:
fieldRef:
fieldPath: metadata.name
- name: POD_NAMESPACE
valueFrom:
fieldRef:
fieldPath: metadata.namespace
volumeMounts:
- name: run
mountPath: /run/flannel
- name: flannel-cfg
mountPath: /etc/kube-flannel/
volumes:
- name: run
hostPath:
path: /run/flannel
- name: cni
hostPath:
path: /etc/cni/net.d
- name: flannel-cfg
configMap:
name: kube-flannel-cfg
将这个文件放到主节点任意目录，然后执行下面命令进行安装即可：
kubectl apply -f kube-flannel.yml
执行之后需要等待一段时间，然后再次查询 k8s 集群状态就可以看到状态都编程 Ready 了，至此，k8s 环境也就搭建完成了。
[root@k8s-master alex]# kubectl get nodes
NAME STATUS ROLES AGE VERSION
k8s-master Ready master 32m v1.16.0
k8s-node01 Ready <none> 20m v1.16.0
k8s-node02 Ready <none> 18m v1.16.0
这个时候可以启动一个简单的服务来验证一下 k8s 环境，下面是我提供的一个简单的 nginx 服务部署的编排，执行 kubectl apply -f nginx.yml 即可启动服务：
---
apiVersion: apps/v1 # 资源api接口版本
kind: Deployment # 资源类型
metadata: # 元数据
name: nginx-deployment # 资源名
spec: # 详情
replicas: 2 # 副本数
selector: # 选择标签
matchLabels: # 标签匹配
app: nginx-server # 定义要匹配的标签，下面pod中必须有这个标签
template: # pod模板
metadata: # pod详情
labels: # 定义标签
app: nginx-server # pod标签
spec: # pod详情
containers: # 容器
- name: nginx # 容器名称
image: nginx:1.7.9 # 容器镜像
ports:
- name: http
containerPort: 80 # 容器暴露端口
---
apiVersion: v1
kind: Service
metadata:
name: simple-service
spec:
ports:
- name: nginx-port
port: 8080 # 暴露给服务的端口
protocol: TCP
targetPort: 80 # 容器本身的端口
nodePort: 31080 # 暴露给node的端口，也就是k8s节点
type: NodePort
selector:
app: nginx-server
遇到的问题
安装完 flannel 之后 node 节点的状态依然是 NotReady
定位和解决方案如下:
- 查看 node 节点日志
cat /var/log/messages，可以看到类似如下日志：
Mar 21 14:43:01 centos-4 kubelet: W0321 14:43:01.075369 4742 cni.go:237] Unable to update cni config: no networks found in /etc/cni/net.d
Mar 21 14:43:03 centos-4 kubelet: E0321 14:43:03.523469 4742 kubelet.go:2187] Container runtime network not ready: NetworkReady=false reason:NetworkPluginNotReady message:docker: network plugin is not ready: cni config uninitialized
将该日志拿去搜索，可以得知问题的原因在于 node 节点下载 flannel 镜像失败，网上也给了定位步骤，比如主节点执行命令 'kubectl get pods -o wide -n kube-system' 查看 pod 状态
[root@k8s-master alex]# kubectl get pods -o wide -n kube-system
NAME READY STATUS RESTARTS AGE IP NODE NOMINATED NODE READINESS GATES
coredns-58cc8c89f4-6svdn 1/1 Running 0 28m 10.244.2.3 k8s-node02 <none> <none>
coredns-58cc8c89f4-gm78v 1/1 Running 0 28m 10.244.2.2 k8s-node02 <none> <none>
etcd-k8s-master 1/1 Running 0 27m 192.168.31.44 k8s-master <none> <none>
kube-apiserver-k8s-master 1/1 Running 0 27m 192.168.31.44 k8s-master <none> <none>
kube-controller-manager-k8s-master 1/1 Running 0 27m 192.168.31.44 k8s-master <none> <none>
kube-flannel-ds-amd64-7tnhr 1/1 Running 0 3m52s 192.168.31.148 k8s-node02 <none> <none>
kube-flannel-ds-amd64-hlqpt 0/1 Init:ImagePullBackOff 0 3m52s 192.168.31.201 k8s-node01 <none> <none>
kube-flannel-ds-amd64-j5m5n 1/1 Running 0 3m52s 192.168.31.44 k8s-master <none> <none>
kube-proxy-95jjd 1/1 Running 0 15m 192.168.31.148 k8s-node02 <none> <none>
kube-proxy-ckq5c 1/1 Running 0 28m 192.168.31.44 k8s-master <none> <none>
kube-proxy-dv2fz 1/1 Running 0 16m 192.168.31.201 k8s-node01 <none> <none>
kube-scheduler-k8s-master 1/1 Running 0 27m 192.168.31.44 k8s-master <none> <none>
这里可以看到果然有个 pod 的状态是 Init:ImagePullBackOff 也就是下载镜像失败，这也即是为什么有的人把 kube-flannel.yml 文件中镜像地址改了的原因，就是为了避免镜像下载失败。
问题知道了，就可以解决，直接去失败的 node 节点上面手动拉取镜像即可（也可以再等等，因为其他节点可以下载，说明网络是通的）。
参考文章
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本文链接：https://tendcode.com/subject/article/k8s_install-k8s/
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zxcvbnm
1 楼 - 4 年，3月前
好棒哇