CentOS7 搭建k8s环境教程

一. 为什么是k8s v1.16.0？

最新版的v1.16.2试过了，一直无法安装完成，安装到kubeadm init那一步执行后，报了很多错，如：node xxx not found等。centos7都重装了几次，还是无法解决。用了一天都没安装完，差点放弃。

后来在网上搜到的安装教程基本都是v1.16.0的，我不太相信是v1.16.2的坑所以先前没打算降级到v1.16.0。没办法了就试着安装v1.16.0版本，竟然成功了。记录在此，避免后来者踩坑。

本篇文章，安装大步骤如下：

• 安装docker-ce 18.09.9（所有机器）
• 设置k8s环境前置条件（所有机器）
• 安装k8s v1.16.0 master管理节点
• 安装k8s v1.16.0 node工作节点
• 安装flannel（master）

这里有重要的一步，请记住自己master和node之间通信的ip，如我的master的ip为192.168.99.104，node的ip为：192.168.99.105. 请确保使用这两个ip在master和node上能互相ping通，这个master的ip 192.168.99.104接下来配置k8s的时候需要用到。

我的环境：

• 操作系统：win10
• 虚拟机：virtual box
• linux发行版：CentOS7
• linux内核(使用uname -r查看)：3.10.0-957.el7.x86_64
• master和node节点通信的ip(master)：192.168.99.104

二. 安装docker-ce 18.09.9（所有机器）

所有安装k8s的机器都需要安装docker，命令如下：

# 安装docker所需的工具

yum install -y yum-utils device-mapper-persistent-data lvm2

# 配置阿里云的docker源

yum-config-manager --add-repo http://mirrors.aliyun.com/docker-ce/linux/centos/docker-ce.repo

# 指定安装这个版本的docker-ce

yum install -y docker-ce-18.09.9-3.el7

# 启动docker

systemctl enable docker && systemctl start docker

三. 设置k8s环境准备条件（所有机器）

安装k8s的机器需要2个CPU和2g内存以上，这个简单，在虚拟机里面配置一下就可以了。然后执行以下脚本做一些准备操作。所有安装k8s的机器都需要这一步操作。

# 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 <  /etc/sysctl.d/k8s.conf

net.bridge.bridge-nf-call-ip6tables = 1

net.bridge.bridge-nf-call-iptables = 1

EOF

sysctl --system

四. 安装k8s v1.16.0 master管理节点

如果还没安装docker，请参照本文步骤二安装docker-ce 18.09.9（所有机器）安装。

如果没设置k8s环境准备条件，请参照本文步骤三设置k8s环境准备条件（所有机器）执行。

以上两个步骤检查完毕之后，继续以下步骤。

1. 安装kubeadm、kubelet、kubectl

由于官方k8s源在google，国内无法访问，这里使用阿里云yum源

# 执行配置k8s阿里云源

cat < /etc/yum.repos.d/kubernetes.repo

[kubernetes]

name=Kubernetes

baseurl=https://mirrors.aliyun.com/kubernetes/yum/repos/kubernetes-el7-x86_64/

enabled=1

gpgcheck=1

repo_gpgcheck=1

gpgkey=https://mirrors.aliyun.com/kubernetes/yum/doc/yum-key.gpg https://mirrors.aliyun.com/kubernetes/yum/doc/rpm-package-key.gpg

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

2. 初始化k8s

以下这个命令开始安装k8s需要用到的docker镜像，因为无法访问到国外网站，所以这条命令使用的是国内的阿里云的源(registry.aliyuncs.com/google_containers)。

另一个非常重要的是：这里的--apiserver-advertise-address使用的是master和node间能互相ping通的ip，我这里是192.168.99.104，刚开始在这里被坑了一个晚上，你请自己修改下ip执行。

这条命令执行时会卡在[preflight] You can also perform this action in beforehand using ''kubeadm config images pull，大概需要2分钟，请耐心等待。

# 下载管理节点中用到的6个docker镜像，你可以使用docker images查看到

# 这里需要大概两分钟等待，会卡在[preflight] You can also perform this action in beforehand using ''kubeadm config images pull

kubeadm init --image-repository registry.aliyuncs.com/google_containers --kubernetes-version v1.16.0 --apiserver-advertise-address 192.168.99.104 --pod-network-cidr=10.244.0.0/16 --token-ttl 0

上面安装完后，会提示你输入如下命令，复制粘贴过来，执行即可。

# 上面安装完成后，k8s会提示你输入如下命令，执行

mkdir -p $HOME/.kube

sudo cp -i /etc/kubernetes/admin.conf $HOME/.kube/config

sudo chown $(id -u):$(id -g) $HOME/.kube/config

3. 记住node加入集群的命令

上面kubeadm init执行成功后会返回给你node节点加入集群的命令，等会要在node节点上执行，需要保存下来，如果忘记了，可以使用如下命令获取。

kubeadm token create --print-join-command 

以上，安装master节点完毕。可以使用kubectl get nodes查看一下，此时master处于NotReady状态，暂时不用管。

五. 安装k8s v1.16.0 node工作节点

如果还没安装docker，请参照本文步骤二安装docker-ce 18.09.9（所有机器）安装。

如果没设置k8s环境准备条件，请参照本文步骤三设置k8s环境准备条件（所有机器）执行。

以上两个步骤检查完毕之后，继续以下步骤。

1. 安装kubeadm、kubelet

# 执行配置k8s阿里云源

cat < /etc/yum.repos.d/kubernetes.repo

[kubernetes]

name=Kubernetes

baseurl=https://mirrors.aliyun.com/kubernetes/yum/repos/kubernetes-el7-x86_64/

enabled=1

gpgcheck=1

repo_gpgcheck=1

gpgkey=https://mirrors.aliyun.com/kubernetes/yum/doc/yum-key.gpg https://mirrors.aliyun.com/kubernetes/yum/doc/rpm-package-key.gpg

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

2. 加入集群

这里加入集群的命令每个人都不一样，可以登录master节点，使用kubeadm token create --print-join-command 来获取。获取后执行如下。

# 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 192.168.99.104:6443 --token ncfrid.7ap0xiseuf97gikl \

    --discovery-token-ca-cert-hash sha256:47783e9851a1a517647f1986225f104e81dbfd8fb256ae55ef6d68ce9334c6a2

加入成功后，可以在master节点上使用kubectl get nodes命令查看到加入的节点。

六. 安装flannel（master机器）

以上步骤安装完后，机器搭建起来了，但状态还是NotReady状态，如下图，master机器需要安装flanneld。

1. 下载官方fannel配置文件

使用wget命令，地址为：(https://raw.githubusercontent.com/coreos/flannel/master/Documentation/kube-flannel.yml)，这个地址国内访问不了，所以我把内容复制下来，为了避免前面文章过长，我把它粘贴到文章末尾第八个步骤附录了。

搜索顶级架构师公众号回复“offer”，送你一份算法面试题和答案惊喜礼包。

这个yml配置文件中配置了一个国内无法访问的地址(quay.io)，我已经将其改为国内可以访问的地址(quay-mirror.qiniu.com)。我们新建一个kube-flannel.yml文件，复制粘贴该内容即可。

2. 安装fannel

kubectl apply -f kube-flannel.yml

七. 大功告成

至此，k8s集群搭建完成，如下图节点已为Ready状态，大功告成，完结撒花。

八. 附录

这是kube-flannel.yml文件的内容，已经将无法访问的地址(quay.io)全部改为国内可以访问的地址(quay-mirror.qiniu.com)。我们新建一个kube-flannel.yml文件，复制粘贴该内容即可。

---

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-mirror.qiniu.com/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-mirror.qiniu.com/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-mirror.qiniu.com/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-mirror.qiniu.com/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-mirror.qiniu.com/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-mirror.qiniu.com/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-mirror.qiniu.com/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-mirror.qiniu.com/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-mirror.qiniu.com/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-mirror.qiniu.com/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​