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在Centos7上安装Kubernetes

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使用KubeAdm官方工具在Centos7上安装kubernetes.

安装环境

OS: Centos7
K8s Version: v1.10.4

环境配置

更新系统

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$ yum update -y

时区

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$ timedatectl set-timezone Asia/Shanghai

配置Hosts

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$ cat /etc/hosts
10.0.100.2 k8smaster
10.0.100.3 k8snode01
10.0.100.4 k8snode02

关闭防火墙

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$ systemctl disable firewalld
$ systemctl stop firewalld
$ systemctl status firewalld

关闭内存交换分区

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$ swapoff -a

# 永久
$ cat /etc/fstab
#/dev/mapper/centos-swap swap                    swap    defaults        0 0

禁用SELINUX

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$ setenforce 0
$ cat /etc/selinux/config
SELINUX=disabled

配置网络

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$ cat <<EOF >  /etc/sysctl.d/k8s.conf
net.bridge.bridge-nf-call-ip6tables = 1
net.bridge.bridge-nf-call-iptables = 1
net.ipv4.ip_forward = 1
EOF
$ modprobe br_netfilter
$ sysctl --system

安装Docker

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$ yum install -y docker

配置cgroupdriver为cgroupfs

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$ sed -i "s/native.cgroupdriver=systemd/native.cgroupdriver=cgroupfs/g" /usr/lib/systemd/system/docker.service
$ cat /usr/lib/systemd/system/docker.service

$ systemctl enable docker && systemctl start docker
$ docker info | grep Cgroup

安装kubeadm kubelet kubectl

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$ cat <<EOF > /etc/yum.repos.d/kubernetes.repo
[kubernetes]
name=Kubernetes
baseurl=https://packages.cloud.google.com/yum/repos/kubernetes-el7-x86_64
enabled=1
gpgcheck=1
repo_gpgcheck=1
gpgkey=https://packages.cloud.google.com/yum/doc/yum-key.gpg https://packages.cloud.google.com/yum/doc/rpm-package-key.gpg
EOF

$ yum install -y kubelet kubeadm kubectl
$ systemctl enable kubelet && systemctl start kubelet

Note: kubelet在这里启动时不会成功的，它会定时检查重启。后面程序安装后，kubectl会启动成功。

配置kubeadm的cgroup driver为Cgroupfs

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$ sed -i "s/cgroup-driver=systemd/cgroup-driver=cgroupfs --runtime-cgroups=\/systemd\/system.slice --kubelet-cgroups=\/systemd\/system.slice/g" /etc/systemd/system/kubelet.service.d/10-kubeadm.conf
$ cat /etc/systemd/system/kubelet.service.d/10-kubeadm.conf

$ systemctl daemon-reload
$ systemctl restart kubelet

查看kubelet日志

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$ journalctl -u kubelet -f

下载镜像

提前下载Dokcer镜像，如果你机器有科学上网请忽略这一步。我提前将Docker镜像下载到国内私有hub中。下面是下载脚本

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#!/bin/bash

ARCH=amd64
mversion=v1.10.4
nversion=1.14.8
username=luoji
password=password
repo=k8s.gcr.io
store_repo=r.xiaozhou.net
store_repo_path=r.xiaozhou.net/kubernetes

images=(${repo}/kube-apiserver-${ARCH}:${mversion} \
	${repo}/kube-controller-manager-${ARCH}:${mversion} \
	${repo}/kube-scheduler-${ARCH}:${mversion} \
	${repo}/kube-proxy-${ARCH}:${mversion} \
	${repo}/etcd-${ARCH}:3.1.12 \
	${repo}/pause-${ARCH}:3.1 \
	${repo}/k8s-dns-sidecar-${ARCH}:${nversion} \
	${repo}/k8s-dns-kube-dns-${ARCH}:${nversion} \
	${repo}/k8s-dns-dnsmasq-nanny-${ARCH}:${nversion} \
	${repo}/kubernetes-dashboard-${ARCH}:v1.8.3 \
    quay.io/coreos/flannel:v0.10.0-amd64 \
	)

docker login -u $username -p $password $store_repo

for url in ${images[@]}
do
    sub=${url%/*}
    idx=${#sub}
    image=${url:$idx+1}
    echo -e "download -> $store_repo_path/$image -> $url"
	docker pull $store_repo_path/$image
	docker tag $store_repo_path/$image $url
	docker rmi $store_repo_path/$image
done

unset ARCH mversion nversion images username password repo store_repo store_repo_path

上传脚本可以在这里找到：https://github.com/gunsluo/k8s-example/tree/master/version

初始化主节点

$ kubeadm init –kubernetes-version v1.10.4 –service-cidr 10.96.0.0/16 –pod-network-cidr 10.244.0.0/16 –apiserver-advertise-address 10.0.100.2
$ kubeadm init –config kubeadm.yaml –service-cidr 10.96.0.0/16 –pod-network-cidr 10.244.0.0/16
$ cat kubeadm.yaml
apiVersion: kubeadm.k8s.io/v1alpha1
kind: MasterConfiguration
kubernetesVersion: v1.10.4
api:
advertiseAddress: ‘10.0.100.2’
etcd:
extraArgs:
‘listen-peer-urls’: ‘http://127.0.0.1:2380'

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$ mkdir -p $HOME/.kube
$ cp -i /etc/kubernetes/admin.conf $HOME/.kube/config
$ chown $(id -u):$(id -g) $HOME/.kube/config

主节点初始化网络

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$ curl -O https://raw.githubusercontent.com/coreos/flannel/v0.10.0/Documentation/kube-flannel.yml

flanneld启动参数加上–iface=

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command:
- /opt/bin/flanneld
args:
- --ip-masq
- --kube-subnet-mgr
- --iface=eth1
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$ kubectl apply -f kube-flannel.yml

$ kubectl get nodes
$ kubectl get pods --all-namespaces

加入工作节点

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$ kubeadm join --token <token> <master-ip>:<master-port> --discovery-token-ca-cert-hash sha256:<hash>

安装Dashboard

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$ curl -O https://raw.githubusercontent.com/kubernetes/dashboard/master/src/deploy/recommended/kubernetes-dashboard.yaml
$ kubectl create -f kubernetes-dashboard.yaml

$ kubectl apply -f kubernetes-dashboard-admin.yaml

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apiVersion: rbac.authorization.k8s.io/v1beta1
kind: ClusterRoleBinding
metadata:
  name: kubernetes-dashboard
  labels:
    k8s-app: kubernetes-dashboard
roleRef:
  apiGroup: rbac.authorization.k8s.io
  kind: ClusterRole
  name: cluster-admin
subjects:
- kind: ServiceAccount
  name: kubernetes-dashboard
  namespace: kube-system

配置代理

将Master节点的/etc/kubernetes/admin.conf拷贝到本机的$HOME/.kube目录下，然后运行kubectl proxy。最后在浏览器中输入：http://localhost:8001/api/v1/namespaces/kube-system/services/https:kubernetes-dashboard:/proxy/ 现在可以登录dashboard

配置远程访问dashboard，上面方法需要在本机启动代理。我们可以直接使用IP进行访问，这需要修改kubernetes-dashboard-admin.yaml配置。

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kind: Service
apiVersion: v1
metadata:
  labels:
    k8s-app: kubernetes-dashboard
  name: kubernetes-dashboard
  namespace: kube-system
spec:
  type: NodePort
  ports:
    - port: 443
      targetPort: 8443
      nodePort: 31000
  selector:
    k8s-app: kubernetes-dashboard

指定NodePort类型和对外提供端口31000。 使用命令kubectl replace -f kubernetes-dashboard.yaml --force重启服务。浏览器中输入: https://ip:31000/ 即可访问。