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CentOS7安装Kubernetes单主节点集群

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在CentOS7环境下，一步步傻瓜式安装Kubernetes单主节点集群环境，Kubernetes为最新版本v1.8.6。

安装docker

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

yum-config-manager \
    --add-repo \
    https://download.docker.com/linux/centos/docker-ce.repo

sed -i 's+download.docker.com+mirrors.tuna.tsinghua.edu.cn/docker-ce+' /etc/yum.repos.d/docker-ce.repo

yum install -y docker-ce docker-ce-cli containerd.io

mkdir /etc/docker
cat <<EOF | sudo tee /etc/docker/daemon.json
{
  "exec-opts": ["native.cgroupdriver=systemd"],
  "log-driver": "json-file",
  "log-opts": {
    "max-size": "100m"
  },
  "storage-driver": "overlay2",
  "storage-opts": [
    "overlay2.override_kernel_check=true"
  ],
  "registry-mirrors": [
        "https://hub-mirror.c.163.com",
        "https://docker.mirrors.ustc.edu.cn",
        "https://mirror.ccs.tencentyun.com",
        "https://reg-mirror.qiniu.com",
        "https://registry.docker-cn.com"
    ]
}
EOF

mkdir -p /etc/systemd/system/docker.service.d

systemctl enable docker
systemctl daemon-reload
systemctl start docker

安装kubernetes

新建 /etc/yum.repos.d/kubernetes.repo，内容为：

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# Add kubernetes repo
cat <<EOF | sudo tee /etc/yum.repos.d/kubernetes.repo
[kubernetes]
name=kubernetes
baseurl=https://mirrors.tuna.tsinghua.edu.cn/kubernetes/yum/repos/kubernetes-el7-\$basearch
enabled=1
gpgcheck=0
EOF

# Disable swap
swapoff -a

# Letting iptables see bridged traffic
cat <<EOF | sudo tee /etc/sysctl.d/k8s.conf
net.bridge.bridge-nf-call-ip6tables = 1
net.bridge.bridge-nf-call-iptables = 1
EOF

sysctl --system

# Set SELinux in permissive mode (effectively disabling it)
setenforce 0
sed -i 's/^SELINUX=enforcing$/SELINUX=permissive/' /etc/selinux/config

yum install -y kubelet kubeadm kubectl --disableexcludes=kubernetes

systemctl enable --now kubelet

主节点初始化

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export K8S_VERSION=v1.18.6
export MASTER_IP=10.0.1.7
export APISERVER_NAME=k8s-m01
export POD_SUBNET=10.100.0.1/16
echo "${MASTER_IP}    ${APISERVER_NAME}" >> /etc/hosts


cat <<EOF > ./kubeadm-config.yaml
apiVersion: kubeadm.k8s.io/v1beta2
kind: InitConfiguration
nodeRegistration:
  name: ${APISERVER_NAME}
---
apiVersion: kubeadm.k8s.io/v1beta2
kind: ClusterConfiguration
kubernetesVersion: ${K8S_VERSION}
imageRepository: registry.aliyuncs.com/k8sxio
controlPlaneEndpoint: "${APISERVER_NAME}:6443"
networking:
  serviceSubnet: "10.96.0.0/16"
  podSubnet: "${POD_SUBNET}"
  dnsDomain: "cluster.local"
EOF

kubeadm init --config=kubeadm-config.yaml --upload-certs

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

如果kube镜像下载不下来可用备选方案

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# plan b
images=(
    kube-apiserver:v1.18.6
    kube-controller-manager:v1.18.6
    kube-scheduler:v1.18.6
    kube-proxy:v1.18.6
)
for imageName in ${images[@]} ; do
    curl -s https://zhangguanzhang.github.io/bash/pull.sh | bash -s -- k8s.gcr.io/$imageName
done

安装网络

  • 安装calico
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curl https://docs.projectcalico.org/manifests/calico.yaml -o calico.yaml
kubectl apply -f calico.yaml
  • 或者安装kube router
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KUBECONFIG=/etc/kubernetes/admin.conf kubectl apply -f https://raw.githubusercontent.com/cloudnativelabs/kube-router/master/daemonset/kubeadm-kuberouter.yaml

验证安装结果

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watch kubectl get pod -n kube-system -o wide
kubectl get nodes -o wide

加入主节点

  1. 在主节点上执行命令

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    kubeadm token create --print-join-command

    例如，输出以下内容

    kubeadm join k8s-m01:6443 –token egc33s.h7xd65n5asw9enya –discovery-token-ca-cert-hash sha256:8b662c0ce7e5e0c49c37ea9a40b8ea4a6e99b6df6ec0e881a368ed8002420ace

  2. 在工作节点上配置hosts

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    echo "192.168.0.146  k8s-w01" >> /etc/hosts

  3. 复制主节点上的命令输出结果，在工作节点上执行加入主节点命令

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    kubeadm join k8s-m01:6443 --token egc33s.h7xd65n5asw9enya --discovery-token-ca-cert-hash sha256:8b662c0ce7e5e0c49c37ea9a40b8ea4a6e99b6df6ec0e881a368ed8002420ace --node-name=k8s-w01

在客户端电脑安装 kubectl

  1. 安装kubectl
  2. 在本机上创建~/.kube/config文件，并直接复制主节点的/etc/kubernetes/admin.conf内容
  3. 配置hosts文件
  4. 验证安装结果，执行命令
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    kubectl get nodes
    输出全部节点都是Reday状态即可

    NAME STATUS ROLES AGE VERSION
    k8s-m01 Ready master 4h15m v1.18.6
    k8s-w01 Ready 4h5m v1.18.6
    k8s-w02 Ready 59m v1.18.6