《Kubernets部署篇:Centos7.6部署单机kubernetes1.17.4》

文章目录

  • 一、架构图
  • 二、部署环境
  • 三、环境初始化
    • 3.1、内核升级
    • 3.2、系统初始化配置
  • 四、Docker部署
  • 五、kubernetes部署
    • 5.1、设置kubernetes源
    • 5.2、安装kubelet、kubeadm和kubectl
    • 5.3、k8s相关镜像下载
    • 5.4、kubeadm初始化master节点
    • 5.5、配置kubectl
    • 5.6、配置flannel网络
    • 5.7、将master标记为可调度
    • 5.8、kubelet服务启动
  • 总结:整理不易,如果对你有帮助,可否点赞关注一下?


一、架构图

《Kubernets部署篇:Centos7.6部署单机kubernetes1.17.4》_第1张图片


二、部署环境

操作系统:centos7.6.1810
内核版本:5.4.13
说明:建议操作系统选择centos7.5或centos7.6,centos7.2,centos7.3,centos7.4版本存在一定几率的kubelet无法启动问题。


三、环境初始化

3.1、内核升级

说明:centos7.6系统内核默认是3.10.0,这里建议内核版本为5.11.16。

内核选择:
kernel-lt(lt=long-term)长期有效
kernel-ml(ml=mainline) 主流版本

升级步骤如下:

# 1、下载内核
CSDN下载地址:https://download.csdn.net/download/m0_37814112/17047556
wget https://elrepo.org/linux/kernel/el7/x86_64/RPMS/kernel-ml-5.11.16-1.el7.elrepo.x86_64.rpm

# 2、安装内核
yum localinstall kernel-ml-5.11.16-1.el7.elrepo.x86_64.rpm -y

# 3、查看当前内核版本
grub2-editenv list

# 4、查看所有内核启动grub2
awk -F \' '$1=="menuentry " {print i++ " : " $2}' /etc/grub2.cfg

# 5、修改为最新的内核启动
grub2-set-default 'CentOS Linux (5.11.16-1.el7.elrepo.x86_64) 7 (Core)'

# 6、再次查看内核版本
grub2-editenv list

# 7、reboot重启服务器

3.2、系统初始化配置

# 1、修改主机名
hostnamectl set-hostname k8s-master

# 2、内核参数修改
cat > /etc/sysctl.d/k8s.conf <<EOF
vm.swappiness = 0
net.ipv4.ip_forward = 1
net.bridge.bridge-nf-call-iptables = 1
net.bridge.bridge-nf-call-ip6tables = 1
net.bridge.bridge-nf-call-arptables = 1
EOF
sysctl --system 

# 3、永久新增br_netfilter模块
# k8s网络使用flannel,该网络需要设置内核参数bridge-nf-call-iptables=1,修改这个参数需要系统有br_netfilter模块。
cat > /etc/rc.sysinit << EOF
#!/bin/bash
for file in /etc/sysconfig/modules/*.modules ; do
[ -x $file ] && $file
done
EOF

cat > /etc/sysconfig/modules/br_netfilter.modules << EOF
modprobe br_netfilter
EOF

chmod 755 /etc/sysconfig/modules/br_netfilter.modules

# 4、关闭防火墙
systemctl stop firewalld && systemctl disable firewalld

# 5、永久关闭selinux
sed -i 's#SELINUX=enforcing#SELINUX=disabled#g' /etc/sysconfig/selinux
sed -i 's#SELINUX=enforcing#SELINUX=disabled#g' /etc/selinux/config

# 6、关闭swap
swapoff -a && sed -i 's/.*swap.*/#&/' /etc/fstab

# 7、安装ipvsadm
yum install ipvsadm -y
cat > /etc/sysconfig/modules/ipvs.modules <<EOF
#!/bin/bash
ipvs_modules="ip_vs ip_vs_lc ip_vs_wlc ip_vs_rr ip_vs_wrr ip_vs_lblc ip_vs_lblcr ip_vs_dh ip_vs_sh ip_vs_fo ip_vs_nq ip_vs_sed ip_vs_ftp nf_conntrack"
for kernel_module in \${ipvs_modules}; do
    /sbin/modinfo -F filename \${kernel_module} > /dev/null 2>&1
    if [ $? -eq 0 ]; then
        /sbin/modprobe \${kernel_module}
    fi
done
EOF
chmod 755 /etc/sysconfig/modules/ipvs.modules && bash /etc/sysconfig/modules/ipvs.modules && lsmod | grep --color ip_vs >/dev/null
lsmod | grep ip_vs

# 8、修改文件描述符和进程数(根据实际情况修改)
vim /etc/security/limits.conf
root soft nofile 65535
root hard nofile 65535
root soft nproc 65535
root hard nproc 65535
root soft memlock unlimited
root hard memlock unlimited
* soft nofile 65535
* hard nofile 65535
* soft nproc 65535
* hard nproc 65535
* soft memlock unlimited
* hard memlock unlimited

# 9、reboot重启服务器(必须)

如下图所示:
《Kubernets部署篇:Centos7.6部署单机kubernetes1.17.4》_第2张图片


四、Docker部署

# 1、安装依赖包
yum install yum-utils device-mapper-persistent-data lvm2 -y 

# 2、设置Docker源
yum-config-manager --add-repo https://download.docker.com/linux/centos/docker-ce.repo
或
yum-config-manager --add-repo http://mirrors.aliyun.com/docker-ce/linux/centos/docker-ce.repo

# 3、docker安装版本查看
yum list docker-ce --showduplicates | sort -r

# 4、指定安装的docker版本为18.09.9
yum install docker-ce-18.09.9 docker-ce-cli-18.09.9 containerd.io -y

# 5、启动Docker
systemctl start docker && systemctl enable docker

# 6、修改Cgroup Driver
# 修改docker数据目录,默认是/var/lib/docker,建议数据目录为主机上最大磁盘空间目录或子目录
vim /etc/docker/daemon.json
{
  "registry-mirrors": ["https://v16stybc.mirror.aliyuncs.com"],
  "exec-opts": ["native.cgroupdriver=systemd"],
  "graph": "/data/docker"  
}
systemctl daemon-reload && systemctl restart docker

如下图所示:
《Kubernets部署篇:Centos7.6部署单机kubernetes1.17.4》_第3张图片


五、kubernetes部署

5.1、设置kubernetes源

cat <<EOF > /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

yum clean all && yum -y makecache

5.2、安装kubelet、kubeadm和kubectl

# 1、版本查看
yum list kubelet --showduplicates | sort -r

# 2、安装1.17.4版本
yum install kubelet-1.17.4 kubeadm-1.17.4 kubectl-1.17.4 -y 

5.3、k8s相关镜像下载

vim get_image.sh 
#!/bin/bash
url=registry.cn-hangzhou.aliyuncs.com/google_containers
version=v1.17.4
images=(`kubeadm config images list --kubernetes-version=$version|awk -F '/' '{print $2}'`)
for imagename in ${images[@]} ; do
  docker pull $url/$imagename
  docker tag $url/$imagename k8s.gcr.io/$imagename
  docker rmi -f $url/$imagename
done
# flannel网络镜像下载
docker pull quay.io/coreos/flannel:v0.14.0-rc1

如下图所示:
《Kubernets部署篇:Centos7.6部署单机kubernetes1.17.4》_第4张图片


5.4、kubeadm初始化master节点

# 1、创建初始化配置文件
kubeadm config print init-defaults > kubeadm-config.yaml

# 根据实际部署环境修改信息:
vim kubeadm-config.yaml

apiVersion: kubeadm.k8s.io/v1beta1
kind: ClusterConfiguration
networking:
  serviceSubnet: "10.96.0.0/16"  #service网段地址
  podSubnet: "10.48.0.0/16"      #pod网段地址
kubernetesVersion: "v1.17.4"     #kubernetes版本
controlPlaneEndpoint: "192.168.1.216:6443"  #apiserver地址
apiServer:
  extraArgs:
    authorization-mode: "Node,RBAC"
    service-node-port-range: 30000-36000  #service端口范围
imageRepository: ""
---
apiVersion: kubeproxy.config.k8s.io/v1alpha1
kind: KubeProxyConfiguration
mode: "ipvs"

# 3、初始化master
kubeadm init --config=kubeadm-config.yaml --upload-certs --ignore-preflight-errors=all 

如下图所示:
《Kubernets部署篇:Centos7.6部署单机kubernetes1.17.4》_第5张图片


5.5、配置kubectl

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

5.6、配置flannel网络

# 1、下载官方模板文件
wget https://raw.githubusercontent.com/coreos/flannel/master/Documentation/kube-flannel.yml

# 2、部署flannel网络
kubectl create -f kube-flannel.yml

# 3、根据实际情况修改kube-flannel.yml
vim kube-flannel.yml
---
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', 'NET_RAW']
  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/v1
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/v1
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": "10.48.0.0/16",  #这里的网段地址需要与kubeadm-config.yaml配置文件定义的必须保持一致
      "Backend": {
        "Type": "vxlan"
      }
    }
---
apiVersion: apps/v1
kind: DaemonSet
metadata:
  name: kube-flannel-ds
  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: kubernetes.io/os
                operator: In
                values:
                - linux
      hostNetwork: true
      priorityClassName: system-node-critical
      tolerations:
      - operator: Exists
        effect: NoSchedule
      serviceAccountName: flannel
      initContainers:
      - name: install-cni
        image: quay.io/coreos/flannel:v0.14.0-rc1
        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:v0.14.0-rc1
        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", "NET_RAW"]
        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

说明:官方模板文件只需要修改"Network": "10.48.0.0/16"这一字段,且这里的网段地址需要与kubeadm-config.yaml配置文件定义的必须保持一致。


5.7、将master标记为可调度

# 当创建单机版的k8s时,这个时候master节点是默认不允许调度pod 的,需要执行
kubectl taint nodes --all node-role.kubernetes.io/master-

5.8、kubelet服务启动

systemctl restart kubelet && systemctl enable kubelet
[root@node6 install-kubernetes]# kubectl get nodes
NAME         STATUS   ROLES    AGE   VERSION
k8s-master   Ready    master   17m   v1.17.4

说明:kubernetes单机版,就部署完成了。

下一章:《Kubernets部署篇:Centos7.6部署kubernetes1.17.4一主多从》


总结:整理不易,如果对你有帮助,可否点赞关注一下?

更多详细内容请参考:企业级K8s集群运维实战

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