kubeadm快速部署kubernetes（十九）

安装要求

部署Kubernetes集群机器需要满足以下几个条件：

• 一台或多台机器，操作系统 CentOS7.x-86_x64
• 硬件配置：2GB或更多RAM，2个CPU或更多CPU，硬盘30GB或更多
• 集群中所有机器之间网络互通
• 可以访问外网，需要拉取镜像
• 禁止swap分区

环境准备

1. 在所有节点上安装Docker和kubeadm

2. 部署Kubernetes Master

3. 部署容器网络插件

4. 部署 Kubernetes Node，将节点加入Kubernetes集群中

5. 部署Dashboard Web页面，可视化查看Kubernetes资源

#添加主机名与IP对应关系（记得设置主机名）：
cat << EOF >> /etc/hosts
192.168.0.122    k8s-master
192.168.0.123    k8s-node1
192.168.0.124    k8s-node2
EOF

#关闭防火墙
systemctl stop firewalld
systemctl disable firewalld
iptables -F && iptables -X && iptables -F -t nat && iptables -X -t nat && iptables -P FORWARD ACCEPT

#关闭selinux
setenforce  0 
sed -i "s/^SELINUX=enforcing/SELINUX=disabled/g" /etc/sysconfig/selinux 
sed -i "s/^SELINUX=enforcing/SELINUX=disabled/g" /etc/selinux/config 
sed -i "s/^SELINUX=permissive/SELINUX=disabled/g" /etc/sysconfig/selinux 
sed -i "s/^SELINUX=permissive/SELINUX=disabled/g" /etc/selinux/config 
getenforce

#关闭swap
swapoff -a
sed -i '/ swap / s/^\(.*\)$/#\1/g' /etc/fstab

#安装ipvs相关模块
yum install -y epel-release conntrack ipvsadm ipset jq sysstat curl iptables libseccomp

#加载内核模块
modprobe br_netfilter
modprobe ip_vs
modprobe ip_vs_rr
modprobe ip_vs_wrr
modprobe ip_vs_sh
modprobe nf_conntrack_ipv4
cat > /etc/sysconfig/modules/ipvs.modules <<EOF
#!/bin/bash
modprobe -- ip_vs
modprobe -- ip_vs_rr
modprobe -- ip_vs_wrr
modprobe -- ip_vs_sh
modprobe -- nf_conntrack_ipv4
modprobe -- br_netfilter
EOF
chmod 755 /etc/sysconfig/modules/ipvs.modules && bash /etc/sysconfig/modules/ipvs.modules
lsmod |grep -e ip_vs -e nf_conntrack_ipv4

#设置内核参数
cat << EOF | tee /etc/sysctl.d/k8s.conf
fs.file-max = 1000000
net.bridge.bridge-nf-call-ip6tables = 1
net.bridge.bridge-nf-call-iptables = 1
net.ipv4.ip_forward = 1
vm.swappiness = 0
net.ipv4.ip_forward = 1
net.ipv4.tcp_max_tw_buckets = 6000
net.ipv4.tcp_sack = 1
net.ipv4.tcp_window_scaling = 1
net.ipv4.tcp_rmem = 4096 87380 4194304
net.ipv4.tcp_wmem = 4096 16384 4194304
net.ipv4.tcp_max_syn_backlog = 16384
net.core.netdev_max_backlog = 32768
net.core.somaxconn = 32768
net.core.wmem_default = 8388608
net.core.rmem_default = 8388608
net.core.rmem_max = 16777216
net.core.wmem_max = 16777216
net.ipv4.tcp_timestamps = 1
net.ipv4.tcp_fin_timeout = 20
net.ipv4.tcp_synack_retries = 2
net.ipv4.tcp_syn_retries = 2
net.ipv4.tcp_syncookies = 1
net.ipv4.tcp_tw_reuse = 1
net.ipv4.tcp_mem = 94500000 915000000 927000000
net.ipv4.tcp_max_orphans = 3276800
net.ipv4.ip_local_port_range = 1024 65000
net.nf_conntrack_max = 6553500
net.netfilter.nf_conntrack_max = 6553500
net.netfilter.nf_conntrack_tcp_timeout_close_wait = 60
net.netfilter.nf_conntrack_tcp_timeout_fin_wait = 120
net.netfilter.nf_conntrack_tcp_timeout_time_wait = 120
net.netfilter.nf_conntrack_tcp_timeout_established = 3600
EOF
sysctl --system

安装docker

yum install -y yum-utils device-mapper-persistent-data lvm2
yum-config-manager --add-repo http://mirrors.aliyun.com/docker-ce/linux/centos/docker-ce.repo
yum makecache fast
yum install -y docker-ce

systemctl enable docker

Docker建议配置阿里云镜像加速

安装完成后配置启动时的命令，否则docker会将iptables FORWARD chain的默认策略设置为DROP

另外Kubeadm建议将systemd设置为cgroup驱动，所以还要修改daemon.json

sed -i "13i ExecStartPost=/usr/sbin/iptables -P FORWARD ACCEPT" /usr/lib/systemd/system/docker.service

tee /etc/docker/daemon.json <<-'EOF'
{
  "registry-mirrors": ["https://bk6kzfqm.mirror.aliyuncs.com"],
  "exec-opts": ["native.cgroupdriver=systemd"],
  "log-driver": "json-file",
  "log-opts": {
    "max-size": "100m"
  },
  "storage-driver": "overlay2",
  "storage-opts": [
    "overlay2.override_kernel_check=true"
  ]
}
EOF

systemctl daemon-reload
systemctl restart docker

安装kubeadm，kubelet和kubectl

#添加阿里云YUM软件源
cat > /etc/yum.repos.d/kubernetes.repo << EOF
[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
yum install -y kubelet kubeadm kubectl
#开机自启
systemctl enable kubelet

部署Kubernetes Master

由于默认拉取镜像地址k8s.gcr.io国内无法访问，这里指定阿里云镜像仓库地址。

初始化master
[root@k8s-master ~]# kubeadm init \
--apiserver-advertise-address=192.168.0.122 \
--image-repository registry.aliyuncs.com/google_containers \
--kubernetes-version v1.15.0 \
--service-cidr=10.1.0.0/16 \
--pod-network-cidr=10.244.0.0/16

#使用kubectl工具：
mkdir -p $HOME/.kube
sudo cp -i /etc/kubernetes/admin.conf $HOME/.kube/config
sudo chown $(id -u):$(id -g) $HOME/.kube/config
kubectl get cs

安装Pod网络插件（CNI）

这里使用canal。

[root@k8s-master ~]# kubectl apply -f https://docs.projectcalico.org/v3.3/getting-started/kubernetes/installation/hosted/canal/rbac.yaml
clusterrole.rbac.authorization.k8s.io/calico created
clusterrole.rbac.authorization.k8s.io/flannel created
clusterrolebinding.rbac.authorization.k8s.io/canal-flannel created
clusterrolebinding.rbac.authorization.k8s.io/canal-calico created
[root@k8s-master ~]# kubectl apply -f https://docs.projectcalico.org/v3.3/getting-started/kubernetes/installation/hosted/canal/canal.yaml
configmap/canal-config created
daemonset.extensions/canal created
serviceaccount/canal created
customresourcedefinition.apiextensions.k8s.io/felixconfigurations.crd.projectcalico.org created
customresourcedefinition.apiextensions.k8s.io/bgpconfigurations.crd.projectcalico.org created
customresourcedefinition.apiextensions.k8s.io/ippools.crd.projectcalico.org created
customresourcedefinition.apiextensions.k8s.io/hostendpoints.crd.projectcalico.org created
customresourcedefinition.apiextensions.k8s.io/clusterinformations.crd.projectcalico.org created
customresourcedefinition.apiextensions.k8s.io/globalnetworkpolicies.crd.projectcalico.org created
customresourcedefinition.apiextensions.k8s.io/globalnetworksets.crd.projectcalico.org created
customresourcedefinition.apiextensions.k8s.io/networkpolicies.crd.projectcalico.org created

[root@k8s-master ~]# kubectl get pod -n kube-system -o wide
NAME                                 READY   STATUS    RESTARTS   AGE     IP              NODE         NOMINATED NODE   READINESS GATES
canal-626dm                          3/3     Running   0          4m20s   192.168.0.122   k8s-master   <none>           <none>
coredns-bccdc95cf-b7cvx              1/1     Running   0          27m     10.244.0.3      k8s-master   <none>           <none>
coredns-bccdc95cf-wzd2t              1/1     Running   0          27m     10.244.0.2      k8s-master   <none>           <none>
etcd-k8s-master                      1/1     Running   0          26m     192.168.0.122   k8s-master   <none>           <none>
kube-apiserver-k8s-master            1/1     Running   0          27m     192.168.0.122   k8s-master   <none>           <none>
kube-controller-manager-k8s-master   1/1     Running   1          27m     192.168.0.122   k8s-master   <none>           <none>
kube-proxy-vbsch                     1/1     Running   0          27m     192.168.0.122   k8s-master   <none>           <none>
kube-scheduler-k8s-master            1/1     Running   1          27m     192.168.0.122   k8s-master   <none>           <none>

加入Kubernetes Node

向集群添加新节点，执行在kubeadm init输出的kubeadm join命令：

[root@k8s-node02 ~]# kubeadm join 192.168.0.122:6443 --token z11w4p.ztixn53mzj0jcl17 \
--discovery-token-ca-cert-hash sha256:4a59c419b68c15908be2773e7c610f4bf514cb7188aee4fcc5edbe46f9459987

[root@k8s-master ~]# kubectl get nodes
NAME         STATUS   ROLES    AGE   VERSION
k8s-master   Ready    master   28m   v1.15.0
k8s-node01   Ready    <none>   17m   v1.15.0
k8s-node02   Ready    <none>   16m   v1.15.0

kube-proxy开启ipvs

kubectl get configmap kube-proxy -n kube-system -o yaml > kube-proxy-configmap.yaml
sed -i 's/mode: ""/mode: "ipvs"/' kube-proxy-configmap.yaml
kubectl apply -f kube-proxy-configmap.yaml
rm -f kube-proxy-configmap.yaml
kubectl get pod -n kube-system | grep kube-proxy | awk '{system("kubectl delete pod "$1" -n kube-system")}'

测试kubernetes集群

[root@k8s-master ~]#  kubectl create deployment nginx --image=nginx
deployment.apps/nginx created
[root@k8s-master ~]# kubectl expose deployment nginx --port=80 --type=NodePort
service/nginx exposed
[root@k8s-master ~]# kubectl get pod,svc -o wide
NAME                         READY   STATUS    RESTARTS   AGE   IP           NODE         NOMINATED NODE   READINESS GATES
pod/nginx-554b9c67f9-6x7vl   1/1     Running   0          67m   10.244.1.2   k8s-node01   <none>           <none>

NAME                 TYPE        CLUSTER-IP     EXTERNAL-IP   PORT(S)        AGE     SELECTOR
service/kubernetes   ClusterIP   10.1.0.1       <none>        443/TCP        3h12m   <none>
service/nginx        NodePort    10.1.116.158   <none>        80:31509/TCP   67m     app=nginx

访问地址：http://NodeIP:Port

 部署 Dashboard（UI）

kubectl apply -f https://raw.githubusercontent.com/kubernetes/dashboard/v1.10.1/src/deploy/recommended/kubernetes-dashboard.yaml

默认镜像国内无法访问，修改镜像地址为：registry.cn-hangzhou.aliyuncs.com/google_containers/kubernetes-dashboard-amd64:v1.10.1

默认Dashboard只能集群内部访问，修改Service为NodePort类型，暴露到外部：

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: 30001
  selector:
    k8s-app: kubernetes-dashboard

访问地址：https://NodeIP:30001