3台centos搭建Kubernetes(k8s)叢集

1.1 準備3台centos

大家根據自己的情況來準備centos7的虛拟機。

要保證彼此之間能夠ping通，也就是處于同一個網絡中，虛拟機的配置要求上面也描述咯。

1.2 更新并安裝依賴

3台機器都需要執行

yum -y update
yum install -y conntrack ipvsadm ipset jq sysstat curl iptables libseccomp
           

1.3 安裝Docker

在每一台機器上都安裝好Docker，版本為18.09.0

01 安裝必要的依賴
	sudo yum install -y yum-utils device-mapper-persistent-data lvm2
 
02 設定docker倉庫
	sudo yum-config-manager --add-repo http://mirrors.aliyun.com/docker-ce/linux/centos/docker-ce.repo
	
【設定要設定一下阿裡雲鏡像加速器】
登入阿裡雲 https://cr.console.aliyun.com/cn-hangzhou/instances/mirrors 容器鏡像服務中檢視，參見下圖
sudo mkdir -p /etc/docker
sudo tee /etc/docker/daemon.json <<-'EOF'
{
 "registry-mirrors": ["https://******.mirror.aliyuncs.com"]
}
EOF
sudo systemctl daemon-reload


03 安裝docker

yum install -y docker-ce-18.09.0 docker-ce-cli-18.09.0 containerd.io


04 啟動docker
	sudo systemctl start docker && sudo systemctl enable docker
           

1.4 修改hosts檔案

(1)master

# 設定hostname

sudo hostnamectl set-hostname master
sudo hostnamectl set-hostname worker1
sudo hostnamectl set-hostname worker2
#上面操作對應虛拟機 分開執行

#修改hosts檔案
vi /etc/hosts

#将下面内容加入所有虛拟機hosts檔案中
192.168.0.111 master 
192.168.0.112 worker1
192.168.0.113 worker2
           

1.5 系統基礎前提配置

# (1)關閉防火牆
systemctl stop firewalld && systemctl disable firewalld

# (2)關閉selinux
setenforce 0
sed -i 's/^SELINUX=enforcing$/SELINUX=permissive/' /etc/selinux/config

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

# (4)配置iptables的ACCEPT規則
iptables -F && iptables -X && iptables -F -t nat && iptables -X -t nat && iptables -P FORWARD ACCEPT

# (5)設定系統參數
cat <<EOF >  /etc/sysctl.d/k8s.conf
net.bridge.bridge-nf-call-ip6tables = 1
net.bridge.bridge-nf-call-iptables = 1
EOF

sysctl --system
           

1.6 Installing kubeadm, kubelet and kubectl

(1)配置yum源

cat <<EOF > /etc/yum.repos.d/kubernetes.repo
[kubernetes]
name=Kubernetes
baseurl=http://mirrors.aliyun.com/kubernetes/yum/repos/kubernetes-el7-x86_64
enabled=1
gpgcheck=0
repo_gpgcheck=0
gpgkey=http://mirrors.aliyun.com/kubernetes/yum/doc/yum-key.gpg
       http://mirrors.aliyun.com/kubernetes/yum/doc/rpm-package-key.gpg
EOF
           

(2)安裝kubeadm&kubelet&kubectl

yum install -y kubeadm kubelet kubectl -y
           

(3)docker和k8s設定同一個cgroup

# docker
vi /etc/docker/daemon.json
    "exec-opts": ["native.cgroupdriver=systemd"],
    
systemctl restart docker
    
# kubelet，這邊如果發現輸出directory not exist，也說明是沒問題的，大家繼續往下進行即可
sed -i "s/cgroup-driver=systemd/cgroup-driver=cgroupfs/g" /etc/systemd/system/kubelet.service.d/10-kubeadm.conf
	
systemctl enable kubelet && systemctl start kubelet
           

1.7 kube init初始化master

# 此操作隻在master節點執行 檢視日志，記錄join資訊
kubeadm init --image-repository registry.aliyuncs.com/google_containers --kubernetes-version v1.15.1 --apiserver-advertise-address 192.168.0.111 --pod-network-cidr=10.244.0.0/16
【若要重新初始化叢集狀态：kubeadm reset，然後再進行上述操作】
           

記得儲存好最後kubeadm join的資訊

(3)根據日志提示

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

1.8 部署calico網絡插件

選擇網絡插件：https://kubernetes.io/docs/concepts/cluster-administration/addons/

calico網絡插件：https://docs.projectcalico.org/v3.9/getting-started/kubernetes/

calico，同樣在master節點上操作

# 在k8s中安裝calico
kubectl apply -f https://docs.projectcalico.org/v3.9/manifests/calico.yaml

# 确認一下calico是否安裝成功
kubectl get pods --all-namespaces -w
           

1.9 kube join

記得儲存初始化master節點的最後列印資訊

kubeadm join 192.168.0.111:6443 --token yu1ak0.2dcecvmpozsy8loh \
    --discovery-token-ca-cert-hash sha256:********************
           

(1)在woker1和worker2上執行上述指令

(2)在master節點上檢查叢集資訊

kubectl get nodes

NAME                   STATUS   ROLES    AGE     VERSION
master-kubeadm-k8s     Ready    master   19m     v1.14.0
worker01-kubeadm-k8s   Ready    <none>   3m6s    v1.14.0
worker02-kubeadm-k8s   Ready    <none>   2m41s   v1.14.0
           

1.10 建立Pod

(1)定義pod.yml檔案，比如pod_nginx_rs.yaml

cat > pod_nginx_rs.yaml <<EOF
apiVersion: apps/v1
kind: ReplicaSet
metadata:
  name: nginx
  labels:
    tier: frontend
spec:
  replicas: 3
  selector:
    matchLabels:
      tier: frontend
  template:
    metadata:
      name: nginx
      labels:
        tier: frontend
    spec:
      containers:
      - name: nginx
        image: nginx
        ports:
        - containerPort: 80
EOF
           

(2)根據pod_nginx_rs.yml檔案建立pod

kubectl apply -f pod_nginx_rs.yaml
           

(3)檢視pod

kubectl get pods
kubectl get pods -o wide
kubectl describe pod nginx
           

(4)通過rs将pod擴容

kubectl scale rs nginx --replicas=5
kubectl get pods -o wide
           

(5)删除pod

kubectl delete -f pod_nginx_rs.yaml