Build K8s cluster [do not need science shangwang]

官网：https://kubernetes.io/docs/setup/production-environment/tools/kubeadm/install-kubeadm/#installing-kubeadm-kubelet-and-kubectl
GitHub：https://github.com/kubernetes/kubeadm

Use kubeadm build a machine consisting of three k8s cluster master node station 1, 2 worker nodes

Configuration (official configuration requirements):

- One or more machines running one of:
  - Ubuntu 16.04+
  - Debian 9+
  - CentOS 7【课程中使用】
  - Red Hat Enterprise Linux (RHEL) 7
  - Fedora 25+
  - HypriotOS v1.0.1+
  - Container Linux (tested with 1800.6.0)
- 2 GB or more of RAM per machine (any less will leave little room for your apps)
- 2 CPUs or more
- Full network connectivity between all machines in the cluster (public or private network is fine)
- Unique hostname, MAC address, and product_uuid for every node. See here for more details.
- Certain ports are open on your machines. See here for more details.
- Swap disabled. You MUST disable swap in order for the kubelet to work properly.

My configuration:

Environmental and mirrored version:

Docker       19.03.5
---
kubeadm-1.14.0-0 
kubelet-1.14.0-0 
kubectl-1.14.0-0
---
k8s.gcr.io/kube-apiserver:v1.14.0
k8s.gcr.io/kube-controller-manager:v1.14.0
k8s.gcr.io/kube-scheduler:v1.14.0
k8s.gcr.io/kube-proxy:v1.14.0
k8s.gcr.io/pause:3.1
k8s.gcr.io/etcd:3.3.10
k8s.gcr.io/coredns:1.3.1
---
calico:v3.9

1. Prepare three centos

要保证彼此之间能够ping通，也就是处于同一个网络中，虚拟机的配置要求如上

2. Update and install dependencies (3 machines need to be performed)

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

3. Install the Docker environment dependent k8s

01 安装必要的依赖

   sudo yum install -y yum-utils \
   device-mapper-persistent-data \
   lvm2
    
    
02 设置docker仓库

   sudo yum-config-manager --add-repo http://mirrors.aliyun.com/docker-ce/linux/centos/docker-ce.repo
    
  【设置要设置一下阿里云镜像加速器】
   sudo mkdir -p /etc/docker
   sudo tee /etc/docker/daemon.json <<-'EOF'
   {
      "registry-mirrors": ["这边替换成自己的实际地址"]
   }
   EOF
   sudo systemctl daemon-reload

03 安装docker

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

04 启动docker
   sudo systemctl start docker && sudo systemctl enable docker

4. Modify the hosts file

# (1)master
# 设置master的hostname，并且修改hosts文件
sudo hostnamectl set-hostname master

vi /etc/hosts
192.168.1.18 master
192.168.1.17 follow1
192.168.1.19 follow2

# (2)两个follow
# 设置follow01/02的hostname，并且修改hosts文件
sudo hostnamectl set-hostname follow1
sudo hostnamectl set-hostname follow2

vi /etc/hosts
192.168.1.18 master
192.168.1.17 follow1
192.168.1.19 follow2

The basic premise of the system configuration

# (1)关闭防火墙
systemctl stop firewalld && systemctl disable firewalld

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

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

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

# (5)设置系统参数
cat <<EOF >  /etc/sysctl.d/k8s.conf
net.bridge.bridge-nf-call-ip6tables = 1
net.bridge.bridge-nf-call-iptables = 1
EOF

sysctl --system

6.Installing kubeadm, omelets 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)安装kubeadm&kubelet&kubectl
yum install -y kubeadm-1.14.0-0 kubelet-1.14.0-0 kubectl-1.14.0-0

# docker和k8s设置同一个cgroup(注意这里必须保证)
# docker
vi /etc/docker/daemon.json
    "exec-opts": ["native.cgroupdriver=systemd"],
    
systemctl restart docker
    
# kubelet，这边如果发现输出directory not exist，也说明是没问题的，大家继续往下进行即可
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

After the setup is complete: ps

# docker 
可以通过docker info查看

# k8s
文件位置/etc/systemd/system/kubelet.service.d/10-kubeadm.conf

7.proxy / pause / scheduler and other domestic Mirror

# (1)查看kubeadm使用的镜像

   kubeadm config images list

# 可以发现这里都是国外的镜像

  k8s.gcr.io/kube-apiserver:v1.14.0
  k8s.gcr.io/kube-controller-manager:v1.14.0
  k8s.gcr.io/kube-scheduler:v1.14.0
  k8s.gcr.io/kube-proxy:v1.14.0
  k8s.gcr.io/pause:3.1
  k8s.gcr.io/etcd:3.3.10
  k8s.gcr.io/coredns:1.3.1

# (2)解决国外镜像不能访问的问题
# 创建kubeadm.sh脚本，用于拉取镜像/打tag/删除原有镜像

#!/bin/bash

set -e

KUBE_VERSION=v1.14.0
KUBE_PAUSE_VERSION=3.1
ETCD_VERSION=3.3.10
CORE_DNS_VERSION=1.3.1

GCR_URL=k8s.gcr.io
ALIYUN_URL=registry.cn-hangzhou.aliyuncs.com/snail-gao

images=(kube-proxy:${KUBE_VERSION}
kube-scheduler:${KUBE_VERSION}
kube-controller-manager:${KUBE_VERSION}
kube-apiserver:${KUBE_VERSION}
pause:${KUBE_PAUSE_VERSION}
etcd:${ETCD_VERSION}
coredns:${CORE_DNS_VERSION})

for imageName in ${images[@]} ; do
  docker pull $ALIYUN_URL/$imageName
  docker tag  $ALIYUN_URL/$imageName $GCR_URL/$imageName
  docker rmi $ALIYUN_URL/$imageName
done

# 运行脚本和查看镜像

# 运行脚本
sh ./kubeadm.sh

# 查看镜像
docker images

# 将这些镜像推送到自己的阿里云仓库【可选，根据自己实际的情况】
# 登录自己的阿里云仓库
docker login --username=xxx registry.cn-hangzhou.aliyuncs.com

# 创建脚本kubeadm-push-aliyun.sh

#!/bin/bash

set -e

KUBE_VERSION=v1.14.0
KUBE_PAUSE_VERSION=3.1
ETCD_VERSION=3.3.10
CORE_DNS_VERSION=1.3.1

GCR_URL=k8s.gcr.io
ALIYUN_URL=registry.cn-hangzhou.aliyuncs.com/snail-gao

images=(kube-proxy:${KUBE_VERSION}
kube-scheduler:${KUBE_VERSION}
kube-controller-manager:${KUBE_VERSION}
kube-apiserver:${KUBE_VERSION}
pause:${KUBE_PAUSE_VERSION}
etcd:${ETCD_VERSION}
coredns:${CORE_DNS_VERSION})

for imageName in ${images[@]} ; do
  docker tag $GCR_URL/$imageName $ALIYUN_URL/$imageName
  docker push $ALIYUN_URL/$imageName
  docker rmi $ALIYUN_URL/$imageName
done

# 运行脚本 sh ./kubeadm-push-aliyun.sh

8.kube init initialization master

# (1)kube init流程

01-进行一系列检查，以确定这台机器可以部署kubernetes

02-生成kubernetes对外提供服务所需要的各种证书可对应目录
/etc/kubernetes/pki/*

03-为其他组件生成访问kube-ApiServer所需的配置文件
    ls /etc/kubernetes/
    admin.conf  controller-manager.conf  kubelet.conf  scheduler.conf
    
04-为 Master组件生成Pod配置文件。
    ls /etc/kubernetes/manifests/*.yaml
    kube-apiserver.yaml 
    kube-controller-manager.yaml
    kube-scheduler.yaml
    
05-生成etcd的Pod YAML文件。
    ls /etc/kubernetes/manifests/*.yaml
    kube-apiserver.yaml 
    kube-controller-manager.yaml
    kube-scheduler.yaml
    etcd.yaml
    
06-一旦这些 YAML 文件出现在被 kubelet 监视的/etc/kubernetes/manifests/目录下，kubelet就会自动创建这些yaml文件定义的pod，即master组件的容器。master容器启动后，kubeadm会通过检查localhost：6443/healthz这个master组件的健康状态检查URL，等待master组件完全运行起来

07-为集群生成一个bootstrap token

08-将ca.crt等 Master节点的重要信息，通过ConfigMap的方式保存在etcd中，工后续部署node节点使用

09-最后一步是安装默认插件，kubernetes默认kube-proxy和DNS两个插件是必须安装的

# (2)初始化master节点
官网：https://kubernetes.io/docs/reference/setup-tools/kubeadm/kubeadm/

# 注意：此操作是在主节点上进行

# 本地有镜像
kubeadm init --kubernetes-version=1.14.0 --apiserver-advertise-address=192.168.1.18 --pod-network-cidr=10.244.0.0/16
【若要重新初始化集群状态：kubeadm reset，然后再进行上述操作】

# 记得保存好最后kubeadm join的信息

Upon completion of the installation effects:

# (3)根据日志提示
mkdir -p $HOME/.kube
sudo cp -i /etc/kubernetes/admin.conf $HOME/.kube/config
sudo chown $(id -u):$(id -g) $HOME/.kube/config

# (4)启动coredns
kubectl get pods -n kube-system

# (5)健康检查
curl -k https://localhost:6443/healthz

9. deploy calico network plug

选择网络插件：https://kubernetes.io/docs/concepts/cluster-administration/addons/
calico网络插件：https://docs.projectcalico.org/v3.9/getting-started/kubernetes/

calico, in the same manner as the master node

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

# 确认一下calico是否安装成功
kubectl get pods --all-namespaces -w

10.kube join

# (1)把刚才安装成功后的配置信息拿过来（这里只是参考）
kubeadm join 192.168.1.18:6443 --token rnqwrl.h3z18ssf1sks9aix \
    --discovery-token-ca-cert-hash sha256:216b14dfbb30588cdb7425a1af128bcb624daec4a15b11ed0047009f526e8c73

# (2)在follow1和follow2上执行上述命令

# (3)在master节点上检查集群信息
NAME      STATUS     ROLES    AGE   VERSION
follow1   NotReady   <none>   25s   v1.14.0
follow2   NotReady   <none>   20s   v1.14.0
master    Ready      master   18m   v1.14.0

11. Experience Pod again

# (1)定义pod.yml文件，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)根据pod_nginx_rs.yml文件创建pod
  kubectl apply -f pod_nginx_rs.yaml

# (3)查看pod
  kubectl get pods
  kubectl get pods -o wide
  kubectl describe pod nginx

# (4)感受通过rs将pod扩容
  kubectl scale rs nginx --replicas=5
  kubectl get pods -o wide

# (5)删除pod
  kubectl delete -f pod_nginx_rs.yaml

Build K8s cluster [do not need science shangwang]

Use kubeadm build a machine consisting of three k8s cluster master node station 1, 2 worker nodes

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