Kubernetes之安装
1. kubernetes官方提供安装方法
1. kubeadm
简单，容易上手,
组件完全容器化部署，kubelet没有容器化（使用systemctl管理）
2. 二进制方法安装（生产常用方法）
部署复杂，但是对整体结构了解，方便后期管理维护，排错
组件都是守护进程
3. minikube
4. yum
2. kubeadm安装
1. 官方社区推出的一个用于快速部署kubernetes集群的工具
2. 通过两个命令完成一个kubernetes集群的部署
1. 创建一个master节点
kubeadm init
2. 将一个node节点加入到当前集群中
kubeadm join <master节点的IP和端口>
3. 准备工作：
1. 禁用swap分区
swapoff -a 临时关闭
sed -ri 's/.*swap.*/#&/' /etc/fstab 永久关闭
2. 关闭firewalled
systemctl stop firewalld.service
systemctl disable firewalld.service
3. 关闭selinux
4. 每个节点的hosts文件
192.168.1.171 k8s-master 192.168.1.42 k8s-node1 192.168.1.181 k8s-node2
5. 将桥接的IPV4流量传递到iptables的链
cat > /etc/sysctl.d/k8s.conf <<EOF
net.bridge.bridge-nf-call-ip6tables = 1 net.bridge.bridge-nf-call-iptables = 1 net.ipv4.ip_forward = 1
EOF
sysctl -p /etc/sysctl.d/k8s.conf
6. 时间同步
yum install ntpdate -y
ntpdate time.windows.com
4. 每个节点上安装docker
yum remove docker* 卸载旧版本
yum install -y yum-utils device-mapper-persistent-data lvm2 安装依赖包
yum-config-manager --add-repo https://download.docker.com/linux/centos/docker-ce.repo 添加docker的repo源
yum install docker-ce-<VERSION_STRING> docker-ce-cli-<VERSION_STRING> containerd.io 指定版本安装，不指定的话，就是最新版本
yum install docker-ce-18.09.9-3.el7 docker-ce-cli-18.09.9-3.el7 -y
systemctl enable docker.service && systemctl start docker.service
启动时候报错：
inotify_add_watch(7, /dev/dm-1, 10) failed: No such file or directory 解决方法： yum update xfsprogs
配置daemon.json文件
cat > /etc/docker/daemon.json << EOF
{
"registry-mirrors": ["https://b9pmyelo.mirror.aliyuncs.com"]
}
EOF
重启docker.service服务
5. 每个节点添加阿里云yum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=0 repo_gpgcheck=0 gpgkey=https://mirrors.aliyun.com/kubernetes/yum/doc/yum-key.gpg https://mirrors.aliyun.com/kubernetes/yum/doc/rpm-package-key.gpg EOF
6. 所有节点安装kubeadm,kubelet,kubectl
yum install -y kubelet-1.16.0 kubeadm-1.16.0 kubectl-1.16.0
systemctl enable kubelet
7. 在master上部署kubernetes master
kubeadm init --apiserver-advertise-address=192.168.1.171 --image-repository registry.aliyuncs.com/google_containers --kubernetes-version v1.16.0 --service-cidr=10.1.0.0/16 --pod-network-cidr=10.244.0.0/16
--apiserver-advertise-address apiserver的IP地址
--image-repository 指定镜像仓库，从互联网pull，改成阿里云地址
--kubernetes-version 指定k8s的版本号
--service-cidr=10.1.0.0/16 集群内部虚拟网络，pod统一访问入口
--pod-network-cidr=10.244.0.0/16 为pod设置网络
--ignore-preflight-errors=all 忽略网络错误
kubeadm reset 清除当前机器的初始化记录
mkdir -p $HOME/.kube
sudo cp -i /etc/kubernetes/admin.conf $HOME/.kube/config
sudo chown $(id -u):$(id -g) $HOME/.kube/config
You should now deploy a pod network to the cluster.
Run "kubectl apply -f [podnetwork].yaml" with one of the options listed at:
https://kubernetes.io/docs/concepts/cluster-administration/addons/
Then you can join any number of worker nodes by running the following on each as root:
kubeadm join 192.168.1.171:6443 --token fto38d.tlorcnr8nulyo1zj \
--discovery-token-ca-cert-hash sha256:88ed078f3e8898bf7216b6e06801ffe281617e4706a302896f678ac90596ea8e
kubeadm init工作流程
1. 安装环境检查
2. 拉取需要的镜像kubeadm config images pull
3. [certs]生成证书，放到/etc/kubernetes/pki
4. [kubeconfig]生成kubeconfig文件
5. [kubelet-start]生成kubelet文件，并启动kubelet。/var/lib/kubelet/config.yaml
6. [control-plane]启动master节点组件
7. 将一些配置文件存储到configMap中，用于其他节点初始化拉取
8. [mark-control-plane]为master节点打污点
9. [bootstrap-token]自动为节点颁发证书
10. [addons]安装插件CoreDNS和kube-proxy
最后拷贝kubectl工具用的kubeconfig到默认路径下
mkdir -p $HOME/.kube
sudo cp -i /etc/kubernetes/admin.conf $HOME/.kube/config
sudo chown $(id -u):$(id -g) $HOME/.kube/config
输出其它节点加入master的命令
kubeadm join 192.168.1.184:6443 --token 7cun2a.w9qcghrjup7u3bxy \
--discovery-token-ca-cert-hash sha256:0e467e4b61191a7fce9a2974329b177537b6661544576b015f28d26efa2363b8
8. 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
9. 在master节点上，安装Pod网络插件（CNI）
查看一下kubelet的日志，journalctl -u kubelet
Feb 09 17:45:38 k8s-master kubelet[3566]: E0209 17:45:38.989810 3566 kubelet.go:2103] Container runtime network not ready: NetworkReady=false reason:Network Feb 09 17:45:41 k8s-master kubelet[3566]: W0209 17:45:41.548503 3566 cni.go:239] Unable to update cni config: no networks found in /etc/cni/net.d
kubectl apply -f https://raw.githubusercontent.com/coreos/flannel/master/Documentation/kube-flannel.yml 此文件自己有的话，直接可以执行，不用下载。
也可以使用calico网络插件，博客园附件中有
10. 在两台node上执行
kubeadm join 192.168.1.171:6443 --token dhgz53.e6x3jiea9dbbn1h5 \
--discovery-token-ca-cert-hash sha256:1da8ea9db3be2d45d64cead9be94c08447b6331d617dc601a63697a87b5be11c
11. 所有节点都启动kubelet
systemctl enable kubelet && systemctl start kubelet
kubelet启动报错，使用命令检查journalctl -xefu kubelet
12. 查看节点
kubectl get nodes,出现下面的结果
NAME STATUS ROLES AGE VERSION
k8s-master Ready master 17h v1.16.0
k8s-node1 Ready <none> 17h v1.16.0
k8s-node2 Ready <none> 17h v1.16.0
13. 查看各个pods的状态
kubectl get pods -n kube-system
NAME READY STATUS RESTARTS AGE
coredns-58cc8c89f4-bkbx9 1/1 Running 0 17h
coredns-58cc8c89f4-pjkb5 1/1 Running 0 17h
etcd-k8s-master 1/1 Running 0 17h
kube-apiserver-k8s-master 1/1 Running 0 17h
kube-controller-manager-k8s-master 1/1 Running 0 17h
kube-flannel-ds-amd64-drtts 1/1 Running 0 14h
kube-flannel-ds-amd64-hvbp6 1/1 Running 0 14h
kube-flannel-ds-amd64-nvrz5 1/1 Running 0 14h
kube-proxy-59nkm 1/1 Running 0 17h
kube-proxy-dv4sd 1/1 Running 0 17h
kube-proxy-plls8 1/1 Running 0 17h
kube-scheduler-k8s-master 1/1 Running 0 17h
14. 创建一个测试
$ kubectl create deployment nginx --image=nginx $ kubectl expose deployment nginx --port=80 --type=NodePort $ kubectl get pod,svc
访问地址：http://NodeIP:Port
15. 在master节点安装dashboard
kubectl apply -f dashboard.yaml
kubectl create serviceaccount dashboard-admin -n kube-system 创建服务账号
kubectl create clusterrolebinding dashboard-admin --clusterrole=cluster-admin --serviceaccount=kube-system:dashboard-admin 绑定账号到角色中
kubectl describe secrets -n kube-system $(kubectl -n kube-system get secret | awk '/dashboard-admin/{print $1}') 产生token
token: eyJhbGciOiJSUzI1NiIsImtpZCI6InhzUXp4Ml83ZFk2WTRUNW5iMlRPQVBGRGExT0J2VEZxWFI1YXlfd2xmQzAifQ.eyJpc3MiOiJrdWJlcm5ldGVzL3NlcnZpY2VhY2NvdW50Iiwia3ViZXJuZXRlcy5pby9zZXJ2aWNlYWNjb3VudC9uYW1lc3BhY2UiOiJrdWJlLXN5c3RlbSIsImt1YmVybmV0ZXMuaW8vc2VydmljZWFjY291bnQvc2VjcmV0Lm5hbWUiOiJkYXNoYm9hcmQtYWRtaW4tdG9rZW4temg2am4iLCJrdWJlcm5ldGVzLmlvL3NlcnZpY2VhY2NvdW50L3NlcnZpY2UtYWNjb3VudC5uYW1lIjoiZGFzaGJvYXJkLWFkbWluIiwia3ViZXJuZXRlcy5pby9zZXJ2aWNlYWNjb3VudC9zZXJ2aWNlLWFjY291bnQudWlkIjoiYThjNDIwYzItM2I3ZC00MjQyLWEyMjItOTc5OTY1ZWI3OWRkIiwic3ViIjoic3lzdGVtOnNlcnZpY2VhY2NvdW50Omt1YmUtc3lzdGVtOmRhc2hib2FyZC1hZG1pbiJ9.LJXUlXQy99xseeCGhWJFAy93th19C8GfbV9ugJk4zdJraR56dws2mCIRKgRpUqM8GKsZrs7FxMyzi-1kqqgjq0KfgtdoaWbcc3hjTAK9WKz72WYEEnz_8Ibi4YXlUx1uDvlSD7A6MiWvQ02WQ2TPzYLDY-sHpTe1RZi60jRKf_yUpyLqkMsOXm_lWoj3JPFtR4ZfYovtA1RrAhj7AzkqQ5ZmY37kBQL1YsqX0_mxamop7t6rg7_Hp01j3vw64hKxlx3T_a5AuyErw63BQymNfuYOzgu32lpZYbJS-XTceVGAO3L60F1CbAkQqy7h1ydU-GncoLNAQE0kInbmlkwofA
查看dashboard的pod kubectl get pod -n kubernetes-dashboard
需要修改dashboard.yml的端口类型为nodeport
16. 登录dashboard
使用火狐或者谷歌浏览器登录，https://nodeIP:nodePort
3. 常见报错
1. node节点加入到master的时候，报错
[root@node4 pki]# kubeadm join 192.168.2.190:6443 --token mvkr39.euqsb8smhr51v2yr --discovery-token-ca-cert-hash sha256:72ff15ba4505228fe4316a10056a6549b8493213147ffec5b704961c6fb3554a
[preflight] Running pre-flight checks
[WARNING IsDockerSystemdCheck]: detected "cgroupfs" as the Docker cgroup driver. The recommended driver is "systemd". Please follow the guide at https://kubernetes.io/docs/setup/cri/
error execution phase preflight: [preflight] Some fatal errors occurred:
[ERROR FileAvailable--etc-kubernetes-kubelet.conf]: /etc/kubernetes/kubelet.conf already exists
[ERROR Port-10250]: Port 10250 is in use
[ERROR FileAvailable--etc-kubernetes-pki-ca.crt]: /etc/kubernetes/pki/ca.crt already exists
[preflight] If you know what you are doing, you can make a check non-fatal with `--ignore-preflight-errors=...`
To see the stack trace of this error execute with --v=5 or higher
解决方法： 在node节点上执行命令：kubeadm reset
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