kubeadm安装k8s完整教程

kubeadm安装k8s完整教程

[TOC]

一：硬件环境准备

三台机器，计划为：一台master，两台node

序号	ip	系统版本	hostname	配置	节点类型
1	192.168.159.210	CentOS 7.7.1908 (Core)	vm210	2核2G	Master
2	192.168.159.211	CentOS 7.7.1908 (Core)	vm211	2核2G	node
3	192.168.159.212	CentOS 7.7.1908 (Core)	vm212	2核2G	node

二：系统软件环境预置

1.设置hosts

vi /etc/hosts
加入以下内容
127.0.0.1 vm210

2.关闭防火墙

[root@vm210 ~]# systemctl stop firewalld
[root@vm210 ~]# systemctl disable firewalld
[root@vm210 ~]# systemctl status firewalld
● firewalld.service - firewalld - dynamic firewall daemon
   Loaded: loaded (/usr/lib/systemd/system/firewalld.service; disabled; vendor preset: enabled)
   Active: inactive (dead)
     Docs: man:firewalld(1)
[root@vm210 ~]# 

3.安装docker

使用yum安装,若已安装可跳过

yum -y install docker

4.配置yum源

vi /etc/yum.repos.d/kubernetes.repo

加入以下内容
[kubernetes]
name=Kubernetes
baseurl=https://mirrors.aliyun.com/kubernetes/yum/repos/kubernetes-el7-x86_64/
enabled=1
gpgcheck=0

5.设置SELinux

vi /etc/selinux/config
添加如下SELINUX=disabled 
注释掉SELINUX=enforcing,SELINUXTYPE=targeted 

# This file controls the state of SELinux on the system.
# SELINUX= can take one of these three values:
#     enforcing - SELinux security policy is enforced.
#     permissive - SELinux prints warnings instead of enforcing.
#     disabled - No SELinux policy is loaded.
#SELINUX=enforcing
# SELINUXTYPE= can take one of three values:
#     targeted - Targeted processes are protected,
#     minimum - Modification of targeted policy. Only selected processes are protected.
#     mls - Multi Level Security protection.
#SELINUXTYPE=targeted 
SELINUX=disabled 

6.关闭swap内存

使用swap会影响性能。kubelet禁用swap

1）系统级零时关闭

​ swapoff -a ，重启后失效

2）系统级全部关闭

​ vi /etc/fstab，注释掉swap那一行

​ 需要重启。重启后不失效

​

#
# /etc/fstab
# Created by anaconda on Mon Dec  2 21:02:22 2019
#
# Accessible filesystems, by reference, are maintained under '/dev/disk'
# See man pages fstab(5), findfs(8), mount(8) and/or blkid(8) for more info
#
/dev/mapper/centos-root /                       xfs     defaults        0 0
UUID=b232659c-bd84-46f0-928b-a46d55500934 /boot                   xfs     defaults        0 0
#/dev/mapper/centos-swap swap  

7.设置iptables

解决iptables而导致流量无法正确路由的问题

cat <<EOF >  /etc/sysctl.d/k8s.conf
net.bridge.bridge-nf-call-ip6tables = 1
net.bridge.bridge-nf-call-iptables = 1
EOF
sysctl --system

三：Master节点安装kubeadm

1.安装kubelet 和kubeadm以及kubectl

yum install -y kubelet kubeadm kubectl --disableexcludes=kubernetes
systemctl enable --now kubelet

2.启动docker

systemctl enable docker && systemctl start docker

3.下载所需要的镜像

for i in `kubeadm config images list`; do 
  imageName=${i#k8s.gcr.io/}
  docker pull registry.aliyuncs.com/google_containers/$imageName
  docker tag registry.aliyuncs.com/google_containers/$imageName k8s.gcr.io/$imageName
  docker rmi registry.aliyuncs.com/google_containers/$imageName
done;

4.更改kubelet的参数

vi /etc/sysconfig/kubelet

改为如下参数
KUBELET_EXTRA_ARGS=--cgroup-driver=systemd

5.kubeadm初始化

kubeadm init

完成之后有如下结果
To start using your cluster, you need to run the following as a regular user:

  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 192.168.159.210:6443 --token ct4248.2egr8dv9k4avqul7 \
    --discovery-token-ca-cert-hash sha256:4ca4f6835e9cd70b43be16b81d8340876dca0e064c6168342c140140d17f449b 
    
    最后的命令需要在node节点中执行，从而加入的k8s集群

依据提示执行如下命令
  mkdir -p $HOME/.kube
  sudo cp -i /etc/kubernetes/admin.conf $HOME/.kube/config
  sudo chown $(id -u):$(id -g) $HOME/.kube/config

四：node节点安装kubeadm

1.安装kubeadm kubelet

yum -y install kubeadm kubelet

2.启动docker

systemctl enable docker && systemctl start docker

3.下载所需要的镜像

for i in `kubeadm config images list`; do 
  imageName=${i#k8s.gcr.io/}
  docker pull registry.aliyuncs.com/google_containers/$imageName
  docker tag registry.aliyuncs.com/google_containers/$imageName k8s.gcr.io/$imageName
  docker rmi registry.aliyuncs.com/google_containers/$imageName
done;

4.更改kubelet的参数

vi /etc/sysconfig/kubelet

改为如下参数
KUBELET_EXTRA_ARGS=--cgroup-driver=systed

5)加入master

token来自master节点执行kubeinit的结果
kubeadm join 192.168.159.210:6443 --token ct4248.2egr8dv9k4avqul7 \
    --discovery-token-ca-cert-hash sha256:4ca4f6835e9cd70b43be16b81d8340876dca0e064c6168342c140140d17f449b 

五：安装网络插件

kubectl apply -f https://docs.projectcalico.org/v3.8/manifests/calico.yaml

六：查询k8s集群状态

1.查询node节点

[root@vm210 k8s]# kubectl get nodes
NAME    STATUS   ROLES    AGE     VERSION
vm210   Ready    master   58m     v1.16.3
vm211   Ready    <none>   21m     v1.16.3
vm212   Ready    <none>   6m29s   v1.16.3

2.查询pods状态

root@vm210 k8s]# kubectl  get pods --namespace=kube-system
NAME                                      READY   STATUS            RESTARTS   AGE
calico-kube-controllers-55754f75c-7wvrb   1/1     Running           0          6m20s
calico-node-9x82m                         1/1     Running           0          6m20s
calico-node-gn5qh                         1/1     Running           0          6m20s
calico-node-h8kvz                         0/1     PodInitializing   0          6m20s
coredns-5644d7b6d9-h9sn2                  1/1     Running           0          59m
coredns-5644d7b6d9-pwfl5                  1/1     Running           0          59m
etcd-vm210                                1/1     Running           0          58m
kube-apiserver-vm210                      1/1     Running           0          58m
kube-controller-manager-vm210             1/1     Running           0          58m
kube-proxy-6hjk2                          1/1     Running           0          22m
kube-proxy-bcmhh                          1/1     Running           0          7m31s
kube-proxy-bt9rn                          1/1     Running           0          59m
kube-scheduler-vm210                      1/1     Running           0          58m

3.查询pod具体状态

kubectl --namespace=kube-system describe pod <pod_name>

kubectl --namespace=kube-system describe pod calico-node-h8kvz

4.master节点也可以像node节点一样调度pod

kubectl taint nodes --all node-role.kubernetes.io/master-


[root@vm210 k8s]# kubectl taint nodes --all node-role.kubernetes.io/master-
node/vm210 untainted
taint "node-role.kubernetes.io/master" not found
taint "node-role.kubernetes.io/master" not found

5.查询k8s版本

[root@vm210 k8s]# kubectl version
Client Version: version.Info{Major:"1", Minor:"16", GitVersion:"v1.16.3", GitCommit:"b3cbbae08ec52a7fc73d334838e18d17e8512749", GitTreeState:"clean", BuildDate:"2019-11-13T11:23:11Z", GoVersion:"go1.12.12", Compiler:"gc", Platform:"linux/amd64"}
Server Version: version.Info{Major:"1", Minor:"16", GitVersion:"v1.16.3", GitCommit:"b3cbbae08ec52a7fc73d334838e18d17e8512749", GitTreeState:"clean", BuildDate:"2019-11-13T11:13:49Z", GoVersion:"go1.12.12", Compiler:"gc", Platform:"linux/amd64"}

至此， 通过kubeadm工具就实现了Kubernetes集群的快速搭建。 如果安装失败， 则可以执行kubeadm reset命令将主机恢复原状， 重新执行kubeadm init，或者kubeadm join命令， 再次进行安装。

安装的过程中，若有任何问题，欢迎添加vx：xydjun 。大家一起交流探讨