CentOS7使用kubeadm在线安装k8s

Posted 2020-12-13

tags:

篇首语：本文由小常识网(cha138.com)小编为大家整理，主要介绍了CentOS7使用kubeadm在线安装k8s相关的知识，希望对你有一定的参考价值。

硬件要求

x86-64 processor
2CPU
2GB RAM
10GB free disk space
RedHat Enterprise Linux 7.x+, CentOS 7.x+, Ubuntu 16.04+, or Debian 9.x+

来自 <https://docs.projectcalico.org/getting-started/kubernetes/quickstart>;

实验环境

主机名	IP	角色	操作系统	CPU/MEM
master	192.168.118.20	Master	CentOS7	2core/2GB
node1	192.168.118.21	node1	CentOS7	2core/2GB
node2	192.168.118.22	node2	CentOS7	2core/2GB

安装步骤

一、环境预设（在所有主机上操作）

1.1、关闭firewalld

?systemctl stop firewalld; systemctl disable firewalld?

1.2、关闭SElinux

?setenforce 0;?sed -i "s/SELINUX=enforcing/SELINUX=disabled/g" /etc/selinux/config?

1.3、关闭Swap

?swapoff -a; sed -i "s//dev/mapper/centos-swap/#/dev/mapper/centos-swap/g" /etc/fstab?
如果不想关闭swap，可以跳过检查
vim /etc/sysconfig/kubelet
KUBELET_EXTRA_ARGS="--fail-swap-on=false"
在初始化时加入参数--ignore-preflight-errors=Swap

1.4、使用阿里云yum源：

?wget -O /etc/yum.repos.d/CentOS7-Aliyun.repo http://mirrors.aliyun.com/repo/Centos-7.repo??

1.5、修改内核参数

[root@master ~]# cat <<EOF >? /etc/sysctl.d/k8s.conf
net.bridge.bridge-nf-call-ip6tables = 1
net.bridge.bridge-nf-call-iptables = 1
net.ipv4.ip_forward = 1
EOF
使配置生效
[root@master ~]# sysctl --system

1.6、配置本地解析

vim /etc/hosts
192.168.118.20 master
192.168.118.21 node1
192.168.118.22 node2

二、. 安装docker引擎（在所有主机上操作）

2.1、安装阿里云docker源?

?wget -O /etc/yum.repos.d/docker-ce.repo http://mirrors.aliyun.com/docker-ce/linux/centos/docker-ce.repo?

2.2、安装docker

?yum install docker-ce -y?

2.3、启动docker

?systemctl enable docker;systemctl start docker?

2.4、调整docker部分参数

mkdir -p /etc/docker
tee /etc/docker/daemon.json <<-‘EOF‘
{
  "registry-mirrors": ["https://dkqah25p.mirror.aliyuncs.com"],　　　// 换成自己的阿里云镜像加速器地址
  "exec-opts": ["native.cgroupdriver=systemd"]　　// 默认cgroupfs，k8s官方推荐systemd，否则初始化出现Warning
}
EOF
systemctl daemon-reload
systemctl restart docker

2.5、检查确认docker的Cgroup Driver信息

[root@master ~]# docker info |grep Cgroup
Cgroup Driver: systemd
?

三、安装kubernetes初始化工具（在所有主机上操作）

3.1、使用阿里云的kubernetes源

cat <<EOF > /etc/yum.repos.d/kubernetes.repo
[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

3.2、安装

yum install -y kubelet kubeadm kubectl?

3.3、启动kubelet

systemctl enable kubelet;systemctl start kubelet?　　
#此时启动不成功正常，初始化后有配置文件了就启动了
?

四、初始化集群（在master节点上操作）

4.1、master初始化

kubeadm init --kubernetes-version=1.18.5  --apiserver-advertise-address=192.168.118.20   --image-repository mirrorgcrio  --service-cidr=10.10.0.0/16 --pod-network-cidr=10.122.0.0/16 --ignore-preflight-errors=Swap,NumCPU
    --kubernetes-version：k8s版本
    --apiserver-advertise-address：spiserver的地址
    --image-repository：由于kubeadm 默认从官网k8s.grc.io下载所需镜像，国内无法访问，因此需要通过–image-repository指定mirrorgcrio。
    --ignore-preflight-errors=Swap,NumCPU：跳过swap和cpu检查

出现以下内容是初始化成功

Your Kubernetes control-plane has initialized successfully!

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 192.168.118.20:6443 --token akiiod.ajlbeux62nhin6kw     --discovery-token-ca-cert-hash sha256:76a5cfca9c7c90e319a0c27731dfab0d6c40932ba4c10b0dfb46d9528492a1d9

4.2、按照提示操作

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

如果是root 可以直接执行
export KUBECONFIG=/etc/kubernetes/admin.conf

以上两个二选一即可，我这里用root
export KUBECONFIG=/etc/kubernetes/admin.conf

确认master各组件状态
[root@k8s-master docker]# kubectl get cs
NAME                 STATUS    MESSAGE             ERROR
scheduler            Healthy   ok                  
controller-manager   Healthy   ok                  
etcd-0               Healthy   {"health":"true"}   

将admin配置文件复制到所有node节点
scp /etc/kubernetes/admin.conf node1:/etc/kubernetes/
scp /etc/kubernetes/admin.conf node2:/etc/kubernetes/

配置环境变量
echo "export KUBECONFIG=/etc/kubernetes/admin.conf" >> ~/.bash_profile

立即生效
source ~/.bash_profile

4.3、重新初始化集群

当初始化中途出现报错时，先重置集群，后重新初始化集群

kubeadm reset
systemctl daemon-reload
systemctl restart kubelet
iptables -F && iptables -t nat -F && iptables -t mangle -F && iptables -X
iptables -nL #检查防火墙规则是否清空
netstat -antlp #检查端口是否全被放开

五、安装calico（在master节点上操作）

5.1、安装

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

5.2、安装成功后查看pod

[root@master ~]# kubectl get pod -n kube-system -owide
NAME                                       READY   STATUS    RESTARTS   AGE     IP               NODE     NOMINATED NODE   READINESS GATES
calico-kube-controllers-58b656d69f-jk7fr   1/1     Running   0          3m42s   10.122.219.67    master   <none>           <none>
calico-node-2jhdt                          1/1     Running   0          3m42s   192.168.118.20   master   <none>           <none>
coredns-54f99b968c-5wmbp                   1/1     Running   0          11m     10.122.219.66    master   <none>           <none>
coredns-54f99b968c-lgvsw                   1/1     Running   0          11m     10.122.219.65    master   <none>           <none>
etcd-master                                1/1     Running   0          11m     192.168.118.20   master   <none>           <none>
kube-apiserver-master                      1/1     Running   0          11m     192.168.118.20   master   <none>           <none>
kube-controller-manager-master             1/1     Running   0          11m     192.168.118.20   master   <none>           <none>
kube-proxy-7ms45                           1/1     Running   0          11m     192.168.118.20   master   <none>           <none>
kube-scheduler-master                      1/1     Running   0          11m     192.168.118.20   master   <none>           <none>

六、node加入集群（非master节点操作）

6.1、加入集群

kubeadm join 192.168.118.20:6443 --token akiiod.ajlbeux62nhin6kw     --discovery-token-ca-cert-hash sha256:76a5cfca9c7c90e319a0c27731dfab0d6c40932ba4c10b0dfb46d9528492a1d9 --ignore-preflight-errors=Swap,NumCPU

6.2、master节点查看node及pod

[root@master ~]# kubectl get pod -n kube-system -owide
NAME                                       READY   STATUS    RESTARTS   AGE     IP               NODE     NOMINATED NODE   READINESS GATES
calico-kube-controllers-58b656d69f-jk7fr   1/1     Running   0          7m39s   10.122.219.67    master   <none>           <none>
calico-node-2jhdt                          1/1     Running   0          7m39s   192.168.118.20   master   <none>           <none>
calico-node-4258m                          0/1     Running   0          119s    192.168.118.21   node1    <none>           <none>
calico-node-lpcvq                          0/1     Running   0          113s    192.168.118.22   node2    <none>           <none>
coredns-54f99b968c-5wmbp                   1/1     Running   0          15m     10.122.219.66    master   <none>           <none>
coredns-54f99b968c-lgvsw                   1/1     Running   0          15m     10.122.219.65    master   <none>           <none>
etcd-master                                1/1     Running   0          15m     192.168.118.20   master   <none>           <none>
kube-apiserver-master                      1/1     Running   0          15m     192.168.118.20   master   <none>           <none>
kube-controller-manager-master             1/1     Running   0          15m     192.168.118.20   master   <none>           <none>
kube-proxy-65tr6                           1/1     Running   0          119s    192.168.118.21   node1    <none>           <none>
kube-proxy-7ms45                           1/1     Running   0          15m     192.168.118.20   master   <none>           <none>
kube-proxy-h7sg5                           1/1     Running   0          113s    192.168.118.22   node2    <none>           <none>
kube-scheduler-master                      1/1     Running   0          15m     192.168.118.20   master   <none>           <none>
[root@master ~]# kubectl get node -n kube-system -owide
NAME     STATUS   ROLES    AGE    VERSION   INTERNAL-IP      EXTERNAL-IP   OS-IMAGE                KERNEL-VERSION          CONTAINER-RUNTIM
Emaster   Ready    master   15m    v1.18.5   192.168.118.20   <none>        CentOS Linux 7 (Core)   3.10.0-693.el7.x86_64   docker://19.3.12
node1    Ready    <none>   2m3s   v1.18.5   192.168.118.21   <none>        CentOS Linux 7 (Core)   3.10.0-693.el7.x86_64   docker://19.3.12
node2    Ready    <none>   117s   v1.18.5   192.168.118.22   <none>        CentOS Linux 7 (Core)   3.10.0-693.el7.x86_64   docker://19.3.12

到此，简单的k8s集群就安装完毕了

参考文章：https://www.jianshu.com/p/ad27168bebb5

以上是关于CentOS7使用kubeadm在线安装k8s的主要内容，如果未能解决你的问题，请参考以下文章

centos7 使用kubeadm 安装 k8s集群

centos7 用kubeadm安装 k8s v1.10.0

Centos7.7使用kubeadm快速部署K8s集群(适合新手)

kubeadm安装高可用k8s集群

kubeadm安装k8s集群1.17版本