Kubeadm搭建kubernetes集群
Kubeadm搭建kubernetes集群
环境说明
| 角色 | ip | 操作系统 |组件 |
| – | – | – |
| master | 192.168.203.100 |centos8 | docker，kubectl，kubeadm，kubelet |
| node2 | 192.168.203.30 |centos8 |docker，kubectl，kubeadm，kubelet|
| node3 | 192.168.203.50 |centos8 |docker，kubectl，kubeadm，kubelet|
配置各个主机的主机名解析文件(3台都要配置)
127.0.0.1 localhost localhost.localdomain localhost4 localhost4.localdomain4
::1 localhost localhost.localdomain localhost6 localhost6.localdomain6
192.168.203.100 master.example.com master
192.168.203.20 node1.example.com node1
192.168.203.30 node2.example.com node2
192.168.203.50 node3.example.com node3
设置时钟同步
master
[root@master ~]# vim /etc/chrony.conf
local stratum 10
[root@master ~]# systemctl restart chronyd
[root@master ~]# systemctl enable chronyd
[root@master ~]# hwclock -w
node2 and 3
[root@node2 ~]# vim /etc/chrony.conf
#pool 2.centos.pool.ntp.org iburst
server master.example.com iburst
[root@node2 ~]# systemctl restart chronyd
[root@node2 ~]# systemctl enable chronyd
[root@node2 ~]# hwclock -w
[root@node3 ~]# vim /etc/chrony.conf
#pool 2.centos.pool.ntp.org iburst
server master.example.com iburst
[root@node3 ~]# systemctl restart chronyd
[root@node3 ~]# systemctl enable chronyd
[root@node3 ~]# hwclock -w
禁用firewalld、selinux、postfix三个主机都需要做
systemctl stop firewalld
systemctl disable firewalld
vim /etc/selinux/conf
SELINUX=disabled
setenforce 0
systemctl stop postfix
systemctl disabled postfix
禁用swap分区 三个主机都需要做
vim /etc/fstab
# /dev/mapper/cs-swap none swap defaults 0 0
swapoff -a 将swap行注释掉
开启IP转发，和修改内核信息—三个节点都需要配置
master
[root@master ~]# vim /etc/sysctl.d/k8s.conf
net.ipv4.ip_forward = 1
net.bridge.bridge-nf-call-ip6tables = 1
net.bridge.bridge-nf-call-iptables = 1
[root@master ~]# modprobe br_netfilter
[root@master ~]# sysctl -p /etc/sysctl.d/k8s.conf
net.ipv4.ip_forward = 1
net.bridge.bridge-nf-call-ip6tables = 1
net.bridge.bridge-nf-call-iptables = 1
node2
[root@node2 ~]# vim /etc/sysctl.d/k8s.conf
net.ipv4.ip_forward = 1
net.bridge.bridge-nf-call-ip6tables = 1
net.bridge.bridge-nf-call-iptables = 1
[root@node2 ~]# modprobe br_netfilter
[root@node2 ~]# sysctl -p /etc/sysctl.d/k8s.conf
net.ipv4.ip_forward = 1
net.bridge.bridge-nf-call-ip6tables = 1
net.bridge.bridge-nf-call-iptables = 1
node3
[root@node3 ~]# vim /etc/sysctl.d/k8s.conf
net.ipv4.ip_forward = 1
net.bridge.bridge-nf-call-ip6tables = 1
net.bridge.bridge-nf-call-iptables = 1
[root@node3 ~]# modprobe br_netfilter
[root@node3 ~]# sysctl -p /etc/sysctl.d/k8s.conf
net.ipv4.ip_forward = 1
net.bridge.bridge-nf-call-ip6tables = 1
net.bridge.bridge-nf-call-iptables = 1
配置IPVS功能（三个节点都做）
master
[root@master ~]# vim /etc/sysconfig/modules/ipvs.modules
#!/bin/bash
modprobe -- ip_vs
modprobe -- ip_vs_rr
modprobe -- ip_vs_wrr
modprobe -- ip_vs_sh
[root@master ~]# chmod +x /etc/sysconfig/modules/ipvs.modules
[root@master ~]# bash /etc/sysconfig/modules/ipvs.modules
[root@master ~]# lsmod | grep -e ip_vs
ip_vs_sh 16384 0
ip_vs_wrr 16384 0
ip_vs_rr 16384 0
ip_vs 172032 6 ip_vs_rr,ip_vs_sh,ip_vs_wrr
nf_conntrack 172032 2 nf_nat,ip_vs
nf_defrag_ipv6 20480 2 nf_conntrack,ip_vs
libcrc32c 16384 5 nf_conntrack,nf_nat,nf_tables,xfs,ip_vs
[root@master ~]# reboot
node2
[root@node2 ~]# vim /etc/sysconfig/modules/ipvs.modules
#!/bin/bash
modprobe -- ip_vs
modprobe -- ip_vs_rr
modprobe -- ip_vs_wrr
modprobe -- ip_vs_sh
[root@node2 ~]# chmod +x /etc/sysconfig/modules/ipvs.modules
[root@node2 ~]# bash /etc/sysconfig/modules/ipvs.modules
[root@node2 ~]# lsmod | grep -e ip_vs
ip_vs_sh 16384 0
ip_vs_wrr 16384 0
ip_vs_rr 16384 0
ip_vs 172032 6 ip_vs_rr,ip_vs_sh,ip_vs_wrr
nf_conntrack 172032 2 nf_nat,ip_vs
nf_defrag_ipv6 20480 2 nf_conntrack,ip_vs
libcrc32c 16384 5 nf_conntrack,nf_nat,nf_tables,xfs,ip_vs
[root@node2 ~]# reboot
node3
[root@node3 ~]# vim /etc/sysconfig/modules/ipvs.modules
#!/bin/bash
modprobe -- ip_vs
modprobe -- ip_vs_rr
modprobe -- ip_vs_wrr
modprobe -- ip_vs_sh
[root@node3 ~]# chmod +x /etc/sysconfig/modules/ipvs.modules
[root@node3 ~]# bash /etc/sysconfig/modules/ipvs.modules
[root@node3 ~]# lsmod | grep -e ip_vs
ip_vs_sh 16384 0
ip_vs_wrr 16384 0
ip_vs_rr 16384 0
ip_vs 172032 6 ip_vs_rr,ip_vs_sh,ip_vs_wrr
nf_conntrack 172032 2 nf_nat,ip_vs
nf_defrag_ipv6 20480 2 nf_conntrack,ip_vs
libcrc32c 16384 5 nf_conntrack,nf_nat,nf_tables,xfs,ip_vs
[root@node3 ~]# reboot
安装docker
配置镜像仓库
[root@master yum.repos.d]# wget -O /etc/yum.repos.d/CentOS-Base.repo https://mirrors.aliyun.com/repo/Centos-vault-8.5.2111.repo
[root@master yum.repos.d]# yum install -y https://mirrors.aliyun.com/epel/epel-release-latest-8.noarch.rpm
[root@master yum.repos.d]# sed -i 's|^#baseurl=https://download.example/pub|baseurl=https://mirrors.aliyun.com|' /etc/yum.repos.d/epel*
[root@master yum.repos.d]# sed -i 's|^metalink|#metalink|' /etc/yum.repos.d/epel*
[root@master yum.repos.d]# wget https://mirrors.aliyun.com/docker-ce/linux/centos/docker-ce.repo
[root@master yum.repos.d]# scp /etc/yum.repos.d/* root@node2:/etc/yum.repos.d/
root@node2's password:
CentOS-Base.repo 100% 2495 3.3MB/s 00:00
docker-ce.repo 100% 2081 2.9MB/s 00:00
epel-modular.repo 100% 1692 2.3MB/s 00:00
epel.repo 100% 1326 1.0MB/s 00:00
epel-testing-modular.repo 100% 1791 1.1MB/s 00:00
epel-testing.repo 100% 1425 1.3MB/s 00:00
[root@master yum.repos.d]# scp /etc/yum.repos.d/* root@node3:/etc/yum.repos.d/
root@node3's password:
CentOS-Base.repo 100% 2495 3.1MB/s 00:00
docker-ce.repo 100% 2081 2.9MB/s 00:00
epel-modular.repo 100% 1692 2.4MB/s 00:00
epel.repo 100% 1326 1.1MB/s 00:00
epel-testing-modular.repo 100% 1791 2.6MB/s 00:00
epel-testing.repo 100% 1425 2.0MB/s 00:00
安装docker
master
[root@master yum.repos.d]# dnf -y install docker-ce --allowerasing
[root@master yum.repos.d]# systemctl restart docker
[root@master yum.repos.d]# systemctl enable docker
[root@master ~]# vim /etc/docker/daemon.json
[root@master ~]# cat /etc/docker/daemon.json
{
"registry-mirrors": [" https://wlfs9l74.mirror.aliyuncs.com"],
"exec-opts": ["native.cgroupdriver=systemd"],
"log-driver": "json-file",
"log-opts": {
"max-size": "100m"
},
"storage-driver": "overlay2"
}
[root@master ~]# systemctl daemon-reload
[root@master ~]# systemctl restart docker
node2
[root@node2 yum.repos.d]# dnf -y install docker-ce --allowerasing
[root@node2 yum.repos.d]# systemctl restart docker
[root@node2 yum.repos.d]# systemctl enable docker
[root@node2 ~]# vim /etc/docker/daemon.json
[root@node2 ~]# cat /etc/docker/daemon.json
{
"registry-mirrors": [" https://wlfs9l74.mirror.aliyuncs.com"],
"exec-opts": ["native.cgroupdriver=systemd"],
"log-driver": "json-file",
"log-opts": {
"max-size": "100m"
},
"storage-driver": "overlay2"
}
[root@node2 ~]# systemctl daemon-reload
[root@node2 ~]# systemctl restart docker
node3
[root@node3 yum.repos.d]# dnf -y install docker-ce --allowerasing
[root@node3 yum.repos.d]# systemctl restart docker
[root@node3 yum.repos.d]# systemctl enable docker
[root@node3 ~]# vim /etc/docker/daemon.json
[root@node3 ~]# cat /etc/docker/daemon.json
{
"registry-mirrors": [" https://wlfs9l74.mirror.aliyuncs.com"],
"exec-opts": ["native.cgroupdriver=systemd"],
"log-driver": "json-file",
"log-opts": {
"max-size": "100m"
},
"storage-driver": "overlay2"
}
[root@node3 ~]# systemctl daemon-reload
[root@node3 ~]# systemctl restart docker
安装k8s组件 三台主机操作均相同
配置仓库 k8s的镜像在国外所以此处切换为国内的镜像源
[root@master ~]# 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
[root@master ~]# yum list | grep kube
安装kubeadm kubelet kubectl工具 三台主机操作均相同
[root@master ~]# dnf -y install kubeadm kubelet kubectl
[root@master ~]# systemctl restart kubelet
[root@master ~]# systemctl enable kubelet
[root@master ~]# systemctl restart kubelet.service
[root@master ~]# systemctl enable kubelet.service
为确保后面集群初始化及加入集群能够成功执行，需要配置containerd的配置文件/etc/containerd/config.toml，此操作需要在所有节点执行
将/etc/containerd/config.toml文件中的k8s镜像仓库改为registry.aliyuncs.com/google_containers
[root@master ~]# containerd config default > /etc/containerd/config.toml
将/etc/containerd/config.toml文件中的k8s镜像仓库改为registry.aliyuncs.com/google_containers
然后重启并设置containerd服务
[root@master ~]# systemctl restart containerd
[root@master ~]# systemctl enable containerd
部署k8s的master节点（在master节点运行）
[root@master ~]# kubeadm init \
> --apiserver-advertise-address=192.168.203.100 \
> --image-repository registry.aliyuncs.com/google_containers \
> --kubernetes-version v1.25.4 \
> --service-cidr=10.96.0.0/12 \
> --pod-network-cidr=10.244.0.0/16
运行后会有初始化内容,建议将初始化内容保存在某个文件中
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
Alternatively, if you are the root user, you can run:
export KUBECONFIG=/etc/kubernetes/admin.conf
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 192.168.203.100:6443 --token lomink.zpqt5wyf6ykae9rp \
--discovery-token-ca-cert-hash sha256:05d83fb4d8e3397b03ba7d8f3c858cc32ee3af130778a14c1d36b328395caff2
[root@master ~]# vim /etc/profile.d/k8s.sh
[root@master ~]# export KUBECONFIG=/etc/kubernetes/admin.conf
[root@master ~]# source /etc/profile.d/k8s.sh
安装pod网络插件（CNI/flannel）
先wget下载
[root@master ~]# wget https://raw.githubusercontent.com/coreos/flannel/master/Documentation/kube-flannel.yml
[root@master ~]# kubectl apply -f kube-flannel.yml
将node节点加入到k8s集群中
node2
[root@node2 ~]# kubeadm join 192.168.203.100:6443 --token lomink.zpqt5wyf6ykae9rp \
> --discovery-token-ca-cert-hash sha256:05d83fb4d8e3397b03ba7d8f3c858cc32ee3af130778a14c1d36b328395caff2
node3
[root@node3 ~]# kubeadm join 192.168.203.100:6443 --token lomink.zpqt5wyf6ykae9rp \
> --discovery-token-ca-cert-hash sha256:05d83fb4d8e3397b03ba7d8f3c858cc32ee3af130778a14c1d36b328395caff2
master中查看
[root@master ~]# kubectl get node
NAME STATUS ROLES AGE VERSION
master.example.com Ready control-plane 141m v1.25.4
node2.example.com Ready <none> 63m v1.25.4
node3.example.com Ready <none> 6m17s v1.25.4
使用k8s集群创建一个pod，运行nginx容器，然后进行测试
[root@master ~]# kubectl create deployment nginx --image nginx
deployment.apps/nginx created
[root@master ~]# kubectl expose deployment nginx --port 80 --type NodePort
service/nginx exposed
[root@master ~]# kubectl get pods -o wide
NAME READY STATUS RESTARTS AGE IP NODE NOMINATED NODE READINESS GATES
nginx-76d6c9b8c-rsrgb 0/1 ContainerCreating 0 14s <none> node3.example.com <none> <none>
[root@master ~]# kubectl get services
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
kubernetes ClusterIP 10.96.0.1 <none> 443/TCP 159m
nginx NodePort 10.97.46.79 <none> 80:32515/TCP 15s
测试访问
修改默认网页
[root@master ~]# kubectl exec -it pod/nginx-76d6c9b8c-rsrgb -- /bin/bash
root@nginx-76d6c9b8c-rsrgb:/# cd /usr/share/nginx/html/
root@nginx-76d6c9b8c-rsrgb:/usr/share/nginx/html# ls
50x.html index.html
root@nginx-76d6c9b8c-rsrgb:/usr/share/nginx/html# echo "fuck world" > index.html
