使用containerd从0搭建k8s(kubernetes)集群
准备环境
准备两台服务器节点，如果需要安装虚拟机，可以参考《wmware和centos安装过程》
| 机器名 | IP | 角色 | CPU | 内存 |
|---|---|---|---|---|
| centos01 | 192.168.109.130 | master | 4核 | 2G |
| centos02 | 192.168.109.131 | node | 4核 | 2G |
设置主机名，所有节点都执行
vim /etc/hosts
增加
192.168.109.130 centos01
192.168.109.131 centos02
关闭防火墙，所有节点都执行
systemctl stop firewalld
systemctl disable firewalld
setenforce 0
vim /etc/selinux/config
修改SELINUX的值
SELINUX=disabled
关闭swap内存，所有节点都执行
swapoff -a
vim /etc/fstab
将该行注释掉
/dev/mapper/cs-swap swap
配置网桥，所有节点都执行
1.修改参数
vim /etc/sysctl.conf
net.bridge.bridge-nf-call-ip6tables = 1
net.bridge.bridge-nf-call-iptables = 1
net.ipv4.ip_forward = 1
vm.swappiness = 0
2.然后，加载如下两个模块，所有节点都执行
modprobe ip_vs_rr
modprobe br_netfilter
3.生效配置
[root@centos01 opt] sysctl -p
net.bridge.bridge-nf-call-ip6tables = 1
net.bridge.bridge-nf-call-iptables = 1
net.ipv4.ip_forward = 1
vm.swappiness = 0
安装containerd
以下步骤所有节点都执行。
安装
wget https://github.com/containerd/containerd/releases/download/v1.7.2/containerd-1.7.2-linux-amd64.tar.gz
tar Cxzvf /usr/local containerd-1.7.2-linux-amd64.tar.gz
修改配置
mkdir /etc/containerd
containerd config default > /etc/containerd/config.toml
vim /etc/containerd/config.toml
SystemdCgroup的值改为true
SystemdCgroup = true
由于国内下载不到registry.k8s.io的镜像，修改sandbox_image的值为：
sandbox_image = "registry.aliyuncs.com/google_containers/pause:3.9"
启动服务
mkdir -p /usr/local/lib/systemd/system
wget https://raw.githubusercontent.com/containerd/containerd/main/containerd.service
mv containerd.service /usr/local/lib/systemd/system
systemctl daemon-reload
systemctl enable --now containerd
验证安装
[root@centos01 opt] ctr version
Client:
Version: v1.7.2
Revision: 0cae528dd6cb557f7201036e9f43420650207b58
Go version: go1.20.4
Server:
Version: v1.7.2
Revision: 0cae528dd6cb557f7201036e9f43420650207b58
UUID: 747cbf1b-17d4-4124-987a-203d8c72de7c
安装runc
以下步骤所有节点都执行。
准备文件
wget https://github.com//opencontainers/runc/releases/download/v1.1.7/runc.amd64
chmod +x runc.amd64
查找containerd安装时已安装的runc所在的位置
[root@centos01 opt] which runc
/usr/bin/runc
替换上一步的结果文件
mv -f runc.amd64 /usr/bin/runc
验证安装
[root@centos01 opt] runc -v
runc version 1.1.7
commit: v1.1.7-0-g860f061b
spec: 1.0.2-dev
go: go1.20.3
libseccomp: 2.5.4
安装kubernetes
添加阿里云的kubernetes源，所有节点都执行
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
安装最新版，所有节点都执行
yum install -y kubeadm kubelet kubectl
开机自启动，所有节点都执行
systemctl enable kubelet
验证安装，所有节点都执行
[root@centos01 opt] kubeadm version
kubeadm version: &version.Info{Major:"1", Minor:"27", GitVersion:"v1.27.1", GitCommit:"4c9411232e10168d7b050c49a1b59f6df9d7ea4b", GitTreeState:"clean", BuildDate:"2023-04-14T13:20:04Z", GoVersion:"go1.20.3", Compiler:"gc", Platform:"linux/amd64"}
初始化集群，仅在master(centos01)上执行
[root@centos01 opt] kubeadm init --apiserver-advertise-address 192.168.109.130 --image-repository registry.aliyuncs.com/google_containers --kubernetes-version v1.27.1 --pod-network-cidr=10.244.0.0/16
...
...
...
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
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 192.168.109.130:6443 --token osh87v.zvo010kamsr8esmp \
--discovery-token-ca-cert-hash sha256:ff4607c7c194e9f756b1eb509e64d2d926b5f8f9556a85c3c14a2d25add28230
其中，
–apiserver-advertise-address：通告侦听地址
–image-repository：指定镜像地址使用阿里云的，默认会使用谷歌镜像
–kubernetes-version：指定当前的kubernetes的版本
–pod-network-cidr=10.244.0.0/16：flannel网络的固定地址范围
仔细阅读kubeadm init执行的结果，根据提示，还需要进行3步操作
1.笔者用的是root用户，仅在master节点执行
vim /etc/profile
在最后一行增加
export KUBECONFIG=/etc/kubernetes/admin.conf
生效环境变量
source /etc/profile
2.安装网络插件，可以选择calico或flannel，这里选择安装flannel，仅在master节点执行
下载安装文件
wget https://github.com/flannel-io/flannel/releases/latest/download/kube-flannel.yml
vim kube-flannel.yml
和--pod-network-cidr的一样
"Network": "10.244.0.0/16"
安装网络插件
kubectl apply -f kube-flannel.yml
3.其他节点加入集群，非master节点都执行
[root@centos02 opt] kubeadm join 192.168.109.130:6443 --token osh87v.zvo010kamsr8esmp --discovery-token-ca-cert-hash sha256:ff4607c7c194e9f756b1eb509e64d2d926b5f8f9556a85c3c14a2d25add28230
验证安装结果，仅在master节点执行
[root@centos01 opt] kubectl get nodes
NAME STATUS ROLES AGE VERSION
centos01 Ready control-plane 134m v1.27.1
centos02 Ready <none> 133m v1.27.1
[root@centos01 opt] kubectl get pods -n kube-system
NAME READY STATUS RESTARTS AGE
coredns-7bdc4cb885-l4vs2 1/1 Running 0 9m3s
coredns-7bdc4cb885-wzc8x 1/1 Running 0 9m3s
etcd-centos01 1/1 Running 0 9m18s
kube-apiserver-centos01 1/1 Running 0 9m18s
kube-controller-manager-centos01 1/1 Running 0 9m19s
kube-proxy-m92hr 1/1 Running 0 28s
kube-proxy-pv4hw 1/1 Running 0 9m3s
kube-scheduler-centos01 1/1 Running 0 9m18s
强烈建议重启一遍所有服务器节点，有可能会暴露出来隐藏的问题，再次验证以上结果，仍然正常。
至此完成安装，接下来可以部署应用了，推荐一个平台：https://gitee.com/i512team/dhorse，是一个简单易用、以应用为中心的云原生DevOps系统，具有持续集成、持续部署、微服务治理等功能，主要特点：部署简单、操作简洁、功能快速。