相关术语
- 主机Master：k8s里面的master指的是集群控制节点。每个k8s集群都需要一个master节点来负责整个集群的管理和控制，基本上k8s所有的控制命令都是发
- 节点Node：负责执行请求和所在分配任务的计算机，由k8s主机负责对节点进行控制；Node可以是一台物理主机，也可以是一台虚拟机
- Pod：Pod就是一组容器的集合，在Pod里面的容器共享网络/存储，所以他们可以通过localhost进行内部通信。虽然网络和存储是共享的，但是cpu和memery不是共享，多容器之间可以有属于自己的CGroup，也就说可以单独对pod中的容器做资源限制
环境准备
0、linux镜像地址：http://mirror.nsc.liu.se/centos-store/7.5.1804/isos/x86_64/
1、关闭防火墙以及开机自启动
#systemctl stop firewalld && systemctl disable firewalld
防火墙导致端口不通2、关闭selinux 以及开机自启
#sestatus // 查看selinux状态
#setenforce 0 // 临时关闭selinux，重启后被打开
#vim /etc/selinux/config
selinux=disabled //重启后关闭
//可能导致错误，selinux已经被flannel网络组件弃用
https://github.com/flannel-io/flannel/issues/7093、关闭内存swap
# swapoff -a
# free -m // 查看是否关闭
total used free shared buff/cache available
Mem: 4460 961 2660 10 839 3430
Swap: 0 0 0
# vim /etc/fstab // 永久关闭，重启生效，注释掉最后一行
#/dev/mapper/centos-swap swap swap defaults 0 04、加载ipvs模块，kube-proxy使用ipvs模式
cat > /etc/sysconfig/modules/ipvs.modules <<EOF
#!/bin/bash
modprobe -- ip_vs
modprobe -- ip_vs_rr
modprobe -- ip_vs_wrr
modprobe -- ip_vs_sh
modprobe -- nf_conntrack_ipv4
EOF
chmod 755 /etc/sysconfig/modules/ipvs.modules && bash /etc/sysconfig/modules/ipvs.modules && lsmod | grep -e ip_vs -e nf_conntrack_ipv4
//可能出现的问题
[ERROR FileContent--proc-sys-net-bridge-bridge-nf-call-iptables]: /proc/sys/net/bridge/bridge-nf-call-iptables contents are not set to 1
# echo "1" >/proc/sys/net/bridge/bridge-nf-call-iptables // 设置错误
5、配置yum源
cat>>/etc/yum.repos.d/kubrenetes.repo<<EOF
[kubernetes]
name=Kubernetes Repo
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
EOF安装
三台虚拟机
| ip | 角色 | 主机名 |
|---|---|---|
| 192.168.42.179 | master主节点 | k8s-master |
| 192.168.47.139 | node1从节点 | k8s-node1 |
- 设置主机名称
hostnamectl --static set-hostname k8s-master
hostnamectl --static set-hostname k8s-node1- 加入/etc/hosts
10.0.0.6 k8s-master
10.0.0.10 k8s-node1
10.0.0.9 k8s-node2- yum 安装软件
- kubeadm：用来初始化集群的指令
- kubelet：在集群中的每个节点用来启动pod和container等
- kubectl：用来与集群通信的命令行工具
yum install -y kubelet kubeadm kubectl
kubelet --version //查看版本
systemctl enable kubelet // 开机启动- 启动master节点
[root@k8s-master ~]# kubeadm init --kubernetes-version=v1.20.4 \
> --image-repository registry.aliyuncs.com/google_containers \
> --apiserver-advertise-address=10.0.0.6 \
> --service-cidr=10.1.0.0/16 \
> --pod-network-cidr=10.244.0.0/16
[init] Using Kubernetes version: v1.20.4
[preflight] Running pre-flight checks
[preflight] Pulling images required for setting up a Kubernetes cluster
[preflight] This might take a minute or two, depending on the speed of your internet connection
[preflight] You can also perform this action in beforehand using 'kubeadm config images pull'
[certs] Using certificateDir folder "/etc/kubernetes/pki"
[certs] Generating "ca" certificate and key
[certs] Generating "apiserver" certificate and key
[certs] apiserver serving cert is signed for DNS names [k8s-master kubernetes kubernetes.default kubernetes.default.svc kubernetes.default.svc.cluster.local] and IPs [10.1.0.1 192.168.42.179]
[certs] Generating "apiserver-kubelet-client" certificate and key
[certs] Generating "front-proxy-ca" certificate and key
[certs] Generating "front-proxy-client" certificate and key
[certs] Generating "etcd/ca" certificate and key
[certs] Generating "etcd/server" certificate and key
[certs] etcd/server serving cert is signed for DNS names [k8s-master localhost] and IPs [192.168.42.179 127.0.0.1 ::1]
[certs] Generating "etcd/peer" certificate and key
[certs] etcd/peer serving cert is signed for DNS names [k8s-master localhost] and IPs [192.168.42.179 127.0.0.1 ::1]
[certs] Generating "etcd/healthcheck-client" certificate and key
[certs] Generating "apiserver-etcd-client" certificate and key
[certs] Generating "sa" key and public key
[kubeconfig] Using kubeconfig folder "/etc/kubernetes"
[kubeconfig] Writing "admin.conf" kubeconfig file
[kubeconfig] Writing "kubelet.conf" kubeconfig file
[kubeconfig] Writing "controller-manager.conf" kubeconfig file
[kubeconfig] Writing "scheduler.conf" kubeconfig file
[kubelet-start] Writing kubelet environment file with flags to file "/var/lib/kubelet/kubeadm-flags.env"
[kubelet-start] Writing kubelet configuration to file "/var/lib/kubelet/config.yaml"
[kubelet-start] Starting the kubelet
[control-plane] Using manifest folder "/etc/kubernetes/manifests"
[control-plane] Creating static Pod manifest for "kube-apiserver"
[control-plane] Creating static Pod manifest for "kube-controller-manager"
[control-plane] Creating static Pod manifest for "kube-scheduler"
[etcd] Creating static Pod manifest for local etcd in "/etc/kubernetes/manifests"
[wait-control-plane] Waiting for the kubelet to boot up the control plane as static Pods from directory "/etc/kubernetes/manifests". This can take up to 4m0s
[kubelet-check] Initial timeout of 40s passed.
[apiclient] All control plane components are healthy after 59.502340 seconds
[upload-config] Storing the configuration used in ConfigMap "kubeadm-config" in the "kube-system" Namespace
[kubelet] Creating a ConfigMap "kubelet-config-1.20" in namespace kube-system with the configuration for the kubelets in the cluster
[upload-certs] Skipping phase. Please see --upload-certs
[mark-control-plane] Marking the node k8s-master as control-plane by adding the labels "node-role.kubernetes.io/master=''" and "node-role.kubernetes.io/control-plane='' (deprecated)"
[mark-control-plane] Marking the node k8s-master as control-plane by adding the taints [node-role.kubernetes.io/master:NoSchedule]
[bootstrap-token] Using token: 08tizs.47bj2g1lc3l7vopr
[bootstrap-token] Configuring bootstrap tokens, cluster-info ConfigMap, RBAC Roles
[bootstrap-token] configured RBAC rules to allow Node Bootstrap tokens to get nodes
[bootstrap-token] configured RBAC rules to allow Node Bootstrap tokens to post CSRs in order for nodes to get long term certificate credentials
[bootstrap-token] configured RBAC rules to allow the csrapprover controller automatically approve CSRs from a Node Bootstrap Token
[bootstrap-token] configured RBAC rules to allow certificate rotation for all node client certificates in the cluster
[bootstrap-token] Creating the "cluster-info" ConfigMap in the "kube-public" namespace
[kubelet-finalize] Updating "/etc/kubernetes/kubelet.conf" to point to a rotatable kubelet client certificate and key
[addons] Applied essential addon: CoreDNS
[addons] Applied essential addon: kube-proxy
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 192.168.42.179:6443 --token 08tizs.47bj2g1lc3l7vopr \
--discovery-token-ca-cert-hash sha256:351888c88e02470dd36753391c34f646a31bf1c1bcdbc7c308b7c024efba44d0
// 启动成功之后，执行--kubernetes-version：指定版本
--apiserver-advertise-address：用户指定master的那个监听地址
--pod-network-cidr：指定pod的网络范围，该参数依赖于使用的网络方案，使用经典的flannel网络
- 查看节点信息
[root@k8s-master ~]# kubectl get node
NAME STATUS ROLES AGE VERSION
k8s-master NotReady control-plane,master 78m v1.20.4- 安装flannel网络组件
[root@k8s-master ~]# kubectl apply -f https://raw.githubusercontent.com/coreos/flannel/master/Documentation/kube-flannel.yml
podsecuritypolicy.policy/psp.flannel.unprivileged created
clusterrole.rbac.authorization.k8s.io/flannel created
clusterrolebinding.rbac.authorization.k8s.io/flannel created
serviceaccount/flannel created
configmap/kube-flannel-cfg created
daemonset.apps/kube-flannel-ds created
[root@k8s-master ~]# kubectl get pod -n kube-system // 查看组件状态
NAME READY STATUS RESTARTS AGE
coredns-7f89b7bc75-lrjcf 1/1 Running 0 91m
coredns-7f89b7bc75-ssm2t 1/1 Running 0 91m
etcd-k8s-master 1/1 Running 0 92m
kube-apiserver-k8s-master 1/1 Running 0 92m
kube-controller-manager-k8s-master 1/1 Running 0 92m
kube-flannel-ds-vwzhq 1/1 Running 0 23s // flannel网络组件
kube-proxy-8bssr 1/1 Running 0 91m
kube-scheduler-k8s-master 1/1 Running 0 92m
- 加入从节点node1，master节点启动成功，可以看到
kubeadm join 192.168.42.179:6443 --token 08tizs.47bj2g1lc3l7vopr \
--discovery-token-ca-cert-hash sha256:351888c88e02470dd36753391c34f646a31bf1c1bcdbc7c308b7c024efba44d0 在master节点上，查看状态
[root@k8s-master ~]# kubectl get node
NAME STATUS ROLES AGE VERSION
k8s-master Ready control-plane,master 94m v1.20.4
k8s-node2 NotReady <none> 7s v1.20.4
[root@k8s-master ~]# kubectl get pod -n kube-system
NAME READY STATUS RESTARTS AGE
coredns-7f89b7bc75-lrjcf 1/1 Running 0 94m
coredns-7f89b7bc75-ssm2t 1/1 Running 0 94m
etcd-k8s-master 1/1 Running 0 95m
kube-apiserver-k8s-master 1/1 Running 0 95m
kube-controller-manager-k8s-master 1/1 Running 0 95m
kube-flannel-ds-vwzhq 1/1 Running 0 3m23s
kube-flannel-ds-xv8fm 1/1 Running 0 35s
kube-proxy-8bssr 1/1 Running 0 94m
kube-proxy-cjrlf 1/1 Running 0 35s
kube-scheduler-k8s-master 1/1 Running 0 95m