Kubernetes 深入学习（一） —— 入门和集群安装部署

k8s使用kubeadm进行安装步骤，使用kubeadm安装k8s会简单很多，一直想总结写一篇简单明了的安装教程，希望能有用。k8s在2020年初发布的第一个版本是1.18.0，目前最新版本是1.19.4，并且1.20的版本应该会在年底发布，但是我们这里安装的版本是1.18。

k8s-基础概念

1.系统准备
搭建虚拟机centos7环境，虚拟机固定IP地址
安装三台虚拟机，一台作master节点，两台作node节点
关闭防护墙
[root@master01 ~]# systemctl stop firewalld
[root@master01 ~]# systemctl disable firewalld
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注：可以不关闭防火墙，但是要设置各个需要的端口的开放规则，比较麻烦，我们自己的开发环境就直接关了防火墙

关闭swap
[root@master01 ~]# vi /etc/fstab
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注释里面的"/dev/mapper/centos-swap swap"



注：
1.swap相当于“虚拟内存”。当物理内存不足时，拿出部分硬盘空间当SWAP分区（虚拟成内存）使用，从而解决内存容量不足的情况。
2.kubelet 在 1.8 版本以后强制要求 swap 必须关闭
3.free -m 命令可以查看交换区的空间大小，我们注释完再使用这个命令发现交换区swap还没关闭，因为需要重启才生效

关闭selinux
[root@master01 ~]# vi /etc/selinux/config
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注释掉SELINUX=disabled,然后重启，reboot


注：
1.selinux这个是用来加强安全性的一个组件，挺复杂的，一般直接禁用
2.关闭selinux以允许容器访问宿主机的文件系统

添加阿里源
[root@master01 ~]# rm -rfv /etc/yum.repos.d/*
[root@master01 ~]# curl -o /etc/yum.repos.d/CentOS-Base.repo http://mirrors.aliyun.com/repo/Centos-7.repo
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注：如果是centos8,则链接最后面的Centos-7.repo修改成Centos-8.repo，否则使用yum安装的时候会提示没有可用的软件包

配置主机名
[root@master01 ~]# hostnamectl set-hostname master01
[root@master01 ~]# more /etc/hostname
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注：这一步如果少了的话，后面执行kubeadm join的时候会报错，提示有相同名称的节点，所有其他机器的hostname不能一样，工作节点可以写node01、node02这样子

2.配置内核参数，将桥接的IPv4流量传递到iptables的链
[root@master01 ~]# cat > /etc/sysctl.d/k8s.conf <<EOF
net.bridge.bridge-nf-call-ip6tables = 1
net.bridge.bridge-nf-call-iptables = 1
EOF
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注：k8s该网络需要设置内核参数bridge-nf-call-iptables=1，没有这个后面添加网络的时候会报错。

3.安装常用包
[root@master01 ~]# yum install vim bash-completion net-tools gcc -y
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4.使用aliyun源安装docker-ce
[root@master01 ~]# yum install -y yum-utils device-mapper-persistent-data lvm2
[root@master01 ~]# yum-config-manager --add-repo https://mirrors.aliyun.com/docker-ce/linux/centos/docker-ce.repo
[root@master01 ~]# yum -y install docker-ce
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注：yum-config-manager命令配置aliyun源，但是这个命令来源于yum-utils，所以需要先安装yum-utils

安装完docker后添加aliyun的docker仓库加速器

[root@master01 ~]# mkdir -p /etc/docker
[root@master01 ~]# tee /etc/docker/daemon.json <<-'EOF'
{
"registry-mirrors": ["https://fl791z1h.mirror.aliyuncs.com"]
}
EOF
[root@master01 ~]# systemctl daemon-reload
[root@master01 ~]# systemctl restart docker
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注：tee /etc/docker/daemon.json <<-'EOF’后面的 <<-'EOF’是没有空格的，如图我第一次有空格输入EOF就没有结束

5.安装kubectl、kubelet、kubeadm
添加阿里kubernetes源

[root@master01 ~]# 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
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安装kubectl、kubelet、kubeadm

[root@master01 ~]# yum -y install kubectl-1.18.0 kubelet-1.18.0 kubeadm-1.18.0
[root@master01 ~]# systemctl enable kubelet
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注： yum install kubectl kubelet kubeadm，这样写会默认安装最新版1.19.4,但是和我后面执行的kubeadm init --kubernetes-version=1.18.0版本不一致，会报错，所以我这里yum后面指定了版本

6.初始化k8s集群(master节点)
这一步开始区分master、ndoe节点执行的命令了，上面的步骤master、node都是一样

[root@master01 ~]# kubeadm init --kubernetes-version=1.18.0 \
--apiserver-advertise-address=192.168.137.110 \
--image-repository registry.aliyuncs.com/google_containers \
--service-cidr=10.10.0.0/16 --pod-network-cidr=10.122.0.0/16
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集群初始化成功后返回如下信息：

W1125 22:47:32.274048 47607 configset.go:202] WARNING: kubeadm cannot validate component configs for API groups [kubelet.config.k8s.io kubeproxy.config.k8s.io]
[init] Using Kubernetes version: v1.18.0
[preflight] Running pre-flight checks
[WARNING IsDockerSystemdCheck]: detected "cgroupfs" as the Docker cgroup driver. The recommended driver is "systemd". Please follow the guide at https://kubernetes.io/docs/setup/cri/
[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'
[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
[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 [localhost.localdomain kubernetes kubernetes.default kubernetes.default.svc kubernetes.default.svc.cluster.local] and IPs [10.10.0.1 192.168.137.110]
[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 [localhost.localdomain localhost] and IPs [192.168.137.110 127.0.0.1 ::1]
[certs] Generating "etcd/peer" certificate and key
[certs] etcd/peer serving cert is signed for DNS names [localhost.localdomain localhost] and IPs [192.168.137.110 127.0.0.1 ::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
[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"
W1125 22:47:35.941950 47607 manifests.go:225] the default kube-apiserver authorization-mode is "Node,RBAC"; using "Node,RBAC"
[control-plane] Creating static Pod manifest for "kube-scheduler"
W1125 22:47:35.943106 47607 manifests.go:225] the default kube-apiserver authorization-mode is "Node,RBAC"; using "Node,RBAC"
[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
[apiclient] All control plane components are healthy after 21.504047 seconds
[upload-config] Storing the configuration used in ConfigMap "kubeadm-config" in the "kube-system" Namespace
[kubelet] Creating a ConfigMap "kubelet-config-1.18" 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 localhost.localdomain as control-plane by adding the label "node-role.kubernetes.io/master=''"
[mark-control-plane] Marking the node localhost.localdomain as control-plane by adding the taints [node-role.kubernetes.io/master:NoSchedule]
[bootstrap-token] Using token: o11ulw.ovtj9vov7ob34hs7
[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

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 192.168.137.110:6443 --token o11ulw.ovtj9vov7ob34hs7 \
--discovery-token-ca-cert-hash sha256:38a93626ac4e86155583e7ef9b32cb13739d5f5bc3da2b4ed7e74aec8112bea7

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记录后面的kubeadm join这段内容，此内容需要在其它节点加入Kubernetes集群时执行。

kubeadm join 192.168.137.110:6443 --token o11ulw.ovtj9vov7ob34hs7 \
--discovery-token-ca-cert-hash sha256:38a93626ac4e86155583e7ef9b32cb13739d5f5bc3da2b4ed7e74aec8112bea7
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创建kubectl

[root@master01 ~]# mkdir -p $HOME/.kube
[root@master01 ~]# sudo cp -i /etc/kubernetes/admin.conf $HOME/.kube/config
[root@master01 ~]# sudo chown $(id -u):$(id -g) $HOME/.kube/config
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注：
1.不配置$HOME/.kube/config的话，kubectl命令不可用，
2.node节点写法有点不一样，node节点的这行为：sudo cp -i /etc/kubernetes/kubelet.conf.conf $HOME/.kube/config

7.安装calico网络（master节点）
[root@master01 ~]# kubectl apply -f https://docs.projectcalico.org/manifests/calico.yaml
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注：
安装calico网络网络后过一会再输入kubectl get node，可以看到节点的STATUS由NotReady变为Ready

8.node节点加入集群（node节点）
[root@node01 ~]# kubeadm join 192.168.137.110:6443 --token o11ulw.ovtj9vov7ob34hs7 --discovery-token-ca-cert-hash sha256:38a93626ac4e86155583e7ef9b32cb13739d5f5bc3da2b4ed7e74aec8112bea7
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注：
1.kubeadm init后得到的token有效期为24小时，过期后需要重新创建token,执行：kubeadm token create获取新token
2.kubeadm token list 查看token列表，

创建kubectl

[root@master01 ~]# mkdir -p $HOME/.kube
[root@master01 ~]# sudo cp -i /etc/kubernetes/kubelet.conf.conf
[root@master01 ~]# sudo chown $(id -u):$(id -g) $HOME/.kube/config
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版权声明：本文为CSDN博主「新林。」的原创文章，遵循CC 4.0 BY-SA版权协议，转载请附上原文出处链接及本声明。
原文链接：https://blog.csdn.net/qq_21187515/article/details/110097982