在之前的文章，我们已经演示了 yum 和二进制方式的安装方式，本文我们将用官方推荐的 kubeadm 来进行安装部署。
kubeadm 是 Kubernetes 官方提供的用于快速安装Kubernetes集群的工具，伴随Kubernetes每个版本的发布都会同步更新，kubeadm会对集群配置方面的一些实践做调整，通过实验kubeadm可以学习到Kubernetes官方在集群配置上一些新的最佳实践。
一、环境准备
1、软件版本
| 软件 | 版本 |
|---|---|
| kubernetes | v1.12.2 |
| CentOS 7.5 | CentOS Linux release 7.5.1804 |
| Docker | v18.06 |
| flannel | 0.10.0 |
2、节点规划
| IP | 角色 | 主机名 |
|---|---|---|
| 172.18.8.200 | k8s master | master.wzlinux.com |
| 172.18.8.201 | k8s node01 | node01.wzlinux.com |
| 172.18.8.202 | k8s node02 | node02.wzlinux.com |
节点及网络规划如下：
3、系统配置
关闭防火墙。
systemctl stop firewalld
systemctl disable firewalld配置/etc/hosts，添加如下内容。
172.18.8.200 master.wzlinux.com master
172.18.8.201 node01.wzlinux.com node01
172.18.8.202 node02.wzlinux.com node02关闭SELinux。
sed -i 's#SELINUX=enforcing#SELINUX=disabled#g' /etc/selinux/config
setenforce 0关闭swap。
swapoff -a
sed -i 's/.*swap.*/#&/' /etc/fstab配置转发参数。
cat <<EOF > /etc/sysctl.d/k8s.conf
net.bridge.bridge-nf-call-ip6tables = 1
net.bridge.bridge-nf-call-iptables = 1
EOFsysctl --system设置国内kubernetes阿里云源。
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
EOF4、docker安装
因为不管是master还是node，都是需要容器引擎，所以我们提前把docker安装好。
设置官方docker源。
wget https://mirrors.aliyun.com/docker-ce/linux/centos/docker-ce.repo -P /etc/yum.repos.d/查看目前官方仓库的docker版本。
[root@master ~]# yum list docker-ce.x86_64 --showduplicates |sort -r
已加载插件：fastestmirror
可安装的软件包
* updates: mirrors.aliyun.com
Loading mirror speeds from cached hostfile
* extras: mirrors.aliyun.com
docker-ce.x86_64 3:18.09.0-3.el7 docker-ce-stable
docker-ce.x86_64 18.06.1.ce-3.el7 docker-ce-stable
docker-ce.x86_64 18.06.0.ce-3.el7 docker-ce-stable
docker-ce.x86_64 18.03.1.ce-1.el7.centos docker-ce-stable
docker-ce.x86_64 18.03.0.ce-1.el7.centos docker-ce-stable
docker-ce.x86_64 17.12.1.ce-1.el7.centos docker-ce-stable
docker-ce.x86_64 17.12.0.ce-1.el7.centos docker-ce-stable
docker-ce.x86_64 17.09.1.ce-1.el7.centos docker-ce-stable
docker-ce.x86_64 17.09.0.ce-1.el7.centos docker-ce-stable
docker-ce.x86_64 17.06.2.ce-1.el7.centos docker-ce-stable
docker-ce.x86_64 17.06.1.ce-1.el7.centos docker-ce-stable
docker-ce.x86_64 17.06.0.ce-1.el7.centos docker-ce-stable
docker-ce.x86_64 17.03.3.ce-1.el7 docker-ce-stable
docker-ce.x86_64 17.03.2.ce-1.el7.centos docker-ce-stable
docker-ce.x86_64 17.03.1.ce-1.el7.centos docker-ce-stable
docker-ce.x86_64 17.03.0.ce-1.el7.centos docker-ce-stable
* base: mirrors.aliyun.com根据官方的推荐要求，我们需要安装v18.06。
yum install docker-ce-18.06.1.ce -y
systemctl enable docker && systemctl start docker配置国内镜像仓库加速器。
sudo mkdir -p /etc/docker
sudo tee /etc/docker/daemon.json <<-'EOF'
{
"registry-mirrors": ["https://hdi5v8p1.mirror.aliyuncs.com"]
}
EOF
sudo systemctl daemon-reload二、安装 master 节点
1、软件安装
因为一些组件都是运行在容器里面的，比如kube-apiserver，kube-controller-manager，kube-scheduler，所以我们master需要安装的软件有docker，kubeadm，kubelet，kubectl。
yum install kubelet kubeadm kubectl -y
systemctl enable kubelet && systemctl start kubelet2、初始化
因为国内没办法访问Google的镜像源，变通的方法是从其他镜像源下载后，注意下载的版本尽量和我们的kubeadm等版本一样，我们选择v1.12.2，修改tag。执行下面这个Shell脚本即可。
#!/bin/bash
kube_version=:v1.12.2
kube_images=(kube-proxy kube-scheduler kube-controller-manager kube-apiserver)
addon_images=(etcd-amd64:3.2.24 coredns:1.2.2 pause-amd64:3.1)
for imageName in ${kube_images[@]} ; do
docker pull registry.cn-hangzhou.aliyuncs.com/google_containers/$imageName-amd64$kube_version
docker image tag registry.cn-hangzhou.aliyuncs.com/google_containers/$imageName-amd64$kube_version k8s.gcr.io/$imageName$kube_version
docker image rm registry.cn-hangzhou.aliyuncs.com/google_containers/$imageName-amd64$kube_version
done
for imageName in ${addon_images[@]} ; do
docker pull registry.cn-hangzhou.aliyuncs.com/google_containers/$imageName
docker image tag registry.cn-hangzhou.aliyuncs.com/google_containers/$imageName k8s.gcr.io/$imageName
docker image rm registry.cn-hangzhou.aliyuncs.com/google_containers/$imageName
done
docker tag k8s.gcr.io/etcd-amd64:3.2.24 k8s.gcr.io/etcd:3.2.24
docker image rm k8s.gcr.io/etcd-amd64:3.2.24
docker tag k8s.gcr.io/pause-amd64:3.1 k8s.gcr.io/pause:3.1
docker image rm k8s.gcr.io/pause-amd64:3.1关于脚本中的各镜像的版本，如果大家不清楚的话，可以先进行
kubeadm init初始化一下，查看一下报错的版本，然后我们在针对获取。
执行脚本，我们就把需要的的镜像下载下来了，我们是使用别人做好的仓库，当然我们也可以建自己的私有仓库。
[root@master ~]# docker images
REPOSITORY TAG IMAGE ID CREATED SIZE
k8s.gcr.io/kube-proxy v1.12.2 15e9da1ca195 4 weeks ago 96.5MB
k8s.gcr.io/kube-apiserver v1.12.2 51a9c329b7c5 4 weeks ago 194MB
k8s.gcr.io/kube-controller-manager v1.12.2 15548c720a70 4 weeks ago 164MB
k8s.gcr.io/kube-scheduler v1.12.2 d6d57c76136c 4 weeks ago 58.3MB
k8s.gcr.io/etcd 3.2.24 3cab8e1b9802 2 months ago 220MB
k8s.gcr.io/coredns 1.2.2 367cdc8433a4 3 months ago 39.2MB
k8s.gcr.io/pause 3.1 da86e6ba6ca1 11 months ago 742kB接下来执行Master节点的初始化。
kubeadm init --kubernetes-version=v1.12.2 --pod-network-cidr=10.244.0.0/16 --service-cidr=10.96.0.0/12[init] using Kubernetes version: v1.12.2
[preflight] running pre-flight checks
[preflight/images] Pulling images required for setting up a Kubernetes cluster
[preflight/images] This might take a minute or two, depending on the speed of your internet connection
[preflight/images] You can also perform this action in beforehand using 'kubeadm config images pull'
[kubelet] Writing kubelet environment file with flags to file "/var/lib/kubelet/kubeadm-flags.env"
[kubelet] Writing kubelet configuration to file "/var/lib/kubelet/config.yaml"
[preflight] Activating the kubelet service
[certificates] Generated front-proxy-ca certificate and key.
[certificates] Generated front-proxy-client certificate and key.
[certificates] Generated etcd/ca certificate and key.
[certificates] Generated apiserver-etcd-client certificate and key.
[certificates] Generated etcd/server certificate and key.
[certificates] etcd/server serving cert is signed for DNS names [master.wzlinux.com localhost] and IPs [127.0.0.1 ::1]
[certificates] Generated etcd/peer certificate and key.
[certificates] etcd/peer serving cert is signed for DNS names [master.wzlinux.com localhost] and IPs [172.18.8.200 127.0.0.1 ::1]
[certificates] Generated etcd/healthcheck-client certificate and key.
[certificates] Generated ca certificate and key.
[certificates] Generated apiserver-kubelet-client certificate and key.
[certificates] Generated apiserver certificate and key.
[certificates] apiserver serving cert is signed for DNS names [master.wzlinux.com kubernetes kubernetes.default kubernetes.default.svc kubernetes.default.svc.cluster.local] and IPs [10.96.0.1 172.18.8.200]
[certificates] valid certificates and keys now exist in "/etc/kubernetes/pki"
[certificates] Generated sa key and public key.
[kubeconfig] Wrote KubeConfig file to disk: "/etc/kubernetes/admin.conf"
[kubeconfig] Wrote KubeConfig file to disk: "/etc/kubernetes/kubelet.conf"
[kubeconfig] Wrote KubeConfig file to disk: "/etc/kubernetes/controller-manager.conf"
[kubeconfig] Wrote KubeConfig file to disk: "/etc/kubernetes/scheduler.conf"
[controlplane] wrote Static Pod manifest for component kube-apiserver to "/etc/kubernetes/manifests/kube-apiserver.yaml"
[controlplane] wrote Static Pod manifest for component kube-controller-manager to "/etc/kubernetes/manifests/kube-controller-manager.yaml"
[controlplane] wrote Static Pod manifest for component kube-scheduler to "/etc/kubernetes/manifests/kube-scheduler.yaml"
[etcd] Wrote Static Pod manifest for a local etcd instance to "/etc/kubernetes/manifests/etcd.yaml"
[init] waiting for the kubelet to boot up the control plane as Static Pods from directory "/etc/kubernetes/manifests"
[init] this might take a minute or longer if the control plane images have to be pulled
[apiclient] All control plane components are healthy after 21.002639 seconds
[uploadconfig] storing the configuration used in ConfigMap "kubeadm-config" in the "kube-system" Namespace
[kubelet] Creating a ConfigMap "kubelet-config-1.12" in namespace kube-system with the configuration for the kubelets in the cluster
[markmaster] Marking the node namenode01 as master by adding the label "node-role.kubernetes.io/master=''"
[markmaster] Marking the node namenode01 as master by adding the taints [node-role.kubernetes.io/master:NoSchedule]
[patchnode] Uploading the CRI Socket information "/var/run/dockershim.sock" to the Node API object "namenode01" as an annotation
[bootstraptoken] using token: vdufzz.0748pbrqzcxmr71a
[bootstraptoken] configured RBAC rules to allow Node Bootstrap tokens to post CSRs in order for nodes to get long term certificate credentials
[bootstraptoken] configured RBAC rules to allow the csrapprover controller automatically approve CSRs from a Node Bootstrap Token
[bootstraptoken] configured RBAC rules to allow certificate rotation for all node client certificates in the cluster
[bootstraptoken] creating the "cluster-info" ConfigMap in the "kube-public" namespace
[addons] Applied essential addon: CoreDNS
[addons] Applied essential addon: kube-proxy
Your Kubernetes master 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/
You can now join any number of machines by running the following on each node
as root:
kubeadm join 172.18.8..200:6443 --token vdufzz.0748pbrqzcxmr71a --discovery-token-ca-cert-hash sha256:39679c09d366c22d525f0db0c61793362409951b70086deba5388cab593ffbe2
至此，master节点我们已经初始化完成。