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CentOS7.5 使用 kubeadm 安装配置 Kubernetes 集群(四)

时间:2018-11-27 16:53:14      阅读:308      评论:0      收藏:0      [点我收藏+]

标签:static   orm   loading   bootstrap   阿里云   mirror   sig   tables   gpg   

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:

技术分享图片

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
EOF
sysctl --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
EOF

4、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-apiserverkube-controller-managerkube-scheduler,所以我们master需要安装的软件有dockerkubeadmkubeletkubectl

yum install kubelet kubeadm kubectl -y
systemctl enable kubelet && systemctl start kubelet

2、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。

CentOS7.5 使用 kubeadm 安装配置 Kubernetes 集群(四)

标签:static   orm   loading   bootstrap   阿里云   mirror   sig   tables   gpg   

原文地址:http://blog.51cto.com/wzlinux/2322616

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