带你玩转kubernetes-k8s（第一篇：k8s kubeadm的安装）

          这是我第一次下决心写一个完整的专栏，以后每周晚上12点之前为大家更新相关内容。相信来看这篇文章的朋友们都是有运维相关经验的朋友。

           言规正传，我们看接下来的内容；本人不打算一上来就讲解一大堆的概念，这样会使各位朋友看着很累，看得云里雾里的，摸不着头脑，第一天我就先带领大家把k8s的环境搭建起来。

  一、环境准备及角色规

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11.关闭selinux。

22.关闭防火墙。

33.配置hosts，修改hostname

44.时间同步

5yum -y install ntp

6ntptime

7timedatectl

8systemctl enable ntpd

9systemctl restart ntpd.service

10ln -sf /usr/share/zoneinfo/Asia/Shanghai /etc/localtime

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二、安装docker

    二标题内的操作需要在三台服务器上均操作

   1.安装yum管理工具及其依赖           

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1yum install -y yum-utils device-mapper-persistent-data lvm2

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  2.添加yum源

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1 yum-config-manager --add-repo https://download.docker.com/linux/centos/docker-ce.repo

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   3.查看docker的可用版本

        我们这里使用的是docker-ce-18.09.6版本

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1 yum list docker-ce --showduplicates | sort -r

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1 yum -y install docker-ce-18.09.6

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   4.启动docker服务并激活开机自动启动

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1 systemctl start docker && systemctl enable docker

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   5.配置国内镜像加速器

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1echo '{"registry-mirrors":["https://361z9p6b.mirror.aliyuncs.com"]}' > /etc/docker/daemon.json

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三、使用kubeadm安装kubernetes集群

 1.添加k8s的yum源，由于我们无法从谷歌直接下载，我们这里切换成阿里的源（ps:三台虚拟机均安装）

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1cat <<EOF > /etc/yum.repos.d/kubernetes.repo

2[kubernetes]

3name=Kubernetes

4baseurl=https://mirrors.aliyun.com/kubernetes/yum/repos/kubernetes-el7-x86_64

5enabled=1

6gpgcheck=1

7repo_gpgcheck=1

8gpgkey=https://mirrors.aliyun.com/kubernetes/yum/doc/yum-key.gpg https://mirrors.aliyun.com/kubernetes/yum/doc/rpm-package-key.gpg

9EOF

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2.临时关闭swap（ps:三台虚拟机均执行）

Kubernetes 1.8 开始要求关闭系统的Swap，如果不关闭，默认配置下 kubelet 将无法启动。可以通过修改 kubelet 的启动参数/etc/sysconfig/kubelet中 –fail-swap-on=false 更改这个限制(4小节的配置文件)

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1swapoff -a   

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3.安装并启动（我们这里安装k8s1.14.2版本，ps:三台虚拟机均执行）

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1yum install -y kubelet-1.14.2 kubeadm-1.14.2 kubectl-1.14.2 --disableexcludes=kubernetes

2#--disableexcludes=kubernetes  禁掉除了这个之外的别的仓库 

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5systemctl enable kubelet && systemctl start kubelet

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4.更改swap限制（ps:三台虚拟机均执行）

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1# cat /etc/sysconfig/kubelet

2KUBELET_EXTRA_ARGS=--fail-swap-on=false

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5.新建init-config.yaml文件定制镜像仓库地址和Pod地址段（ps:仅在k8s-master上创建改文件）

     podSubnet:ip根据自己的喜欢设置

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1# cat init-config.yaml 

2apiVersion: kubeadm.k8s.io/v1beta1

3kind: ClusterConfiguration

4imageRepository: docker.io/dustise

5kubernetesVersion: v1.14.0

6networking:

7  podSubnet: "192.168.0.0/16"

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6.下载k8s-master所需镜像及其依赖（ps:仅在k8s-master操作）

   这个过程需要等待一段时间，具体看网速。

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1# kubeadm config images pull --config=init-config.yaml

2[config/images] Pulled docker.io/dustise/kube-apiserver:v1.14.0

3[config/images] Pulled docker.io/dustise/kube-controller-manager:v1.14.0

4[config/images] Pulled docker.io/dustise/kube-scheduler:v1.14.0

5[config/images] Pulled docker.io/dustise/kube-proxy:v1.14.0

6[config/images] Pulled docker.io/dustise/pause:3.1

7[config/images] Pulled docker.io/dustise/etcd:3.3.10

8[config/images] Pulled docker.io/dustise/coredns:1.3.1

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7.编辑文件/usr/lib/systemd/system/docker.service(ps:在三台虚拟机上均操作)

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1ExecStart=/usr/bin/dockerd --exec-opt native.cgroupdriver=systemd

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修改文件之后docker.deamon加载该文件，并重新启动docker

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1systemctl daemon-reload

2systemctl restart docker

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8.安装k8s-Master（ps:仅在k8s-master操作）

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1kubeadm init --config=init-config.yaml

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如果执行过程中报以下错误：

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1[ERROR FileContent--proc-sys-net-bridge-bridge-nf-call-iptables]: 

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3/proc/sys/net/bridge/bridge-nf-call-iptables contents are not set to 1

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解决方案执行以下命令即可：

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1 echo "1" >/proc/sys/net/bridge/bridge-nf-call-iptables

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再次进行kubeadm 初始化。

提示如下：

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1[root@k8s-1master ~]#  kubeadm init --config=init-config.yaml

2[init] Using Kubernetes version: v1.14.0

3[preflight] Running pre-flight checks

4[preflight] Pulling images required for setting up a Kubernetes cluster

5[preflight] This might take a minute or two, depending on the speed of your internet connection

6[preflight] You can also perform this action in beforehand using 'kubeadm config images pull'

7[kubelet-start] Writing kubelet environment file with flags to file "/var/lib/kubelet/kubeadm-flags.env"

8[kubelet-start] Writing kubelet configuration to file "/var/lib/kubelet/config.yaml"

9[kubelet-start] Activating the kubelet service

10[certs] Using certificateDir folder "/etc/kubernetes/pki"

11[certs] Generating "etcd/ca" certificate and key

12[certs] Generating "apiserver-etcd-client" certificate and key

13[certs] Generating "etcd/server" certificate and key

14[certs] etcd/server serving cert is signed for DNS names [k8s-1master localhost] and IPs [20.0.40.50 127.0.0.1 ::1]

15[certs] Generating "etcd/peer" certificate and key

16[certs] etcd/peer serving cert is signed for DNS names [k8s-1master localhost] and IPs [20.0.40.50 127.0.0.1 ::1]

17[certs] Generating "etcd/healthcheck-client" certificate and key

18[certs] Generating "ca" certificate and key

19[certs] Generating "apiserver" certificate and key

20[certs] apiserver serving cert is signed for DNS names [k8s-1master kubernetes kubernetes.default kubernetes.default.svc kubernetes.default.svc.cluster.local] and IPs [10.96.0.1 20.0.40.50]

21[certs] Generating "apiserver-kubelet-client" certificate and key

22[certs] Generating "front-proxy-ca" certificate and key

23[certs] Generating "front-proxy-client" certificate and key

24[certs] Generating "sa" key and public key

25[kubeconfig] Using kubeconfig folder "/etc/kubernetes"

26[kubeconfig] Writing "admin.conf" kubeconfig file

27[kubeconfig] Writing "kubelet.conf" kubeconfig file

28[kubeconfig] Writing "controller-manager.conf" kubeconfig file

29[kubeconfig] Writing "scheduler.conf" kubeconfig file

30[control-plane] Using manifest folder "/etc/kubernetes/manifests"

31[control-plane] Creating static Pod manifest for "kube-apiserver"

32[control-plane] Creating static Pod manifest for "kube-controller-manager"

33[control-plane] Creating static Pod manifest for "kube-scheduler"

34[etcd] Creating static Pod manifest for local etcd in "/etc/kubernetes/manifests"

35[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

36[apiclient] All control plane components are healthy after 17.001456 seconds

37[upload-config] storing the configuration used in ConfigMap "kubeadm-config" in the "kube-system" Namespace

38[kubelet] Creating a ConfigMap "kubelet-config-1.14" in namespace kube-system with the configuration for the kubelets in the cluster

39[upload-certs] Skipping phase. Please see --experimental-upload-certs

40[mark-control-plane] Marking the node k8s-1master as control-plane by adding the label "node-role.kubernetes.io/master=''"

41[mark-control-plane] Marking the node k8s-1master as control-plane by adding the taints [node-role.kubernetes.io/master:NoSchedule]

42[bootstrap-token] Using token: 3wtp5h.dmuu9sn3bryfg4mj

43[bootstrap-token] Configuring bootstrap tokens, cluster-info ConfigMap, RBAC Roles

44[bootstrap-token] configured RBAC rules to allow Node Bootstrap tokens to post CSRs in order for nodes to get long term certificate credentials

45[bootstrap-token] configured RBAC rules to allow the csrapprover controller automatically approve CSRs from a Node Bootstrap Token

46[bootstrap-token] configured RBAC rules to allow certificate rotation for all node client certificates in the cluster

47[bootstrap-token] creating the "cluster-info" ConfigMap in the "kube-public" namespace

48[addons] Applied essential addon: CoreDNS

49[addons] Applied essential addon: kube-proxy

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51Your Kubernetes control-plane has initialized successfully!

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53To start using your cluster, you need to run the following as a regular user:

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55  mkdir -p $HOME/.kube

56  sudo cp -i /etc/kubernetes/admin.conf $HOME/.kube/config

57  sudo chown $(id -u):$(id -g) $HOME/.kube/config

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59You should now deploy a pod network to the cluster.

60Run "kubectl apply -f [podnetwork].yaml" with one of the options listed at:

61  https://kubernetes.io/docs/concepts/cluster-administration/addons/

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63Then you can join any number of worker nodes by running the following on each as root:

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65kubeadm join 20.0.40.50:6443 --token 3wtp5h.dmuu9sn3bryfg4mj \

66    --discovery-token-ca-cert-hash sha256:833c7a61fe7500401789395477ce874199986209205a145f6c8052d56fd92fe1 

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按照提示复制配置文件到用户目录下

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1mkdir -p $HOME/.kube

2sudo cp -i /etc/kubernetes/admin.conf $HOME/.kube/config

3sudo chown $(id -u):$(id -g) $HOME/.kube/config

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查看ConfigMap

查看初始化情况

9.安装网络插件weave

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1kubectl apply -f "https://cloud.weave.works/k8s/net?k8s-version=$(kubectl version | base64 | tr -d '\n')"

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10.配置node加入集群

  在k8s-master上查看添加node的命令

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1kubeadm token create --print-join-command

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 在k8s-node1,k8s-node2上均执行查看到的命令

查看node状态

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1kubectl get node

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查看pods安装进度

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1kubectl get pods --all-namespaces

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到这里我们的k8s基本已经部署完成了。

谢谢大家的浏览，如果部署过程中出现什么问题，可以随时留言，谢谢！

明天将带领大家装dashboard仪表盘，部署实例等内容