使用kubernetes 官網工具kubeadm部署kubernetes(使用阿里雲鏡像)

時間 2020-05-07

標籤使用 kubernetes 工具 kubeadm 部署阿里鏡像欄目阿里巴巴简体版

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系列目錄html

kubernetes簡介

Kubernetes節點架構圖：node

kubernetes組件架構圖：linux

準備基礎環境

咱們將使用kubeadm部署3個節點的 Kubernetes Cluster，總體結構圖：nginx

節點詳細信息：

無特殊說明如下操做在全部節點執行：git

修改主機名：

#master節點:
hostnamectl set-hostname k8s-master
#node1節點：
hostnamectl set-hostname k8s-node1
#node2節點:
hostnamectl set-hostname k8s-node2

基本配置：

#修改/etc/hosts文件
cat >> /etc/hosts << EOF
192.168.92.56 k8s-master
192.168.92.57 k8s-node1
192.168.92.58 k8s-node2
EOF

#關閉防火牆和selinux
systemctl stop firewalld && systemctl disable firewalld
sed -i 's/^SELINUX=enforcing$/SELINUX=disabled/' /etc/selinux/config && setenforce 0

#關閉swap
swapoff -a
yes | cp /etc/fstab /etc/fstab_bak
cat /etc/fstab_bak |grep -v swap > /etc/fstab

配置時間同步

使用chrony同步時間，配置master節點與網絡NTP服務器同步時間，全部node節點與master節點同步時間。github

配置master節點：docker

#安裝chrony：
yum install -y chrony
#註釋默認ntp服務器
sed -i 's/^server/#&/' /etc/chrony.conf
#指定上游公共 ntp 服務器，並容許其餘節點同步時間
cat >> /etc/chrony.conf << EOF
server 0.asia.pool.ntp.org iburst
server 1.asia.pool.ntp.org iburst
server 2.asia.pool.ntp.org iburst
server 3.asia.pool.ntp.org iburst
allow all
EOF
#重啓chronyd服務並設爲開機啓動：
systemctl enable chronyd && systemctl restart chronyd
#開啓網絡時間同步功能
timedatectl set-ntp true

配置全部node節點：

(注意修改master IP地址)bootstrap

#安裝chrony：
yum install -y chrony
#註釋默認服務器
sed -i 's/^server/#&/' /etc/chrony.conf
#指定內網 master節點爲上游NTP服務器
echo server 192.168.92.56 iburst >> /etc/chrony.conf
#重啓服務並設爲開機啓動：
systemctl enable chronyd && systemctl restart chronyd

全部節點執行chronyc sources命令，查看存在以^*開頭的行，說明已經與服務器時間同步centos

修改iptables相關參數 RHEL / CentOS 7上的一些用戶報告了因爲iptables被繞過而致使流量路由不正確的問題。建立/etc/sysctl.d/k8s.conf文件，添加以下內容：

cat <<EOF >  /etc/sysctl.d/k8s.conf
vm.swappiness = 0
net.bridge.bridge-nf-call-ip6tables = 1
net.bridge.bridge-nf-call-iptables = 1
net.ipv4.ip_forward = 1
EOF

# 使配置生效
modprobe br_netfilter
sysctl -p /etc/sysctl.d/k8s.conf

加載ipvs相關模塊

因爲ipvs已經加入到了內核的主幹，因此爲kube-proxy開啓ipvs的前提須要加載如下的內核模塊：在全部的Kubernetes節點執行如下腳本:api

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

#執行腳本
chmod 755 /etc/sysconfig/modules/ipvs.modules && bash /etc/sysconfig/modules/ipvs.modules && lsmod | grep -e ip_vs -e nf_conntrack_ipv4

上面腳本建立了/etc/sysconfig/modules/ipvs.modules文件，保證在節點重啓後能自動加載所需模塊。使用lsmod | grep -e ip_vs -e nf_conntrack_ipv4命令查看是否已經正確加載所需的內核模塊。接下來還須要確保各個節點上已經安裝了ipset軟件包。爲了便於查看ipvs的代理規則，最好安裝一下管理工具ipvsadm。

yum install ipset ipvsadm -y

安裝Docker

Kubernetes默認的容器運行時仍然是Docker，使用的是kubelet中內置dockershim CRI實現。須要注意的是，Kubernetes 1.13最低支持的Docker版本是1.11.1，最高支持是18.06，而Docker最新版本已是18.09了，故咱們安裝時須要指定版本爲18.06.1-ce。

#配置docker yum源
yum-config-manager --add-repo http://mirrors.aliyun.com/docker-ce/linux/centos/docker-ce.repo

#安裝指定版本，這裏安裝18.06
yum list docker-ce --showduplicates | sort -r
yum install -y docker-ce-18.06.1.ce-3.el7
systemctl start docker && systemctl enable docker

安裝kubeadm、kubelet、kubectl 官方安裝文檔能夠參考： https://kubernetes.io/docs/setup/independent/install-kubeadm/

kubelet 在羣集中全部節點上運行的核心組件, 用來執行如啓動pods和containers等操做。
ubeadm 引導啓動k8s集羣的命令行工具，用於初始化 Cluster。
kubectl 是 Kubernetes 命令行工具。經過 kubectl 能夠部署和管理應用，查看各類資源，建立、刪除和更新各類組件。

#配置kubernetes.repo的源，因爲官方源國內沒法訪問，這裏使用阿里雲yum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

#在全部節點上安裝指定版本 kubelet、kubeadm 和 kubectl
yum install -y kubelet-1.13.1 kubeadm-1.13.1 kubectl-1.13.1

#啓動kubelet服務
systemctl enable kubelet && systemctl start kubelet

部署master節點

完整的官方文檔能夠參考： https://kubernetes.io/docs/setup/independent/create-cluster-kubeadm/ https://kubernetes.io/docs/reference/setup-tools/kubeadm/kubeadm-init/ Master節點執行初始化：

注意這裏執行初始化用到了- -image-repository選項，指定初始化須要的鏡像源從阿里雲鏡像倉庫拉取。

kubeadm init \
    --apiserver-advertise-address=192.168.92.56 \
    --image-repository registry.aliyuncs.com/google_containers \
    --kubernetes-version v1.13.1 \
    --pod-network-cidr=10.244.0.0/16

初始化命令說明：

--apiserver-advertise-address

指明用 Master 的哪一個 interface 與 Cluster 的其餘節點通訊。若是 Master 有多個 interface，建議明確指定，若是不指定，kubeadm 會自動選擇有默認網關的 interface。

--pod-network-cidr

指定 Pod 網絡的範圍。Kubernetes 支持多種網絡方案，並且不一樣網絡方案對 --pod-network-cidr 有本身的要求，這裏設置爲 10.244.0.0/16 是由於咱們將使用 flannel 網絡方案，必須設置成這個 CIDR。

--image-repository

Kubenetes默認Registries地址是 k8s.gcr.io，在國內並不能訪問 gcr.io，在1.13版本中咱們能夠增長–image-repository參數，默認值是 k8s.gcr.io，將其指定爲阿里雲鏡像地址：registry.aliyuncs.com/google_containers。

--kubernetes-version=v1.13.1

關閉版本探測，由於它的默認值是stable-1，會致使從https://dl.k8s.io/release/stable-1.txt下載最新的版本號，咱們能夠將其指定爲固定版本（最新版：v1.13.1）來跳過網絡請求。

初始化過程以下：

[root@k8s-master ~]# kubeadm init \
> --image-repository registry.aliyuncs.com/google_containers \
> --kubernetes-version v1.13.1 \
> --pod-network-cidr=10.244.0.0/16
[init] Using Kubernetes version: v1.13.1
[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'
[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] Activating the kubelet service
[certs] Using certificateDir folder "/etc/kubernetes/pki"
[certs] Generating "etcd/ca" certificate and key
[certs] Generating "etcd/healthcheck-client" certificate and key
[certs] Generating "apiserver-etcd-client" 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 [192.168.92.56 127.0.0.1 ::1]
[certs] Generating "etcd/peer" certificate and key
[certs] etcd/peer serving cert is signed for DNS names [k8s-master localhost] and IPs [192.168.92.56 127.0.0.1 ::1]
[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 [10.96.0.1 192.168.92.56]
[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 "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"
[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
[apiclient] All control plane components are healthy after 21.009858 seconds
[uploadconfig] storing the configuration used in ConfigMap "kubeadm-config" in the "kube-system" Namespace
[kubelet] Creating a ConfigMap "kubelet-config-1.13" in namespace kube-system with the configuration for the kubelets in the cluster
[patchnode] Uploading the CRI Socket information "/var/run/dockershim.sock" to the Node API object "k8s-master" as an annotation
[mark-control-plane] Marking the node k8s-master as control-plane by adding the label "node-role.kubernetes.io/master=''"
[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: 60syk6.vnplamkn3zhwu3s3
[bootstrap-token] Configuring bootstrap tokens, cluster-info ConfigMap, RBAC Roles
[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 192.168.92.56:6443 --token 60syk6.vnplamkn3zhwu3s3 --discovery-token-ca-cert-hash sha256:7d50e704bbfe69661e37c5f3ad13b1b88032b6b2b703ebd4899e259477b5be69

[root@k8s-master ~]#

(注意記錄下初始化結果中的kubeadm join命令，部署worker節點時會用到)

初始化過程說明：

[preflight] kubeadm 執行初始化前的檢查。
[kubelet-start] 生成kubelet的配置文件」/var/lib/kubelet/config.yaml」
[certificates] 生成相關的各類token和證書
[kubeconfig] 生成 KubeConfig 文件，kubelet 須要這個文件與 Master 通訊
[control-plane] 安裝 Master 組件，會從指定的 Registry 下載組件的 Docker 鏡像。
[bootstraptoken] 生成token記錄下來，後邊使用kubeadm join往集羣中添加節點時會用到
[addons] 安裝附加組件 kube-proxy 和 kube-dns。
Kubernetes Master 初始化成功，提示如何配置常規用戶使用kubectl訪問集羣。
提示如何安裝 Pod 網絡。
提示如何註冊其餘節點到 Cluster。

配置 kubectl

kubectl 是管理 Kubernetes Cluster 的命令行工具，前面咱們已經在全部的節點安裝了 kubectl。Master 初始化完成後須要作一些配置工做，而後 kubectl 就能使用了。依照 kubeadm init 輸出的最後提示，推薦用 Linux 普通用戶執行 kubectl。

建立普通用戶centos

#建立普通用戶並設置密碼123456
useradd centos && echo "centos:123456" | chpasswd centos

#追加sudo權限,並配置sudo免密
sed -i '/^root/a\centos  ALL=(ALL)       NOPASSWD:ALL' /etc/sudoers

#保存集羣安全配置文件到當前用戶.kube目錄
su - centos
mkdir -p $HOME/.kube
sudo cp -i /etc/kubernetes/admin.conf $HOME/.kube/config
sudo chown $(id -u):$(id -g) $HOME/.kube/config

#啓用 kubectl 命令自動補全功能（註銷從新登陸生效）
echo "source <(kubectl completion bash)" >> ~/.bashrc

須要這些配置命令的緣由是：Kubernetes 集羣默認須要加密方式訪問。因此，這幾條命令，就是將剛剛部署生成的 Kubernetes 集羣的安全配置文件，保存到當前用戶的.kube 目錄下，kubectl 默認會使用這個目錄下的受權信息訪問 Kubernetes 集羣。若是不這麼作的話，咱們每次都須要經過 export KUBECONFIG 環境變量告訴 kubectl 這個安全配置文件的位置。配置完成後centos用戶就可使用 kubectl 命令管理集羣了。

查看集羣狀態：

[centos@k8s-master ~]$ kubectl get cs NAME STATUS MESSAGE ERROR scheduler Healthy ok controller-manager Healthy ok etcd-0 Healthy {"health": "true"} [centos@k8s-master ~]$

確認各個組件都處於healthy狀態。查看節點狀態

[centos@k8s-master ~]$ kubectl get nodes 
NAME         STATUS     ROLES    AGE   VERSION
k8s-master   NotReady   master   36m   v1.13.1
[centos@k8s-master ~]$

能夠看到，當前只存在1個master節點，而且這個節點的狀態是 NotReady。使用 kubectl describe 命令來查看這個節點（Node）對象的詳細信息、狀態和事件（Event）：

[centos@k8s-master ~]$ kubectl describe node k8s-master 
......
Events:
  Type    Reason                   Age                From                    Message
  ----    ------                   ----               ----                    -------
  Normal  Starting                 33m                kubelet, k8s-master     Starting kubelet.
  Normal  NodeHasSufficientMemory  33m (x8 over 33m)  kubelet, k8s-master     Node k8s-master status is now: NodeHasSufficientMemory
  Normal  NodeHasNoDiskPressure    33m (x8 over 33m)  kubelet, k8s-master     Node k8s-master status is now: NodeHasNoDiskPressure
  Normal  NodeHasSufficientPID     33m (x7 over 33m)  kubelet, k8s-master     Node k8s-master status is now: NodeHasSufficientPID
  Normal  NodeAllocatableEnforced  33m                kubelet, k8s-master     Updated Node Allocatable limit across pods
  Normal  Starting                 33m                kube-proxy, k8s-master  Starting kube-proxy.

經過 kubectl describe 指令的輸出，咱們能夠看到 NodeNotReady 的緣由在於，咱們還沒有部署任何網絡插件，kube-proxy等組件還處於starting狀態。另外，咱們還能夠經過 kubectl 檢查這個節點上各個系統 Pod 的狀態，其中，kube-system 是 Kubernetes 項目預留的系統 Pod 的工做空間（Namepsace，注意它並非 Linux Namespace，它只是 Kubernetes 劃分不一樣工做空間的單位）：

[centos@k8s-master ~]$ kubectl get pod -n kube-system -o wide
NAME                                 READY   STATUS    RESTARTS   AGE   IP              NODE         NOMINATED NODE   READINESS GATES
coredns-78d4cf999f-7jdx7             0/1     Pending   0          29m   <none>          <none>       <none>           <none>
coredns-78d4cf999f-s6mhk             0/1     Pending   0          29m   <none>          <none>       <none>           <none>
etcd-k8s-master                      1/1     Running   0          34m   192.168.92.56   k8s-master   <none>           <none>
kube-apiserver-k8s-master            1/1     Running   0          34m   192.168.92.56   k8s-master   <none>           <none>
kube-controller-manager-k8s-master   1/1     Running   0          34m   192.168.92.56   k8s-master   <none>           <none>
kube-proxy-przwf                     1/1     Running   0          34m   192.168.92.56   k8s-master   <none>           <none>
kube-scheduler-k8s-master            1/1     Running   0          34m   192.168.92.56   k8s-master   <none>           <none>
[centos@k8s-master ~]$

能夠看到，CoreDNS依賴於網絡的 Pod 都處於 Pending 狀態，即調度失敗。這固然是符合預期的：由於這個 Master 節點的網絡還沒有就緒。集羣初始化若是遇到問題，可使用kubeadm reset命令進行清理而後從新執行初始化。

部署網絡插件要讓 Kubernetes Cluster 可以工做，必須安裝 Pod 網絡，不然 Pod 之間沒法通訊。 Kubernetes 支持多種網絡方案，這裏咱們使用 flannel 執行以下命令部署 flannel： kubectl apply -f https://raw.githubusercontent.com/coreos/flannel/master/Documentation/kube-flannel.yml

[centos@k8s-master ~]$ kubectl apply -f https://raw.githubusercontent.com/coreos/flannel/master/Documentation/kube-flannel.yml
clusterrole.rbac.authorization.k8s.io/flannel created
clusterrolebinding.rbac.authorization.k8s.io/flannel created
serviceaccount/flannel created
configmap/kube-flannel-cfg created
daemonset.extensions/kube-flannel-ds-amd64 created
daemonset.extensions/kube-flannel-ds-arm64 created
daemonset.extensions/kube-flannel-ds-arm created
daemonset.extensions/kube-flannel-ds-ppc64le created
daemonset.extensions/kube-flannel-ds-s390x created
[centos@k8s-master ~]$

部署完成後，咱們能夠經過 kubectl get 從新檢查 Pod 的狀態：

[centos@k8s-master ~]$ kubectl get pod -n kube-system -o wide
NAME                                 READY   STATUS    RESTARTS   AGE   IP              NODE         NOMINATED NODE   READINESS GATES
coredns-78d4cf999f-7jdx7             1/1     Running   0          11h   10.244.0.3      k8s-master   <none>           <none>
coredns-78d4cf999f-s6mhk             1/1     Running   0          11h   10.244.0.2      k8s-master   <none>           <none>
etcd-k8s-master                      1/1     Running   1          11h   192.168.92.56   k8s-master   <none>           <none>
kube-apiserver-k8s-master            1/1     Running   1          11h   192.168.92.56   k8s-master   <none>           <none>
kube-controller-manager-k8s-master   1/1     Running   1          11h   192.168.92.56   k8s-master   <none>           <none>
kube-flannel-ds-amd64-lkf2f          1/1     Running   0          10h   192.168.92.56   k8s-master   <none>           <none>
kube-proxy-przwf                     1/1     Running   1          11h   192.168.92.56   k8s-master   <none>           <none>
kube-scheduler-k8s-master            1/1     Running   1          11h   192.168.92.56   k8s-master   <none>           <none>
[centos@k8s-master ~]$

能夠看到，全部的系統 Pod 都成功啓動了，而剛剛部署的flannel網絡插件則在 kube-system 下面新建了一個名叫kube-flannel-ds-amd64-lkf2f的 Pod，通常來講，這些 Pod 就是容器網絡插件在每一個節點上的控制組件。 Kubernetes 支持容器網絡插件，使用的是一個名叫 CNI 的通用接口，它也是當前容器網絡的事實標準，市面上的全部容器網絡開源項目均可以經過 CNI 接入 Kubernetes，好比 Flannel、Calico、Canal、Romana 等等，它們的部署方式也都是相似的「一鍵部署」。再次查看master節點狀態已經爲ready狀態：

[centos@k8s-master ~]$ kubectl get nodes 
NAME         STATUS   ROLES    AGE   VERSION
k8s-master   Ready    master   11h   v1.13.1
[centos@k8s-master ~]$

至此，Kubernetes 的 Master 節點就部署完成了。若是你只須要一個單節點的 Kubernetes，如今你就可使用了。不過，在默認狀況下，Kubernetes 的 Master 節點是不能運行用戶 Pod 的。

部署worker節點

Kubernetes 的 Worker 節點跟 Master 節點幾乎是相同的，它們運行着的都是一個 kubelet 組件。惟一的區別在於，在 kubeadm init 的過程當中，kubelet 啓動後，Master 節點上還會自動運行 kube-apiserver、kube-scheduler、kube-controller-manger 這三個系統 Pod。在 k8s-node1 和 k8s-node2 上分別執行以下命令，將其註冊到 Cluster 中：

#執行如下命令將節點接入集羣
kubeadm join 192.168.92.56:6443 --token 67kq55.8hxoga556caxty7s --discovery-token-ca-cert-hash sha256:7d50e704bbfe69661e37c5f3ad13b1b88032b6b2b703ebd4899e259477b5be69

#若是執行kubeadm init時沒有記錄下加入集羣的命令，能夠經過如下命令從新建立
kubeadm token create --print-join-command

在k8s-node1上執行kubeadm join ：

[root@k8s-node1 ~]# kubeadm join 192.168.92.56:6443 --token 67kq55.8hxoga556caxty7s --discovery-token-ca-cert-hash sha256:7d50e704bbfe69661e37c5f3ad13b1b88032b6b2b703ebd4899e259477b5be69
[preflight] Running pre-flight checks
[discovery] Trying to connect to API Server "192.168.92.56:6443"
[discovery] Created cluster-info discovery client, requesting info from "https://192.168.92.56:6443"
[discovery] Requesting info from "https://192.168.92.56:6443" again to validate TLS against the pinned public key
[discovery] Cluster info signature and contents are valid and TLS certificate validates against pinned roots, will use API Server "192.168.92.56:6443"
[discovery] Successfully established connection with API Server "192.168.92.56:6443"
[join] Reading configuration from the cluster...
[join] FYI: You can look at this config file with 'kubectl -n kube-system get cm kubeadm-config -oyaml'
[kubelet] Downloading configuration for the kubelet from the "kubelet-config-1.13" ConfigMap in the kube-system namespace
[kubelet-start] Writing kubelet configuration to file "/var/lib/kubelet/config.yaml"
[kubelet-start] Writing kubelet environment file with flags to file "/var/lib/kubelet/kubeadm-flags.env"
[kubelet-start] Activating the kubelet service
[tlsbootstrap] Waiting for the kubelet to perform the TLS Bootstrap...
[patchnode] Uploading the CRI Socket information "/var/run/dockershim.sock" to the Node API object "k8s-node1" as an annotation

This node has joined the cluster:
* Certificate signing request was sent to apiserver and a response was received.
* The Kubelet was informed of the new secure connection details.

Run 'kubectl get nodes' on the master to see this node join the cluster.

[root@k8s-node1 ~]#

重複執行以上操做將k8s-node2也加進去（注意從新執行kubeadm token create --print-join-command）。而後根據提示，咱們能夠經過 kubectl get nodes 查看節點的狀態：

[centos@k8s-master ~]$ kubectl get nodes
NAME         STATUS   ROLES    AGE    VERSION
k8s-master   Ready    master   11h    v1.13.1
k8s-node1    Ready    <none>   24m    v1.13.1
k8s-node2    Ready    <none>   4m9s   v1.13.1
[centos@k8s-master ~]$

nodes狀態所有爲ready，因爲每一個節點都須要啓動若干組件，若是node節點的狀態是 NotReady，能夠查看全部節點pod狀態，確保全部pod成功拉取到鏡像並處於running狀態：

[centos@k8s-master ~]$ kubectl get pod --all-namespaces -o wide
NAMESPACE     NAME                                 READY   STATUS    RESTARTS   AGE     IP              NODE         NOMINATED NODE   READINESS GATES
kube-system   coredns-78d4cf999f-7jdx7             1/1     Running   0          11h     10.244.0.3      k8s-master   <none>           <none>
kube-system   coredns-78d4cf999f-s6mhk             1/1     Running   0          11h     10.244.0.2      k8s-master   <none>           <none>
kube-system   etcd-k8s-master                      1/1     Running   1          12h     192.168.92.56   k8s-master   <none>           <none>
kube-system   kube-apiserver-k8s-master            1/1     Running   1          12h     192.168.92.56   k8s-master   <none>           <none>
kube-system   kube-controller-manager-k8s-master   1/1     Running   1          12h     192.168.92.56   k8s-master   <none>           <none>
kube-system   kube-flannel-ds-amd64-d2r8p          1/1     Running   0          6m43s   192.168.92.58   k8s-node2    <none>           <none>
kube-system   kube-flannel-ds-amd64-d85c6          1/1     Running   0          27m     192.168.92.57   k8s-node1    <none>           <none>
kube-system   kube-flannel-ds-amd64-lkf2f          1/1     Running   0          11h     192.168.92.56   k8s-master   <none>           <none>
kube-system   kube-proxy-k8jx8                     1/1     Running   0          6m43s   192.168.92.58   k8s-node2    <none>           <none>
kube-system   kube-proxy-n95ck                     1/1     Running   0          27m     192.168.92.57   k8s-node1    <none>           <none>
kube-system   kube-proxy-przwf                     1/1     Running   1          12h     192.168.92.56   k8s-master   <none>           <none>
kube-system   kube-scheduler-k8s-master            1/1     Running   1          12h     192.168.92.56   k8s-master   <none>           <none>
[centos@k8s-master ~]$

這時，全部的節點都已經 Ready，Kubernetes Cluster 建立成功，一切準備就緒。若是pod狀態爲Pending、ContainerCreating、ImagePullBackOff 都代表 Pod 沒有就緒，Running 纔是就緒狀態。若是有pod提示Init:ImagePullBackOff，說明這個pod的鏡像在對應節點上拉取失敗，咱們能夠經過 kubectl describe pod 查看 Pod 具體狀況，以確認拉取失敗的鏡像：

[centos@k8s-master ~]$ kubectl describe pod kube-flannel-ds-amd64-d2r8p --namespace=kube-system
......
Events:
  Type     Reason     Age                 From                Message
  ----     ------     ----                ----                -------
  Normal   Scheduled  2m14s               default-scheduler   Successfully assigned kube-system/kube-flannel-ds-amd64-lzx5v to k8s-node2
  Warning  Failed     109s                kubelet, k8s-node2  Failed to pull image "quay.io/coreos/flannel:v0.10.0-amd64": rpc error: code = Unknown desc = Error response from daemon: Get https://quay.io/v2/: net/http: TLS handshake timeout
  Warning  Failed     109s                kubelet, k8s-node2  Error: ErrImagePull
  Normal   BackOff    108s                kubelet, k8s-node2  Back-off pulling image "quay.io/coreos/flannel:v0.10.0-amd64"
  Warning  Failed     108s                kubelet, k8s-node2  Error: ImagePullBackOff
  Normal   Pulling    94s (x2 over 2m6s)  kubelet, k8s-node2  pulling image "quay.io/coreos/flannel:v0.10.0-amd64"

這裏看最後events輸出內容，能夠看到在下載 image 時失敗，若是網絡質量很差，這種狀況是很常見的。咱們能夠耐心等待，由於 Kubernetes 會重試，咱們也能夠本身手工執行 docker pull 去下載這個鏡像。

[root@k8s-node2 ~]# docker pull quay.io/coreos/flannel:v0.10.0-amd64
v0.10.0-amd64: Pulling from coreos/flannel
ff3a5c916c92: Already exists
8a8433d1d437: Already exists
306dc0ee491a: Already exists
856cbd0b7b9c: Already exists
af6d1e4decc6: Already exists
Digest: sha256:88f2b4d96fae34bfff3d46293f7f18d1f9f3ca026b4a4d288f28347fcb6580ac
Status: Image is up to date for quay.io/coreos/flannel:v0.10.0-amd64
[root@k8s-node2 ~]#

若是沒法從 quay.io/coreos/flannel:v0.10.0-amd64 下載鏡像，能夠從阿里雲或者dockerhub鏡像倉庫下載，而後改回原來的tag便可：

docker pull registry.cn-hangzhou.aliyuncs.com/kubernetes_containers/flannel:v0.10.0-amd64
docker tag registry.cn-hangzhou.aliyuncs.com/kubernetes_containers/flannel:v0.10.0-amd64 quay.io/coreos/flannel:v0.10.0-amd64
docker rmi registry.cn-hangzhou.aliyuncs.com/kubernetes_containers/flannel:v0.10.0-amd64

查看master節點下載了哪些鏡像

[centos@k8s-master ~]$ sudo docker images
REPOSITORY                                                        TAG                 IMAGE ID            CREATED             SIZE
registry.aliyuncs.com/google_containers/kube-proxy                v1.13.1             fdb321fd30a0        2 weeks ago         80.2MB
registry.aliyuncs.com/google_containers/kube-apiserver            v1.13.1             40a63db91ef8        2 weeks ago         181MB
registry.aliyuncs.com/google_containers/kube-scheduler            v1.13.1             ab81d7360408        2 weeks ago         79.6MB
registry.aliyuncs.com/google_containers/kube-controller-manager   v1.13.1             26e6f1db2a52        2 weeks ago         146MB
registry.aliyuncs.com/google_containers/coredns                   1.2.6               f59dcacceff4        8 weeks ago         40MB
registry.aliyuncs.com/google_containers/etcd                      3.2.24              3cab8e1b9802        3 months ago        220MB
quay.io/coreos/flannel                                            v0.10.0-amd64       f0fad859c909        11 months ago       44.6MB
registry.aliyuncs.com/google_containers/pause                     3.1                 da86e6ba6ca1        12 months ago       742kB
[centos@k8s-master ~]$

查看node節點下載了哪些鏡像：

[root@k8s-node1 ~]# docker images
REPOSITORY                                           TAG                 IMAGE ID            CREATED             SIZE
registry.aliyuncs.com/google_containers/kube-proxy   v1.13.1             fdb321fd30a0        2 weeks ago         80.2MB
quay.io/coreos/flannel                               v0.10.0-amd64       f0fad859c909        11 months ago       44.6MB
registry.aliyuncs.com/google_containers/pause        3.1                 da86e6ba6ca1        12 months ago       742kB
[root@k8s-node1 ~]#

測試集羣各個組件首先驗證kube-apiserver, kube-controller-manager, kube-scheduler, pod network 是否正常：部署一個 Nginx Deployment，包含2個Pod 參考：https://kubernetes.io/docs/concepts/workloads/controllers/deployment/

[centos@k8s-master ~]$ kubectl create deployment nginx --image=nginx:alpine
deployment.apps/nginx created
[centos@k8s-master ~]$ kubectl scale deployment nginx --replicas=2
deployment.extensions/nginx scaled
[centos@k8s-master ~]$

驗證Nginx Pod是否正確運行，而且會分配10.244.開頭的集羣IP

[centos@k8s-master ~]$ kubectl get pods -l app=nginx -o wide
NAME                     READY   STATUS    RESTARTS   AGE    IP           NODE        NOMINATED NODE   READINESS GATES
nginx-54458cd494-p2qgx   1/1     Running   0          111s   10.244.1.2   k8s-node1   <none>           <none>
nginx-54458cd494-sdlm7   1/1     Running   0          103s   10.244.2.2   k8s-node2   <none>           <none>
[centos@k8s-master ~]$

再驗證一下kube-proxy是否正常：

以 NodePort 方式對外提供服務參考：https://kubernetes.io/docs/concepts/services-networking/connect-applications-service/

[centos@k8s-master ~]$ kubectl expose deployment nginx --port=80 --type=NodePort
service/nginx exposed
[centos@k8s-master ~]$ kubectl get services nginx
NAME    TYPE       CLUSTER-IP    EXTERNAL-IP   PORT(S)        AGE
nginx   NodePort   10.108.17.2   <none>        80:30670/TCP   12s
[centos@k8s-master ~]$

能夠經過任意 NodeIP:Port 在集羣外部訪問這個服務：

[centos@k8s-master ~]$ curl 192.168.92.56:30670
[centos@k8s-master ~]$ curl 192.168.92.57:30670
[centos@k8s-master ~]$ curl 192.168.92.58:30670

訪問k8s-master ip

訪問k8s-node1 ip

訪問k8s-node2 ip

最後驗證一下dns, pod network是否正常：運行Busybox並進入交互模式

[centos@k8s-master ~]$ kubectl run -it curl --image=radial/busyboxplus:curl
kubectl run --generator=deployment/apps.v1 is DEPRECATED and will be removed in a future version. Use kubectl run --generator=run-pod/v1 or kubectl create instead.
If you don't see a command prompt, try pressing enter.
[ root@curl-66959f6557-s5qqs:/ ]$

輸入nslookup nginx查看是否能夠正確解析出集羣內的IP，以驗證DNS是否正常

[ root@curl-66959f6557-s5qqs:/ ]$ nslookup nginx
Server:    10.96.0.10
Address 1: 10.96.0.10 kube-dns.kube-system.svc.cluster.local

Name:      nginx
Address 1: 10.108.17.2 nginx.default.svc.cluster.local

經過服務名進行訪問，驗證kube-proxy是否正常

[ root@curl-66959f6557-q472z:/ ]$ curl http://nginx/
<!DOCTYPE html>
<html>
<head>
<title>Welcome to nginx!</title>
......
</body>
</html>
[ root@curl-66959f6557-q472z:/ ]$

分別訪問一下2個Pod的內網IP，驗證跨Node的網絡通訊是否正常

[ root@curl-66959f6557-s5qqs:/ ]$ curl 10.244.1.2
<!DOCTYPE html>
<html>
<head>
<title>Welcome to nginx!</title>
......
</body>
</html>
[ root@curl-66959f6557-s5qqs:/ ]$ curl 10.244.2.2
<!DOCTYPE html>
<html>
<head>
<title>Welcome to nginx!</title>
......
</body>
</html>
[ root@curl-66959f6557-s5qqs:/ ]$

Pod調度到Master節點出於安全考慮，默認配置下Kubernetes不會將Pod調度到Master節點。查看Taints字段默認配置：

[centos@k8s-master ~]$ kubectl describe node k8s-master 
......
Taints:             node-role.kubernetes.io/master:NoSchedule

若是但願將k8s-master也看成Node節點使用，能夠執行以下命令,其中k8s-master是主機節點hostname：

kubectl taint node k8s-master node-role.kubernetes.io/master-

修改後Taints字段狀態：

[centos@k8s-master ~]$ kubectl describe node k8s-master                             
......
Taints:             <none>

若是要恢復Master Only狀態，執行以下命令：

kubectl taint node k8s-master node-role.kubernetes.io/master=:NoSchedule

kube-proxy開啓ipvs 修改ConfigMap的kube-system/kube-proxy中的config.conf，mode: 「ipvs」：

[centos@k8s-master ~]$ kubectl edit cm kube-proxy -n kube-system
configmap/kube-proxy edited

以後重啓各個節點上的kube-proxy pod：

[centos@k8s-master ~]$ kubectl get pod -n kube-system | grep kube-proxy | awk '{system("kubectl delete pod "$1" -n kube-system")}'
pod "kube-proxy-2w9sh" deleted
pod "kube-proxy-gw4lx" deleted
pod "kube-proxy-thv4c" deleted
[centos@k8s-master ~]$ kubectl get pod -n kube-system | grep kube-proxy
kube-proxy-6qlgv                        1/1     Running   0          65s
kube-proxy-fdtjd                        1/1     Running   0          47s
kube-proxy-m8zkx                        1/1     Running   0          52s
[centos@k8s-master ~]$

查看日誌：

[centos@k8s-master ~]$ kubectl logs kube-proxy-6qlgv -n kube-system
I1213 09:50:15.414493       1 server_others.go:189] Using ipvs Proxier.
W1213 09:50:15.414908       1 proxier.go:365] IPVS scheduler not specified, use rr by default
I1213 09:50:15.415021       1 server_others.go:216] Tearing down inactive rules.
I1213 09:50:15.461658       1 server.go:464] Version: v1.13.0
I1213 09:50:15.467827       1 conntrack.go:52] Setting nf_conntrack_max to 131072
I1213 09:50:15.467997       1 config.go:202] Starting service config controller
I1213 09:50:15.468010       1 controller_utils.go:1027] Waiting for caches to sync for service config controller
I1213 09:50:15.468092       1 config.go:102] Starting endpoints config controller
I1213 09:50:15.468100       1 controller_utils.go:1027] Waiting for caches to sync for endpoints config controller
I1213 09:50:15.568766       1 controller_utils.go:1034] Caches are synced for endpoints config controller
I1213 09:50:15.568950       1 controller_utils.go:1034] Caches are synced for service config controller
[centos@k8s-master ~]$

日誌中打印出了Using ipvs Proxier，說明ipvs模式已經開啓。

移除節點和集羣 kubernetes集羣移除節點以移除k8s-node2節點爲例，在Master節點上運行： kubectl drain k8s-node2 --delete-local-data --force --ignore-daemonsets kubectl delete node k8s-node2 上面兩條命令執行完成後，在k8s-node2節點執行清理命令，重置kubeadm的安裝狀態： kubeadm reset 在master上刪除node並不會清理k8s-node2運行的容器，須要在刪除節點上面手動運行清理命令。若是你想從新配置集羣，使用新的參數從新運行kubeadm init或者kubeadm join便可。

至此3個節點的集羣搭建完成，後續能夠繼續添加node節點，或者部署dashboard、helm包管理工具、EFK日誌系統、Prometheus Operator監控系統、rook+ceph存儲系統等組件。

原文連接