kubeadm安裝K8s 1.16集羣

1、環境介紹

centos7.4 系統機器兩臺：

機器	主機名
10.1.31.36	kubernetes master
10.1.31.24	kubernetes node1

2、準備工做

如下步驟在兩臺臺主機上都要操做。
須要pull docker鏡像，請先安裝docker。

一、K8s和docker版本關係

[`https://github.com/kubernetes/kubernetes`]()

二、安裝docker

從CentOS OS存儲庫中使用docker，則docker版本可能較舊，沒法與Kubernetes v1.13.0及更高版本一塊兒使用。
這裏咱們安裝18.06.3版本

yum install -y -q yum-utils device-mapper-persistent-data lvm2 > /dev/null 2>&1
yum-config-manager --add-repo https://download.docker.com/linux/centos/docker-ce.repo > /dev/null 2>&1
yum install -y -q docker-ce-18.06.3.ce >/dev/null 2>&1

啓動docker

systemctl enable docker && systemctl start docker
docker version

三、關閉系統運行的防火牆

若是系統開啓了防火牆則按以下步驟關閉防火牆

[root@localhost]# systemctl stop firewalld
[root@localhost]# systemctl disable firewalld

四、關閉selinux

[root@localhost]# setenforce 0
[root@localhost]# sed -i '/^SELINUX=/cSELINUX=disabled' /etc/sysconfig/selinux

或者編輯/etc/selinux/config

root@localhost]# vi /etc/selinux/config
將SELINUX=enforcing改成SELINUX=disabled，重啓後生效
查看狀態
[root@localhost]# sestatus
SELinux status: disabled

五、關閉swap

kubeadm不支持swap
執行

[root@localhost yum.repos.d]# swapoff -a
#或者編輯/etc/fstab註釋掉swap
[root@localhost yum.repos.d]# cat /etc/fstab
# /etc/fstab
# Created by anaconda on Fri Oct 18 00:03:01 2019
#
# Accessible filesystems, by reference, are maintained under '/dev/disk'
# See man pages fstab(5), findfs(8), mount(8) and/or blkid(8) for more info
#
UUID=1a73fb9d-095b-4302-aa87-4a49783c0133 /                       xfs     defaults        0 0
UUID=e293a721-617e-4cdd-8cb9-d2e895427b03 /boot                   xfs     defaults        0 0
#UUID=73e88a54-4574-4f0a-8a4f-d57d2bc2ee46 swap                    swap    defaults        0 0

六、修改主機名

三臺主機分別設置master、node1

[root@localhost kubernetes]# cat >> /etc/sysconfig/network << EOF
hostname=master
EOF
[root@localhost kubernetes]# cat /etc/sysconfig/network
# Created by anaconda
hostname=master

或者

[root@localhost]#hostnamectl set-hostname master
[root@localhost]#hostnamectl set-hostname node1
[root@localhost]#hostnamectl set-hostname node2

七、配置/etc/hosts

每臺主機上都執行

[root@localhost]#echo "192.168.3.100 master" >> /etc/hosts
[root@localhost]#echo "192.168.3.101 node1" >> /etc/hosts
[root@localhost]#echo "192.168.3.102 node2" >> /etc/hosts

八、配置內核參數

將橋接的IPv4流量傳遞到iptables的鏈

[root@localhost]#cat <<EOF >  /etc/sysctl.d/k8s.conf
net.bridge.bridge-nf-call-ip6tables = 1
net.bridge.bridge-nf-call-iptables = 1
----net.bridge.bridge-nf-call-arptables = 1
net.ipv4.ip_forward = 1
EOF

使如上配置生效

[root@localhost]#sysctl --system

九、配置CentOS YUM源

//配置國內tencent yum源地址、epel源地址、Kubernetes源地址

[root@localhost]#mkdir -p /etc/yum.repos.d/repos.bak
[root@localhost]#mv /etc/yum.repos.d/*.repo /etc/yum.repos.d/repos.bak
[root@localhost]#wget -O /etc/yum.repos.d/CentOS-Base.repo http://mirrors.cloud.tencent.com/repo/centos7_base.repo
[root@localhost]#wget -O /etc/yum.repos.d/epel.repo http://mirrors.cloud.tencent.com/repo/epel-7.repo
[root@localhost]#yum clean all && yum makecache

//配置國內Kubernetes源地址
[root@localhost]#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

十、安裝工具

指定版本號

[root@localhost]#yum install -y kubelet-1.16.0 kubeadm-1.16.0 kubectl-1.16.0 --disableexcludes=kubernetes

不指定版本號

install -y kubelet kubeadm kubectl --disableexcludes=kubernetes

說明：–disableexcludes=kubernetes #禁用除kubernetes以外的倉庫，能夠不帶這個參數
啓動工具

[root@localhost]#systemctl enable kubelet
[root@localhost]#systemctl start kubelet

其餘命令

systemctl status kubelet
systemctl stop kubelet
systemctl restart kubelet

##3# 十一、初始化獲取要下載的鏡像列表

[root@master ~]# cd /home
[root@master home]# ls
apache-zookeeper-3.5.6-bin  jdk1.8.0_231  kafka_2.12-2.3.1
[root@master home]# kubeadm config images list
W1115 18:05:31.432259   17146 version.go:101] could not fetch a Kubernetes version from the internet: unable to get URL "https://dl.k8s.io/release/stable-1.txt": Get https://dl.k8s.io/release/stable-1.txt: net/http: request canceled while waiting for connection (Client.Timeout exceeded while awaiting headers)
W1115 18:05:31.436956   17146 version.go:102] falling back to the local client version: v1.16.3
k8s.gcr.io/kube-apiserver:v1.16.3
k8s.gcr.io/kube-controller-manager:v1.16.3
k8s.gcr.io/kube-scheduler:v1.16.3
k8s.gcr.io/kube-proxy:v1.16.3
k8s.gcr.io/pause:3.1
k8s.gcr.io/etcd:3.3.15-0
k8s.gcr.io/coredns:1.6.2

十二、生成默認kubeadm.conf文件

執行下面命令，會在當前目錄生成kubeadm.conf文件

[root@master home]#kubeadm config print init-defaults > kubeadm.conf

1三、修改kubeadm.conf鏡像源

kubeadm.conf這個配置文件默認會從google的鏡像倉庫地址k8s.gcr.io下載鏡像，國內下載不了。所以，咱們經過下面的方法把地址改爲國內的，好比用阿里的。
編輯kubeadm.conf文件，把imageRepository的value改爲下面的
imageRepository: registry.aliyuncs.com/google_containers
kubeadm.conf文件裏的kubeadm和k8s版本必須匹配，不能一高一低，若是不匹配，修改kubeadm.conf下面k8s的版本號便可

[root@master home]#vi kubeadm.conf

1四、下載須要用到的鏡像

在kubeadm.conf所在目錄執行

[[root@master home]#kubeadm config images pull --config kubeadm.conf
[root@master home]# docker images

1五、docker鏡像從新打tag

鏡像下載好後，還須要tag下載好的鏡像，讓下載好的鏡像都是帶有 k8s.gcr.io 標識的，若是不打tag變成k8s.gcr.io，那麼後面用kubeadm安裝會出現問題，由於kubeadm裏面只認 google自身的模式。打tag後刪除帶有 registry.aliyuncs.com 標識的鏡像。

從新打tag

docker tag  registry.aliyuncs.com/google_containers/kube-apiserver:v1.16.0    k8s.gcr.io/kube-apiserver:v1.16.0
docker tag  registry.aliyuncs.com/google_containers/kube-proxy:v1.16.0    k8s.gcr.io/kube-proxy:v1.16.0
docker tag  registry.aliyuncs.com/google_containers/kube-controller-manager:v1.16.0  k8s.gcr.io/kube-controller-manager:v1.16.0
docker tag  registry.aliyuncs.com/google_containers/kube-scheduler:v1.16.0   k8s.gcr.io/kube-scheduler:v1.16.0
docker tag  registry.aliyuncs.com/google_containers/etcd:3.3.15-0  k8s.gcr.io/etcd:3.3.15-0
docker tag  registry.aliyuncs.com/google_containers/coredns:1.6.2   k8s.gcr.io/coredns:1.6.2
docker tag  registry.aliyuncs.com/google_containers/pause:3.1  k8s.gcr.io/pause:3.1

3、部署master節點

一、Kubernetes集羣初始化

執行

[root@master ~]# kubeadm init --kubernetes-version=v1.16.0 --pod-network-cidr= 10.244.0.0/16 --apiserver-advertise-address=192.168.3.100

執行成功結果

[init] Using Kubernetes version: v1.16.0
[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 "ca" certificate and key
[certs] Generating "apiserver" certificate and key
[certs] apiserver serving cert is signed for DNS names [master kubernetes kubernetes.default kubernetes.default.svc kubernetes.default.svc.cluster.local] and IPs [10.96.0.1 192.168.3.100]
[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 [master localhost] and IPs [192.168.3.100 127.0.0.1 ::1]
[certs] Generating "etcd/peer" certificate and key
[certs] etcd/peer serving cert is signed for DNS names [master localhost] and IPs [192.168.3.100 127.0.0.1 ::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"
[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
[kubelet-check] Initial timeout of 40s passed.
[apiclient] All control plane components are healthy after 209.010947 seconds
[upload-config] Storing the configuration used in ConfigMap "kubeadm-config" in the "kube-system" Namespace
[kubelet] Creating a ConfigMap "kubelet-config-1.16" 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 master as control-plane by adding the label "node-role.kubernetes.io/master=''"
[mark-control-plane] Marking the node master as control-plane by adding the taints [node-role.kubernetes.io/master:NoSchedule]
[bootstrap-token] Using token: vmuuvn.q7q14t5135zm9xk0
[bootstrap-token] Configuring bootstrap tokens, cluster-info ConfigMap, RBAC Roles
[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
[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 192.168.3.100:6443 --token vmuuvn.q7q14t5135zm9xk0 \
    --discovery-token-ca-cert-hash sha256:c302e2c93d2fe86be7f817534828224469a19c5ccbbf9b246f3695127c3ea611

記錄最後的輸出，node節點加入須要用到

kubeadm join 192.168.3.100:6443 --token vmuuvn.q7q14t5135zm9xk0 
–discovery-token-ca-cert-hash sha256:c302e2c93d2fe86be7f817534828224469a19c5ccbbf9b246f3695127c3ea611

若是init失敗，重啓kubeadm再執行init

[root@master ~]# kubeadm reset

初始化成功後會在/etc/kubernetes/成下面的文件，若是沒有須要從新init

[root@master home]# ll /etc/kubernetes/
total 36
-rw-------  1 root root 5453 Nov 15 17:42 admin.conf
-rw-------  1 root root 5485 Nov 15 17:42 controller-manager.conf
-rw-------  1 root root 5457 Nov 15 17:42 kubelet.conf
drwxr-xr-x. 2 root root  113 Nov 15 17:42 manifests
drwxr-xr-x  3 root root 4096 Nov 15 17:42 pki
-rw-------  1 root root 5437 Nov 15 17:42 scheduler.conf

注意：kubeadm reset是清理環境，執行後，master要從新init。若是node已經加入集羣，那麼node也要reset重啓kubelet並要從新join

[root@node1 home]#kubeadm reset
[root@node1 home]#systemctl daemon-reload && systemctl restart kubelet
[root@node1 home]# kubeadm join 192.168.3.100:6443 --token vmuuvn.q7q14t5135zm9xk0 \
    --discovery-token-ca-cert-hash sha256:c302e2c93d2fe86be7f817534828224469a19c5ccbbf9b246f3695127c3ea611

二、配置權限

當前用戶，執行如下步驟(系統由admin.conf文件啓動kubernetes,若是不配置會起不來)

root@master home]# mkdir -p $HOME/.kube
[root@master home]# cp -i /etc/kubernetes/admin.conf $HOME/.kube/config
[root@master home]# chown $(id -u):$(id -g) $HOME/.kube/config

三、部署flannel網絡（安裝pod網絡附加組件）

k8s 支持不少種網絡方案，在這裏使用的是經典的 flannel 方案，還有Calico方式。

查看flannel版本
https://github.com/coreos/flannel

執行命令開始安裝。注：下面這個地址是v0.11.0-amd6版本的

[root@master home]#kubectl apply -f https://raw.githubusercontent.com/coreos/flannel/62e44c867a2846fefb68bd5f178daf4da3095ccb/Documentation/kube-flannel.yml

安裝結果

clusterrole.rbac.authorization.k8s.io/flannel created
clusterrolebinding.rbac.authorization.k8s.io/flannel created
serviceaccount/flannel created
configmap/kube-flannel-cfg created
unable to recognize "https://raw.githubusercontent.com/coreos/flannel/62e44c867a2846fefb68bd5f178daf4da3095ccb/Documentation/kube-flannel.yml": no matches for kind "PodSecurityPolicy" in version "extensions/v1beta1"
unable to recognize "https://raw.githubusercontent.com/coreos/flannel/62e44c867a2846fefb68bd5f178daf4da3095ccb/Documentation/kube-flannel.yml": no matches for kind "DaemonSet" in version "extensions/v1beta1"
unable to recognize "https://raw.githubusercontent.com/coreos/flannel/62e44c867a2846fefb68bd5f178daf4da3095ccb/Documentation/kube-flannel.yml": no matches for kind "DaemonSet" in version "extensions/v1beta1"
unable to recognize "https://raw.githubusercontent.com/coreos/flannel/62e44c867a2846fefb68bd5f178daf4da3095ccb/Documentation/kube-flannel.yml": no matches for kind "DaemonSet" in version "extensions/v1beta1"
unable to recognize "https://raw.githubusercontent.com/coreos/flannel/62e44c867a2846fefb68bd5f178daf4da3095ccb/Documentation/kube-flannel.yml": no matches for kind "DaemonSet" in version "extensions/v1beta1"
unable to recognize "https://raw.githubusercontent.com/coreos/flannel/62e44c867a2846fefb68bd5f178daf4da3095ccb/Documentation/kube-flannel.yml": no matches for kind "DaemonSet" in version "extensions/v1beta1"

若是一直pull不下來，默認的flannel配置文件拉取鏡像在國外，國內拉取失敗，不少網上文章沒注意這一步，致使flannel部署失敗，以下解決
訪問:https://blog.51cto.com/14040759/2492764

[root@master home]# mkdir flannel
#把內容粘貼到下面的文本後保存
[root@master home]# vim kube-flannel.yml
[root@master home]#  kubectl apply -f flannel/kube-flannel.yml
[root@master home]#

執行獲取pods列表命令，查看相關狀態

[root@master home]# kubectl get pods --all-namespaces
NAMESPACE     NAME                             READY   STATUS    RESTARTS   AGE
kube-system   coredns-5644d7b6d9-5zsbb         0/1      Pending  0          6h17m
kube-system   coredns-5644d7b6d9-pvsm9         0/1     Pending   1          6h17m
kube-system   etcd-master                      1/1     Running   0          6h16m
kube-system   kube-apiserver-master            1/1     Running   0          6h16m
kube-system   kube-controller-manager-master   1/1     Running   0          6h16m
kube-system   kube-flannel-ds-amd64-7x9fv      1/1     Running   0          6h16m
kube-system   kube-flannel-ds-amd64-n6kpw      1/1     Running   0          6h14m
kube-system   kube-proxy-8zl82                 1/1     Running   0          6h14m
kube-system   kube-proxy-gqmxx                 1/1     Running   0          6h17m
kube-system   kube-scheduler-master            1/1     Running   0          6h16m

查看主節點狀況

[root@master ~]# kubectl get nodes

四、將Master做爲工做節點（可選）

使用kubeadm初始化的集羣，出於安全考慮Pod不會被調度到Master Node上，也就是說Master Node不參與工做負載，這樣Master的資源就浪費了。在Master節點上，能夠運行如下命令使其做爲一個工做節點

[root@master ~]#kubectl taint nodes --all node-role.kubernetes.io/master-

禁止master部署pod

[root@master ~]#kubectl taint nodes k8s node-role.kubernetes.io/master=true:NoSchedule

關於污點，網上資料參考：
使用kubeadm搭建的集羣默認就給 master 節點添加了一個污點標記，因此咱們看到咱們平時的 pod 都沒有被調度到 master 上去。

[root@master ~]#kubectl describe node master  | grep Taints（注：master node name）

有一條關於 Taints 的信息：node-role.kubernetes.io/master:NoSchedule，就表示給 master 節點打了一個污點的標記，其中影響的參數是NoSchedule，表示 pod 不會被調度到標記爲 taints 的節點，除了 NoSchedule 外，還有另外兩個選項：
PreferNoSchedule：NoSchedule 的軟策略版本，表示儘可能不調度到污點節點上去
NoExecute：該選項意味着一旦 Taint 生效，如該節點內正在運行的 pod 沒有對應 Tolerate 設置，會直接被逐出

4、部署node節點

jion集羣

[root@node1 ~]# kubeadm join 10.1.31.36:6443 --token vmuuvn.q7q14t5135zm9xk0 \
    --discovery-token-ca-cert-hash sha256:c302e2c93d2fe86be7f817534828224469a19c5ccbbf9b246f3695127c3ea611

若是在master初始化的時候沒有記下jion命令，在master上使用kubeadm token create --print-join-command查詢

5、卸載k8s

一、清理運行到k8s羣集中的pod

$ kubectl delete node --all

二、刪除數據卷和備份

$ for service in kube-apiserver kube-controller-manager kubectl kubelet kube-proxy kube-scheduler; do
      systemctl stop $service
  done
$ yum -y remove kubernetes #if it's registered as a service

三、卸載工具

yum remove -y kubelet kubectl

四、清理文件/文件夾

rm -rf ~/.kube/
rm -rf /etc/kubernetes/
rm -rf /etc/systemd/system/kubelet.service.d
rm -rf /etc/systemd/system/kubelet.service
rm -rf /usr/bin/kube*
rm -rf /etc/cni
rm -rf /opt/cni
rm -rf /var/lib/etcd
rm -rf /var/etcd
rm -rf /var/lib/cni/flannel/* && rm -rf /var/lib/cni/networks/cbr0/* && ip link delete cni0
rm -rf /var/lib/cni/networks/cni0/*

五、清理容器

docker rm -f $(docker ps -qa)
#刪除全部的數據卷
docker volume rm $(docker volume ls -q)
#再次顯示全部的容器和數據卷，確保沒有殘留
docker ps -a
docker volume ls

6、驗證

[root@master ~]# kubectl get nodes -o wide

7、部署產生的問題

https://blog.51cto.com/blogger/success/2492786