kubenetes 入门系列安装之kubeadm安装 – 21运维
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kubenetes 入门系列安装之kubeadm安装

K8S 21运维 92浏览

k8s的安装有多种方式,如yum安装,kubeadm安装,kubemini安装,二进制安装(生产环境多采用此方式精确控制安装)等。本文是入门系列验证,之前进行过yum安装,可以查看文章《k8s入门系列之集群yum安装篇》   。这里进行kubeadm安装一次了解安装过程,真正的学习、测试环境和生产环境都不建议此方法,都建议yum安装或者二进制安装,这样才可以详细了解到k8s的工作原理和工作过程。

平台 :CentOS Linux release 7.5.1804 (Core)
master: 10.1.14.12
node1:  10.1.14.17
node2:  10.1.14.14

一,三台机器前期工作准备
1,关闭防火墙服务,避免与docker容器的防火墙规则冲突。
systemctl stop firewalld
systemctl disable firewalld

2,关闭selinux:
修改/etc/selinux/config为SELINUX=disabled
重启后配置生效。不建议临时关闭(setenfore 0),防止机器重启失效。

3,关闭swap:
临时关闭:

swapoff -a 

永久关闭:

sed -i 's/.*swap.*/#&/' /etc/fstab

4,host定向,将机器内部主机名通信打通:
vi /etc/hosts

10.1.14.12 master
10.1.14.17 node01
10.1.14.14 node02

5,master机器设置免密钥登陆其他两个node

ssh-keygen   #生成密钥对
cd  /root/.ssh/
ssh-copy-id   -i  id_rsa.pub  node01
ssh-copy-id   -i  id_rsa.pub  node02

6,配置ntp:

yum install  ntpdate  -y
systemctl enable ntpdate.service
systemctl start  ntpdate.service
临时同步:ntpdate   time7.aliyun.com
设置任务计划crontab -e:
*/30 * * * * /usr/sbin/ntpdate time7.aliyun.com >/dev/null 2>&1

7,设置内核,建议安装标准系统初始化进行(部分厂商的机器已经进行了默认参数优化)

echo "* soft nofile 65536">> /etc/security/limits.conf
echo "* hard nofile 65536" >> /etc/security/limits.conf
echo "* soft nproc 65536"  >> /etc/security/limits.conf
echo "* hard nproc 65536"  >> /etc/security/limits.conf
echo "* soft  memlock  unlimited" >> /etc/security/limits.conf
echo "* hard memlock  unlimited"  >> /etc/security/limits.conf

修正转发:

modprobe br_netfilter
cat < < EOF >  /etc/sysctl.d/k8s.conf
net.bridge.bridge-nf-call-ip6tables = 1
net.bridge.bridge-nf-call-iptables = 1
EOF
sysctl -p /etc/sysctl.d/k8s.conf

8,设置yum源

epel源:
yum install -y epel-release

#kubenetes yum源 ,采用阿里云
cat &lt;  /etc/yum.repos.d/kubernetes.repo
[kubernetes]
name=Kubernetes
baseurl=http://mirrors.aliyun.com/kubernetes/yum/repos/kubernetes-el7-x86_64
enabled=1
gpgcheck=0
repo_gpgcheck=0
gpgkey=http://mirrors.aliyun.com/kubernetes/yum/doc/yum-key.gpg  http://mirrors.aliyun.com/kubernetes/yum/doc/rpm-package-key.gpg
EOF
--------------------- 
#docker yum源 采用阿里云
wget https://mirrors.aliyun.com/docker-ce/linux/centos/docker-ce.repo
yum clean all  &amp;&amp; yum makecache fast

9,安装依赖包

yum install -y yum-utils device-mapper-persistent-data lvm2 net-tools conntrack-tools wget vim  ntpdate libseccomp libtool-ltdl 

二,进行kubeadm 集群安装部署
1,组件安装
master节点安装etcd:

yum install  etcd -y
systemctl restart etcd
systemctl enable etcd

由于采用外部 etcd,所以要在 master 节点安装 etcd服务,这里也是etcd是单节点。不管是etcd集群还是单机,或者是 http, https都可以,只要在 kubeadm 中配置好就行。
实验中是单机 etcd,然后监听地址为 https://10.1.14.12:2379

master和其他node:

yum install docker-ce kubelet kubeadm kubectl ipvsadm -y
systemctl restart kubelet
systemctl restart docker 
systemctl enable kubelet
systemctl enable docker

2,kubeadm安装配置 kubenetes 1.12.2集群

kubeadm init  --kubernetes-version=v1.12.2 --pod-network-cidr=10.244.0.0/16  --apiserver-advertise-address=10.1.14.12

这里由于我的虚拟机都设置了科学上网,所以可以直接去下载。 没有配置科学上网的,建议采用阿里云的镜像下载后更改tag处理再kubeadm安装。
安装完信息如下,则说明初始化成功:

[[email protected] docker]# kubeadm init  --kubernetes-version=v1.12.2 --pod-network-cidr=10.244.0.0/16  --apiserver-advertise-address=10.1.14.12
[init] using Kubernetes version: v1.12.2
[preflight] running pre-flight checks
        [WARNING Service-Docker]: docker service is not enabled, please run 'systemctl enable docker.service'
[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 ca certificate and key.
[certificates] Generated apiserver certificate and key.
[certificates] 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 10.1.14.12]
[certificates] Generated apiserver-kubelet-client certificate and key.
[certificates] Generated etcd/ca certificate and key.
[certificates] Generated etcd/peer certificate and key.
[certificates] etcd/peer serving cert is signed for DNS names [master localhost] and IPs [10.1.14.12 127.0.0.1 ::1]
[certificates] Generated etcd/healthcheck-client 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 localhost] and IPs [127.0.0.1 ::1]
[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 39.007740 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 master as master by adding the label "node-role.kubernetes.io/master=''"
[markmaster] Marking the node master 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 "master" as an annotation
[bootstraptoken] using token: wzh9es.gaz6xloz7omrswvs
[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 10.1.14.12:6443 --token wzh9es.gaz6xloz7omrswvs --discovery-token-ca-cert-hash sha256:0a2135bbdfd174d5f9e4d4afb8d15b54f066ac261722e1ab7171cee62b7b158b

里边的信息量很大,可以多仔细看两遍,其中最后将node加入集群的命令可以记录一下。

按照提示,在开始使用集群之前,执行如下命令(提示信息直接贴过来即可):

  mkdir -p $HOME/.kube
  sudo cp -i /etc/kubernetes/admin.conf $HOME/.kube/config
  sudo chown $(id -u):$(id -g) $HOME/.kube/config

配置完毕以后查看node信息:

[[email protected] ~]# kubectl  get node
NAME     STATUS     ROLES    AGE    VERSION
master   NotReady   master   8m5s   v1.12.2

原因是flannel没有配置,配置flannel:

kubectl apply -f https://raw.githubusercontent.com/coreos/flannel/master/Documentation/kube-flannel.yml
kubectl apply -f https://raw.githubusercontent.com/coreos/flannel/master/Documentation/k8s-manifests/kube-flannel-rbac.yml

重新查看:

[[email protected] ~]# kubectl get node
NAME     STATUS   ROLES    AGE   VERSION
master   Ready    master   16m   v1.12.2
[[email protected] ~]# kubectl get pods --all-namespaces
NAMESPACE     NAME                             READY   STATUS    RESTARTS   AGE
kube-system   coredns-576cbf47c7-ftvc8         1/1     Running   0          15m
kube-system   coredns-576cbf47c7-rtm6f         1/1     Running   0          15m
kube-system   etcd-master                      1/1     Running   0          75s
kube-system   kube-apiserver-master            1/1     Running   0          66s
kube-system   kube-controller-manager-master   1/1     Running   0          77s
kube-system   kube-flannel-ds-amd64-488hv      1/1     Running   0          99s
kube-system   kube-proxy-d4v7j                 1/1     Running   0          15m
kube-system   kube-scheduler-master            1/1     Running   0          77s
[[email protected] ~]# kubectl get cs
NAME                 STATUS    MESSAGE              ERROR
scheduler            Healthy   ok                   
controller-manager   Healthy   ok                   
etcd-0               Healthy   {"health": "true"}  

3,node节点配置
node01和node02分别执行之前的命令提示,将node01 node02加入到集群:

kubeadm join 10.1.14.12:6443 --token wzh9es.gaz6xloz7omrswvs --discovery-token-ca-cert-hash sha256:0a2135bbdfd174d5f9e4d4afb8d15b54f066ac261722e1ab7171cee62b7b158b

master查看:

[[email protected] ~]# kubectl get node
NAME     STATUS   ROLES    AGE     VERSION
master   Ready    master   21m     v1.12.2
node01   Ready       2m38s   v1.12.2
node02   Ready       2m35s   v1.12.2

4,集群信息查看

[[email protected] ~]# kubeadm config view
apiServerExtraArgs:
  authorization-mode: Node,RBAC
apiVersion: kubeadm.k8s.io/v1alpha3
auditPolicy:
  logDir: /var/log/kubernetes/audit
  logMaxAge: 2
  path: ""
certificatesDir: /etc/kubernetes/pki
clusterName: kubernetes
controlPlaneEndpoint: ""
etcd:
  local:
    dataDir: /var/lib/etcd
    image: ""
imageRepository: k8s.gcr.io
kind: ClusterConfiguration
kubernetesVersion: v1.12.2
networking:
  dnsDomain: cluster.local
  podSubnet: 10.244.0.0/16
  serviceSubnet: 10.96.0.0/12
unifiedControlPlaneImage: 

5,集群重装

kubeadm reset


本安装顺利实现参考了如下文章:

kubeadm安装k8s测试环境:https://blog.csdn.net/orangleliu/article/details/81284633
Kubernetes 学习总结 2 安装与入门: https://www.itency.com/topic/show.do?id=592252

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