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 < /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 && 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：
[root@master 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：
[root@master ~]# 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：
[root@master ~]# kubectl get node
NAME STATUS ROLES AGE VERSION
master Ready master 16m v1.12.2
[root@master ~]# 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
[root@master ~]# 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：
[root@master ~]# 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
[root@master ~]# 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
转载请注明：21运维 » kubenetes 入门系列安装之kubeadm安装