k8s实验环境的快速搭建

Posted 2020-11-01

大部分搜索了网上的文章，有些自己遇到的问题也标记了处理方法！

Kubeadm 安装k8s
准备环境：
1.配置好各节点hosts文件
2.关闭系统防火墙
3.关闭SElinux
4.关闭swap
5.配置系统内核参数使流过网桥的流量也进入iptables/netfilter框架中，在/etc/sysctl.conf中添加以下配置：
net.bridge.bridge-nf-call-iptables?=?1
net.bridge.bridge-nf-call-ip6tables?=?1
sysctl?-p
使用kubeadm安装：
1.首先配置阿里K8S 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=0
EOF
yum?-y?install?epel-release
yum?clean?all
yum?makecache

2.安装kubeadm和相关工具包
yum?-y?install?docker?kubelet?kubeadm?kubectl?kubernetes-cni
?
3.启动Docker与kubelet服务

systemctl?enable?docker?&&?systemctl?start?docker
systemctl?enable?kubelet?&&?systemctl?start?kubelet

提示：此时kubelet的服务运行状态是异常的，因为缺少主配置文件kubelet.conf。但可以暂不处理，因为在完成Master节点的初始化后才会生成这个配置文件。

4.下载K8S相关镜像
因为无法直接访问gcr.io下载镜像，所以需要配置一个国内的容器镜像加速器
配置一个阿里云的加速器：
登录?https://cr.console.aliyun.com/
在页面中找到并点击镜像加速按钮，即可看到属于自己的专属加速链接，选择Centos版本后即可看到配置方法。
?提示：在阿里云上使用 Docker 并配置阿里云镜像加速器，可能会遇到 daemon.json 导致 docker daemon 无法启动的问题，可以通过以下方法解决。

5.下载K8S相关镜像
OK，解决完加速器的问题之后，开始下载k8s相关镜像，下载后将镜像名改为k8s.gcr.io/开头的名字，以便kubeadm识别使用。

#!/bin/bash

images=(kube-proxy-amd64:v1.10.0?kube-scheduler-amd64:v1.10.0?kube-controller-manager-amd64:v1.10.0?kube-apiserver-amd64:v1.10.0br/>etcd-amd64:3.1.12?pause-amd64:3.1?kubernetes-dashboard-amd64:v1.8.3?k8s-dns-sidecar-amd64:1.14.8?k8s-dns-kube-dns-amd64:1.14.8
k8s-dns-dnsmasq-nanny-amd64:1.14.8)
for?imageName?in?${images[@]}?;?do
??docker?pull?keveon/$imageName
??docker?tag?keveon/$imageName?k8s.gcr.io/$imageName
??docker?rmi?keveon/$imageName
done
上面的shell脚本主要做了3件事，下载各种需要用到的容器镜像、重新打标记为符合k8s命令规范的版本名称、清除旧的容器镜像。
提示：镜像版本一定要和kubeadm安装的版本一致，否则会出现time out问题。

6.初始化安装K8S Master
执行上述shell脚本，等待下载完成后，执行kubeadm init --kubernetes-version=v1.10.0 --pod-network-cidr=10.224.0.0/16
提示：选项–kubernetes-version=v1.10.0是必须的，否则会因为访问google网站被墙而无法执行命令。这里使用v1.10.0版本，刚才前面也说到了下载的容器镜像版本必须与K8S版本一致否则会出现time out。
上面的命令大约需要1分钟的过程，期间可以观察下tail -f /var/log/message日志文件的输出，掌握该配置过程和进度。上面最后一段的输出信息保存一份，后续添加工作节点还要用到。

7.配置kubectl认证信息

#?对于非root用户
mkdir?-p?$HOME/.kube
sudo?cp?-i?/etc/kubernetes/admin.conf?$HOME/.kube/config
sudo?chown?$(id?-u):$(id?-g)?$HOME/.kube/config
#?对于root用户
export?KUBECONFIG=/etc/kubernetes/admin.conf
也可以直接放到~/.bash_profile
echo?"export?KUBECONFIG=/etc/kubernetes/admin.conf"?>>?~/.bash_profile
8.安装flannel网络
wget https://raw.githubusercontent.com/coreos/flannel/master/Documentation/kube-flannel.yml
kubectl apply -f kube-flannel.yml
9.让node1、node2加入集群
提示：细心的童鞋应该会发现，这段命令其实就是前面K8S Matser安装成功后我让你们保存的那段命令。
?默认情况下，Master节点不参与工作负载，但如果希望安装出一个All-In-One的k8s环境，则可以执行以下命令，让Master节点也成为一个Node节点：

kubectl?taint?nodes?--all?node-role.kubernetes.io/master-

10.验证K8S Master是否搭建成功
#?查看节点状态
kubectl?get?nodes
#?查看pods状态
kubectl?get?pods?--all-namespaces
#?查看K8S集群状态
kubectl?get?cs

初始化集群

[[email protected] ~]# kubeadm init --kubernetes-version=v1.10.0 --pod-network-cidr=10.224.0.0/16
[init] Using Kubernetes version: v1.10.0
[init] Using Authorization modes: [Node RBAC]
[preflight] Running pre-flight checks.
[WARNING Service-Docker]: docker service is not enabled, please run ‘systemctl enable docker.service‘
[WARNING FileExisting-crictl]: crictl not found in system path
Suggestion: go get github.com/kubernetes-incubator/cri-tools/cmd/crictl
[preflight] Starting the kubelet service
[certificates] Generated ca certificate and key.
[certificates] Generated apiserver certificate and key.
[certificates] apiserver serving cert is signed for DNS names [vm-for-lhz-test-191 kubernetes kubernetes.default kubernetes.default.svc kubernetes.default.svc.cluster.local] and IPs [10.96.0.1 192.168.100.191]
[certificates] Generated apiserver-kubelet-client certificate and key.
[certificates] Generated etcd/ca certificate and key.
[certificates] Generated etcd/server certificate and key.
[certificates] etcd/server serving cert is signed for DNS names [localhost] and IPs [127.0.0.1]
[certificates] Generated etcd/peer certificate and key.
[certificates] etcd/peer serving cert is signed for DNS names [vm-for-lhz-test-191] and IPs [192.168.100.191]
[certificates] Generated etcd/healthcheck-client certificate and key.
[certificates] Generated apiserver-etcd-client certificate and key.
[certificates] Generated sa key and public key.
[certificates] Generated front-proxy-ca certificate and key.
[certificates] Generated front-proxy-client certificate and key.
[certificates] Valid certificates and keys now exist in "/etc/kubernetes/pki"
[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 30.504825 seconds
[uploadconfig]?Storing the configuration used in ConfigMap "kubeadm-config" in the "kube-system" Namespace
[markmaster] Will mark node vm-for-lhz-test-191 as master by adding a label and a taint
[markmaster] Master vm-for-lhz-test-191 tainted and labelled with key/value: node-role.kubernetes.io/master=""
[bootstraptoken] Using token: nz32q6.6hgq3hhrmokdprnr
[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: kube-dns
[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/

wget https://raw.githubusercontent.com/coreos/flannel/master/Documentation/kube-flannel.yml

You can now join any number of machines by running the following on each node
as root:

如果忘记token可以在master节点上创建新的token kubeadm token create
[[email protected] ~]# kubeadm join 192.168.100.191:6443 --token b3cr72.33pjt6evrwtxrgsh --discovery-token-unsafe-skip-ca-verification
[preflight] Running pre-flight checks.
[WARNING FileExisting-crictl]: crictl not found in system path
Suggestion: go get github.com/kubernetes-incubator/cri-tools/cmd/crictl
[preflight] Starting the kubelet service
[discovery] Trying to connect to API Server "192.168.100.191:6443"
[discovery] Created cluster-info discovery client, requesting info from "https://192.168.100.191:6443"
[discovery] Cluster info signature and contents are valid and no TLS pinning was specified, will use API Server "192.168.100.191:6443"
[discovery] Successfully established connection with API Server "192.168.100.191:6443"

This node has joined the cluster:

• Certificate signing request was sent to master 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.

[[email protected] ~]# kubectl get nodes --all-namespaces=true
NAMESPACE NAME STATUS ROLES AGE VERSION
vm-for-lhz-test-191 Ready master 42m v1.10.0
vm-for-lhz-test-192 Ready <none> 3m v1.10.0
vm-for-lhz-test-193 Ready <none> 11m v1.10.0
vm-for-lhz-test-194 Ready <none> 3m v1.10.0

错误问题 需要更改docker的cgroups 为systemd的驱动
Apr 14 18:16:40 vm-for-lhz-test-193 kubelet: F0414 18:16:40.481654 18286 server.go:233] failed to run Kubelet: failed to create kubelet: misconfiguration: kubelet cgroup driver: "systemd" is different from docker cgroup driver: "cgroupfs"

vi /lib/systemd/system/docker.service
ExecStart=/usr/bin/dockerd --exec-opt native.cgroupdriver=systemd