k8s如何设置和使用集群？

今天小编就为大家带来一篇k8s设置和使用集群的文章。小编觉得挺实用的，为此分享给大家做个参考。一起跟随小编过来看看吧。

K8S设置：

（1）添加阿里docker 源

shell> wget https://mirrors.aliyun.com/docker-ce/linux/centos/docker-ce.repo  -O /etc/yum.repos.d/docker-ce.repo

（2）安装docker
shell>yum -y install docker-ce
shell>docker -v
shell> systemctl enable docker
shell>systemctl start docker

（3）安装kubernetes,增加源
shell> 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
##所有节点安装
shell> yum install -y kubelet kubeadm kubectl
shell> systemctl enable kubelet && systemctl start kubelet

（4）初始化k8s master
shell> kubeadm init --apiserver-advertise-address 10.10.202.140 --pod-network-cidr=10.244.0.0/16

kubeadm init \
--apiserver-advertise-address=10.10.202.140 \
--image-repository registry.aliyuncs.com/google_containers \
--pod-network-cidr=10.244.0.0/16
--apiserver-advertise-address 指明用 Master 的哪个 interface 与 Cluster 的其他节点通信。
如果 Master 有多个 interface，建议明确指定，如果不指定，kubeadm 会自动选择有默认网关的 interface。
--pod-network-cidr 指定 Pod 网络的范围。Kubernetes 支持多种网络方案，而且不同网络方案对 --pod-network-cidr 有自己的要求，这里设置为 10.244.0.0/16 是因为我们将使用 flannel 网络方案，必须设置成这个 CIDR

[root@node140 /]# kubeadm init \

--apiserver-advertise-address=10.10.202.140 \
--image-repository registry.aliyuncs.com/google_containers \
--pod-network-cidr=10.244.0.0/16
W1211 22:26:52.608250   70792 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)
W1211 22:26:52.608464   70792 version.go:102] falling back to the local client version: v1.17.0
W1211 22:26:52.608775   70792 validation.go:28] Cannot validate kube-proxy config - no validator is available
W1211 22:26:52.608797   70792 validation.go:28] Cannot validate kubelet config - no validator is available
[init] Using Kubernetes version: v1.17.0
[preflight] Running pre-flight checks
[WARNING IsDockerSystemdCheck]: detected "cgroupfs" as the Docker cgroup driver. The recommended driver is "systemd". Please follow the guide at https://kubernetes.io/docs/setup/cri/
[WARNING Service-Kubelet]: kubelet service is not enabled, please run 'systemctl enable kubelet.service'
[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] Starting the kubelet
[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 [node140 kubernetes kubernetes.default kubernetes.default.svc kubernetes.default.svc.cluster.local] and IPs [10.96.0.1 10.10.202.140]
[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 [node140 localhost] and IPs [10.10.202.140 127.0.0.1 ::1]
[certs] Generating "etcd/peer" certificate and key
[certs] etcd/peer serving cert is signed for DNS names [node140 localhost] and IPs [10.10.202.140 127.0.0.1 ::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"
W1211 22:27:45.746769   70792 manifests.go:214] the default kube-apiserver authorization-mode is "Node,RBAC"; using "Node,RBAC"
[control-plane] Creating static Pod manifest for "kube-scheduler"
W1211 22:27:45.748837   70792 manifests.go:214] the default kube-apiserver authorization-mode is "Node,RBAC"; using "Node,RBAC"
[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 34.003938 seconds
[upload-config] Storing the configuration used in ConfigMap "kubeadm-config" in the "kube-system" Namespace
[kubelet] Creating a ConfigMap "kubelet-config-1.17" 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 node140 as control-plane by adding the label "node-role.kubernetes.io/master=''"
[mark-control-plane] Marking the node node140 as control-plane by adding the taints [node-role.kubernetes.io/master:NoSchedule]
[bootstrap-token] Using token: y6wdsf.dkce7wf8lij4rbgf
[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
[kubelet-finalize] Updating "/etc/kubernetes/kubelet.conf" to point to a rotatable kubelet client certificate and key
[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 10.10.202.140:6443 --token y6wdsf.dkce7wf8lij4rbgf \
--discovery-token-ca-cert-hash sha256:2c307c40531df0dec0908647a9913c09174a0962531694c383fbc14315c1ae07

kubeadm 执行初始化前的检查。

② 生成 token 和证书。

③ 生成 KubeConfig 文件，kubelet 需要这个文件与 Master 通信。

④ 安装 Master 组件，会从 goolge 的 Registry 下载组件的 Docker 镜像，这一步可能会花一些时间，主要取决于网络质量。

⑤ 安装附加组件 kube-proxy 和 kube-dns。

⑥ Kubernetes Master 初始化成功。

⑦ 提示如何配置 kubectl，后面会实践。

⑧ 提示如何安装 Pod 网络，后面会实践。

⑨ 提示如何注册其他节点到 Cluster，后面会实践。

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

（6）安装pod 网络
kubectl apply -f https://raw.githubusercontent.com/coreos/flannel/master/Documentation/kube-flannel.yml

（7） 主机添加进入集群

shell> kubeadm join 10.10.202.140:6443 --token y6wdsf.dkce7wf8lij4rbgf \
--discovery-token-ca-cert-hash sha256:2c307c40531df0dec0908647a9913c09174a0962531694c383fbc14315c1ae07

报错：3个报错
[preflight] WARNING: JoinControlPane.controlPlane settings will be ignored when control-plane flag is not set.
[preflight] Running pre-flight checks
[WARNING IsDockerSystemdCheck]: detected "cgroupfs" as the Docker cgroup driver. The recommended driver is "systemd". Please follow the guide at https://kubernetes.io/docs/setup/cri/
[WARNING Service-Kubelet]: kubelet service is not enabled, please run 'systemctl enable kubelet.service'
error execution phase preflight: [preflight] Some fatal errors occurred:
[ERROR FileContent--proc-sys-net-bridge-bridge-nf-call-iptables]: /proc/sys/net/bridge/bridge-nf-call-iptables contents are not set to 1
[preflight] If you know what you are doing, you can make a check non-fatal with --ignore-preflight-errors=...
To see the stack trace of this error execute with --v=5 or higher

第一个错误：dockers不是systemd启动 ,处理过程修改docker.service
#ExecStart=/usr/bin/dockerd -H fd:// --containerd=/run/containerd/containerd.sock
ExecStart=/usr/bin/dockerd --exec-opt native.cgroupdriver=systemd

第二个没有设置：    systemctl enable kubelet.service
第三个内核没设置：    echo 1 > /proc/sys/net/bridge/bridge-nf-call-iptables
具体根据报错进行解决

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

（8）查看集群状态
shell> kubectl get cs
NAME                 STATUS    MESSAGE             ERROR
scheduler            Healthy   ok                  
controller-manager   Healthy   ok                  
etcd-0               Healthy   {"health":"true"}

（9）将节点加入集群
第一步：环境准备
1.node节点关闭防火墙和selinux
2.禁用swap

1. 解析主机名
   4.启动内核功能
   启动kubeket

第二步：加入node141 node142 node143
shell> kubeadm join 10.10.202.141:6443 --token y6wdsf.dkce7wf8lij4rbgf \
--discovery-token-ca-cert-hash sha256:2c307c40531df0dec0908647a9913c09174a0962531694c383fbc14315c1ae07

(10)查看集群
shell> kubectl get nodes
NAME      STATUS   ROLES    AGE   VERSION
node140   Ready    master   90d   v1.17.0
node141   Ready    <none>   90d   v1.17.0
node142   Ready    <none>   90d   v1.17.0
node143   Ready    <none>   90d   v1.17.0
等一会才会变成read状态

（11）移除一个node节点的方法：
（1）进入维护模式
shell> kubectl drain host1 --delete-local-data --force --ignore-daemonsets
（2）删除节点
shell> kubectl delete node node141

以上就是k8s设置和使用集群的具体介绍，内容较为全面，而且我也相信有相当的一些工具可能是我们日常工作可能会见到或用到的。通过这篇文章，希望你能收获更多。