Kubernetes是一个可移植的，可扩展的开源平台，用于管理容器化的工作负载和服务，可促进声明式配置和自动化。它拥有一个庞大且快速增长的生态系统。Kubernetes的服务，支持和工具广泛可用。
Kubernetes这个名字起源于希腊语，意思是舵手或飞行员。Google在2014年开源了Kubernetes项目。Kubernetes建立在Google大规模运行生产工作负载的十年半的经验的基础上，并结合了社区中最好的想法和实践。
Kubeadm 是一个工具，它提供了 kubeadm init 以及 kubeadm join 这两个命令作为快速创建 kubernetes 集群的最佳实践。
相关配置来自李哥博客
配置软件源:
# 安装系统工具 apt-get update && apt-get install -y apt-transport-https # 安装 GPG 证书 curl https://mirrors.aliyun.com/kubernetes/apt/doc/apt-key.gpg | apt-key add - # 写入软件源；注意：我们用系统代号为 bionic，但目前阿里云不支持，所以沿用 16.04 的 xenial cat << EOF >/etc/apt/sources.list.d/kubernetes.list > deb https://mirrors.aliyun.com/kubernetes/apt/ kubernetes-xenial main > EOF
安装 kubeadm, kubelet 和 kubectl:
apt-get update apt-get install -y kubelet kubeadm kubectl Reading package lists... Done root@boke-master:~# apt-get install -y kubelet kubeadm kubectl Reading package lists... Done Building dependency tree Reading state information... Done The following additional packages will be installed: conntrack cri-tools kubernetes-cni socat The following NEW packages will be installed: conntrack cri-tools kubeadm kubectl kubelet kubernetes-cni socat 0 upgraded, 7 newly installed, 0 to remove and 140 not upgraded. Need to get 54.3 MB of archives. After this operation, 291 MB of additional disk space will be used. Get:1 http://mirrors.aliyun.com/ubuntu bionic/main amd64 conntrack amd64 1:1.4.4+snapshot20161117-6ubuntu2 [30.6 kB] Get:2 http://mirrors.aliyun.com/ubuntu bionic/main amd64 socat amd64 1.7.3.2-2ubuntu2 [342 kB] Get:3 https://mirrors.aliyun.com/kubernetes/apt kubernetes-xenial/main amd64 cri-tools amd64 1.13.0-00 [8,776 kB] Get:4 https://mirrors.aliyun.com/kubernetes/apt kubernetes-xenial/main amd64 kubernetes-cni amd64 0.7.5-00 [6,473 kB] Get:5 https://mirrors.aliyun.com/kubernetes/apt kubernetes-xenial/main amd64 kubelet amd64 1.16.2-00 [20.7 MB] Get:6 https://mirrors.aliyun.com/kubernetes/apt kubernetes-xenial/main amd64 kubectl amd64 1.16.2-00 [9,234 kB] Get:7 https://mirrors.aliyun.com/kubernetes/apt kubernetes-xenial/main amd64 kubeadm amd64 1.16.2-00 [8,761 kB] Fetched 54.3 MB in 6s (9,086 kB/s) Selecting previously unselected package conntrack. (Reading database ... 83213 files and directories currently installed.) Preparing to unpack .../0-conntrack_1%3a1.4.4+snapshot20161117-6ubuntu2_amd64.deb ... Unpacking conntrack (1:1.4.4+snapshot20161117-6ubuntu2) ... Selecting previously unselected package cri-tools. Preparing to unpack .../1-cri-tools_1.13.0-00_amd64.deb ... Unpacking cri-tools (1.13.0-00) ... Selecting previously unselected package kubernetes-cni. Preparing to unpack .../2-kubernetes-cni_0.7.5-00_amd64.deb ... Unpacking kubernetes-cni (0.7.5-00) ... Selecting previously unselected package socat. Preparing to unpack .../3-socat_1.7.3.2-2ubuntu2_amd64.deb ... Unpacking socat (1.7.3.2-2ubuntu2) ... Selecting previously unselected package kubelet. Preparing to unpack .../4-kubelet_1.16.2-00_amd64.deb ... Unpacking kubelet (1.16.2-00) ... Selecting previously unselected package kubectl. Preparing to unpack .../5-kubectl_1.16.2-00_amd64.deb ... Unpacking kubectl (1.16.2-00) ... Selecting previously unselected package kubeadm. Preparing to unpack .../6-kubeadm_1.16.2-00_amd64.deb ... Unpacking kubeadm (1.16.2-00) ... Setting up conntrack (1:1.4.4+snapshot20161117-6ubuntu2) ... Setting up kubernetes-cni (0.7.5-00) ... Setting up cri-tools (1.13.0-00) ... Setting up socat (1.7.3.2-2ubuntu2) ... Setting up kubelet (1.16.2-00) ... Created symlink /etc/systemd/system/multi-user.target.wants/kubelet.service → /lib/systemd/system/kubelet.service. Setting up kubectl (1.16.2-00) ... Processing triggers for man-db (2.8.3-2ubuntu0.1) ...
# 注意这里的kubeadm版本号 后面要用到 Setting up kubeadm (1.16.2-00) ...
# 设置 kubelet 自启动，并启动 kubelet
systemctl enable kubelet && systemctl start kubelet# 导出配置文件 kubeadm config print init-defaults --kubeconfig ClusterConfiguration > kubeadm.yml
修改配置文件:
apiVersion: kubeadm.k8s.io/v1beta2
bootstrapTokens:
- groups:
- system:bootstrappers:kubeadm:default-node-token
token: abcdef.0123456789abcdef
ttl: 24h0m0s
usages:
- signing
- authentication
kind: InitConfiguration
localAPIEndpoint:
# 修改为自己的ip
advertiseAddress: 192.168.17.180
bindPort: 6443
nodeRegistration:
criSocket: /var/run/dockershim.sock
name: boke-master
taints:
- effect: NoSchedule
key: node-role.kubernetes.io/master
---
apiServer:
timeoutForControlPlane: 4m0s
apiVersion: kubeadm.k8s.io/v1beta2
certificatesDir: /etc/kubernetes/pki
clusterName: kubernetes
controllerManager: {}
dns:
type: CoreDNS
etcd:
local:
dataDir: /var/lib/etcd
# 修改阿里云镜像
imageRepository: registry.aliyuncs.com/google_containers
kind: ClusterConfiguration
# 修改版本号
kubernetesVersion: v1.16.2
networking:
dnsDomain: cluster.local
# 配置成 Calico 的网段（后面会用到）
podSubnet: "10.244.0.0/16"
serviceSubnet: 10.96.0.0/12
scheduler: {}
---
# 开启 IPVS 模式
apiVersion: kubeproxy.config.k8s.io/v1alpha1
kind: KubeProxyConfiguration
featureGates:
SupportIPVSProxyMode: true
mode: ipvs
初始化kubeadm:
kubeadm init --config=kubeadm.yml | tee kubeadm-init.log
[init] Using Kubernetes version: v1.16.2
[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/
[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 [boke-master kubernetes kubernetes.default kubernetes.default.svc kubernetes.default.svc.cluster.local] and IPs [10.96.0.1 192.168.17.180]
[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 [boke-master localhost] and IPs [192.168.17.180 127.0.0.1 ::1]
[certs] Generating "etcd/peer" certificate and key
[certs] etcd/peer serving cert is signed for DNS names [boke-master localhost] and IPs [192.168.17.180 127.0.0.1 ::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
[apiclient] All control plane components are healthy after 16.002589 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 boke-master as control-plane by adding the label "node-role.kubernetes.io/master=''"
[mark-control-plane] Marking the node boke-master as control-plane by adding the taints [node-role.kubernetes.io/master:NoSchedule]
[bootstrap-token] Using token: abcdef.0123456789abcdef
[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:
# 配置kubectl
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:
# 子节点加入命令
kubeadm join 192.168.17.180:6443 --token abcdef.0123456789abcdef \
--discovery-token-ca-cert-hash sha256:ea37964dc96f76f3e658b27ffdc220f60ced82de387aafd8effafe9618f5e6cb
子节点加入命令的token有效期默认是1天，可以在kubeadm.yml中修改，失效可以从官方文档查看解决办法
配置kubectl:
mkdir -p $HOME/.kube sudo cp -i /etc/kubernetes/admin.conf $HOME/.kube/config sudo chown $(id -u):$(id -g) $HOME/.kube/config
查看是否配置成功:
kubectl get nodes
# 能打印出节点信息就成功了 NAME STATUS ROLES AGE VERSION boke-master NotReady master 39m v1.16.2