安装Pod所需的volume。
下载Pod的Secrets。
Pod中运行的 docker（或experimentally，rkt）容器。
定期执行容器健康检查。
Reports the status of the pod back to the rest of the system, by creating a mirror pod if necessary.
Reports the status of the node back to the rest of the system.
kube-proxy
kube-proxy通过在主机上维护网络规则并执行连接转发来实现Kubernetes服务抽象。
docker version
Client:
Version: 18.09.6
API version: 1.39
Go version: go1.10.8
Git commit: 481bc77
Built: Sat May 4 02:35:57 2019 OS/Arch: linux/amd64
Experimental: falseServer: Docker Engine - Community
Engine:
Version: 18.09.6
API version: 1.39 (minimum version 1.12) Go version: go1.10.8
Git commit: 481bc77
Built: Sat May 4 01:59:36 2019 OS/Arch: linux/amd64
Experimental: false
安装 kubernetes 主节点
执行以下命令初始化主节点，该命令指定了初始化时需要使用的配置文件，其中添加 –upload-certs 参数可以在后续执行加入节点时自动分发证书文件。追加的 tee kubeadm-init.log 用以输出日志。
kubeadm init --config=kubeadm.yml --experimental-upload-certs | tee kubeadm-init.log
#your configuration file uses a deprecated API spec: "kubeadm.k8s.io/v1beta1". Please use 'kubeadm config migrate --old-config old.yaml --new-config new.yaml', which will write the new, similar spec using a newer API version.W0106 17:26:39.941946 25748 common.go:77] your configuration file uses a deprecated API spec: "kubeadm.k8s.io/v1beta1". Please use 'kubeadm config migrate --old-config old.yaml --new-config new.yaml', which will write the new, similar spec using a newer API version.
W0106 17:26:39.944487 25748 validation.go:28] Cannot validate kube-proxy config - no validator is available
W0106 17:26:39.944533 25748 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/
[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 [kubernetes-master kubernetes kubernetes.default kubernetes.default.svc kubernetes.default.svc.cluster.local] and IPs [10.96.0.1 192.168.62.159][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 [kubernetes-master localhost] and IPs [192.168.62.159 127.0.0.1 ::1][certs] Generating "etcd/peer" certificate and key
[certs] etcd/peer serving cert is signed for DNS names [kubernetes-master localhost] and IPs [192.168.62.159 127.0.0.1 ::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"W0106 17:26:44.531537 25748 manifests.go:214] the default kube-apiserver authorization-mode is "Node,RBAC"; using "Node,RBAC"[control-plane] Creating static Pod manifest for"kube-controller-manager"W0106 17:26:44.532749 25748 manifests.go:214] the default kube-apiserver authorization-mode is "Node,RBAC"; using "Node,RBAC"[control-plane] Creating static Pod manifest for"kube-scheduler"[etcd] Creating static Pod manifest forlocal 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 24.504808 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] Storing the certificates in Secret "kubeadm-certs" in the "kube-system" Namespace
[upload-certs] Using certificate key:
781e69718ac47389e4e65f025cb9cb842ae621f495323b08f8c3cc5fe69c5a82
[mark-control-plane] Marking the node kubernetes-master as control-plane by adding the label "node-role.kubernetes.io/master=''"[mark-control-plane] Marking the node kubernetes-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
[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:
Kubernetes 中的 CNI 插件
CNI 的初衷是创建一个框架，用于在配置或销毁容器时动态配置适当的网络配置和资源。插件负责为接口配置和管理 IP 地址，并且通常提供与 IP 管理、每个容器的 IP 分配、以及多主机连接相关的功能。容器运行时会调用网络插件，从而在容器启动时分配 IP 地址并配置网络，并在删除容器时再次调用它以清理这些资源。
运行时或协调器决定了容器应该加入哪个网络以及它需要调用哪个插件。然后，插件会将接口添加到容器网络命名空间中，作为一个 veth 对的一侧。接着，它会在主机上进行更改，包括将 veth 的其他部分连接到网桥。再之后，它会通过调用单独的 IPAM（IP地址管理）插件来分配 IP 地址并设置路由。
configmap/calico-config created
customresourcedefinition.apiextensions.k8s.io/felixconfigurations.crd.projectcalico.org created
customresourcedefinition.apiextensions.k8s.io/ipamblocks.crd.projectcalico.org created
customresourcedefinition.apiextensions.k8s.io/blockaffinities.crd.projectcalico.org created
customresourcedefinition.apiextensions.k8s.io/ipamhandles.crd.projectcalico.org created
customresourcedefinition.apiextensions.k8s.io/ipamconfigs.crd.projectcalico.org created
customresourcedefinition.apiextensions.k8s.io/bgppeers.crd.projectcalico.org created
customresourcedefinition.apiextensions.k8s.io/bgpconfigurations.crd.projectcalico.org created
customresourcedefinition.apiextensions.k8s.io/ippools.crd.projectcalico.org created
customresourcedefinition.apiextensions.k8s.io/hostendpoints.crd.projectcalico.org created
customresourcedefinition.apiextensions.k8s.io/clusterinformations.crd.projectcalico.org created
customresourcedefinition.apiextensions.k8s.io/globalnetworkpolicies.crd.projectcalico.org created
customresourcedefinition.apiextensions.k8s.io/globalnetworksets.crd.projectcalico.org created
customresourcedefinition.apiextensions.k8s.io/networkpolicies.crd.projectcalico.org created
customresourcedefinition.apiextensions.k8s.io/networksets.crd.projectcalico.org created
clusterrole.rbac.authorization.k8s.io/calico-kube-controllers created
clusterrolebinding.rbac.authorization.k8s.io/calico-kube-controllers created
clusterrole.rbac.authorization.k8s.io/calico-node created
clusterrolebinding.rbac.authorization.k8s.io/calico-node created
daemonset.extensions/calico-node created
serviceaccount/calico-node created
deployment.extensions/calico-kube-controllers created
```serviceaccount/calico-kube-controllers created
kubectl get cs
输出如下
NAME STATUS MESSAGE ERROR
调度服务，主要作用是将 POD 调度到 Node
scheduler Healthy ok
自动化修复服务，主要作用是 Node 宕机后自动修复 Node 回到正常的工作状态
controller-manager Healthy ok
服务注册与发现
etcd-0 Healthy {“health”:”true”}检查 Master 状态
kubectl cluster-info
#输出如下Kubernetes master is running at https://192.168.62.159:6443
KubeDNS is running at https://192.168.62.159:6443/api/v1/namespaces/kube-system/services/kube-dns:dns/proxy
To further debug and diagnose cluster problems, use ‘kubectl cluster-info dump’.
kubectl run nginx --image=nginx --replicas=2 --port=80
kubectl run --generator=deployment/apps.v1 is DEPRECATED and will be removed in a future version. Use kubectl run --generator=run-pod/v1 or kubectl create instead.
deployment.apps/nginx created
查看全部 Pods 的状态
kubectl get pods
nginx-5578584966-f7vl5 0/1 ContainerCreating 0 55s
nginx-5578584966-p9s24 0/1 ContainerCreating 0 55s
nginx-5578584966-f7vl5 1/1 Running 0 18m
nginx-5578584966-p9s24 1/1 Running 0 18m
查看已部署的服务
```bash
kubectl get deployment
输出如下
NAME READY UP-TO-DATE AVAILABLE AGE
nginx 2/2 22 91m
kubectl get services
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
kubernetes ClusterIP 10.96.0.1 443/TCP 21h
nginx LoadBalancer 10.96.133.79 80:31091/TCP 13m