Kubernetes(K8S)做为容器编排的系统，被广泛应用于容器、微服务、服务网格中。
想体验、学习 K8S 的话，首先得把它装好。但由于国内的 GFW 网络、公司内部局域网的各种限制，安装过程会出现一些坑。故整理一下新鲜出炉的步骤，尽量把坑填上。
在这安装过程中，我准备了 Ubuntu 22.04 的系统，一台做为 Master，另一台做为 Worker，一起组成一个集群。
安装 Docker
此步骤，所有机器都需要做。
具体安装步骤请参考：
禁用 Swap
此步骤，所有机器都需要做。
分两步，一步时临时禁用，并马上生效；另一步是永久性禁用。
sudo swapoff -a
sudo sed -i '/ swap / s/^\(.*\)$/#\1/g' /etc/fstab加载内核模块
此步骤，所有机器都需要做。
cat <<EOF | sudo tee /etc/modules-load.d/k8s.conf
overlay
br_netfilter
EOF
sudo modprobe overlay
sudo modprobe br_netfilter设置 sysctl 参数
此步骤，所有机器都需要做。
cat <<EOF | sudo tee /etc/sysctl.d/k8s.conf
net.bridge.bridge-nf-call-iptables = 1
net.bridge.bridge-nf-call-ip6tables = 1
net.ipv4.ip_forward = 1
EOF
sudo sysctl --system安装 K8S
此步骤，所有机器都需要做。
sudo apt-get update
sudo apt-get install -y apt-transport-https ca-certificates curl
sudo curl --insecure -fsSLo https://mirrors.aliyun.com/kubernetes/apt/doc/apt-key.gpg | apt-key add -
sudo cat <<EOF >/etc/apt/sources.list.d/kubernetes.list
deb https://mirrors.aliyun.com/kubernetes/apt/ kubernetes-xenial main
EOF
sudo apt-get update
sudo apt-get install -y kubelet kubeadm kubectl
sudo apt-mark hold kubelet kubeadm kubectl目前最新版的 K8S 是 1.27.1。这些步骤做完之后，会被安装到两台机器上。
修改 containerd 配置
此步骤，所有机器都需要做。
主要修改两个地方，一个是从阿里云下载镜像；另一个是启用 systemd。
第一个修改是启用 systemd：
containerd config default | sudo tee /etc/containerd/config.toml >/dev/null 2>&1
sudo sed -i 's/SystemdCgroup \= false/SystemdCgroup \= true/g' /etc/containerd/config.toml第二个修改是把远程下载地址从 Google 家的改为阿里云的：
sudo vim /etc/containerd/config.toml把这行：sandbox_image = "registry.k8s.io/pause:3.6"
改成：sandbox_image = "registry.aliyuncs.com/google_containers/pause:3.9"
其实用 sed，跟第一个 systemd 的修改一起做了也行。
然后重启 containerd：
sudo systemctl restart containerd这一步如果不做的话，后面的 kubeadm init 会因为无法下载镜像而一直失败。
初始化 Master 节点
此步骤，仅需要在 Master 节点上操作。
sudo kubeadm init --apiserver-advertise-address 192.168.111.128 --pod-network-cidr 10.244.0.0/16 --image-repository registry.aliyuncs.com/google_containers192.168.111.128为主机IP
因为后面打算用 Flannel 来作为 CNI，所以 CIDR 按要求配置了：10.244.0.0/16。
如果一切正常的话，可以看到这样的输出：
[init] Using Kubernetes version: v1.27.1
[preflight] Running pre-flight checks
[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'
W0421 15:26:43.924760 8817 images.go:80] could not find officially supported version of etcd for Kubernetes v1.27.1, falling back to the nearest etcd version (3.5.7-0)
[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 kubernetes.default kubernetes.default.svc kubernetes.default.svc.cluster.local ycwang-ubuntu] and IPs [10.96.0.1 192.168.111.128]
[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 [localhost ycwang-ubuntu] and IPs [192.168.111.128 127.0.0.1 ::1]
[certs] Generating "etcd/peer" certificate and key
[certs] etcd/peer serving cert is signed for DNS names [localhost ycwang-ubuntu] and IPs [192.168.111.128 127.0.0.1 ::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
[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
[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"
W0421 15:26:46.894146 8817 images.go:80] could not find officially supported version of etcd for Kubernetes v1.27.1, falling back to the nearest etcd version (3.5.7-0)
[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 5.502175 seconds
[upload-config] Storing the configuration used in ConfigMap "kubeadm-config" in the "kube-system" Namespace
[kubelet] Creating a ConfigMap "kubelet-config" 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 ycwang-ubuntu as control-plane by adding the labels: [node-role.kubernetes.io/control-plane node.kubernetes.io/exclude-from-external-load-balancers]
[mark-control-plane] Marking the node ycwang-ubuntu as control-plane by adding the taints [node-role.kubernetes.io/control-plane:NoSchedule]
[bootstrap-token] Using token: sd27s0.dpnlrf96at6uwgl0
[bootstrap-token] Configuring bootstrap tokens, cluster-info ConfigMap, RBAC Roles
[bootstrap-token] Configured RBAC rules to allow Node Bootstrap tokens to get nodes
[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
Alternatively, if you are the root user, you can run:
export KUBECONFIG=/etc/kubernetes/admin.conf
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 192.168.111.128:6443 --token sd27s0.dpnlrf96at6uwgl0 \
--discovery-token-ca-cert-hash sha256:7a6acd******3e154c这样，集群的 Master 节点基本上好了。
配置 Master 节点
此步骤，仅需要在 Master 节点上操作。
根据上面的输出，在 Master 节点输入命令，使得可以用非 root 用户操作 kubectl：
mkdir -p $HOME/.kube
sudo cp -i /etc/kubernetes/admin.conf $HOME/.kube/config
sudo chown $(id -u):$(id -g) $HOME/.kube/config继续输入这些命令，实现 Shell 命令自动补全：
echo 'source <(kubectl completion bash)' >> ~/.bashrc
source ~/.bashrc安装 Flannel 网络
此步骤，仅需要在 Master 节点上操作。
在 Master 节点上，安装 Flannel：
kubectl apply -f https://github.com/flannel-io/flannel/releases/latest/download/kube-flannel.yml至此，Master 节点的安装、配置都结束了。
下一步，把 Worker 节点加入集群。
Worker 加入集群
sudo kubeadm join 192.168.111.128:6443 --token sd27s0.dpnlrf96at6uwgl0 \
--discovery-token-ca-cert-hash sha256:7a6acd******3e154c一切正常的话，可以看到这样的输出，表明该机器已经加入集群了：
[preflight] Running pre-flight checks
[preflight] Reading configuration from the cluster...
[preflight] FYI: You can look at this config file with 'kubectl -n kube-system get cm kubeadm-config -o yaml'
[kubelet-start] Writing kubelet configuration to file "/var/lib/kubelet/config.yaml"
[kubelet-start] Writing kubelet environment file with flags to file "/var/lib/kubelet/kubeadm-flags.env"
[kubelet-start] Starting the kubelet
[kubelet-start] Waiting for the kubelet to perform the TLS Bootstrap...
This node has joined the cluster:
* Certificate signing request was sent to apiserver and a response was received.
* The Kubelet was informed of the new secure connection details.
Run 'kubectl get nodes' on the control-plane to see this node join the cluster.查看集群信息
回到 Master 节点，可以看到集群已经建立：
kubectl get nodesNAME STATUS ROLES AGE VERSION
ycwang-ubuntu NotReady control-plane 30m v1.27.1
ycwang-ubuntu-worker NotReady <none> 43s v1.27.1一开始的时候，状态都是 NotReady。
稍等片刻，等需要的镜像都下载、运行之后，就会全部变成 Ready 了。
kubectl get nodesNAME STATUS ROLES AGE VERSION
ycwang-ubuntu Ready control-plane 33m v1.27.1
ycwang-ubuntu-worker Ready <none> 3m23s v1.27.1可以看到所有的 Pod 都在正常运行了：
kubectl get pods --all-namespaces -o wideNAMESPACE NAME READY STATUS RESTARTS AGE IP NODE NOMINATED NODE READINESS GATES
kube-flannel kube-flannel-ds-gl795 1/1 Running 0 6m10s 192.168.111.128 ycwang-ubuntu <none> <none>
kube-flannel kube-flannel-ds-lq8p8 1/1 Running 0 6m10s 192.168.111.129 ycwang-ubuntu-worker <none> <none>
kube-system coredns-7bdc4cb885-lgsvw 1/1 Running 0 36m 10.244.1.3 ycwang-ubuntu-worker <none> <none>
kube-system coredns-7bdc4cb885-ss4n5 1/1 Running 0 36m 10.244.1.2 ycwang-ubuntu-worker <none> <none>
kube-system etcd-ycwang-ubuntu 1/1 Running 0 36m 192.168.111.128 ycwang-ubuntu <none> <none>
kube-system kube-apiserver-ycwang-ubuntu 1/1 Running 0 36m 192.168.111.128 ycwang-ubuntu <none> <none>
kube-system kube-controller-manager-ycwang-ubuntu 1/1 Running 0 36m 192.168.111.128 ycwang-ubuntu <none> <none>
kube-system kube-proxy-wtg74 1/1 Running 0 6m48s 192.168.111.129 ycwang-ubuntu-worker <none> <none>
kube-system kube-proxy-x4s95 1/1 Running 0 36m 192.168.111.128 ycwang-ubuntu <none> <none>
kube-system kube-scheduler-ycwang-ubuntu 1/1 Running 0 36m 192.168.111.128 ycwang-ubuntu <none> <none>这样，整个集群搭建成功。可以开始使用了。
验证通过后，可以把上述命令合到一起，保存成一个 Shell 文件。以后每次执行该文件即可。
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