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，我准备了两台 Ubuntu 22.04 的系统，一台做为 Master，另一台做为 Worker，一起组成一个 mini 版的集群。
0. 证书问题 - 可选
如果你在公司内部的局域网，而且通过公司提供的代理服务器上网，那么，多半需要此步骤。否则会遇到各种自签名证书验证失败的问题。
此步骤，两台机器都需要做。
具体的证书下载，各个公司都不一样，请咨询你们家的 IT 人员。下载完之后，执行：update-ca-certificates。
# 下载你家的自签名证书$ sudo cp 自签名证书.crt /usr/local/share/ca-certificates/$ sudo update-ca-certificates
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这样，可以避免后续的各种证书验证失败。
1. 安装 Docker
此步骤，两台机器都需要做。
具体安装步骤请参考：
Install Docker Engine on Ubuntu | Docker Documentation
2. 禁用 Swap
此步骤，两台机器都需要做。
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
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3. 加载内核模块
此步骤，两台机器都需要做。
$ cat <<EOF | sudo tee /etc/modules-load.d/k8s.confoverlaybr_netfilterEOF
$ sudo modprobe overlay$ sudo modprobe br_netfilter
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4. 设置 sysctl 参数
此步骤，两台机器都需要做。
$ cat <<EOF | sudo tee /etc/sysctl.d/k8s.confnet.bridge.bridge-nf-call-iptables = 1net.bridge.bridge-nf-call-ip6tables = 1net.ipv4.ip_forward = 1EOF
sudo sysctl --system
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5. 安装 K8S
此步骤，两台机器都需要做。
$ sudo apt-get update$ sudo apt-get install -y apt-transport-https ca-certificates curl$ sudo curl --insecure -fsSLo /etc/apt/keyrings/kubernetes-archive-keyring.gpg https://packages.cloud.google.com/apt/doc/apt-key.gpg$ echo "deb [signed-by=/etc/apt/keyrings/kubernetes-archive-keyring.gpg] https://apt.kubernetes.io/ kubernetes-xenial main" | sudo tee /etc/apt/sources.list.d/kubernetes.list$ sudo apt-get update$ sudo apt-get install -y kubelet kubeadm kubectl$ sudo apt-mark hold kubelet kubeadm kubectl
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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。
6. 修改 containerd 配置
此步骤，两台机器都需要做。
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
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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
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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
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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。
7. 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_containers
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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
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这样，集群的 Master 节点基本上好了。
8. 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
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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
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9. 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
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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。
10. Worker 加入集群
此步骤，仅需要在 Worker 节点上操作。
如果你有多台 Worker 节点，每个结点都需要做一次。
把第 7 步的 join 命令 Copy 出来，然后执行：
$ sudo kubeadm join 192.168.111.128:6443 --token sd27s0.dpnlrf96at6uwgl0 \ --discovery-token-ca-cert-hash sha256:7a6acd******3e154c
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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.
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11. 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 VERSIONycwang-ubuntu NotReady control-plane 30m v1.27.1ycwang-ubuntu-worker NotReady <none> 43s v1.27.1
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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 VERSIONycwang-ubuntu Ready control-plane 33m v1.27.1ycwang-ubuntu-worker Ready <none> 3m23s v1.27.1
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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 GATESkube-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>
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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。
欢迎来到微服务、云原生的时代！
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