前言
kubeadm 是 Kubernetes 官方提供的用于快速安部署 Kubernetes 集群的工具，伴随 Kubernetes 每个版本的发布都会同步更新，kubeadm 会对集群配置方面的一些实践做调整，通过实验 kubeadm 可以学习到 Kubernetes 官方在集群配置上一些新的最佳实践。
一、准备
1.1、系统配置
在安装之前，需要先做好如下准备。3 台 CentOS 7.9 主机如下：
cat /etc/hosts
192.168.96.151 node1
192.168.96.152 node2
192.168.96.153 node3
在各个主机上完成下面的系统配置。如果各个主机启用了防火墙策略，需要开放 Kubernetes 各个组件所需要的端口，可以查看 Ports and Protocols 中的内容, 开放相关端口或者关闭主机的防火墙。
禁用SELINUX：
setenforce 0
vi /etc/selinux/config
SELINUX=disabled
创建/etc/modules-load.d/containerd.conf 配置文件:
cat << EOF > /etc/modules-load.d/containerd.conf
overlay
br_netfilter
EOF
执行以下命令使配置生效:
modprobe overlay
modprobe br_netfilter
创建/etc/sysctl.d/99-kubernetes-cri.conf 配置文件：
cat << EOF > /etc/sysctl.d/99-kubernetes-cri.conf
net.bridge.bridge-nf-call-ip6tables = 1
net.bridge.bridge-nf-call-iptables = 1
net.ipv4.ip_forward = 1
user.max_user_namespaces=28633
EOF
执行以下命令使配置生效:
sysctl -p /etc/sysctl.d/99-kubernetes-cri.conf
1.2、配置服务器支持开启ipvs的前提条件
由于ipvs 已经加入到了内核的主干，所以为 kube-proxy 开启 ipvs 的前提需要加载以下的内核模块：
ip_vs
ip_vs_rr
ip_vs_wrr
ip_vs_sh
nf_conntrack_ipv4
在各个服务器节点上执行以下脚本:
cat > /etc/sysconfig/modules/ipvs.modules <<EOF
#!/bin/bash
modprobe -- ip_vs
modprobe -- ip_vs_rr
modprobe -- ip_vs_wrr
modprobe -- ip_vs_sh
modprobe -- nf_conntrack_ipv4
EOF
chmod 755 /etc/sysconfig/modules/ipvs.modules && bash /etc/sysconfig/modules/ipvs.modules && lsmod | grep -e ip_vs -e nf_conntrack_ipv4
上面脚本创建了的 /etc/sysconfig/modules/ipvs.modules 文件，保证在节点重启后能自动加载所需模块。 使用 lsmod | grep -e ip_vs -e nf_conntrack_ipv4 命令查看是否已经正确加载所需的内核模块。接下来还需要确保各个节点上已经安装了 ipset 软件包，为了便于查看 ipvs 的代理规则，最好安装一下管理工具 ipvsadm。
yum install -y ipset ipvsadm
如果不满足以上前提条件，则即使 kube-proxy 的配置开启了 ipvs 模式，也会退回到 iptables 模式。
1.3、部署容器运行时 Containerd
在各个服务器节点上安装容器运行时 Containerd。下载Containerd的二进制包:
wget https://github.com/containerd/containerd/releases/download/v1.6.4/cri-containerd-cni-1.6.4-linux-amd64.tar.gz
cri-containerd-cni-1.6.4-linux-amd64.tar.gz 压缩包中已经按照官方二进制部署推荐的目录结构布局好。 里面包含了 systemd 配置文件，containerd 以及 cni 的部署文件。 将解压缩到系统的根目录 / 中:
tar -zxvf cri-containerd-cni-1.6.4-linux-amd64.tar.gz -C /
etc/
etc/systemd/
etc/systemd/system/
etc/systemd/system/containerd.service
etc/crictl.yaml
etc/cni/
etc/cni/net.d/
etc/cni/net.d/10-containerd-net.conflist
usr/
usr/local/
usr/local/sbin/
usr/local/sbin/runc
usr/local/bin/
usr/local/bin/critest
usr/local/bin/containerd-shim
usr/local/bin/containerd-shim-runc-v1
usr/local/bin/ctd-decoder
usr/local/bin/containerd
usr/local/bin/containerd-shim-runc-v2
usr/local/bin/containerd-stress
usr/local/bin/ctr
usr/local/bin/crictl
......
opt/cni/
opt/cni/bin/
opt/cni/bin/bridge
......
注意经测试 cri-containerd-cni-1.6.4-linux-amd64.tar.gz 包中包含的 runc 在 CentOS 7 下的动态链接有问题，这里从 runc 的 github 上单独下载 runc，并替换上面安装的 containerd 中的 runc:
wget https://github.com/opencontainers/runc/releases/download/v1.1.2/runc.amd64
接下来生成 containerd 的配置文件:
mkdir -p /etc/containerd
containerd config default > /etc/containerd/config.toml
根据文档 Container runtimes 中的内容，对于使用 systemd 作为 init system 的 Linux 的发行版，使用 systemd 作为容器的 cgroup driver 可以确保服务器节点在资源紧张的情况更加稳定，因此这里配置各个节点上 containerd 的 cgroup driver 为 systemd。修改前面生成的配置文件 /etc/containerd/config.toml：
[plugins."io.containerd.grpc.v1.cri".containerd.runtimes.runc]
...
[plugins."io.containerd.grpc.v1.cri".containerd.runtimes.runc.options]
SystemdCgroup = true
再修改/etc/containerd/config.toml 中的
[plugins."io.containerd.grpc.v1.cri"]
...
# sandbox_image = "k8s.gcr.io/pause:3.6"
sandbox_image = "registry.aliyuncs.com/google_containers/pause:3.7"
配置containerd 开机启动，并启动 containerd
systemctl enable containerd --now
使用crictl 测试一下，确保可以打印出版本信息并且没有错误信息输出:
crictl version
Version: 0.1.0
RuntimeName: containerd
RuntimeVersion: v1.6.4
RuntimeApiVersion: v1alpha2
二、使用 kubeadm 部署 Kubernetes
2.1、安装 kubeadm 和 kubelet
下面在各节点安装 kubeadm 和 kubelet：
cat <<EOF > /etc/yum.repos.d/kubernetes.repo
[kubernetes]
name=Kubernetes
baseurl=http://mirrors.aliyun.com/kubernetes/yum/repos/kubernetes-el7-x86_64
enabled=1
gpgcheck=1
repo_gpgcheck=0
gpgkey=http://mirrors.aliyun.com/kubernetes/yum/doc/yum-key.gpg
http://mirrors.aliyun.com/kubernetes/yum/doc/rpm-package-key.gpg
EOF
yum makecache fast
yum install kubelet kubeadm kubectl
运行kubelet --help 可以看到原来 kubelet 的绝大多数命令行 flag 参数都被 DEPRECATED 了，官方推荐我们使用 --config 指定配置文件，并在配置文件中指定原来这些 flag 所配置的内容。具体内容可以查看这里 Set Kubelet parameters via a config file。最初 Kubernetes 这么做是为了支持动态 Kubelet 配置（Dynamic Kubelet Configuration），但动态 Kubelet 配置特性从 k8s 1.22 中已弃用，并在 1.24 中被移除。如果需要调整集群汇总所有节点 kubelet 的配置，还是推荐使用 ansible 等工具将配置分发到各个节点。kubelet 的配置文件必须是 json 或 yaml 格式，具体可查看这里。Kubernetes 1.8 开始要求关闭系统的 Swap，如果不关闭，默认配置下 kubelet 将无法启动。 关闭系统的 Swap 方法如下:
swapoff -a
修改/etc/fstab 文件，注释掉 SWAP 的自动挂载，使用 free -m 确认 swap 已经关闭。swappiness 参数调整，修改 /etc/sysctl.d/99-kubernetes-cri.conf 添加下面一行：
vm.swappiness=0
执行sysctl -p /etc/sysctl.d/99-kubernetes-cri.conf 使修改生效。
2.2、使用 kubeadm init 初始化集群
在各节点开机启动 kubelet 服务：
systemctl enable kubelet.service
使用kubeadm config print init-defaults --component-configs KubeletConfiguration 可以打印集群初始化默认的使用的配置：
apiVersion: kubeadm.k8s.io/v1beta3
bootstrapTokens:
- groups:
- system:bootstrappers:kubeadm:default-node-token
token: abcdef.0123456789abcdef
ttl: 24h0m0s
usages:
- signing
- authentication
kind: InitConfiguration
localAPIEndpoint:
advertiseAddress: 1.2.3.4
bindPort: 6443
nodeRegistration:
criSocket: unix:///var/run/containerd/containerd.sock
imagePullPolicy: IfNotPresent
name: node
taints: null
---
apiServer:
timeoutForControlPlane: 4m0s
apiVersion: kubeadm.k8s.io/v1beta3
certificatesDir: /etc/kubernetes/pki
clusterName: kubernetes
controllerManager: {}
dns: {}
etcd:
local:
dataDir: /var/lib/etcd
imageRepository: k8s.gcr.io
kind: ClusterConfiguration
kubernetesVersion: 1.24.0
networking:
dnsDomain: cluster.local
serviceSubnet: 10.96.0.0/12
scheduler: {}
---
apiVersion: kubelet.config.k8s.io/v1beta1
authentication:
anonymous:
enabled: false
webhook:
cacheTTL: 0s
enabled: true
x509:
clientCAFile: /etc/kubernetes/pki/ca.crt
authorization:
mode: Webhook
webhook:
cacheAuthorizedTTL: 0s
cacheUnauthorizedTTL: 0s
cgroupDriver: systemd
clusterDNS:
- 10.96.0.10
clusterDomain: cluster.local
cpuManagerReconcilePeriod: 0s
evictionPressureTransitionPeriod: 0s
fileCheckFrequency: 0s
healthzBindAddress: 127.0.0.1
healthzPort: 10248
httpCheckFrequency: 0s
imageMinimumGCAge: 0s
kind: KubeletConfiguration
logging:
flushFrequency: 0
options:
json:
infoBufferSize: "0"
verbosity: 0
memorySwap: {}
nodeStatusReportFrequency: 0s
nodeStatusUpdateFrequency: 0s
rotateCertificates: true
runtimeRequestTimeout: 0s
shutdownGracePeriod: 0s
shutdownGracePeriodCriticalPods: 0s
staticPodPath: /etc/kubernetes/manifests
streamingConnectionIdleTimeout: 0s
syncFrequency: 0s
volumeStatsAggPeriod: 0s
从默认的配置中可以看到，可以使用 imageRepository 定制在集群初始化时拉取 k8s 所需镜像的地址。基于默认配置定制出本次使用 kubeadm 初始化集群所需的配置文件 kubeadm.yaml：
apiVersion: kubeadm.k8s.io/v1beta3
kind: InitConfiguration
localAPIEndpoint:
advertiseAddress: 192.168.96.151
bindPort: 6443
nodeRegistration:
criSocket: unix:///run/containerd/containerd.sock
taints:
- effect: PreferNoSchedule
key: node-role.kubernetes.io/master
---
apiVersion: kubeadm.k8s.io/v1beta2
kind: ClusterConfiguration
kubernetesVersion: v1.24.0
imageRepository: registry.aliyuncs.com/google_containers
networking:
podSubnet: 10.244.0.0/16
---
apiVersion: kubelet.config.k8s.io/v1beta1
kind: KubeletConfiguration
cgroupDriver: systemd
failSwapOn: false
---
apiVersion: kubeproxy.config.k8s.io/v1alpha1
kind: KubeProxyConfiguration
mode: ipvs
这里定制了 imageRepository 为阿里云的 registry，避免因 gcr 被墙，无法直接拉取镜像。criSocket 设置了容器运行时为 containerd。 同时设置 kubelet 的 cgroupDriver 为 systemd，设置 kube-proxy 代理模式为 ipvs。在开始初始化集群之前可以使用 kubeadm config images pull --config kubeadm.yaml 预先在各个服务器节点上拉取所 k8s 需要的容器镜像。
kubeadm config images pull --config kubeadm.yaml
[config/images] Pulled registry.aliyuncs.com/google_containers/kube-apiserver:v1.24.0
[config/images] Pulled registry.aliyuncs.com/google_containers/kube-controller-manager:v1.24.0
[config/images] Pulled registry.aliyuncs.com/google_containers/kube-scheduler:v1.24.0
[config/images] Pulled registry.aliyuncs.com/google_containers/kube-proxy:v1.24.0
[config/images] Pulled registry.aliyuncs.com/google_containers/pause:3.7
[config/images] Pulled registry.aliyuncs.com/google_containers/etcd:3.5.3-0
[config/images] Pulled registry.aliyuncs.com/google_containers/coredns:v1.8.6
接下来使用 kubeadm 初始化集群，选择 node1 作为 Master Node，在 node1 上执行下面的命令：
kubeadm init --config kubeadm.yaml
W0526 10:22:26.657615 24076 common.go:83] your configuration file uses a deprecated API spec: "kubeadm.k8s.io/v1beta2". 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.
W0526 10:22:26.660300 24076 initconfiguration.go:120] Usage of CRI endpoints without URL scheme is deprecated and can cause kubelet errors in the future. Automatically prepending scheme "unix" to the "criSocket" with value "/run/containerd/containerd.sock". Please update your configuration!
[init] Using Kubernetes version: v1.24.0
[preflight] Running pre-flight checks
[WARNING Swap]: swap is enabled; production deployments should disable swap unless testing the NodeSwap feature gate of the kubelet
[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'
[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 node1] and IPs [10.96.0.1 192.168.96.151]
[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 node1] and IPs [192.168.96.151 127.0.0.1 ::1]
[certs] Generating "etcd/peer" certificate and key
[certs] etcd/peer serving cert is signed for DNS names [localhost node1] and IPs [192.168.96.151 127.0.0.1 ::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"
[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 17.506804 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 node1 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 node1 as control-plane by adding the taints [node-role.kubernetes.io/master:PreferNoSchedule]
[bootstrap-token] Using token: uufqmm.bvtfj4drwfvvbcev
[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 192.168.96.151:6443 --token uufqmm.bvtfj4drwfvvbcev \
--discovery-token-ca-cert-hash sha256:5814415567d93f6d2d41fe4719be8221f45c29c482b5059aec2e27a832ac36e6
上面记录了完成的初始化输出的内容，根据输出的内容基本上可以看出手动初始化安装一个 Kubernetes 集群所需要的关键步骤。 其中有以下关键内容：
- [certs]生成相关的各种证书
- [kubeconfig]生成相关的kubeconfig文件
- [kubelet-start] 生成kubelet的配置文件"/var/lib/kubelet/config.yaml"
- [control-plane]使用/etc/kubernetes/manifests目录中的yaml文件创建apiserver、controller-manager、scheduler的静态pod
- [bootstraptoken]生成token记录下来，后边使用kubeadm join往集群中添加节点时会用到
- 下面的命令是配置常规用户如何使用kubectl访问集群：mkdir -p
$HOME/.kube
sudo cp -i /etc/kubernetes/admin.conf $HOME/.kube/config
sudo chown $(id -u):$(id -g) $HOME/.kube/config- 最后给出了将节点加入集群的命令kubeadm join 192.168.96.151:6443 --token uufqmm.bvtfj4drwfvvbcev \ --discovery-token-ca-cert-hash sha256:5814415567d93f6d2d41fe4719be8221f45c29c482b5059aec2e27a832ac36e6
查看一下集群状态，确认个组件都处于 healthy 状态，结果出现了错误:
kubectl get cs
Warning: v1 ComponentStatus is deprecated in v1.19+
NAME STATUS MESSAGE ERROR
scheduler Healthy ok
controller-manager Healthy ok
etcd-0 Healthy {"health":"true","reason":""}
集群初始化如果遇到问题，可以使用 kubeadm reset 命令进行清理。
2.3、安装包管理器 helm 3
Helm 是 Kubernetes 的包管理器，后续流程也将使用 Helm 安装 Kubernetes 的常用组件。 这里先在 master 节点 node1 上安装 helm。
wget https://get.helm.sh/helm-v3.9.0-linux-amd64.tar.gz
tar -zxvf helm-v3.9.0-linux-amd64.tar.gz
mv linux-amd64/helm /usr/local/bin/
执行helm list 确认没有错误输出。
2.4、部署 Pod Network 组件 Calico
选择calico 作为 k8s 的 Pod 网络组件，下面使用 helm 在 k8s 集群中安装 calico。下载 tigera-operator 的 helm chart:
wget https://github.com/projectcalico/calico/releases/download/v3.23.1/tigera-operator-v3.23.1.tgz
查看这个 chart 的中可定制的配置:
helm show values tigera-operator-v3.23.1.tgz
imagePullSecrets: {}
installation:
enabled: true
kubernetesProvider: ""
apiServer:
enabled: true
certs:
node:
key:
cert:
commonName:
typha:
key:
cert:
commonName:
caBundle:
resources: {}
# Configuration for the tigera operator
tigeraOperator:
image: tigera/operator
version: v1.27.1
registry: quay.io
calicoctl:
image: docker.io/calico/ctl
tag: v3.23.1
定制的values.yaml 如下:
# 可针对上面的配置进行定制,例如 calico 的镜像改成从私有库拉取。
# 这里只是个人本地环境测试 k8s 新版本，因此保留 value.yaml 为空即可
使用helm 安装 calico：
helm install calico tigera-operator-v3.23.1.tgz -n kube-system --create-namespace -f values.yaml
等待并确认所有 pod 处于 Running状态:
kubectl get pod -n kube-system | grep tigera-operator
tigera-operator-5fb55776df-wxbph 1/1 Running 0 5m10s
kubectl get pods -n calico-system
NAME READY STATUS RESTARTS AGE
calico-kube-controllers-68884f975d-5d7p9 1/1 Running 0 5m24s
calico-node-twbdh 1/1 Running 0 5m24s
calico-typha-7b4bdd99c5-ssdn2 1/1 Running 0 5m24s
查看一下 calico 向 k8s 中添加的 api 资源:
kubectl api-resources | grep calico
bgpconfigurations crd.projectcalico.org/v1 false BGPConfiguration
bgppeers crd.projectcalico.org/v1 false BGPPeer
blockaffinities crd.projectcalico.org/v1 false BlockAffinity
caliconodestatuses crd.projectcalico.org/v1 false CalicoNodeStatus
clusterinformations crd.projectcalico.org/v1 false ClusterInformation
felixconfigurations crd.projectcalico.org/v1 false FelixConfiguration
globalnetworkpolicies crd.projectcalico.org/v1 false GlobalNetworkPolicy
globalnetworksets crd.projectcalico.org/v1 false GlobalNetworkSet
hostendpoints crd.projectcalico.org/v1 false HostEndpoint
ipamblocks crd.projectcalico.org/v1 false IPAMBlock
ipamconfigs crd.projectcalico.org/v1 false IPAMConfig
ipamhandles crd.projectcalico.org/v1 false IPAMHandle
ippools crd.projectcalico.org/v1 false IPPool
ipreservations crd.projectcalico.org/v1 false IPReservation
kubecontrollersconfigurations crd.projectcalico.org/v1 false KubeControllersConfiguration
networkpolicies crd.projectcalico.org/v1 true NetworkPolicy
networksets crd.projectcalico.org/v1 true NetworkSet
bgpconfigurations bgpconfig,bgpconfigs projectcalico.org/v3 false BGPConfiguration
bgppeers projectcalico.org/v3 false BGPPeer
caliconodestatuses caliconodestatus projectcalico.org/v3 false CalicoNodeStatus
clusterinformations clusterinfo projectcalico.org/v3 false ClusterInformation
felixconfigurations felixconfig,felixconfigs projectcalico.org/v3 false FelixConfiguration
globalnetworkpolicies gnp,cgnp,calicoglobalnetworkpolicies projectcalico.org/v3 false GlobalNetworkPolicy
globalnetworksets projectcalico.org/v3 false GlobalNetworkSet
hostendpoints hep,heps projectcalico.org/v3 false HostEndpoint
ippools projectcalico.org/v3 false IPPool
ipreservations projectcalico.org/v3 false IPReservation
kubecontrollersconfigurations projectcalico.org/v3 false KubeControllersConfiguration
networkpolicies cnp,caliconetworkpolicy,caliconetworkpolicies projectcalico.org/v3 true NetworkPolicy
networksets netsets projectcalico.org/v3 true NetworkSet
profiles projectcalico.org/v3 false Profile
这些api 资源是属于 calico 的，因此不建议使用 kubectl 来管理，推荐按照 calicoctl 来管理这些 api 资源。 将 calicoctl 安装为 kubectl 的插件:
cd /usr/local/bin
curl -o kubectl-calico -O -L "https://github.com/projectcalico/calicoctl/releases/download/v3.21.5/calicoctl-linux-amd64"
chmod +x kubectl-calico
验证插件正常工作:
kubectl calico -h
2.5、验证 k8s DNS 是否可用
kubectl run curl --image=radial/busyboxplus:curl -it
If you don't see a command prompt, try pressing enter.
[ root@curl:/ ]$
进入后执行 nslookup kubernetes.default 确认解析正常:
nslookup kubernetes.default
Server: 10.96.0.10
Address 1: 10.96.0.10 kube-dns.kube-system.svc.cluster.local
Name: kubernetes.default
Address 1: 10.96.0.1 kubernetes.default.svc.cluster.local
2.6、向 Kubernetes 集群中添加 Node 节点
下面将node2, node3 添加到 Kubernetes 集群中，分别在 node2, node3 上执行:
kubeadm join 192.168.96.151:6443 --token uufqmm.bvtfj4drwfvvbcev \
--discovery-token-ca-cert-hash sha256:5814415567d93f6d2d41fe4719be8221f45c29c482b5059aec2e27a832ac36e6
node2 和 node3 加入集群很是顺利，在 master 节点上执行命令查看集群中的节点：
kubectl get node
NAME STATUS ROLES AGE VERSION
node1 Ready control-plane,master 29m v1.24.0
node2 Ready <none> 70s v1.24.0
node3 Ready <none> 58s v1.24.0
三、Kubernetes 常用组件部署
3.1、使用 Helm 部署 ingress-nginx
为了便于将集群中的服务暴露到集群外部，需要使用 Ingress。接下来使用 Helm 将 ingress-nginx 部署到 Kubernetes上。 Nginx Ingress Controller 被部署在 Kubernetes 的边缘节点上。
这里将node1(192.168.96.151) 作为边缘节点，打上 Label：
kubectl label node node1 node-role.kubernetes.io/edge=
下载ingress-nginx 的 helm chart:
wget https://github.com/kubernetes/ingress-nginx/releases/download/helm-chart-4.1.2/ingress-nginx-4.1.2.tgz
查看ingress-nginx-4.1.2.tgz 这个 chart 的可定制配置:
helm show values ingress-nginx-4.1.2.tgz
对values.yaml 配置定制如下:
controller:
ingressClassResource:
name: nginx
enabled: true
default: true
controllerValue: "k8s.io/ingress-nginx"
admissionWebhooks:
enabled: false
replicaCount: 1
image:
# registry: k8s.gcr.io
# image: ingress-nginx/controller
# tag: "v1.1.0"
registry: docker.io
image: unreachableg/k8s.gcr.io_ingress-nginx_controller
tag: "v1.2.0"
digest: sha256:314435f9465a7b2973e3aa4f2edad7465cc7bcdc8304be5d146d70e4da136e51
hostNetwork: true
nodeSelector:
node-role.kubernetes.io/edge: ''
affinity:
podAntiAffinity:
requiredDuringSchedulingIgnoredDuringExecution:
- labelSelector:
matchExpressions:
- key: app
operator: In
values:
- nginx-ingress
- key: component
operator: In
values:
- controller
topologyKey: kubernetes.io/hostname
tolerations:
- key: node-role.kubernetes.io/master
operator: Exists
effect: NoSchedule
- key: node-role.kubernetes.io/master
operator: Exists
effect: PreferNoSchedule
nginx ingress controller 的副本数 replicaCount 为 1，将被调度到 node1 这个边缘节点上。这里并没有指定 nginx ingress controller service 的 externalIPs，而是通过 hostNetwork: true 设置 nginx ingress controller 使用宿主机网络。 因为 k8s.gcr.io 被墙，这里替换成 unreachableg/k8s.gcr.io_ingress-nginx_controller 提前拉取一下镜像:
crictl pull unreachableg/k8s.gcr.io_ingress-nginx_controller:v1.2.0
helm install ingress-nginx ingress-nginx-4.1.2.tgz --create-namespace -n ingress-nginx -f values.yaml
kubectl get pod -n ingress-nginx
NAME READY STATUS RESTARTS AGE
ingress-nginx-controller-7f574989bc-xwbf4 1/1 Running 0 117s
测试访问 http://192.168.96.151 返回默认的 nginx 404 页，则部署完成。
3.2、使用 Helm 部署 dashboard
先部署metrics-server：
wget https://github.com/kubernetes-sigs/metrics-server/releases/download/metrics-server-helm-chart-3.8.2/components.yaml
修改components.yaml 中的 image 为 docker.io/unreachableg/k8s.gcr.io_metrics-server_metrics-server:v0.5.2。 修改 components.yaml 中容器的启动参数，加入 --kubelet-insecure-tls。
kubectl apply -f components.yaml
metrics-server 的 pod 正常启动后，等一段时间就可以使用 kubectl top 查看集群和 pod 的 metrics 信息:
kubectl top node
NAME CPU(cores) CPU% MEMORY(bytes) MEMORY%
node1 509m 12% 3654Mi 47%
node2 133m 3% 1786Mi 23%
node3 117m 2% 1810Mi 23%
kubectl top pod -n kube-system
NAME CPU(cores) MEMORY(bytes)
coredns-74586cf9b6-575nl 6m 16Mi
coredns-74586cf9b6-mbn8s 5m 17Mi
etcd-node1 49m 91Mi
kube-apiserver-node1 142m 490Mi
kube-controller-manager-node1 38m 54Mi
kube-proxy-k5lzs 26m 19Mi
kube-proxy-rb5pf 9m 15Mi
kube-proxy-w5zpk 27m 16Mi
kube-scheduler-node1 7m 18Mi
metrics-server-8dfd488f5-r8pbh 8m 21Mi
tigera-operator-5fb55776df-wxbph 10m 38Mi
接下来使用 helm 部署 k8s 的 dashboard，添加 chart repo:
helm repo add kubernetes-dashboard https://kubernetes.github.io/dashboard/
helm repo update
查看chart 的可定制配置:
helm show values kubernetes-dashboard/kubernetes-dashboard
对values.yaml 定制配置如下:
image:
repository: kubernetesui/dashboard
tag: v2.5.1
ingress:
enabled: true
annotations:
nginx.ingress.kubernetes.io/ssl-redirect: "true"
nginx.ingress.kubernetes.io/backend-protocol: "HTTPS"
hosts:
- k8s.example.com
tls:
- secretName: example-com-tls-secret
hosts:
- k8s.example.com
metricsScraper:
enabled: true
先创建存放 k8s.example.comssl 证书的 secret:
kubectl create secret tls example-com-tls-secret \
--cert=cert.pem \
--key=key.pem \
-n kube-system
使用helm 部署 dashboard:
helm install kubernetes-dashboard kubernetes-dashboard/kubernetes-dashboard \
-n kube-system \
-f values.yaml
确认上面的命令部署成功。创建管理员 sa:
kubectl create serviceaccount kube-dashboard-admin-sa -n kube-system
kubectl create clusterrolebinding kube-dashboard-admin-sa \
--clusterrole=cluster-admin --serviceaccount=kube-system:kube-dashboard-admin-sa
创建集群管理员登录 dashboard 所需 token:
kubectl create token kube-dashboard-admin-sa -n kube-system --duration=87600h
eyJhbGciOiJSUzI1NiIsImtpZCI6IlU1SlpSTS1YekNuVzE0T1k5TUdTOFFqN25URWxKckt6OUJBT0xzblBsTncifQ.eyJhdWQiOlsiaHR0cHM6Ly9rdWJlcm5ldGVzLmRlZmF1bHQuc3ZjLmNsdXN0ZXIubG9jYWwiXSwiZXhwIjoxOTY4OTA4MjgyLCJpYXQiOjE2NTM1NDgyODIsImlzcyI6Imh0dHBzOi8va3ViZXJuZXRlcy5kZWZhdWx0LnN2Yy5jbHVzdGVyLmxvY2FsIiwia3ViZXJuZXRlcy5pbyI6eyJuYW1lc3BhY2UiOiJrdWJlLXN5c3RlbSIsInNlcnZpY2VhY2NvdW50Ijp7Im5hbWUiOiJrdWJlLWRhc2hib2FyZC1hZG1pbi1zYSIsInVpZCI6IjY0MmMwMmExLWY1YzktNDFjNy04Mjc5LWQ1ZmI3MGRjYTQ3ZSJ9fSwibmJmIjoxNjUzNTQ4MjgyLCJzdWIiOiJzeXN0ZW06c2VydmljZWFjY291bnQ6a3ViZS1zeXN0ZW06a3ViZS1kYXNoYm9hcmQtYWRtaW4tc2EifQ.Xqxlo2vJ9Hb6UUVIqwvc8I5bahdxKzSRSaQI_67Yt7_YEHmkkHApxUGlwJYTKF9ufww3btlCmM8PtRn5_Q1yv-HAFyTOYKo8WHZ9UCm1bT3X8V8g4GQwZIl2dwmlUmKb1unBz2-em2uThQ015bMPDE8a42DV_bOwWjljVXat0nwV14nGorC8vKLjXbohrIJ3G1pgCJvlBn99F1RelmSUSQLlolUFoxpN6MamYTElwR6FfD-AGmFXvZSbcFaqVW0oxJHV70Gjs2igOtpqHFxxPlHT8aQzlRiybPtFyBf9Ll87TmVJimT89z8wv2si2Nee8bB2jhsApLn8TJyUSlbTXA
使用上面的 token 登录 k8s dashboard。
参考
- Installing kubeadm
- Creating a cluster with kubeadm
- https://github.com/containerd/containerd
- https://pkg.go.dev/k8s.io/kubernetes/cmd/kubeadm/app/apis/kubeadm/v1beta2
- https://docs.projectcalico.org/
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