目录
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。
1 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 7.8主机如下：
- 系统环境：CentOS Linux release 7.8.2003 (Core)
- k8s 版本： 1.26
| IP | 主机名 | 规划角色 |
|---|---|---|
| 10.0.4.21 | vm21 | master |
| 10.0.4.22 | vm22 | worker |
| 10.0.4.23 | vm23 | worker |
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
赋权：
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:
可先在网络可达的机器上下载好，再上传到服务器
wget https://github.com/containerd/containerd/releases/download/v1.6.14/cri-containerd-cni-1.6.14-linux-amd64.tar.gz
cri-containerd-cni-1.6.14-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-1.6.14-linux-amd64.tar.gz -C /
etc/
etc/cni/
etc/cni/net.d/
etc/cni/net.d/10-containerd-net.conflist
etc/systemd/
etc/systemd/system/
etc/systemd/system/containerd.service
etc/crictl.yaml
usr/
usr/local/
usr/local/sbin/
usr/local/sbin/runc
usr/local/bin/
usr/local/bin/containerd-stress
usr/local/bin/containerd-shim
usr/local/bin/containerd-shim-runc-v1
usr/local/bin/crictl
usr/local/bin/critest
usr/local/bin/containerd-shim-runc-v2
usr/local/bin/ctd-decoder
usr/local/bin/containerd
usr/local/bin/ctr
opt/
opt/cni/
opt/cni/bin/
opt/cni/bin/ptp
opt/cni/bin/bandwidth
opt/cni/bin/static
opt/cni/bin/dhcp
...
opt/containerd/
opt/containerd/cluster/
...
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:3.9"
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: v1.6.14
RuntimeApiVersion: v1
2.使用kubeadm部署Kubernetes
2.1 安装kubeadm和kubelet
下面在各节点安装kubeadm和kubelet,创建yum源：
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 -y 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: registry.k8s.io
kind: ClusterConfiguration
kubernetesVersion: 1.26.0
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，特别注意修改advertiseAddress为你的master节点主机地址，这里用的是vm21，即第一台master的ip
apiVersion: kubeadm.k8s.io/v1beta3
kind: InitConfiguration
localAPIEndpoint:
advertiseAddress: 10.0.4.21
bindPort: 6443
nodeRegistration:
criSocket: unix:///run/containerd/containerd.sock
taints:
- effect: PreferNoSchedule
key: node-role.kubernetes.io/master
---
apiVersion: kubeadm.k8s.io/v1beta3
kind: ClusterConfiguration
kubernetesVersion: 1.26.0
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:v1.26.0
[config/images] Pulled registry.aliyuncs.com/google_containers/kube-controller-manager:v1.26.0
[config/images] Pulled registry.aliyuncs.com/google_containers/kube-scheduler:v1.26.0
[config/images] Pulled registry.aliyuncs.com/google_containers/kube-proxy:v1.26.0
[config/images] Pulled registry.aliyuncs.com/google_containers/pause:3.9
[config/images] Pulled registry.aliyuncs.com/google_containers/etcd:3.5.6-0
[config/images] Pulled registry.aliyuncs.com/google_containers/coredns:v1.9.3
接下来使用kubeadm初始化集群，选择vm21作为Master Node，在vm21上执行下面的命令：
[root@vm21 opt]# kubeadm config images pull --config kubeadm.yaml
[config/images] Pulled registry.aliyuncs.com/google_containers/kube-apiserver:v1.26.0
[config/images] Pulled registry.aliyuncs.com/google_containers/kube-controller-manager:v1.26.0
[config/images] Pulled registry.aliyuncs.com/google_containers/kube-scheduler:v1.26.0
[config/images] Pulled registry.aliyuncs.com/google_containers/kube-proxy:v1.26.0
[config/images] Pulled registry.aliyuncs.com/google_containers/pause:3.9
[config/images] Pulled registry.aliyuncs.com/google_containers/etcd:3.5.6-0
[config/images] Pulled registry.aliyuncs.com/google_containers/coredns:v1.9.3
[root@vm21 opt]# kubeadm init --config kubeadm.yaml
[init] Using Kubernetes version: v1.26.0
[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'
[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 vm21] and IPs [10.96.0.1 10.0.4.21]
[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 vm21] and IPs [10.0.4.21 127.0.0.1 ::1]
[certs] Generating "etcd/peer" certificate and key
[certs] etcd/peer serving cert is signed for DNS names [localhost vm21] and IPs [10.0.4.21 127.0.0.1 ::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 6.504506 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 vm21 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 vm21 as control-plane by adding the taints [node-role.kubernetes.io/master:PreferNoSchedule]
[bootstrap-token] Using token: 957r3e.sanmpgyjhozmdv9p
[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 10.0.4.21:6443 --token 957r3e.sanmpgyjhozmdv9p \
--discovery-token-ca-cert-hash sha256:6f7c594910cf33d849e0f2d48fb6529ef451e6840bf144d830848304a18bbfc0
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 -
[addons]安装基本插件:CoreDNS,kube-proxy -
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
- 最后给出了将另外2个节点加入集群的命令:
kubeadm join 10.0.4.21:6443 --token 957r3e.sanmpgyjhozmdv9p \
--discovery-token-ca-cert-hash sha256:6f7c594910cf33d849e0f2d48fb6529ef451e6840bf144d830848304a18bbfc0
查看一下集群状态，确认个组件都处于healthy状态
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-v3.10.3-linux-amd64.tar.gz
tar -zxvf helm-v3.10.3-linux-amd64.tar.gz
mv linux-amd64/helm /usr/local/bin/
执行helm list确认没有错误输出。
helm list
NAME NAMESPACE REVISION UPDATED STATUS CHART APP VERSION
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/v3.24.5/tigera-operator-v3.24.5.tgz
查看这个chart的中可定制的配置:
helm show values tigera-operator-v3.24.5.tgz
imagePullSecrets: {}
installation:
enabled: true
kubernetesProvider: ""
apiServer:
enabled: true
certs:
node:
key:
cert:
commonName:
typha:
key:
cert:
commonName:
caBundle:
# Resource requests and limits for the tigera/operator pod.
resources: {}
# Tolerations for the tigera/operator pod.
tolerations:
- effect: NoExecute
operator: Exists
- effect: NoSchedule
operator: Exists
# NodeSelector for the tigera/operator pod.
nodeSelector:
kubernetes.io/os: linux
# Custom annotations for the tigera/operator pod.
podAnnotations: {}
# Custom labels for the tigera/operator pod.
podLabels: {}
# Image and registry configuration for the tigera/operator pod.
tigeraOperator:
image: tigera/operator
version: v1.28.5
registry: quay.io
calicoctl:
image: docker.io/calico/ctl
tag: v3.24.5
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，这里只有下面几行配置
apiServer:
enabled: false
使用helm安装calico：
helm install calico tigera-operator-v3.24.5.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
tigera-operator-7795f5d79b-cflnb 1/1 Running 0 22h
kubectl get pods -n calico-system
NAME READY STATUS RESTARTS AGE
calico-kube-controllers-67df98bdc8-rwlq6 1/1 Running 0 22h
calico-node-5pkkn 1/1 Running 0 22h
calico-node-wtxpk 1/1 Running 0 22h
calico-node-xgj8t 1/1 Running 0 22h
calico-typha-5bf9c7b58-2w6gc 1/1 Running 0 22h
calico-typha-5bf9c7b58-jx575 1/1 Running 0 22h
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
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
首次验证：
kubectl run curl --image=radial/busyboxplus:curl -it
If you don't see a command prompt, try pressing enter.
[ root@curl:/ ]$
后续进入相同的容器可继续执行命令
kubectl exec -it curl -- /bin/sh
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
将vm22, vm23添加到Kubernetes集群中，分别在vm22,vm23上执行:
kubeadm join 10.0.4.21:6443 --token 957r3e.sanmpgyjhozmdv9p \
--discovery-token-ca-cert-hash sha256:6f7c594910cf33d849e0f2d48fb6529ef451e6840bf144d830848304a18bbfc0
成功加入节点后，在master节点可查看集群中当前的节点：
kubectl get nodes
NAME STATUS ROLES AGE VERSION
vm21 Ready control-plane,edge 23h v1.26.1
vm22 Ready <none> 23h v1.26.1
vm23 Ready <none> 23h v1.26.1
3.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vm21(10.0.4.21)作为边缘节点，打上Label：
kubectl label node vm21 node-role.kubernetes.io/edge=
下载ingress-nginx的helm chart:
wget https://github.com/kubernetes/ingress-nginx/releases/download/helm-chart-4.4.2/ingress-nginx-4.4.2.tgz
查看ingress-nginx-4.4.2.tgz这个chart的可定制配置:
helm show values ingress-nginx-4.4.2.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: registry.k8s.io
# image: ingress-nginx/controller
# tag: "v1.5.1"
registry: docker.io
image: unreachableg/registry.k8s.io_ingress-nginx_controller
tag: "v1.5.1"
digest: sha256:97fa1ff828554ff4ee1b0416e54ae2238b27d1faa6d314d5a94a92f1f99cf767
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/registry.k8s.io_ingress-nginx_controller提前拉取一下镜像:
crictl pull unreachableg/registry.k8s.io_ingress-nginx_controller:v1.5.1
部署：
helm install ingress-nginx ingress-nginx-4.4.2.tgz --create-namespace -n ingress-nginx -f values.yaml
查看部署结果
kubectl get pods -n ingress-nginx
NAME READY STATUS RESTARTS AGE
ingress-nginx-controller-7c96f857f-szcct 1/1 Running 0 22h
测试访问http://10.0.4.21返回默认的nginx 404页，则部署完成。
3.2 使用Helm部署 dashboard
K8s本身就具备一些基本的服务器监控工具，例如：
K8s Dashboard：插件工具，展示每个 K8s 集群上的资源利用情况，也是实现资源和环境管理与交互的主要工具。Pod liveness probe：Container健康状态诊断工具。Kubelet：每个 Node 上都运行著 Kubelet，监控Container的运行情况。 Kubelet 也是 Control Plane 与各个 Node 通信的渠道。
kubelet default 监听的port是10250，所以可以在Control Plane或Node上直接访问 curl https://127.0.0.1:10250/metrics/cadvisor -k
- 需使用 https
- metrics/cAdvisor 是 kubelet Pod 相关的监控指标，它还有一个 metrics，是 kubelet 自身的监控指标
- -k 表示不验证 kubelet 证书，因整个K8s集群都是使用自签署证书，因此没必要验证
先部署metrics-server：
wget https://github.com/kubernetes-sigs/metrics-server/releases/download/metrics-server-helm-chart-3.8.3/components.yaml
修改components.yaml中的image为docker.io/unreachableg/k8s.gcr.io_metrics-server_metrics-server:v0.6.2。
修改components.yaml中容器的启动参数，加入--kubelet-insecure-tls。
spec:
containers:
- args:
- --cert-dir=/tmp
- --secure-port=4443
- --kubelet-preferred-address-types=InternalIP,ExternalIP,Hostname
- --kubelet-use-node-status-port
- --kubelet-insecure-tls
- --metric-resolution=15s
#image: k8s.gcr.io/metrics-server/metrics-server:v0.6.2
image: docker.io/unreachableg/k8s.gcr.io_metrics-server_metrics-server:v0.6.2
检查 metrics-server 的运行状态：
kubectl get deploy -n kube-system
NAME READY UP-TO-DATE AVAILABLE AGE
coredns 2/2 2 2 23h
metrics-server 1/1 1 1 42s
tigera-operator 1/1 1 1 23h
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%
vm21 372m 9% 2198Mi 59%
vm22 174m 4% 1936Mi 52%
vm23 150m 3% 1967Mi 53%
kubectl top pod -n kube-system
NAME CPU(cores) MEMORY(bytes)
coredns-5bbd96d687-4fgcp 3m 20Mi
coredns-5bbd96d687-l4bd7 3m 21Mi
etcd-vm21 54m 154Mi
kube-apiserver-vm21 99m 463Mi
kube-controller-manager-vm21 35m 76Mi
kube-proxy-6x5cx 9m 18Mi
kube-proxy-jz7ls 1m 25Mi
kube-proxy-vxf64 9m 21Mi
kube-scheduler-vm21 7m 33Mi
metrics-server-6f67c7d9b4-b99gm 6m 17Mi
tigera-operator-7795f5d79b-cflnb 5m 44Mi
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/
"kubernetes-dashboard" has been added to your repositories
helm repo update
Hang tight while we grab the latest from your chart repositories...
...Successfully got an update from the "kubernetes-dashboard" chart repository
Update Complete. ⎈Happy Helming!⎈
查看chart的可定制配置:
helm show values kubernetes-dashboard/kubernetes-dashboard
- 开启HTTPS访问
dashboard将通过ingress以域名k8s.example.com暴露出来, 并为此域名开启HTTPS。
为了开启HTTPS，需要为此域名申请SSL证书或使用自签证书，这里使用的证书和私钥文件分别为scert.pem和skey.pem。
证书和私钥文件需要事先生成，这里是测试环境，使用openssl 生成本地证书即可，shell 脚本如下：
服务器上需要先安装openssl, yum install -y openssl openssl-devel
#!/bin/sh
country="CN"
state="SZ"
city="NS"
org="SRE"
unit="MONITOR"
commonname="k8s.init.com"
email="[email protected]"
openssl req -new -x509 -days 3650 -nodes -out scert.pem -keyout skey.pem<<EOF
$country
$state
$city
$org
$unit
$commonname
$email
EOF
在当前目录下生成了两个文件：
ll *.pem
-rw-r--r--. 1 root root 1379 Jan 29 05:41 scert.pem
-rw-r--r--. 1 root root 1704 Jan 29 05:41 skey.pem
创建存放k8s.example.comssl证书的secret:
kubectl create secret tls init-com-tls-secret --cert=scert.pem --key=skey.pem -n kube-system
secret/init-com-tls-secret created
对values.yaml定制配置如下:
image:
repository: kubernetesui/dashboard
tag: v2.7.0
ingress:
enabled: true
annotations:
nginx.ingress.kubernetes.io/ssl-redirect: "true"
nginx.ingress.kubernetes.io/backend-protocol: "HTTPS"
hosts:
- k8s.init.com
tls:
- secretName: init-com-tls-secret
hosts:
- k8s.init.com
metricsScraper:
enabled: true
使用helm部署dashboard:
helm install kubernetes-dashboard kubernetes-dashboard/kubernetes-dashboard -n kube-system -f dashboard-value.yaml
# 以下为输出结果
NAME: kubernetes-dashboard
LAST DEPLOYED: Sun Jan 29 04:45:40 2023
NAMESPACE: kube-system
STATUS: deployed
REVISION: 1
TEST SUITE: None
NOTES:
*********************************************************************************
*** PLEASE BE PATIENT: kubernetes-dashboard may take a few minutes to install ***
*********************************************************************************
From outside the cluster, the server URL(s) are:
https://k8s.init.com
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
eyJhbGciOiJSUzI1NiIsImtpZCI6Il9zMmg4bHZRSXBWSWFkcWhQcDM1WnJadlF1NHNEblBXaWZ5b2hFcmtnRU0ifQ.eyJhdWQiOlsiaHR0cHM6Ly9rdWJlcm5ldGVzLmRlZmF1bHQuc3ZjLmNsdXN0ZXIubG9jYWwiXSwiZXhwIjoxOTkwMzQ2MTAxLCJpYXQiOjE2NzQ5ODYxMDEsImlzcyI6Imh0dHBzOi8va3ViZXJuZXRlcy5kZWZhdWx0LnN2Yy5jbHVzdGVyLmxvY2FsIiwia3ViZXJuZXRlcy5pbyI6eyJuYW1lc3BhY2UiOiJrdWJlLXN5c3RlbSIsInNlcnZpY2VhY2NvdW50Ijp7Im5hbWUiOiJrdWJlLWRhc2hib2FyZC1hZG1pbi1zYSIsInVpZCI6ImE3ZjZiOGM1LWQyYjUtNGU4ZS1iNGEzLTcwMWVkZWNiNGNkZSJ9fSwibmJmIjoxNjc0OTg2MTAxLCJzdWIiOiJzeXN0ZW06c2VydmljZWFjY291bnQ6a3ViZS1zeXN0ZW06a3ViZS1kYXNoYm9hcmQtYWRtaW4tc2EifQ.xnLhaAkfUXPJfbgThsqK3ToEJstYCRh756aDJN9s_DI4ao4rbwffHUW9Tv_5eEHIxLTyZc40ctsNek-hR7ey_MCUyhClJd1x8WbGlyKXyOcUMXRq3VFQVa3HJ_ria0tX-S6UWtR8xmY1h5QuxyYFVWRhevHdAv4SSPYBxzvM6uwhS1xqPzEqclxDfrWXkkQ_FcRHgJLoAipLHJSyGkmOsdwWh3Ih0wdaGXgeAu5eFBLnwvDZYKJE-WLIFH0mS0P3Tz9i6-XNu05xIq9kba6aPw-xR-D1fh8McSi13BpuQtn2m8e0rRLDIqw0JfWLu7EuSZhAuHLpBTkN0RN-Yfo4pg
使用上面的token登录k8s dashboard。
注意在访问dashboard上添加本地host,如 10.0.4.21 k8s.init.com
参考
https://blog.frognew.com/2023/01/kubeadm-install-kubernetes-1.26.html
标签：Kubernetes,kubernetes,k8s01,kubelet,io,containerd,kubeadm,kube,config From： https://www.cnblogs.com/unchch/p/17071166.html