使用kubeadm部署Kubernetes 1.21
2021-06-25
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 7.9主机如下：
1cat /etc/hosts
2192.168.96.151 node1
3192.168.96.152 node2
4192.168.96.153 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Installing kubeadm中的"Check required ports"一节开放相关端口或者关闭主机的防火墙。
禁用SELINUX：
1setenforce 0
1vi /etc/selinux/config
2SELINUX=disabled
创建/etc/modules-load.d/containerd.conf配置文件:
1cat << EOF > /etc/modules-load.d/containerd.conf
2overlay
3br_netfilter
4EOF
执行以下命令使配置生效:
1modprobe overlay
2modprobe br_netfilter
创建/etc/sysctl.d/99-kubernetes-cri.conf配置文件：
1cat << EOF > /etc/sysctl.d/99-kubernetes-cri.conf
2net.bridge.bridge-nf-call-ip6tables = 1
3net.bridge.bridge-nf-call-iptables = 1
4net.ipv4.ip_forward = 1
5user.max_user_namespaces=28633
6EOF
执行以下命令使配置生效:
1sysctl -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：
1ip_vs
2ip_vs_rr
3ip_vs_wrr
4ip_vs_sh
5nf_conntrack_ipv4
在各个服务器节点上执行以下脚本:
1cat > /etc/sysconfig/modules/ipvs.modules <<EOF
2#!/bin/bash
3modprobe -- ip_vs
4modprobe -- ip_vs_rr
5modprobe -- ip_vs_wrr
6modprobe -- ip_vs_sh
7modprobe -- nf_conntrack_ipv4
8EOF
9chmod 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。
1yum install -y ipset ipvsadm
如果以上前提条件如果不满足，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:
1wget https://github.com/containerd/containerd/releases/download/v1.5.2/cri-containerd-cni-1.5.2-linux-amd64.tar.gz
cri-containerd-cni-1.5.2-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:
1tar -zxvf cri-containerd-cni-1.5.2-linux-amd64.tar.gz -C /
2
3etc/
4etc/systemd/
5etc/systemd/system/
6etc/systemd/system/containerd.service
7etc/crictl.yaml
8etc/cni/
9etc/cni/net.d/
10etc/cni/net.d/10-containerd-net.conflist
11usr/
12usr/local/
13usr/local/sbin/
14usr/local/sbin/runc
15usr/local/bin/
16usr/local/bin/critest
17usr/local/bin/containerd-shim
18usr/local/bin/containerd-shim-runc-v1
19usr/local/bin/ctd-decoder
20usr/local/bin/containerd
21usr/local/bin/containerd-shim-runc-v2
22usr/local/bin/containerd-stress
23usr/local/bin/ctr
24usr/local/bin/crictl
25......
26opt/cni/
27opt/cni/bin/
28opt/cni/bin/bridge
29......
接下来生成containerd的配置文件:
1mkdir -p /etc/containerd
2containerd 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：
1[plugins."io.containerd.grpc.v1.cri".containerd.runtimes.runc]
2 ...
3 [plugins."io.containerd.grpc.v1.cri".containerd.runtimes.runc.options]
4 SystemdCgroup = true
再修改/etc/containerd/config.toml中的
1[plugins."io.containerd.grpc.v1.cri"]
2 ...
3 # sandbox_image = "k8s.gcr.io/pause:3.5"
4 sandbox_image = "registry.aliyuncs.com/google_containers/pause:3.4.1"
配置containerd开机启动，并启动containerd
1systemctl enable containerd
2systemctl start containerd
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:
1crictl version
2Version: 0.1.0
3RuntimeName: containerd
4RuntimeVersion: v1.5.2
5RuntimeApiVersion: v1alpha2
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：
1cat <<EOF > /etc/yum.repos.d/kubernetes.repo
2[kubernetes]
3name=Kubernetes
4baseurl=http://mirrors.aliyun.com/kubernetes/yum/repos/kubernetes-el7-x86_64
5enabled=1
6gpgcheck=1
7repo_gpgcheck=1
8gpgkey=http://mirrors.aliyun.com/kubernetes/yum/doc/yum-key.gpg
9 http://mirrors.aliyun.com/kubernetes/yum/doc/rpm-package-key.gpg
10EOF
1yum makecache fast
2yum 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。这也是Kubernetes为了支持动态Kubelet配置（Dynamic Kubelet Configuration）才这么做的，参考Reconfigure a Node’s Kubelet in a Live Cluster。
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:
1swapoff -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：
1vm.swappiness=0
执行sysctl -p /etc/sysctl.d/99-kubernetes-cri.conf使修改生效。
因为这里用于测试3台主机上还运行其他服务，关闭swap可能会对其他服务产生影响，所以这里修改kubelet的配置去掉这个限制。
使用kubelet的启动参数--fail-swap-on=false去掉必须关闭Swap的限制，修改/etc/sysconfig/kubelet，加入：
1KUBELET_EXTRA_ARGS=--fail-swap-on=false
2.2 使用kubeadm init初始化集群 #
在各节点开机启动kubelet服务：
1systemctl 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：
1apiVersion: kubeadm.k8s.io/v1beta2
2bootstrapTokens:
3- groups:
4 - system:bootstrappers:kubeadm:default-node-token
5 token: abcdef.0123456789abcdef
6 ttl: 24h0m0s
7 usages:
8 - signing
9 - authentication
10kind: InitConfiguration
11localAPIEndpoint:
12 advertiseAddress: 1.2.3.4
13 bindPort: 6443
14nodeRegistration:
15 criSocket: /var/run/dockershim.sock
16 name: node
17 taints: null
18---
19apiServer:
20 timeoutForControlPlane: 4m0s
21apiVersion: kubeadm.k8s.io/v1beta2
22certificatesDir: /etc/kubernetes/pki
23clusterName: kubernetes
24controllerManager: {}
25dns:
26 type: CoreDNS
27etcd:
28 local:
29 dataDir: /var/lib/etcd
30imageRepository: k8s.gcr.io
31kind: ClusterConfiguration
32kubernetesVersion: 1.21.0
33networking:
34 dnsDomain: cluster.local
35 serviceSubnet: 10.96.0.0/12
36scheduler: {}
37---
38apiVersion: kubelet.config.k8s.io/v1beta1
39authentication:
40 anonymous:
41 enabled: false
42 webhook:
43 cacheTTL: 0s
44 enabled: true
45 x509:
46 clientCAFile: /etc/kubernetes/pki/ca.crt
47authorization:
48 mode: Webhook
49 webhook:
50 cacheAuthorizedTTL: 0s
51 cacheUnauthorizedTTL: 0s
52clusterDNS:
53- 10.96.0.10
54clusterDomain: cluster.local
55cpuManagerReconcilePeriod: 0s
56evictionPressureTransitionPeriod: 0s
57fileCheckFrequency: 0s
58healthzBindAddress: 127.0.0.1
59healthzPort: 10248
60httpCheckFrequency: 0s
61imageMinimumGCAge: 0s
62kind: KubeletConfiguration
63logging: {}
64nodeStatusReportFrequency: 0s
65nodeStatusUpdateFrequency: 0s
66rotateCertificates: true
67runtimeRequestTimeout: 0s
68shutdownGracePeriod: 0s
69shutdownGracePeriodCriticalPods: 0s
70staticPodPath: /etc/kubernetes/manifests
71streamingConnectionIdleTimeout: 0s
72syncFrequency: 0s
73volumeStatsAggPeriod: 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：
1apiVersion: kubeadm.k8s.io/v1beta2
2kind: InitConfiguration
3localAPIEndpoint:
4 advertiseAddress: 192.168.96.151
5 bindPort: 6443
6nodeRegistration:
7 criSocket: /run/containerd/containerd.sock
8 taints:
9 - effect: PreferNoSchedule
10 key: node-role.kubernetes.io/master
11---
12apiVersion: kubeadm.k8s.io/v1beta2
13kind: ClusterConfiguration
14kubernetesVersion: v1.21.2
15imageRepository: registry.aliyuncs.com/google_containers
16networking:
17 podSubnet: 10.244.0.0/16
18---
19apiVersion: kubelet.config.k8s.io/v1beta1
20kind: KubeletConfiguration
21cgroupDriver: systemd
22failSwapOn: false
23---
24apiVersion: kubeproxy.config.k8s.io/v1alpha1
25kind: KubeProxyConfiguration
26mode: 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。
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。
1kubeadm config images pull --config kubeadm.yaml
2
3[config/images] Pulled registry.aliyuncs.com/google_containers/kube-apiserver:v1.21.2
4[config/images] Pulled registry.aliyuncs.com/google_containers/kube-controller-manager:v1.21.2
5[config/images] Pulled registry.aliyuncs.com/google_containers/kube-scheduler:v1.21.2
6[config/images] Pulled registry.aliyuncs.com/google_containers/kube-proxy:v1.21.2
7[config/images] Pulled registry.aliyuncs.com/google_containers/pause:3.4.1
8[config/images] Pulled registry.aliyuncs.com/google_containers/etcd:3.4.13-0
9failed to pull image "registry.aliyuncs.com/google_containers/coredns:v1.8.0": output: time="2021-06-25T21:34:38+08:00" level=fatal msg="pulling image: rpc error: code = NotFound desc = failed to pull and unpack image \"registry.aliyuncs.com/google_containers/coredns:v1.8.0\": failed to resolve reference \"registry.aliyuncs.com/google_containers/coredns:v1.8.0\": registry.aliyuncs.com/google_containers/coredns:v1.8.0: not found"
10, error: exit status 1
11To see the stack trace of this error execute with --v=5 or higher
上面的命令执行出现了拉取registry.aliyuncs.com/google_containers/coredns:v1.8.0出错，看来阿里云上的镜像也不全，手动pull并tag coredns的镜像:
1crictl pull docker.io/coredns/coredns:1.8.0
2ctr -n k8s.io i tag docker.io/coredns/coredns:1.8.0 registry.aliyuncs.com/google_containers/coredns:v1.8.0
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：
1kubeadm init --config kubeadm.yaml --ignore-preflight-errors=Swap
2
3[init] Using Kubernetes version: v1.21.2
4[preflight] Running pre-flight checks
5 [WARNING Swap]: running with swap on is not supported. Please disable swap
6[preflight] Pulling images required for setting up a Kubernetes cluster
7[preflight] This might take a minute or two, depending on the speed of your internet connection
8[preflight] You can also perform this action in beforehand using 'kubeadm config images pull'
9[certs] Using certificateDir folder "/etc/kubernetes/pki"
10[certs] Generating "ca" certificate and key
11[certs] Generating "apiserver" certificate and key
12[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]
13[certs] Generating "apiserver-kubelet-client" certificate and key
14[certs] Generating "front-proxy-ca" certificate and key
15[certs] Generating "front-proxy-client" certificate and key
16[certs] Generating "etcd/ca" certificate and key
17[certs] Generating "etcd/server" certificate and key
18[certs] etcd/server serving cert is signed for DNS names [localhost node1] and IPs [192.168.96.151 127.0.0.1 ::1]
19[certs] Generating "etcd/peer" certificate and key
20[certs] etcd/peer serving cert is signed for DNS names [localhost node1] and IPs [192.168.96.151 127.0.0.1 ::1]
21[certs] Generating "etcd/healthcheck-client" certificate and key
22[certs] Generating "apiserver-etcd-client" certificate and key
23[certs] Generating "sa" key and public key
24[kubeconfig] Using kubeconfig folder "/etc/kubernetes"
25[kubeconfig] Writing "admin.conf" kubeconfig file
26[kubeconfig] Writing "kubelet.conf" kubeconfig file
27[kubeconfig] Writing "controller-manager.conf" kubeconfig file
28[kubeconfig] Writing "scheduler.conf" kubeconfig file
29[kubelet-start] Writing kubelet environment file with flags to file "/var/lib/kubelet/kubeadm-flags.env"
30[kubelet-start] Writing kubelet configuration to file "/var/lib/kubelet/config.yaml"
31[kubelet-start] Starting the kubelet
32[control-plane] Using manifest folder "/etc/kubernetes/manifests"
33[control-plane] Creating static Pod manifest for "kube-apiserver"
34[control-plane] Creating static Pod manifest for "kube-controller-manager"
35[control-plane] Creating static Pod manifest for "kube-scheduler"
36[etcd] Creating static Pod manifest for local etcd in "/etc/kubernetes/manifests"
37[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
38[apiclient] All control plane components are healthy after 17.504697 seconds
39[upload-config] Storing the configuration used in ConfigMap "kubeadm-config" in the "kube-system" Namespace
40[kubelet] Creating a ConfigMap "kubelet-config-1.21" in namespace kube-system with the configuration for the kubelets in the cluster
41[upload-certs] Skipping phase. Please see --upload-certs
42[mark-control-plane] Marking the node node1 as control-plane by adding the labels: [node-role.kubernetes.io/master(deprecated) node-role.kubernetes.io/control-plane node.kubernetes.io/exclude-from-external-load-balancers]
43[mark-control-plane] Marking the node node1 as control-plane by adding the taints [node-role.kubernetes.io/master:PreferNoSchedule]
44[bootstrap-token] Using token: xgmqxq.4fj36rn694vaqymm
45[bootstrap-token] Configuring bootstrap tokens, cluster-info ConfigMap, RBAC Roles
46[bootstrap-token] configured RBAC rules to allow Node Bootstrap tokens to get nodes
47[bootstrap-token] configured RBAC rules to allow Node Bootstrap tokens to post CSRs in order for nodes to get long term certificate credentials
48[bootstrap-token] configured RBAC rules to allow the csrapprover controller automatically approve CSRs from a Node Bootstrap Token
49[bootstrap-token] configured RBAC rules to allow certificate rotation for all node client certificates in the cluster
50[bootstrap-token] Creating the "cluster-info" ConfigMap in the "kube-public" namespace
51[kubelet-finalize] Updating "/etc/kubernetes/kubelet.conf" to point to a rotatable kubelet client certificate and key
52[addons] Applied essential addon: CoreDNS
53[addons] Applied essential addon: kube-proxy
54
55Your Kubernetes control-plane has initialized successfully!
56
57To start using your cluster, you need to run the following as a regular user:
58
59 mkdir -p $HOME/.kube
60 sudo cp -i /etc/kubernetes/admin.conf $HOME/.kube/config
61 sudo chown $(id -u):$(id -g) $HOME/.kube/config
62
63Alternatively, if you are the root user, you can run:
64
65 export KUBECONFIG=/etc/kubernetes/admin.conf
66
67You should now deploy a pod network to the cluster.
68Run "kubectl apply -f [podnetwork].yaml" with one of the options listed at:
69 https://kubernetes.io/docs/concepts/cluster-administration/addons/
70
71Then you can join any number of worker nodes by running the following on each as root:
72
73kubeadm join 192.168.96.151:6443 --token xgmqxq.4fj36rn694vaqymm \
74 --discovery-token-ca-cert-hash sha256:94f55d3468d90c3cfea5d9b0ad3a48706e20aad3b4233ac02ff0321e9f167645
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：
1mkdir -p $HOME/.kube 2sudo cp -i /etc/kubernetes/admin.conf $HOME/.kube/config 3sudo 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 xgmqxq.4fj36rn694vaqymm \ --discovery-token-ca-cert-hash sha256:94f55d3468d90c3cfea5d9b0ad3a48706e20aad3b4233ac02ff0321e9f167645
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:
1kubectl get cs
2Warning: v1 ComponentStatus is deprecated in v1.19+
3NAME STATUS MESSAGE ERROR
4controller-manager Unhealthy Get "http://127.0.0.1:10252/healthz": dial tcp 127.0.0.1:10252: connect: connection refused
5scheduler Unhealthy Get "http://127.0.0.1:10251/healthz": dial tcp 127.0.0.1:10251: connect: connection refused
6etcd-0 Healthy {"health":"true"}
controller-manager和scheduler为不健康状态，修改/etc/kubernetes/manifests/下的静态pod配置文件kube-controller-manager.yaml和kube-scheduler.yaml，删除这两个文件中命令选项中的- --port=0这行，重启kubelet，再次查看一切正常。
1kubectl get cs
2Warning: v1 ComponentStatus is deprecated in v1.19+
3NAME STATUS MESSAGE ERROR
4controller-manager Healthy ok
5scheduler Healthy ok
6etcd-0 Healthy {"health":"true"}
集群初始化如果遇到问题，可以使用kubeadm reset命令进行清理：
2.4 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上按照helm。
1wget https://get.helm.sh/helm-v3.6.0-linux-amd64.tar.gz
2tar -zxvf helm-v3.6.0-linux-amd64.tar.gz
3mv linux-amd64/helm /usr/local/bin/
执行helm list确认没有错误输出。
2.5 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集群中按照calico。
下载tigera-operator的helm chart:
1wget https://github.com/projectcalico/calico/releases/download/v3.19.1/tigera-operator-v3.19.1-2.tgz
查看这个chart的中可定制的配置:
1helm show values tigera-operator-v3.19.1-2.tgz
2
3imagePullSecrets: {}
4
5installation:
6 enabled: true
7 kubernetesProvider: ""
8
9certs:
10 node:
11 key:
12 cert:
13 commonName:
14 typha:
15 key:
16 cert:
17 commonName:
18 caBundle:
19
20# Configuration for the tigera operator
21tigeraOperator:
22 image: tigera/operator
23 version: v1.17.4
24 registry: quay.io
25calicoctl:
26 image: quay.io/docker.io/calico/ctl
27 tag: v3.19.1
定制的values.yaml如下:
1# 可针对上面的配置进行定制,这里略过
使用helm安装calico：
1helm install calico tigera-operator-v3.19.1-2.tgz -f values.yaml
等待并确认所有pod处于Running状态:
1watch kubectl get pods -n calico-system
2NAME READY STATUS RESTARTS AGE
3calico-kube-controllers-7f58dbcbbd-kdnlg 1/1 Running 0 2m34s
4calico-node-nv794 1/1 Running 0 2m34s
5calico-typha-65f579bc5d-4pbfz 1/1 Running 0 2m34s
查看一下calico向k8s中添加的api资源:
1 kubectl api-resources | grep calico
2bgpconfigurations crd.projectcalico.org/v1 false BGPConfiguration
3bgppeers crd.projectcalico.org/v1 false BGPPeer
4blockaffinities crd.projectcalico.org/v1 false BlockAffinity
5clusterinformations crd.projectcalico.org/v1 false ClusterInformation
6felixconfigurations crd.projectcalico.org/v1 false FelixConfiguration
7globalnetworkpolicies crd.projectcalico.org/v1 false GlobalNetworkPolicy
8globalnetworksets crd.projectcalico.org/v1 false GlobalNetworkSet
9hostendpoints crd.projectcalico.org/v1 false HostEndpoint
10ipamblocks crd.projectcalico.org/v1 false IPAMBlock
11ipamconfigs crd.projectcalico.org/v1 false IPAMConfig
12ipamhandles crd.projectcalico.org/v1 false IPAMHandle
13ippools crd.projectcalico.org/v1 false IPPool
14kubecontrollersconfigurations crd.projectcalico.org/v1 false KubeControllersConfiguration
15networkpolicies crd.projectcalico.org/v1 true NetworkPolicy
16networksets 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:
1cd /usr/local/bin
2curl -o kubectl-calico -O -L "https://github.com/projectcalico/calicoctl/releases/download/v3.19.1/calicoctl"
3chmod +x kubectl-calico
验证插件正常工作:
1kubectl calico -h
2.6 验证k8s DNS是否可用 #
1kubectl run curl --image=radial/busyboxplus:curl -it
2If you don't see a command prompt, try pressing enter.
3[ root@curl:/ ]$
进入后执行nslookup kubernetes.default确认解析正常:
1nslookup kubernetes.default
2Server: 10.96.0.10
3Address 1: 10.96.0.10 kube-dns.kube-system.svc.cluster.local
4
5Name: kubernetes.default
6Address 1: 10.96.0.1 kubernetes.default.svc.cluster.local
2.7 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:
1kubeadm join 192.168.96.151:6443 --token xgmqxq.4fj36rn694vaqymm \
2 --discovery-token-ca-cert-hash sha256:94f55d3468d90c3cfea5d9b0ad3a48706e20aad3b4233ac02ff0321e9f167645 \
3 --ignore-preflight-errors=Swap
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：
1kubectl get node
2NAME STATUS ROLES AGE VERSION
3node1 Ready control-plane,master 15m v1.21.2
4node2 Ready <none> 48s v1.21.2
5node3 Ready <none> 32s v1.21.2
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node1(192.168.96.151)作为边缘节点，打上Label：
1kubectl label node node1 node-role.kubernetes.io/edge=
安装ingress-nginx的helm repo:
1helm repo add ingress-nginx https://kubernetes.github.io/ingress-nginx
2helm repo update
查看ingress-nginx/ingress-nginx这个chart的可定制配置:
1helm show values ingress-nginx/ingress-nginx
对values.yaml配置定制如下:
1controller:
2 replicaCount: 1
3 image:
4 # registry: k8s.gcr.io
5 # image: ingress-nginx/controller
6 # tag: "v0.47.0"
7 registry: docker.io
8 image: unreachableg/k8s.gcr.io_ingress-nginx_controller
9 tag: "v0.47.0"
10 digest: sha256:4497b1b260d4f1aa4617b19880169389aac7d9f249485eafc038682abc45ea75
11 hostNetwork: true
12 nodeSelector:
13 node-role.kubernetes.io/edge: ''
14 affinity:
15 podAntiAffinity:
16 requiredDuringSchedulingIgnoredDuringExecution:
17 - labelSelector:
18 matchExpressions:
19 - key: app
20 operator: In
21 values:
22 - nginx-ingress
23 - key: component
24 operator: In
25 values:
26 - controller
27 topologyKey: kubernetes.io/hostname
28 tolerations:
29 - key: node-role.kubernetes.io/master
30 operator: Exists
31 effect: NoSchedule
32 - key: node-role.kubernetes.io/master
33 operator: Exists
34 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:
1crictl pull unreachableg/k8s.gcr.io_ingress-nginx_controller:v0.47.0
1helm install ingress-nginx ingress-nginx/ingress-nginx --create-namespace -n ingress-nginx -f values.yaml
1kubectl get pod -n ingress-nginx
2NAME READY STATUS RESTARTS AGE
3ingress-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：
1wget https://github.com/kubernetes-sigs/metrics-server/releases/download/v0.5.0/components.yaml
修改components.yaml中的image为docker.io/unreachableg/k8s.gcr.io_metrics-server_metrics-server:v0.5.0。
修改components.yaml中容器的启动参数，加入--kubelet-insecure-tls。
1kubectl 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:
1kubectl top node --use-protocol-buffers=true
2NAME CPU(cores) CPU% MEMORY(bytes) MEMORY%
3node1 219m 5% 3013Mi 39%
4node2 102m 2% 1576Mi 20%
5node3 110m 2% 1696Mi 21%
6
7kubectl top pod -n kube-system --use-protocol-buffers=true
8NAME CPU(cores) MEMORY(bytes)
9coredns-59d64cd4d4-9mclj 4m 17Mi
10coredns-59d64cd4d4-fj7xr 4m 17Mi
11etcd-node1 25m 154Mi
12kube-apiserver-node1 80m 465Mi
13kube-controller-manager-node1 17m 61Mi
14kube-proxy-hhlhc 1m 21Mi
15kube-proxy-nrhq7 1m 19Mi
16kube-proxy-phmrw 1m 17Mi
17kube-scheduler-node1 4m 24Mi
18kubernetes-dashboard-5cb95fd47f-6lfnm 3m 36Mi
19metrics-server-9ddcc8ddf-jvlzs 5m 21Mi
接下来使用helm部署k8s的dashboard，添加chart repo:
1helm repo add kubernetes-dashboard https://kubernetes.github.io/dashboard/
2helm repo update
查看chart的可定制配置:
1helm show values kubernetes-dashboard/kubernetes-dashboard
对value.yaml定制配置如下:
1image:
2 repository: kubernetesui/dashboard
3 tag: v2.3.1
4ingress:
5 enabled: true
6 annotations:
7 nginx.ingress.kubernetes.io/ssl-redirect: "true"
8 nginx.ingress.kubernetes.io/backend-protocol: "HTTPS"
9 hosts:
10 - k8s.example.com
11 tls:
12 - secretName: example-com-tls-secret
13 hosts:
14 - k8s.example.com
15metricsScraper:
16 enabled: true
先创建存放k8s.example.comssl证书的secret:
1kubectl create secret tls example-com-tls-secret \
2 --cert=cert.pem \
3 --key=key.pem \
4 -n kube-system
使用helm部署dashboard:
1helm install kubernetes-dashboard kubernetes-dashboard/kubernetes-dashboard \
2-n kube-system \
3-f values.yaml
创建管理员sa:
1kubectl create serviceaccount kube-dashboard-admin-sa -n kube-system
2
3kubectl create clusterrolebinding kube-dashboard-admin-sa \
4--clusterrole=cluster-admin --serviceaccount=kube-system:kube-dashboard-admin-sa
获取集群管理员登录dashboard所需token:
1kubectl -n kube-system get secret | grep kube-dashboard-admin-sa-token
2kube-dashboard-admin-sa-token-rcwlb kubernetes.io/service-account-token 3 68s
3
4kubectl describe -n kube-system secret/kube-dashboard-admin-sa-token-rcwlb
5Name: kube-dashboard-admin-sa-token-rcwlb
6Namespace: kube-system
7Labels: <none>
8Annotations: kubernetes.io/service-account.name: kube-dashboard-admin-sa
9 kubernetes.io/service-account.uid: fcdf27f6-f6f9-4f76-b64e-edc91fb1479b
10
11Type: kubernetes.io/service-account-token
12
13Data
14====
15namespace: 11 bytes
16token: eyJhbGciOiJSUzI1NiIsImtpZCI6IkYxWTd5aDdzYWsyeWJVMFliUUhJMXI4YWtMZFd4dGFDT1N4eEZoam9HLUEifQ.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.R3l19_Nal4B2EktKFSJ7CgOqAngG_MTgzHRRjWdREN7dLALyfiRXYIgZQ90hxM-a9z2sPXBzfJno4OGP4fPX33D8h_4fgxfpVLjKqjdlZ_HAks_6sV9PBzDNXb_loNW8ECfsleDgn6CZin8Vx1w7sgkoEIKq0H-iZ8V9pRV0fTuOZcB-70pV_JX6H6WBEOgRIAZswhAoyUMvH1qNl47J5xBNwKRgcqP57NCIODo6FiClxfY3MWo2vz44R5wYCuBJJ70p6aBWixjDSxnp5u9mUP0zMF_igICl_OfgKuPyaeuIL83U8dS5ovEwPPGzX5mHUgaPH7JLZmKRNXJqLhTweA
17ca.crt: 1066 bytes
使用上面的token登录k8s dashboard。
