部署一個 Containerd 容器運行時的 Kubernetes 集群
前面我們介紹了 containerd 的基本使用，也了解了如何將現(xiàn)有 docker 容器運行時的 Kubernetes 集群切換成 containerd，接下來我們使用 kubeadm 從頭搭建一個使用 containerd 作為容器運行時的 Kubernetes 集群，這里我們安裝最新的 v1.22.1 版本。
環(huán)境準備
3個節(jié)點，都是 Centos 7.6 系統(tǒng)，內(nèi)核版本：3.10.0-1062.4.1.el7.x86_64，在每個節(jié)點上添加 hosts 信息：
? ~ cat /etc/hosts
192.168.31.30 master
192.168.31.95 node1
192.168.31.215 node2
“節(jié)點的 hostname 必須使用標準的 DNS 命名，另外千萬不用什么默認的
”localhost的 hostname，會導致各種錯誤出現(xiàn)的。在 Kubernetes 項目里，機器的名字以及一切存儲在 Etcd 中的 API 對象，都必須使用標準的 DNS 命名（RFC 1123）?？梢允褂妹?hostnamectl set-hostname node1來修改 hostname。
禁用防火墻：
? ~ systemctl stop firewalld
? ~ systemctl disable firewalld
禁用 SELINUX：
? ~ setenforce 0
? ~ cat /etc/selinux/config
SELINUX=disabled
由于開啟內(nèi)核 ipv4 轉(zhuǎn)發(fā)需要加載 br_netfilter 模塊，所以加載下該模塊：
? ~ modprobe br_netfilter
創(chuàng)建/etc/sysctl.d/k8s.conf文件，添加如下內(nèi)容：
net.bridge.bridge-nf-call-ip6tables = 1
net.bridge.bridge-nf-call-iptables = 1
net.ipv4.ip_forward = 1
bridge-nf 使得 netfilter 可以對 Linux 網(wǎng)橋上的 IPv4/ARP/IPv6 包過濾。比如，設置net.bridge.bridge-nf-call-iptables＝1后，二層的網(wǎng)橋在轉(zhuǎn)發(fā)包時也會被 iptables的 FORWARD 規(guī)則所過濾。常用的選項包括：
net.bridge.bridge-nf-call-arptables：是否在 arptables 的 FORWARD 中過濾網(wǎng)橋的 ARP 包 net.bridge.bridge-nf-call-ip6tables：是否在 ip6tables 鏈中過濾 IPv6 包 net.bridge.bridge-nf-call-iptables：是否在 iptables 鏈中過濾 IPv4 包 net.bridge.bridge-nf-filter-vlan-tagged：是否在 iptables/arptables 中過濾打了 vlan 標簽的包。
執(zhí)行如下命令使修改生效：
? ~ sysctl -p /etc/sysctl.d/k8s.conf
安裝 ipvs：
? ~ 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
上面腳本創(chuàng)建了的/etc/sysconfig/modules/ipvs.modules文件，保證在節(jié)點重啟后能自動加載所需模塊。使用lsmod | grep -e ip_vs -e nf_conntrack_ipv4命令查看是否已經(jīng)正確加載所需的內(nèi)核模塊。
接下來還需要確保各個節(jié)點上已經(jīng)安裝了 ipset 軟件包：
? ~ yum install ipset
為了便于查看 ipvs 的代理規(guī)則，最好安裝一下管理工具 ipvsadm：
? ~ yum install ipvsadm
同步服務器時間
? ~ yum install chrony -y
? ~ systemctl enable chronyd
? ~ systemctl start chronyd
? ~ chronyc sources
210 Number of sources = 4
MS Name/IP address Stratum Poll Reach LastRx Last sample
===============================================================================
^+ sv1.ggsrv.de 2 6 17 32 -823us[-1128us] +/- 98ms
^- montreal.ca.logiplex.net 2 6 17 32 -17ms[ -17ms] +/- 179ms
^- ntp6.flashdance.cx 2 6 17 32 -32ms[ -32ms] +/- 161ms
^* 119.28.183.184 2 6 33 32 +661us[ +357us] +/- 38ms
? ~ date
Tue Aug 31 14:36:14 CST 2021
關閉 swap 分區(qū)：
? ~ swapoff -a
修改/etc/fstab文件，注釋掉 SWAP 的自動掛載，使用free -m確認 swap 已經(jīng)關閉。swappiness 參數(shù)調(diào)整，修改/etc/sysctl.d/k8s.conf添加下面一行：
vm.swappiness=0
執(zhí)行 sysctl -p /etc/sysctl.d/k8s.conf 使修改生效。
安裝 Containerd
我們已經(jīng)了解過容器運行時 containerd 的一些基本使用，接下來在各個節(jié)點上安裝 Containerd。
由于 containerd 需要調(diào)用 runc，所以我們也需要先安裝 runc，不過 containerd 提供了一個包含相關依賴的壓縮包 cri-containerd-cni-${VERSION}.${OS}-${ARCH}.tar.gz，可以直接使用這個包來進行安裝。首先從 release 頁面下載最新版本的壓縮包，當前為 1.5.5 版本：
? ~ wget https://github.com/containerd/containerd/releases/download/v1.5.5/cri-containerd-cni-1.5.5-linux-amd64.tar.gz
# 如果有限制，也可以替換成下面的 URL 加速下載
# wget https://download.fastgit.org/containerd/containerd/releases/download/v1.5.5/cri-containerd-cni-1.5.5-linux-amd64.tar.gz
直接將壓縮包解壓到系統(tǒng)的各個目錄中：
? ~ tar -C / -xzf cri-containerd-cni-1.5.5-linux-amd64.tar.gz
然后要將 /usr/local/bin 和 /usr/local/sbin 追加到 ~/.bashrc 文件的 PATH 環(huán)境變量中：
export PATH=$PATH:/usr/local/bin:/usr/local/sbin
然后執(zhí)行下面的命令使其立即生效：
? ~ source ~/.bashrc
containerd 的默認配置文件為 /etc/containerd/config.toml，我們可以通過如下所示的命令生成一個默認的配置：
? ~ mkdir -p /etc/containerd
? ~ containerd config default > /etc/containerd/config.toml
對于使用 systemd 作為 init system 的 Linux 的發(fā)行版，使用 systemd 作為容器的 cgroup driver 可以確保節(jié)點在資源緊張的情況更加穩(wěn)定，所以推薦將 containerd 的 cgroup driver 配置為 systemd。/etc/containerd/config.toml，在 plugins."io.containerd.grpc.v1.cri".containerd.runtimes.runc.options 配置塊下面將 SystemdCgroup 設置為 true：
[plugins."io.containerd.grpc.v1.cri".containerd.runtimes.runc]
...
[plugins."io.containerd.grpc.v1.cri".containerd.runtimes.runc.options]
SystemdCgroup = true
....
然后再為鏡像倉庫配置一個加速器，需要在 cri 配置塊下面的 registry 配置塊下面進行配置 registry.mirrors：
[plugins."io.containerd.grpc.v1.cri"]
...
# sandbox_image = "k8s.gcr.io/pause:3.5"
sandbox_image = "registry.aliyuncs.com/k8sxio/pause:3.5"
...
[plugins."io.containerd.grpc.v1.cri".registry]
[plugins."io.containerd.grpc.v1.cri".registry.mirrors]
[plugins."io.containerd.grpc.v1.cri".registry.mirrors."docker.io"]
endpoint = ["https://bqr1dr1n.mirror.aliyuncs.com"]
[plugins."io.containerd.grpc.v1.cri".registry.mirrors."k8s.gcr.io"]
endpoint = ["https://registry.aliyuncs.com/k8sxio"]
由于上面我們下載的 containerd 壓縮包中包含一個 etc/systemd/system/containerd.service 的文件，這樣我們就可以通過 systemd 來配置 containerd 作為守護進程運行了，現(xiàn)在我們就可以啟動 containerd 了，直接執(zhí)行下面的命令即可：
? ~ systemctl daemon-reload
? ~ systemctl enable containerd --now
啟動完成后就可以使用 containerd 的本地 CLI 工具 ctr 和 crictl 了，比如查看版本：
? ~ ctr version
Client:
Version: v1.5.5
Revision: 72cec4be58a9eb6b2910f5d10f1c01ca47d231c0
Go version: go1.16.6
Server:
Version: v1.5.5
Revision: 72cec4be58a9eb6b2910f5d10f1c01ca47d231c0
UUID: cd2894ad-fd71-4ef7-a09f-5795c7eb4c3b
? ~ crictl version
Version: 0.1.0
RuntimeName: containerd
RuntimeVersion: v1.5.5
RuntimeApiVersion: v1alpha2
使用 kubeadm 部署 Kubernetes
上面的相關環(huán)境配置也完成了，現(xiàn)在我們就可以來安裝 Kubeadm 了，我們這里是通過指定yum 源的方式來進行安裝的：
? ~ cat <<EOF > /etc/yum.repos.d/kubernetes.repo
[kubernetes]
name=Kubernetes
baseurl=https://packages.cloud.google.com/yum/repos/kubernetes-el7-x86_64
enabled=1
gpgcheck=1
repo_gpgcheck=1
gpgkey=https://packages.cloud.google.com/yum/doc/yum-key.gpg
https://packages.cloud.google.com/yum/doc/rpm-package-key.gpg
EOF
當然了，上面的 yum 源是需要科學上網(wǎng)的，如果不能科學上網(wǎng)的話，我們可以使用阿里云的源進行安裝：
? ~ 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=0
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
然后安裝 kubeadm、kubelet、kubectl：
# --disableexcludes 禁掉除了kubernetes之外的別的倉庫
? ~ yum makecache fast
? ~ yum install -y kubelet-1.22.1 kubeadm-1.22.1 kubectl-1.22.1 --disableexcludes=kubernetes
? ~ kubeadm version
kubeadm version: &version.Info{Major:"1", Minor:"22", GitVersion:"v1.22.1", GitCommit:"632ed300f2c34f6d6d15ca4cef3d3c7073412212", GitTreeState:"clean", BuildDate:"2021-08-19T15:44:22Z", GoVersion:"go1.16.7", Compiler:"gc", Platform:"linux/amd64"}
可以看到我們這里安裝的是 v1.22.1 版本，然后將 master 節(jié)點的 kubelet 設置成開機啟動：
? ~ systemctl enable --now kubelet
“到這里為止上面所有的操作都需要在所有節(jié)點執(zhí)行配置。
”
初始化集群
當我們執(zhí)行 kubelet --help 命令的時候可以看到原來大部分命令行參數(shù)都被 DEPRECATED了，這是因為官方推薦我們使用 --config 來指定配置文件，在配置文件中指定原來這些參數(shù)的配置，可以通過官方文檔 Set Kubelet parameters via a config file 了解更多相關信息，這樣 Kubernetes 就可以支持動態(tài) Kubelet 配置（Dynamic Kubelet Configuration）了，參考 Reconfigure a Node’s Kubelet in a Live Cluster。
然后我們可以通過下面的命令在 master 節(jié)點上輸出集群初始化默認使用的配置：
? ~ kubeadm config print init-defaults --component-configs KubeletConfiguration > kubeadm.yaml
然后根據(jù)我們自己的需求修改配置，比如修改 imageRepository 指定集群初始化時拉取 Kubernetes 所需鏡像的地址，kube-proxy 的模式為 ipvs，另外需要注意的是我們這里是準備安裝 flannel 網(wǎng)絡插件的，需要將 networking.podSubnet 設置為10.244.0.0/16：
# kubeadm.yaml
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: 192.168.31.30 # 指定master節(jié)點內(nèi)網(wǎng)IP
bindPort: 6443
nodeRegistration:
criSocket: /run/containerd/containerd.sock # 使用 containerd的Unix socket 地址
imagePullPolicy: IfNotPresent
name: master
taints: # 給master添加污點，master節(jié)點不能調(diào)度應用
- effect: "NoSchedule"
key: "node-role.kubernetes.io/master"
---
apiVersion: kubeproxy.config.k8s.io/v1alpha1
kind: KubeProxyConfiguration
mode: ipvs # kube-proxy 模式
---
apiServer:
timeoutForControlPlane: 4m0s
apiVersion: kubeadm.k8s.io/v1beta3
certificatesDir: /etc/kubernetes/pki
clusterName: kubernetes
controllerManager: {}
dns: {}
etcd:
local:
dataDir: /var/lib/etcd
imageRepository: registry.aliyuncs.com/k8sxio
kind: ClusterConfiguration
kubernetesVersion: 1.22.1
networking:
dnsDomain: cluster.local
serviceSubnet: 10.96.0.0/12
podSubnet: 10.244.0.0/16 # 指定 pod 子網(wǎng)
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
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
cgroupDriver: systemd # 配置 cgroup driver
logging: {}
memorySwap: {}
nodeStatusReportFrequency: 0s
nodeStatusUpdateFrequency: 0s
rotateCertificates: true
runtimeRequestTimeout: 0s
shutdownGracePeriod: 0s
shutdownGracePeriodCriticalPods: 0s
staticPodPath: /etc/kubernetes/manifests
streamingConnectionIdleTimeout: 0s
syncFrequency: 0s
volumeStatsAggPeriod: 0s
“對于上面的資源清單的文檔比較雜，要想完整了解上面的資源對象對應的屬性，可以查看對應的 godoc 文檔，地址: https://godoc.org/k8s.io/kubernetes/cmd/kubeadm/app/apis/kubeadm/v1beta3。
”
在開始初始化集群之前可以使用kubeadm config images pull --config kubeadm.yaml預先在各個服務器節(jié)點上拉取所k8s需要的容器鏡像。
配置文件準備好過后，可以使用如下命令先將相關鏡像 pull 下面：
? ~ kubeadm config images pull --config kubeadm.yaml
[config/images] Pulled registry.aliyuncs.com/k8sxio/kube-apiserver:v1.22.1
[config/images] Pulled registry.aliyuncs.com/k8sxio/kube-controller-manager:v1.22.1
[config/images] Pulled registry.aliyuncs.com/k8sxio/kube-scheduler:v1.22.1
[config/images] Pulled registry.aliyuncs.com/k8sxio/kube-proxy:v1.22.1
[config/images] Pulled registry.aliyuncs.com/k8sxio/pause:3.5
[config/images] Pulled registry.aliyuncs.com/k8sxio/etcd:3.5.0-0
failed to pull image "registry.aliyuncs.com/k8sxio/coredns:v1.8.4": output: time="2021-08-31T15:09:13+08:00" level=fatal msg="pulling image: rpc error: code = NotFound desc = failed to pull and unpack image \"registry.aliyuncs.com/k8sxio/coredns:v1.8.4\": failed to resolve reference \"registry.aliyuncs.com/k8sxio/coredns:v1.8.4\": registry.aliyuncs.com/k8sxio/coredns:v1.8.4: not found"
, error: exit status 1
To see the stack trace of this error execute with --v=5 or higher
上面在拉取 coredns 鏡像的時候出錯了，沒有找到這個鏡像，我們可以手動 pull 該鏡像，然后重新 tag 下鏡像地址即可：
? ~ ctr -n k8s.io i pull docker.io/coredns/coredns:1.8.4
docker.io/coredns/coredns:1.8.4: resolved |++++++++++++++++++++++++++++++++++++++|
index-sha256:6e5a02c21641597998b4be7cb5eb1e7b02c0d8d23cce4dd09f4682d463798890: done |++++++++++++++++++++++++++++++++++++++|
manifest-sha256:10683d82b024a58cc248c468c2632f9d1b260500f7cd9bb8e73f751048d7d6d4: done |++++++++++++++++++++++++++++++++++++++|
layer-sha256:bc38a22c706b427217bcbd1a7ac7c8873e75efdd0e59d6b9f069b4b243db4b4b: done |++++++++++++++++++++++++++++++++++++++|
config-sha256:8d147537fb7d1ac8895da4d55a5e53621949981e2e6460976dae812f83d84a44: done |++++++++++++++++++++++++++++++++++++++|
layer-sha256:c6568d217a0023041ef9f729e8836b19f863bcdb612bb3a329ebc165539f5a80: exists |++++++++++++++++++++++++++++++++++++++|
elapsed: 12.4s total: 12.0 M (991.3 KiB/s)
unpacking linux/amd64 sha256:6e5a02c21641597998b4be7cb5eb1e7b02c0d8d23cce4dd09f4682d463798890...
done: 410.185888ms
? ~ ctr -n k8s.io i tag docker.io/coredns/coredns:1.8.4 registry.aliyuncs.com/k8sxio/coredns:v1.8.4
然后就可以使用上面的配置文件在 master 節(jié)點上進行初始化：
? ~ kubeadm init --config kubeadm.yaml
[init] Using Kubernetes version: v1.22.1
[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'
[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 master] and IPs [10.96.0.1 192.168.31.30]
[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 master] and IPs [192.168.31.30 127.0.0.1 ::1]
[certs] Generating "etcd/peer" certificate and key
[certs] etcd/peer serving cert is signed for DNS names [localhost master] and IPs [192.168.31.30 127.0.0.1 ::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 12.501933 seconds
[upload-config] Storing the configuration used in ConfigMap "kubeadm-config" in the "kube-system" Namespace
[kubelet] Creating a ConfigMap "kubelet-config-1.22" 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 master 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]
[mark-control-plane] Marking the node master as control-plane by adding the taints [node-role.kubernetes.io/master:NoSchedule]
[bootstrap-token] Using token: abcdef.0123456789abcdef
[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 192.168.31.30:6443 --token abcdef.0123456789abcdef \
--discovery-token-ca-cert-hash sha256:8c1f43da860b0e7bd9f290fe057f08cf7650b89e650ff316ce4a9cad3834475c
根據(jù)安裝提示拷貝 kubeconfig 文件：
? ~ mkdir -p $HOME/.kube
? ~ sudo cp -i /etc/kubernetes/admin.conf $HOME/.kube/config
? ~ sudo chown $(id -u):$(id -g) $HOME/.kube/config
然后可以使用 kubectl 命令查看 master 節(jié)點已經(jīng)初始化成功了：
? ~ kubectl get nodes
NAME STATUS ROLES AGE VERSION
master Ready control-plane,master 2m10s v1.22.1
添加節(jié)點
記住初始化集群上面的配置和操作要提前做好，將 master 節(jié)點上面的 $HOME/.kube/config 文件拷貝到 node 節(jié)點對應的文件中，安裝 kubeadm、kubelet、kubectl（可選），然后執(zhí)行上面初始化完成后提示的 join 命令即可：
? ~ kubeadm join 192.168.31.30:6443 --token abcdef.0123456789abcdef \
> --discovery-token-ca-cert-hash sha256:8c1f43da860b0e7bd9f290fe057f08cf7650b89e650ff316ce4a9cad3834475c
[preflight] Running pre-flight checks
[preflight] WARNING: Couldn't create the interface used for talking to the container runtime: docker is required for container runtime: exec: "docker": executable file not found in $PATH
[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.
“如果忘記了上面的 join 命令可以使用命令
”kubeadm token create --print-join-command重新獲取。
執(zhí)行成功后運行 get nodes 命令：
? ~ kubectl get nodes
NAME STATUS ROLES AGE VERSION
master Ready control-plane,master 47m v1.22.1
node2 NotReady <none> 46s v1.22.1
可以看到是 NotReady 狀態(tài)，這是因為還沒有安裝網(wǎng)絡插件，接下來安裝網(wǎng)絡插件，可以在文檔 https://kubernetes.io/docs/setup/production-environment/tools/kubeadm/create-cluster-kubeadm/ 中選擇我們自己的網(wǎng)絡插件，這里我們安裝 flannel:
? ~ wget https://raw.githubusercontent.com/coreos/flannel/master/Documentation/kube-flannel.yml
# 如果有節(jié)點是多網(wǎng)卡，則需要在資源清單文件中指定內(nèi)網(wǎng)網(wǎng)卡
# 搜索到名為 kube-flannel-ds 的 DaemonSet，在kube-flannel容器下面
? ~ vi kube-flannel.yml
......
containers:
- name: kube-flannel
image: quay.io/coreos/flannel:v0.14.0
command:
- /opt/bin/flanneld
args:
- --ip-masq
- --kube-subnet-mgr
- --iface=eth0 # 如果是多網(wǎng)卡的話，指定內(nèi)網(wǎng)網(wǎng)卡的名稱
......
? ~ kubectl apply -f kube-flannel.yml # 安裝 flannel 網(wǎng)絡插件
隔一會兒查看 Pod 運行狀態(tài)：
? ~ kubectl get pods -n kube-system
NAME READY STATUS RESTARTS AGE
coredns-7568f67dbd-5mg59 1/1 Running 0 8m32s
coredns-7568f67dbd-b685t 1/1 Running 0 8m31s
etcd-master 1/1 Running 0 66m
kube-apiserver-master 1/1 Running 0 66m
kube-controller-manager-master 1/1 Running 0 66m
kube-flannel-ds-dsbt6 1/1 Running 0 11m
kube-flannel-ds-zwlm6 1/1 Running 0 11m
kube-proxy-jq84n 1/1 Running 0 66m
kube-proxy-x4hbv 1/1 Running 0 19m
kube-scheduler-master 1/1 Running 0 66m
“當我們部署完網(wǎng)絡插件后執(zhí)行 ifconfig 命令，正常會看到新增的
”cni0與flannel1這兩個虛擬設備，但是如果沒有看到cni0這個設備也不用太擔心，我們可以觀察/var/lib/cni目錄是否存在，如果不存在并不是說部署有問題，而是該節(jié)點上暫時還沒有應用運行，我們只需要在該節(jié)點上運行一個 Pod 就可以看到該目錄會被創(chuàng)建，并且cni0設備也會被創(chuàng)建出來。
網(wǎng)絡插件運行成功了，node 狀態(tài)也正常了：
? ~ kubectl get nodes
NAME STATUS ROLES AGE VERSION
master Ready control-plane,master 111m v1.22.1
node2 Ready <none> 64m v1.22.1
用同樣的方法添加另外一個節(jié)點即可。
Dashboard
v1.22.1 版本的集群需要安裝最新的 2.0+ 版本的 Dashboard：
# 推薦使用下面這種方式
? ~ wget https://raw.githubusercontent.com/kubernetes/dashboard/v2.3.1/aio/deploy/recommended.yaml
? ~ vi recommended.yaml
# 修改Service為NodePort類型
......
kind: Service
apiVersion: v1
metadata:
labels:
k8s-app: kubernetes-dashboard
name: kubernetes-dashboard
namespace: kubernetes-dashboard
spec:
ports:
- port: 443
targetPort: 8443
selector:
k8s-app: kubernetes-dashboard
type: NodePort # 加上type=NodePort變成NodePort類型的服務
......直接創(chuàng)建：
? ~ kubectl apply -f recommended.yaml
新版本的 Dashboard 會被默認安裝在 kubernetes-dashboard 這個命名空間下面：
? ~ kubectl get pods -n kubernetes-dashboard -o wide
NAME READY STATUS RESTARTS AGE IP NODE NOMINATED NODE READINESS GATES
dashboard-metrics-scraper-856586f554-pllvt 1/1 Running 0 24m 10.88.0.7 master <none> <none>
kubernetes-dashboard-76597d7df5-82998 1/1 Running 0 21m 10.88.0.2 node2 <none> <none>
我們仔細看可以發(fā)現(xiàn)上面的 Pod 分配的 IP 段是 10.88.xx.xx，包括前面自動安裝的 CoreDNS 也是如此，我們前面不是配置的 podSubnet 為 10.244.0.0/16 嗎？我們先去查看下 CNI 的配置文件：
? ~ ls -la /etc/cni/net.d/
total 8
drwxr-xr-x 2 1001 docker 67 Aug 31 16:45 .
drwxr-xr-x. 3 1001 docker 19 Jul 30 01:13 ..
-rw-r--r-- 1 1001 docker 604 Jul 30 01:13 10-containerd-net.conflist
-rw-r--r-- 1 root root 292 Aug 31 16:45 10-flannel.conflist
可以看到里面包含兩個配置，一個是 10-containerd-net.conflist，另外一個是我們上面創(chuàng)建的 Flannel 網(wǎng)絡插件生成的配置，我們的需求肯定是想使用 Flannel 的這個配置，我們可以查看下 containerd 這個自帶的 cni 插件配置：
? ~ cat /etc/cni/net.d/10-containerd-net.conflist
{
"cniVersion": "0.4.0",
"name": "containerd-net",
"plugins": [
{
"type": "bridge",
"bridge": "cni0",
"isGateway": true,
"ipMasq": true,
"promiscMode": true,
"ipam": {
"type": "host-local",
"ranges": [
[{
"subnet": "10.88.0.0/16"
}],
[{
"subnet": "2001:4860:4860::/64"
}]
],
"routes": [
{ "dst": "0.0.0.0/0" },
{ "dst": "::/0" }
]
}
},
{
"type": "portmap",
"capabilities": {"portMappings": true}
}
]
}
可以看到上面的 IP 段恰好就是 10.88.0.0/16，但是這個 cni 插件類型是 bridge 網(wǎng)絡，網(wǎng)橋的名稱為 cni0：
? ~ ip a
...
6: cni0: <BROADCAST,MULTICAST,PROMISC,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP group default qlen 1000
link/ether 9a:e7:eb:40:e8:66 brd ff:ff:ff:ff:ff:ff
inet 10.88.0.1/16 brd 10.88.255.255 scope global cni0
valid_lft forever preferred_lft forever
inet6 2001:4860:4860::1/64 scope global
valid_lft forever preferred_lft forever
inet6 fe80::98e7:ebff:fe40:e866/64 scope link
valid_lft forever preferred_lft forever
...
但是使用 bridge 網(wǎng)絡的容器無法跨多個宿主機進行通信，跨主機通信需要借助其他的 cni 插件，比如上面我們安裝的 Flannel，或者 Calico 等等，由于我們這里有兩個 cni 配置，所以我們需要將 10-containerd-net.conflist 這個配置刪除，因為如果這個目錄中有多個 cni 配置文件，kubelet 將會使用按文件名的字典順序排列的第一個作為配置文件，所以前面默認選擇使用的是 containerd-net 這個插件。
? ~ mv /etc/cni/net.d/10-containerd-net.conflist /etc/cni/net.d/10-containerd-net.conflist.bak
? ~ ifconfig cni0 down && ip link delete cni0
? ~ systemctl daemon-reload
? ~ systemctl restart containerd kubelet
然后記得重建 coredns 和 dashboard 的 Pod，重建后 Pod 的 IP 地址就正常了：
? ~ kubectl get pods -n kubernetes-dashboard -o wide
NAME READY STATUS RESTARTS AGE IP NODE NOMINATED NODE READINESS GATES
dashboard-metrics-scraper-856586f554-tp8m5 1/1 Running 0 42s 10.244.1.6 node2 <none> <none>
kubernetes-dashboard-76597d7df5-9rmbx 1/1 Running 0 66s 10.244.1.5 node2 <none> <none>
? ~ kubectl get pods -n kube-system -o wide -l k8s-app=kube-dns
NAME READY STATUS RESTARTS AGE IP NODE NOMINATED NODE READINESS GATES
coredns-7568f67dbd-n7bfx 1/1 Running 0 5m40s 10.244.1.2 node2 <none> <none>
coredns-7568f67dbd-plrv8 1/1 Running 0 3m47s 10.244.1.4 node2 <none> <none>
查看 Dashboard 的 NodePort 端口：
? ~ kubectl get svc -n kubernetes-dashboard
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
dashboard-metrics-scraper ClusterIP 10.99.37.172 <none> 8000/TCP 25m
kubernetes-dashboard NodePort 10.103.102.27 <none> 443:31050/TCP 25m
然后可以通過上面的 31050 端口去訪問 Dashboard，要記住使用 https，Chrome 不生效可以使用Firefox 測試，如果沒有 Firefox 下面打不開頁面，可以點擊下頁面中的信任證書即可：
信任后就可以訪問到 Dashboard 的登錄頁面了：
然后創(chuàng)建一個具有全局所有權限的用戶來登錄 Dashboard：(admin.yaml)
kind: ClusterRoleBinding
apiVersion: rbac.authorization.k8s.io/v1
metadata:
name: admin
roleRef:
kind: ClusterRole
name: cluster-admin
apiGroup: rbac.authorization.k8s.io
subjects:
- kind: ServiceAccount
name: admin
namespace: kubernetes-dashboard
---
apiVersion: v1
kind: ServiceAccount
metadata:
name: admin
namespace: kubernetes-dashboard
直接創(chuàng)建：
? ~ kubectl apply -f admin.yaml
? ~ kubectl get secret -n kubernetes-dashboard|grep admin-token
admin-token-lwmmx kubernetes.io/service-account-token 3 1d
? ~ kubectl get secret admin-token-lwmmx -o jsonpath={.data.token} -n kubernetes-dashboard |base64 -d
# 會生成一串很長的base64后的字符串
然后用上面的 base64 解碼后的字符串作為 token 登錄 Dashboard 即可，新版本還新增了一個暗黑模式：
最終我們就完成了使用 kubeadm 搭建 v1.22.1 版本的 kubernetes 集群、coredns、ipvs、flannel、containerd。
? ~ kubectl get nodes -o wide
NAME STATUS ROLES AGE VERSION INTERNAL-IP EXTERNAL-IP OS-IMAGE KERNEL-VERSION CONTAINER-RUNTIME
master Ready control-plane,master 36m v1.22.1 192.168.31.30 <none> CentOS Linux 7 (Core) 3.10.0-1160.25.1.el7.x86_64 containerd://1.5.5
node2 Ready <none> 27m v1.22.1 192.168.31.215 <none> CentOS Linux 7 (Core) 3.10.0-1160.25.1.el7.x86_64 containerd://1.5.5
清理
如果你的集群安裝過程中遇到了其他問題，我們可以使用下面的命令來進行重置：
? ~ kubeadm reset
? ~ ifconfig cni0 down && ip link delete cni0
? ~ ifconfig flannel.1 down && ip link delete flannel.1
? ~ rm -rf /var/lib/cni/
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