使用Kubernetes、K3s和Traefik2进行本地开发使用Kubernetes、K3s和Traefik2进行

作者简介
Vyacheslav，拥有运维和项目管理经验的软件工程师

文章图片
在这里插入图片描述这篇文章将承接我此前搭建的本地Docker开发环境，具体步骤已经放在在以下网址：
https://github.com/Voronenko/traefik2-compose-template
除了经典的docker化的项目之外，我还有其他的Kubernetes项目。尽管Kubernetes已经成为容器编排的事实标准，但是不得不承认Kubernetes是一个既消耗资源又消耗金钱的平台。由于我并不经常需要外部集群，因此我使用轻量级K3s发行版来进行Kubernetes本地开发。
K3s是为IoT和边缘计算而构建的经过认证的Kubernetes发行版之一，还能够按产品规模部署到VM。
我使用K3s的方式是这样的：在我的工作笔记本上本地安装K3s，尽管有时我需要在本地部署较重的测试工作负载，为此，我准备了两个神器——两个运行ESXi的外部Intel NUCs。
默认情况下，K3s安装Traefik 1.x作为ingress，如果你对此十分满意，那么无需往下继续阅读了。
在我的场景中，我同时会牵涉到好几个项目，特别是经典的docker和docker swarm，因此我经常遇到在独立模式下部署Traefik的情况。
因此，本文其余部分将深入介绍如何将外部traefik2配置为K3s集群的ingress。
安装Kubernetes K3s系列集群你可以按照常规方式使用命令curl -sfL https://get.k3s.io | sh -安装K3s，或者你可以使用轻量实用程序k3sup安装（https://github.com/alexellis/k3sup）。具体步骤在之前的文章介绍过。
与我们的设置不同的是，我们使用命令--no-deploy traefik专门安装了不带traefik组件的K3s。

export CLUSTER_MASTER=192.168.3.100 export CLUSTER_DEPLOY_USER=slavko k3sup install --ip $CLUSTER_MASTER --user $CLUSTER_DEPLOY_USER --k3s-extra-args '--no-deploy traefik'

执行后，你将获得使用kubectl所需的连接详细信息。安装K3s后，你可以快速检查是否可以看到节点。

# Test your cluster with - export path to k3s cluster kubeconfig: export KUBECONFIG=/home/slavko/kubeconfig kubectl get node -o wide

注：这里没有固定的安装模式，你甚至可以使用docker-compose自行启动它。

server: image: rancher/k3s:v0.8.0 command: server --disable-agent --no-deploy traefik environment: - K3S_CLUSTER_SECRET=somethingtotallyrandom - K3S_KUBECONFIG_OUTPUT=/output/kubeconfig.yaml - K3S_KUBECONFIG_MODE=666 volumes: # k3s will generate a kubeconfig.yaml in this directory. This volume is mounted # on your host, so you can then 'export KUBECONFIG=/somewhere/on/your/host/out/kubeconfig.yaml', # in order for your kubectl commands to work. - /somewhere/on/your/host/out:/output # This directory is where you put all the (yaml) configuration files of # the Kubernetes resources. - /somewhere/on/your/host/in:/var/lib/rancher/k3s/server/manifests ports: - 6443:6443node: image: rancher/k3s:v0.8.0 privileged: true links: - server environment: - K3S_URL=https://server:6443 - K3S_CLUSTER_SECRET=somethingtotallyrandom volumes: # this is where you would place a alternative traefik image (saved as a .tar file with # 'docker save'), if you want to use it, instead of the traefik:v2.0 image. - /sowewhere/on/your/host/custom-image:/var/lib/rancher/k3s/agent/images

配置Traefik 2，与Kubernetes一起使用在文章开头提到的链接中，我已经在我的系统中安装了Traefik 2，并根据该链接内容，服务于一些需求。现在是时候配置Traefik 2 Kubernetes后端了。
Traefik 2使用CRD（自定义资源定义）来完成这一点。定义的最新示例可以在以下链接中找到，但这些示例仅适用于Traefik 2也作为Kubernetes工作负载的一部分执行的情况：
https://docs.traefik.io/reference/dynamic-configuration/kubernetes-crd/
对于外部Traefik 2，我们仅需要以下描述的定义子集。
我们引入一系列自定义资源定义，以允许我们来描述我们的Kubernetes服务将会如何暴露到外部，traefik-crd.yaml：

apiVersion: apiextensions.k8s.io/v1beta1 kind: CustomResourceDefinition metadata: name: ingressroutes.traefik.containo.usspec: group: traefik.containo.us version: v1alpha1 names: kind: IngressRoute plural: ingressroutes singular: ingressroute scope: Namespaced--- apiVersion: apiextensions.k8s.io/v1beta1 kind: CustomResourceDefinition metadata: name: ingressroutetcps.traefik.containo.usspec: group: traefik.containo.us version: v1alpha1 names: kind: IngressRouteTCP plural: ingressroutetcps singular: ingressroutetcp scope: Namespaced--- apiVersion: apiextensions.k8s.io/v1beta1 kind: CustomResourceDefinition metadata: name: middlewares.traefik.containo.usspec: group: traefik.containo.us version: v1alpha1 names: kind: Middleware plural: middlewares singular: middleware scope: Namespaced--- apiVersion: apiextensions.k8s.io/v1beta1 kind: CustomResourceDefinition metadata: name: tlsoptions.traefik.containo.usspec: group: traefik.containo.us version: v1alpha1 names: kind: TLSOption plural: tlsoptions singular: tlsoption scope: Namespaced--- apiVersion: apiextensions.k8s.io/v1beta1 kind: CustomResourceDefinition metadata: name: traefikservices.traefik.containo.usspec: group: traefik.containo.us version: v1alpha1 names: kind: TraefikService plural: traefikservices singular: traefikservice scope: Namespaced

同时，我们需要集群角色traefik-ingress-controller，以提供对服务、端点和secret的只读访问权限以及自定义的traefik.containo.us组，traefik-clusterrole.yaml：

kind: ClusterRole apiVersion: rbac.authorization.k8s.io/v1beta1 metadata: name: traefik-ingress-controllerrules: - apiGroups: - "" resources: - services - endpoints - secrets verbs: - get - list - watch - apiGroups: - extensions resources: - ingresses verbs: - get - list - watch - apiGroups: - extensions resources: - ingresses/status verbs: - update - apiGroups: - traefik.containo.us resources: - middlewares verbs: - get - list - watch - apiGroups: - traefik.containo.us resources: - ingressroutes verbs: - get - list - watch - apiGroups: - traefik.containo.us resources: - ingressroutetcps verbs: - get - list - watch - apiGroups: - traefik.containo.us resources: - tlsoptions verbs: - get - list - watch - apiGroups: - traefik.containo.us resources: - traefikservices verbs: - get - list - watch

最后，我们需要系统服务账号traefik-ingress-controller与之前创建的集群角色traefik-ingress-controller相关联。

--- kind: ServiceAccount apiVersion: v1 metadata: namespace: kube-system name: traefik-ingress-controller--- kind: ClusterRoleBinding apiVersion: rbac.authorization.k8s.io/v1beta1 metadata: name: traefik-ingress-controllerroleRef: apiGroup: rbac.authorization.k8s.io kind: ClusterRole name: traefik-ingress-controller subjects: - kind: ServiceAccount name: traefik-ingress-controller namespace: kube-system

我们应用以上资源之后：

apply: kubectl apply -f traefik-crd.yaml kubectl apply -f traefik-clusterrole.yaml kubectl apply -f traefik-service-account.yaml

我们已经准备好开始调整Traefik 2
将Traefik 2指向K3s集群根据Traefik文档的建议，当Traefik部署到Kubernetes中时，它将读取环境变量KUBERNETES_SERVICE_HOST和KUBERNETES_SERVICE_PORT或KUBECONFIG来构造端点。
在/var/run/secrets/kubernetes.io/serviceaccount/token中查找访问token，而SSL CA证书将在/var/run/secrets/kubernetes.io/serviceaccount/ca.crt.中查找。当部署到Kubernetes内部时，两者都会自动提供挂载。
当无法找到环境变量时，Traefik会尝试使用external-cluster客户端连接到Kubernetes API server。这一情况下，需要设置endpoint。具体来说，可以将其设置为kubectl代理使用的URL，以使用相关的kubeconfig授予的身份验证和授权连接到Kubernetes集群。
Traefik 2可以使用任何受支持的配置类型来静态配置-toml、yaml或命令行交换。

[providers.kubernetesCRD] endpoint = "http://localhost:8080" token = "mytoken"

providers: kubernetesCRD: endpoint = "http://localhost:8080" token = "mytoken" # ...

--providers.kubernetescrd.endpoint=http://localhost:8080 --providers.kubernetescrd.token=mytoken

第一次运行时，如果你在外部有Traefik，很有可能没有traefik-ingress-controller访问token来指定mytoken。那么，你需要执行以下命令：

# Check all possible clusters, as your .KUBECONFIG may have multiple contexts: kubectl config view -o jsonpath='{"Cluster name\tServer\n"}{range .clusters[*]}{.name}{"\t"}{.cluster.server}{"\n"}{end}'# Output kind of # Alias tip: k config view -o jsonpath='{"Cluster name\tServer\n"}{range .clusters[*]}{.name}{"\t"}{.cluster.server}{"\n"}{end}' # Cluster nameServer # defaulthttps://127.0.0.1:6443# You are interested in: "default", if you did not name it differently# Select name of cluster you want to interact with from above output: export CLUSTER_NAME="default"# Point to the API server referring the cluster name export APISERVER=$(kubectl config view -o jsonpath="{.clusters[?(@.name==\"$CLUSTER_NAME\")].cluster.server}") # usually https://127.0.0.1:6443# Gets the token value export TOKEN=$(kubectl get secrets -o jsonpath="{.items[?(@.metadata.annotations['kubernetes\.io/service-account\.name']=='traefik-ingress-controller')].data.token}" --namespace kube-system|base64 --decode)# Explore the API with TOKEN

如果成功了，你应该收到以下响应：

{ "kind": "APIVersions", "versions": [ "v1" ], "serverAddressByClientCIDRs": [ { "clientCIDR": "0.0.0.0/0", "serverAddress": "192.168.3.100:6443" } ]

以及一些事实，如token：

eyJhbGciOiJSUzI1NiIsImtpZCI6IjBUeTQyNm5nakVWbW5PaTRRbDhucGlPeWhlTHhxTXZjUDJsRmNacURjVnMifQ.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.Mk8EBS4soO8uX-uSnV3o4qZKR6Iw6bgeSmPhHbJ2fjuqFgLnLh4ggxa-N9AqmCsEWiYjSi5oKAu986UEC-_kGQh3xaCYsUwlkM8147fsnwCbomSeGIct14JztVL9F8JwoDH6T0BOEjn-J9uY8-fUKYL_Y7uTrilhFapuILPsj_bFfgIeOOapRD0XshKBQV9Qzg8URxyQyfzl68ilm1Q13h3jLj8CFE2RlgEUFk8TqYH4T4fhfpvV-gNdmKJGODsJDI1hOuWUtBaH_ce9w6woC9K88O3FLKVi7fbvlDFrFoJ2iVZbrRALPjoFN92VA7a6R3pXUbKebTI3aUJiXyfXRQ

根据上次响应的API server的外部地址：https://192.168.3.100:6443
【使用Kubernetes、K3s和Traefik2进行本地开发】同样，提供的token中没有任何特殊之处：这是JWT的token，你可以使用https://jwt.io/#debugger-io，检查它的内容。

{ "alg": "RS256", "kid": "0Ty426ngjEVmnOi4Ql8npiOyheLxqMvcP2lFcZqDcVs" } { "iss": "kubernetes/serviceaccount", "kubernetes.io/serviceaccount/namespace": "kube-system", "kubernetes.io/serviceaccount/secret.name": "traefik-ingress-controller-token-vzc7v", "kubernetes.io/serviceaccount/service-account.name": "traefik-ingress-controller", "kubernetes.io/serviceaccount/service-account.uid": "d9577e91-7e64-4c06-bd82-cde949c81251", "sub": "system:serviceaccount:kube-system:traefik-ingress-controller" }

正确的配置非常重要，因此请确保对APISERVER的两个调用均返回合理的响应。

export APISERVER=YOURAPISERVER export TOKEN=YOURTOKENcurl -X GET $APISERVER/api --header "Authorization: Bearer $TOKEN" --insecurecurl -X GET $APISERVER/api/v1/endpoints --header "Authorization: Bearer $TOKEN" --insecure

创建其他访问token
控制器循环确保每个服务账户都有一个带有API token的secret，可以像我们之前那样被发现。
此外，你还可以为一个服务账户创建额外的token，创建一个ServiceAccountToken类型的secret，并为服务账户添加一个注释，控制器会用生成的token来更新它。

--- apiVersion: v1 kind: Secret namespace: kube-system metadata: name: traefik-manual-token annotations: kubernetes.io/service-account.name: traefik-ingress-controller type: kubernetes.io/service-account-token# Any tokens for non-existent service accounts will be cleaned up by the token controller.# kubectl describe secrets/traefik-manual-token

用以下命令创建：

kubectl create -f ./traefik-service-account-secret.yaml kubectl describe secret traefik-manual-token

删除/无效：

kubectl delete secret traefik-manual-token

对外部traefik 2的更改构成定义
我们需要在文章开头给出的链接中获得的traefik2配置进行哪些更改？
https://github.com/Voronenko/traefik2-compose-template
a）我们在新文件夹kubernetes_data中存储ca.crt文件，该文件用于验证对Kubernetes授权的调用。这是可以在kubeconfig文件的clusters-> cluster-> certificate-authority-data下找到的证书。
该volume将映射在/var/run/secrets/kubernetes.io/serviceaccount下以获取官方Traefik 2镜像

volumes: ... - ./kubernetes_data:/var/run/secrets/kubernetes.io/serviceaccount

b）调整Traefik 2 kubernetescrd后端以提供3个参数：endpoint、证书路径和token。请注意，作为外部Traefik作为docker容器，你需要指定正确的endpoint地址，并确保以安全的方式进行。

- "--providers.kubernetescrd=true" - "--providers.kubernetescrd.endpoint=https://192.168.3.100:6443" - "--providers.kubernetescrd.certauthfilepath=/var/run/secrets/kubernetes.io/serviceaccount/ca.crt" - "--providers.kubernetescrd.token=YOURTOKENWITHOUTANYQUOTES

如果你都执行正确了，那么你现在应该在Traefik UI上看到了一些希望。如果你没有看到traefik，或者在运行Traefik时有问题，你可以查看之后的故障排除部分。
现在是时候通过Trafik 2暴露一些Kubernetes服务了，以确保Traefik 2能够作为ingress工作。让我们来看经典案例whoami服务，whoami-service.yaml

apiVersion: v1 kind: Service metadata: name: whoamispec: ports: - protocol: TCP name: web port: 80 selector: app: whoami--- kind: Deployment apiVersion: apps/v1 metadata: namespace: default name: whoami labels: app: whoamispec: replicas: 2 selector: matchLabels: app: whoami template: metadata: labels: app: whoami spec: containers: - name: whoami image: containous/whoami ports: - name: web containerPort: 80

并且以http或https的方式暴露它，whoami.k.voronenko.net全限定域名下的whoami-ingress-route.yaml。

apiVersion: traefik.containo.us/v1alpha1 kind: IngressRoute metadata: name: ingressroute-notls namespace: default spec: entryPoints: - web routes: - match: Host(`whoami.k.voronenko.net`) kind: Rule services: - name: whoami port: 80--- apiVersion: traefik.containo.us/v1alpha1 kind: IngressRoute metadata: name: ingressroute-tls namespace: default spec: entryPoints: - websecure routes: - match: Host(`whoami.k.voronenko.net`) kind: Rule services: - name: whoami port: 80 tls: certResolver: default

然后应用它：

kubectl apply -f whoami-service.yaml kubectl apply -f whoami-ingress-route.yaml

应用后，你应该会在Traefik dashboard上看到一些希望，即KubernetesCRD后端。
正如你所看到的，Traefik已经检测到我们的K3s Kubernetes集群上运行的新工作负载，而且它与我们在同一个盒子上的经典Docker工作负载（如portainer）很好地共存。
让我们检查一下Traefik 2是否将Traefik路由到了我们的Kubernetes工作负载：如你所见，你可以在http和https endpoint上成功地接触到whoami工作负载，浏览器接受你的证书为可信任的“绿标签”。
我们的目标达到了！我们在本地笔记本上配置了Traefik 2。Traefik 2将你的docker或Kubernetes工作流暴露在http或https endpoint上。带可选的 letsencrypt 的 Traefik 2 将负责 https。
故障排查
正如你所知，在配置过程可能存在多个问题，你可以考虑使用一些分析工具，如：
https://github.com/Voronenko/dotfiles/blob/master/Makefile#L185
我特别建议：
a） VMWare octant：这是一个基于Web的功能强大的Kubernetes dashboard，你可以在上面使用你的kubeconfig
b） Rakess：这是一个独立工具也是一个kubectl插件，用于显示Kubernetes服务器资源的访问矩阵（https://github.com/corneliusweig/rakkess）
检查系统账户的凭据

rakkess --sa kube-system:traefik-ingress-controller

c） kubectl
检查哪些角色与服务账户相关联

kubectl get clusterrolebindings -o json | jq -r ' .items[] | select( .subjects // [] | .[] | [.kind,.namespace,.name] == ["ServiceAccount","kube-system","traefik-ingress-controller"] ) | .metadata.name'

d） Traefik 文档：例如kubernetescrd后端提供了更多配置开关的方式。

--providers.kubernetescrd(Default: "false") Enable Kubernetes backend with default settings. --providers.kubernetescrd.certauthfilepath(Default: "") Kubernetes certificate authority file path (not needed for in-cluster client). --providers.kubernetescrd.disablepasshostheaders(Default: "false") Kubernetes disable PassHost Headers. --providers.kubernetescrd.endpoint(Default: "") Kubernetes server endpoint (required for external cluster client). --providers.kubernetescrd.ingressclass(Default: "") Value of kubernetes.io/ingress.class annotation to watch for. --providers.kubernetescrd.labelselector(Default: "") Kubernetes label selector to use. --providers.kubernetescrd.namespaces(Default: "") Kubernetes namespaces. --providers.kubernetescrd.throttleduration(Default: "0") Ingress refresh throttle duration --providers.kubernetescrd.token(Default: "") Kubernetes bearer token (not needed for in-cluster client). --providers.kubernetesingress(Default: "false") Enable Kubernetes backend with default settings. --providers.kubernetesingress.certauthfilepath(Default: "") Kubernetes certificate authority file path (not needed for in-cluster client). --providers.kubernetesingress.disablepasshostheaders(Default: "false") Kubernetes disable PassHost Headers. --providers.kubernetesingress.endpoint(Default: "") Kubernetes server endpoint (required for external cluster client). --providers.kubernetesingress.ingressclass(Default: "") Value of kubernetes.io/ingress.class annotation to watch for. --providers.kubernetesingress.ingressendpoint.hostname(Default: "") Hostname used for Kubernetes Ingress endpoints. --providers.kubernetesingress.ingressendpoint.ip(Default: "") IP used for Kubernetes Ingress endpoints. --providers.kubernetesingress.ingressendpoint.publishedservice(Default: "") Published Kubernetes Service to copy status from. --providers.kubernetesingress.labelselector(Default: "") Kubernetes Ingress label selector to use. --providers.kubernetesingress.namespaces(Default: "") Kubernetes namespaces. --providers.kubernetesingress.throttleduration(Default: "0") Ingress refresh throttle duration --providers.kubernetesingress.token(Default: "") Kubernetes bearer token (not needed for in-cluster client).

e）确保Traefik有足够的权限可以访问apiserver endpoint
如果你希望Traefik为你查询信息：通过在配置中放置一些错误的apiserver地址，可以查看访问的endpoint和查询顺序。有了这些知识和你的Traefik Kubernetes token，你就可以使用Traefik凭证检查这些endpoint是否可以访问。

traefik_1| E0421 12:30:12.6248771 reflector.go:125] pkg/mod/k8s.io/client-go@v0.0.0-20190718183610-8e956561bbf5/tools/cache/reflector.go:98: Failed to list *v1.Endpoints: Get https://192.168.3.101:6443/api/v1/endpoints?limit=500&resourceVersion=0: traefik_1| E0421 12:30:12.6253411 reflector.go:125] pkg/mod/k8s.io/client-go@v0.0.0-20190718183610-8e956561bbf5/tools/cache/reflector.go:98: Failed to list *v1.Service: Get https://192.168.3.101:6443/api/v1/services?limit=500&resourceVersion=0: traefik_1| E0421 12:30:12.6253951 reflector.go:125] pkg/mod/k8s.io/client-go@v0.0.0-20190718183610-8e956561bbf5/tools/cache/reflector.go:98: Failed to list *v1beta1.Ingress: Get https://192.168.3.101:6443/apis/extensions/v1beta1/ingresses?limit=500&resourceVersion=0: traefik_1| E0421 12:30:12.6254491 reflector.go:125] pkg/mod/k8s.io/client-go@v0.0.0-20190718183610-8e956561bbf5/tools/cache/reflector.go:98: Failed to list *v1alpha1.Middleware: Get https://192.168.3.101:6443/apis/traefik.containo.us/v1alpha1/middlewares?limit=500&resourceVersion=0: traefik_1| E0421 12:30:12.6254921 reflector.go:125] pkg/mod/k8s.io/client-go@v0.0.0-20190718183610-8e956561bbf5/tools/cache/reflector.go:98: Failed to list *v1alpha1.IngressRoute: Get https://192.168.3.101:6443/apis/traefik.containo.us/v1alpha1/ingressroutes?limit=500&resourceVersion=0: traefik_1| E0421 12:30:12.6255311 reflector.go:125] pkg/mod/k8s.io/client-go@v0.0.0-20190718183610-8e956561bbf5/tools/cache/reflector.go:98: Failed to list *v1alpha1.TraefikService: Get https://192.168.3.101:6443/apis/traefik.containo.us/v1alpha1/traefikservices?limit=500&resourceVersion=0: traefik_1| E0421 12:30:12.6255721 reflector.go:125] pkg/mod/k8s.io/client-go@v0.0.0-20190718183610-8e956561bbf5/tools/cache/reflector.go:98: Failed to list *v1alpha1.TLSOption: Get https://192.168.3.101:6443/apis/traefik.containo.us/v1alpha1/tlsoptions?limit=500&resourceVersion=0: traefik_1| E0421 12:30:12.6256101 reflector.go:125] pkg/mod/k8s.io/client-go@v0.0.0-20190718183610-8e956561bbf5/tools/cache/reflector.go:98: Failed to list *v1alpha1.IngressRouteTCP: Get https://192.168.3.101:6443/apis/traefik.containo.us/v1alpha1/ingressroutetcps?limit=500&resourceVersion=0:

f）记录K3s本身
安装脚本将自动检测你的操作系统是使用systemd还是openrc并启动服务。使用openrc运行时，将在/var/log/k3s.log中创建日志。使用systemd运行时，将在/var/log/syslog中创建日志，并使用journalctl -u k3s查看。
在那里，你可能会得到一些提示，例如：

кв? 21 15:42:44 u18d k3s[612]: E0421 15:42:44.936960612 authentication.go:104] Unable to authenticate the request due to an error: invalid bearer token

这将为你提供有关K8s Traefik起初使用时出现问题的线索，Enjoy your journey！
相关代码你可以在以下链接中找到：
https://github.com/Voronenko/k3s-mini