您的位置:首页 > 其它

在K3s上使用Kong网关插件,开启K3s的无限可能!

spring_poll 2020-08-14 14:24 176 查看 https://www.cnblogs.com/k3s201

我的工作中很重要的一部分是参加各种各样的技术会议。最近参加的是去年11月的北美KubeCon,在会议的最后一天,所有人都焦头烂额,我也一直机械地向不同的人重复我的自我介绍。后来,我已经十分烦躁,决定逃离人群好好听一场演讲。无意间,我碰上了Darren Shepherd的演讲,他是Rancher的CTO,他的演讲主题是“K3s的背后:构建一个生产级轻量Kubernetes发行版”。我被演讲深深吸引,此后我开始慢慢深入了解K3s。

K3s是由业界应用最为广泛的Kubernetes管理平台创建者Rancher Labs打造的面向物联网和边缘计算的轻量级Kubernetes发行版,它是100%开源的。它拥有小型的二进制文件并且针对ARM进行了优化使得它非常适合我的IoT家庭项目。接着,我开始思考如何让K3s上运行的Kong网关暴露K3s server内的服务。

出乎我意料的是,K3s在默认情况下是带有一个Ingress controller的。虽然默认的proxy/负载均衡器可以工作,但我需要一些插件的功能它并不支持,除非我使用Kong网关。所以,让我们通过一个快速指南来了解如何在Ubuntu中启动K3s,配置它以支持Kubernetes的Kong,并部署一些服务/插件。

配置K3s以部署Kong Ingress Controller

首先,从https://get.k3s.io 使用安装脚本在systemd和基于openrc的系统上将K3s作为一个服务进行安装。但是我们需要添加一些额外的环境变量来配置安装。首先

--no-deploy
,这一命令可以关掉现有的ingress controller,因为我们想要部署Kong以利用一些插件。其次
--write-kubeconfig-mode
,它允许写入kubeconfig文件。这对于允许将K3s集群导入Rancher很有用。

$ curl -sfL https://get.k3s.io | sh -s - --no-deploy traefik --write-kubeconfig-mode 644
[INFO]  Finding release for channel stable
[INFO]  Using v1.18.4+k3s1 as release
[INFO]  Downloading hash https://github.com/rancher/k3s/releases/download/v1.18.4+k3s1/sha256sum-amd64.txt
[INFO]  Downloading binary https://github.com/rancher/k3s/releases/download/v1.18.4+k3s1/k3s
[INFO]  Verifying binary download
[INFO]  Installing k3s to /usr/local/bin/k3s
[INFO]  Skipping /usr/local/bin/kubectl symlink to k3s, already exists
[INFO]  Creating /usr/local/bin/crictl symlink to k3s
[INFO]  Skipping /usr/local/bin/ctr symlink to k3s, command exists in PATH at /usr/bin/ctr
[INFO]  Creating killall script /usr/local/bin/k3s-killall.sh
[INFO]  Creating uninstall script /usr/local/bin/k3s-uninstall.sh
[INFO]  env: Creating environment file /etc/systemd/system/k3s.service.env
[INFO]  systemd: Creating service file /etc/systemd/system/k3s.service
[INFO]  systemd: Enabling k3s unit
Created symlink from /etc/systemd/system/multi-user.target.wants/k3s.service to /etc/systemd/system/k3s.service.
[INFO]  systemd: Starting k3s

要检查节点和 pod是否都已启动并运行,使用

k3s kubectl...
运行与 kubectl 相同的命令。

$ k3s kubectl get nodes
NAME            STATUS   ROLES    AGE     VERSION
ubuntu-xenial   Ready    master   4m38s   v1.18.4+k3s1

$ k3s kubectl get pods -A
NAMESPACE     NAME                                     READY   STATUS    RESTARTS   AGE
kube-system   metrics-server-7566d596c8-vqqz7          1/1     Running   0          4m30s
kube-system   local-path-provisioner-6d59f47c7-tcs2l   1/1     Running   0          4m30s
kube-system   coredns-8655855d6-rjzrq                  1/1     Running   0          4m30s

在K3s 上安装Kong for Kubernetes

K3s启动并运行后,你可以按照正常的步骤安装Kong for Kubernetes,比如如下所示的manifest:

$ k3s kubectl create -f https://bit.ly/k4k8s
namespace/kong created
customresourcedefinition.apiextensions.k8s.io/kongclusterplugins.configuration.konghq.com created
customresourcedefinition.apiextensions.k8s.io/kongconsumers.configuration.konghq.com created
customresourcedefinition.apiextensions.k8s.io/kongcredentials.configuration.konghq.com created
customresourcedefinition.apiextensions.k8s.io/kongingresses.configuration.konghq.com created
customresourcedefinition.apiextensions.k8s.io/kongplugins.configuration.konghq.com created
customresourcedefinition.apiextensions.k8s.io/tcpingresses.configuration.konghq.com created
serviceaccount/kong-serviceaccount created
clusterrole.rbac.authorization.k8s.io/kong-ingress-clusterrole created
clusterrolebinding.rbac.authorization.k8s.io/kong-ingress-clusterrole-nisa-binding created
service/kong-proxy created
service/kong-validation-webhook created
deployment.apps/ingress-kong created

当Kong proxy和ingress controller安装到K3s server上后,你检查服务应该能看到kong-proxy LoadBalancer的外部IP。

$ k3s kubectl get svc --namespace kong
NAME                      TYPE           CLUSTER-IP      EXTERNAL-IP   PORT(S)                      AGE
kong-validation-webhook   ClusterIP      10.43.157.178   <none>        443/TCP                      61s
kong-proxy                LoadBalancer   10.43.63.117    10.0.2.15     80:32427/TCP,443:30563/TCP

运行以下命令,将IP导出为一个变量:

$ PROXY_IP=$(k3s kubectl get services --namespace kong kong-proxy -o jsonpath={.status.loadBalancer.ingress[0].ip})

最后,在我们抛出proxy后的任何服务之前,检查proxy是否有响应:

$ curl -i $PROXY_IP
HTTP/1.1 404 Not Found
Date: Mon, 29 Jun 2020 20:31:16 GMT
Content-Type: application/json; charset=utf-8
Connection: keep-alive
Content-Length: 48
X-Kong-Response-Latency: 0
Server: kong/2.0.4

{"message":"no Route matched with those values"}

它应该返回404,因为我们还没有在K3s中添加任何服务。但正如你在请求头(header)中看到的那样,它正在被最新版本的Kong代理,并显示了一些额外的信息,比如响应延迟。

设置你的K3s应用程序以测试Kong Ingress Controller

现在,让我们在K3s中设置一个回显服务器(echo server)应用程序以演示如何使用Kong Ingress Cont 56c roller:

$ k3s kubectl apply -f https://bit.ly/echo-service
service/echo created
deployment.apps/echo created

接下来,创建一个ingress规则以代理之前创建的echo-server:

$ echo "
apiVersion: extensions/v1beta1
kind: Ingress
metadata:
name: demo
spec:
rules:
- http:
paths:
- path: /foo
backend:
serviceName: echo
servicePort: 80
" | k3s kubectl apply -f -
ingress.extensions/demo created

测试Ingress 规则:

$ curl -i $PROXY_IP/foo
HTTP/1.1 200 OK
Content-Type: text/plain; charset=UTF-8
Transfer-Encoding: chunked
Connection: keep-alive
Date: Mon, 29 Jun 2020 20:31:07 GMT
Server: echoserver
X-Kong-Upstream-Latency: 0
X-Kong-Proxy-Latency: 1
Via: kong/2.0.4

Hostname: echo-78b867555-jkhhl

Pod Information:
node name:  ubuntu-xenial
pod name:  echo-78b867555-jkhhl
pod namespace:  default
pod IP:  10.42.0.7
<-- clipped -->

如果一切都部署正确,你应该看到以上响应。这验证了Kong可以正确路由流量到运行在Kubernetes中的应用程序。

使用Kong Ingress安装一个速率限制插件

Kong Ingress允许插件在服务级别上执行,也就是说,每当一个请求被发送到一个特 56c 定的K3s服务时,无论它来自哪个Ingress路径,Kong都会执行一个插件。你也可以在Ingress路径上附加插件。但在下面的步骤中,我将使用限制速率插件来限制IP在任何一个特定的服务上发出过多的请求。

创建一个KongPlugin资源:

$ echo "
apiVersion: configuration.konghq.com/v1
kind: KongPlugin
metadata:
name: rl-by-ip
config:
minute: 5
limit_by: ip
policy: local
plugin: rate-limiting
" | k3s kubectl apply -f -
kongplugin.configuration.konghq.com/rl-by-ip created

接下来,在需要限制速率的K3s服务上应用konghq.com/plugins注释。

$ k3s kubectl patch svc echo -p '{"metadata":{"annotations":{"konghq.com/plugins": "rl-by-ip\n"}}}'
service/echo patched

现在,任何发送到这项服务的请求都将受到Kong执行的速率限制的保护:

$ curl -I $PROXY_IP/foo
HTTP/1.1 200 OK
Content-Type: text/plain; charset=UTF-8
Connection: keep-alive
Date: Mon, 29 Jun 2020 20:35:40 GMT
Server: echoserver
X-RateLimit-Remaining-Minute: 4
X-RateLimit-Limit-Minute: 5
RateLimit-Remaining: 4
RateLimit-Limit: 5
RateLimit-Reset: 20
X-Kong-Upstream-Latency: 5
X-Kong-Proxy-Latency: 2
Via: kong/2.0.4

从这一个小小的实践可以看出来,K3s其 56c 实拥有无限可能,因为你可以将任何插件添加到任何Ingress路径或服务上。你可以从Kong Hub上找到所有插件。在家庭自动化项目中,这十分方便,你还可以利用树莓派来运行K3s,并通过各类插件赋予K3s更多可能。

标签: 
相关文章推荐