基于Kubernetes的框架和应用系列之一：Kubernetes无服务方案kubeless

系统管理员 2022-10-01 12:57 173阅读 0赞

### 一、前言 ###

云计算架构最新的一次演进应该是面向serverless(无服务架构)方向，几大世界级公有云厂商都提供了具有竞争力的产品：

*  AWS Lambda
 *  Google Cloud Functions
 *  Microsoft Azure Functions
 *  阿里云Function Compute

无服务架构将进一步降低云计算的接入门槛，降低对云计算使用者在基础设施技术栈层面的要求，创造真正的云原生的开发、部署、运营生态。

CNCF对于无服务架构的定义如下：

> Serverless computing refers to the concept of building and running applications that do not require server management. It describes a finer-grained deployment model where applications, bundled as one or more functions, are uploaded to a platform and then executed, scaled, and billed in response to the exact demand needed at the moment.

如下正是改定义所描述的无服务架构的三大特点：

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2Nsb3VkdnRlY2g_size_16_color_FFFFFF_t_70][]

根据文章[《The Leading Open Source Serverless Solutions for Kubernetes》][The Leading Open Source Serverless Solutions for Kubernetes]的描述，当前比较热门的基于Kubernetes的serverless方案如下：

![uploading.4e448015.gif][]转存失败重新上传取消![uploading.4e448015.gif][]转存失败重新上传取消![serverless-on-kubernetes-2019-logos.png][]![uploading.4e448015.gif][]转存失败重新上传取消

其中Knative是Google押注的亲儿子。

下文在kubernetes安装kubeless来尝鲜基于容器云的无服务计算。

转载自https://blog.csdn.net/cloudvtech

### 二、kubeless的安装 ###

**2.1 kubeless基础**

kubeless现在是bitnami驱动的产品，主要包括如下功能：

>  *  Support for Python, Node.js, Ruby, PHP, Golang, .NET, Ballerina and custom runtimes
>  *  CLI compliant with AWS Lambda CLI
>  *  Event triggers using Kafka messaging system and HTTP events
>  *  Prometheus monitoring of functions calls and function latency by default
>  *  Serverless Framework plugin

其架构如下：

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2Nsb3VkdnRlY2g_size_16_color_FFFFFF_t_70 1][]

Kubeless使用CRD提供function compute服务，kubeless controller监听CRD来启动POD运行on-demond的无服务计算请求所需的runtime并且将用户的function代码注入到runtime。

**2.2 获取安装包**

> export RELEASE=$(curl -s [https://api.github.com/repos/kubeless/kubeless/releases/latest][https_api.github.com_repos_kubeless_kubeless_releases_latest] | grep tag\_name | cut -d '"' -f 4)
> 
> wget [https://github.com/kubeless/kubeless/releases/download/$RELEASE/kubeless-$RELEASE.yaml][https_github.com_kubeless_kubeless_releases_download_RELEASE_kubeless-_RELEASE.yaml]
> 
> curl -OL [https://github.com/kubeless/kubeless/releases/download/$RELEASE/kubeless\_$OS-amd64.zip][https_github.com_kubeless_kubeless_releases_download_RELEASE_kubeless_OS-amd64.zip] &&   unzip kubeless\_$OS-amd64.zip

**2.3 安装controller**

> kubectl create ns kubeless
> 
> kubectl apply -f kubeless-v1.0.0-alpha.8.yaml
> 
> \[root@k8s-master-01 config\]\# kubectl get pods -n kubeless
> 
> NAME                                                                      READY     STATUS    RESTARTS   AGE
> 
> kubeless-controller-manager-66868fb689-cmv9c   3/3             Running    0                   1h

**2.4 安装web UI**

> kubectl create -f [https://raw.githubusercontent.com/kubeless/kubeless-ui/master/k8s.yaml][https_raw.githubusercontent.com_kubeless_kubeless-ui_master_k8s.yaml]
> 
> \[root@k8s-master-01 config\]\# kubectl get pods -n kubeless
> 
> NAME                                           READY     STATUS    RESTARTS   AGE
> 
> kubeless-controller-manager-66868fb689-cmv9c   3/3       Running   0          1h
> 
> ui-6d868664c5-wc6cd                            2/2       Running   0          45m

转载自https://blog.csdn.net/cloudvtech

### 三、在kubeless运行无服务计算代码 ###

** 3.1 在本地编写代码pi.py**

import math
    def pi(event, context):
            print event
     	print '\nComputing Pi v.01\n'
     	
     	a = 1.0
     	b = 1.0/math.sqrt(2)
     	t = 1.0/4.0
     	p = 1.0
     		
     	for i in range(int(10)):
     		at = (a+b)/2
     		bt = math.sqrt(a*b)
     		tt = t - p*(a-at)**2
     		pt = 2*p
     		
     		a = at;b = bt;t = tt;p = pt
     		
     	my_pi = (a+b)**2/(4*t)
     	accuracy = 100*(math.pi-my_pi)/my_pi
     		
     	print "Pi is approximately: " + str(my_pi)
     	print "Accuracy with math.pi: " + str(accuracy)
     	return str(my_pi)

**3.2 部署代码**

> ./kubeless function deploy pi --runtime python2.7 --from-file  pi.py --handler pi.pi
> 
> kubectl get pod -o wide | grep ^pi
> 
> pi-75b9754485-vp47f                                1/1       Running                 0          11m       10.244.89.131    k8s-node-03   <none>

**3.3 运行Faas**

> curl -L --data '1000' --header "Content-Type:application/txt" 10.244.89.131:8080/
> 
> 3.14159265359

**3.4 通过web UI查看**

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2Nsb3VkdnRlY2g_size_16_color_FFFFFF_t_70 2][]

转载自https://blog.csdn.net/cloudvtech

[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2Nsb3VkdnRlY2g_size_16_color_FFFFFF_t_70]: /images/20220118/41cd500bbecf43b7925681291cef23e8.png
[The Leading Open Source Serverless Solutions for Kubernetes]: https://gravitational.com/blog/serverless-on-kubernetes
[uploading.4e448015.gif]: /images/20220118/eb37bc27eacb4f51aa5ab2a1cce5522f.png
[serverless-on-kubernetes-2019-logos.png]: https://imgconvert.csdnimg.cn/aHR0cHM6Ly9ncmF2aXRhdGlvbmFsLmNvbS9ibG9nL2ltYWdlcy8yMDE5L3NlcnZlcmxlc3Mtb24ta3ViZXJuZXRlcy0yMDE5LWxvZ29zLnBuZw?x-oss-process=image/format,png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2Nsb3VkdnRlY2g_size_16_color_FFFFFF_t_70 1]: /images/20220118/81d0855eda3c4972b79f80ef7b02b768.png
[https_api.github.com_repos_kubeless_kubeless_releases_latest]: https://api.github.com/repos/kubeless/kubeless/releases/latest
[https_github.com_kubeless_kubeless_releases_download_RELEASE_kubeless-_RELEASE.yaml]: https://github.com/kubeless/kubeless/releases/download/$RELEASE/kubeless-$RELEASE.yaml
[https_github.com_kubeless_kubeless_releases_download_RELEASE_kubeless_OS-amd64.zip]: https://github.com/kubeless/kubeless/releases/download/$RELEASE/kubeless_$OS-amd64.zip
[https_raw.githubusercontent.com_kubeless_kubeless-ui_master_k8s.yaml]: https://raw.githubusercontent.com/kubeless/kubeless-ui/master/k8s.yaml
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2Nsb3VkdnRlY2g_size_16_color_FFFFFF_t_70 2]: /images/20220118/7e19f184871a4985b01df71050e865df.png