Deploying a Service Fabric cluster to run Windows containers

From container perspective, Service Fabric is a container orchestrator which supports both Windows and Linux containers. In legacy application lift and shift scenarios, we usually containerize the legacy application with minimal code change. And Service Fabric is a good platform to run these containers.

To deploy a Service Fabric cluster on Azure which is suitable for running containers, we can use ARM template. I created a template with the following special settings:

1 – An additional data disk is attached to the VMs in the cluster to host the downloaded container images. We need this disk is because by default all container images would be downloaded to C drive of the VMs. The C drive may run out of space if there are several large images downloaded.

[code lang=”HTML”] "dataDisks": [ { "lun": 0, "createOption": "Empty", "caching": "None", "managedDisk": { "storageAccountType": "Standard_LRS" }, "diskSizeGB": 100 } ] [/code]

2 – A custom script extension is used to run a custom script to format the data disk and change the configuration of dockerd service.

[code lang=”HTML”] { "properties": { "publisher": "Microsoft.Compute", "type": "CustomScriptExtension", "typeHandlerVersion": "1.9", "autoUpgradeMinorVersion": true, "settings": { "fileUris": [ "https://gist.githubusercontent.com/chunliu/8b3c495f7ff0289c19d7d359d9e14f0d/raw/2fdcd207f795756dd94ad7aef4cdb3a97e03d9f8/config-docker.ps1" ], "commandToExecute": "powershell -ExecutionPolicy Unrestricted -File config-docker.ps1" } }, "name": "VMCustomScriptVmExt_vmNodeType0Name" } [/code]

The customer script is as follows:





Create authorization header for Cosmos DB with Go

I started a side project to create a client package for Cosmos DB SQL API with Go so I can try Go in a real project. My plan is to implement something similar to .NET Core SDK with Go. As this is a project for learning and practice, I will do it little by little, and there is no timeline regarding when it can be done.

I build the project based on SQL API via REST. To access resources in Cosmos DB with SQL API via REST, an authorization header is required for the requests. The value of the authorization header has the following format, as it is mentioned in this document.


In the above string, the values of type and version are simple: type is either master or resource, while the current version is 1.0. The value of signature is a bit complex. It is a hash of several other values by using the access key of Cosmos DB as the hash key. The document has all details in it and even better it has a sample written in C#.

So following the document and the sample, I implemented a Go equivalence as follows. It is a good example to try the base64 encoding and HMAC hash in Go.

The date format in the signature is required to be in HTTP-date format defined by RFC7231. However, the time package in the Go standard library doesn’t seem to support this format out of the box, but it provides a very easy way to create custom format. The utcNow() function in the above code is what I implemented to format the time to RFC7231 format.



如果在网络上搜索这个问题,会看到各种各样的解决方法。有每个月多花点钱,开通短信漫游服务的;有使用联通的沃信,或移动的Jego服务的;还有用Raspberry Pi来硬件hack,将短信转发到邮箱的。可以说海外的华人在这个问题上充分发挥了聪明才智。


可是这个月初,Jego服务突然中断了。账号无法登录,给他们的客服发邮件,也如石沉大海,没有回应。上网查了查,有人说Jego服务没人管了,人员都被调去做无忧行了。也不知真假。直到前两天,Jego的客服忽然回复了我邮件,确认说Jego服务已经停了,他们推出了Jego升级版,Jego trip,也就是无忧行。新版比原来的Jego功能更多,支持“免费接收来电和短信”,他们建议我换无忧行。




这个邮件服务器我一直在用。大部分时间是用来收邮件,偶尔也发邮件。我原来配置的时候,邮件收发都是启用了TLS的,只是一直用的是自签名的证书,除了在配置客户端的时候,要专门信任一下证书之外,也没什么大的影响。可是最近随着各大邮件服务商,比如outlook和gmail,纷纷升级了TLS策略之后,似乎都不再信任用自签名证书发送的邮件了,必须使用由受信任CA签发的证书。各大浏览器也早已对http的页面提出安全警告了。今后要想玩自建网站和邮箱,一张由CA签发的证书是标配。还好有Let’s Encrypt出来提供免费的证书服务,否则网站和邮箱就没法随便玩了。














Go的最突出的几个特性是,可编译;静态类型,但也有部分类型推导;垃圾收集,这是其它大部分编译型静态类型语言所没有的;基于CSP(Communicating sequential processes)的并发编程;等等。

这两年,Go语言社区成长很快。据说Go是2017年,GitHub上用户增长最多的语言。而stack overflow的2017年开发者调查中,Go是most loved第五名,most wanted第三名,足见其火爆。

Most Wanted vs. Most Loved


可是我们已经有无数种编程语言了,为什么还需要go呢?这就要从go试图解决什么问题说起了。根据go的创始人之一,Rob Pike,的说法,go的设计初衷是为了解决两个问题:

  1. Google的问题:big hardware, big software. 编译慢;依赖关系复杂;每个程序员都有自己的风格,不易合作;缺少文档;升级困难;经常重复造轮子;等等。
  2. 让Go的设计者的日常工作能够更轻松,生活更美好。


  1. 极简:使用类Pascal语法,语法简单,关键字少;不支持类,继承,泛型等语言特性。
  2. 正交:数据结构和方法分开,通过聚合而非继承来联系二者;类型抽象通过接口实现;数据结构和接口都可以通过内嵌的方式来扩展。


但也由于这两条哲学,我觉得导致Go,至少是Go 1,并没有很好的解决所有它的设计者打算解决的问题。比如,Go的依赖通过package实现,但是它并没能解决大型项目的依赖问题。这个问题Go通过不同的package试了好几次,不过看来又要推倒重来,Go 1.11会有新的依赖管理工具。再比如不支持泛型,导致重复造轮子变成了免不了的问题。这些都是Go在大受欢迎的同时,为人诟病的问题。


目前看了,Go使用比较多的场景,还是在服务端的后台程序。容器领域里,Go俨然成为了标准语言。Docker, Kubernetes等等都是Go编写的。根据Go 2017 Survey的结果,其它go比较流行的领域包括中间件,微服务等等。Go比较不适合用来写桌面GUI应用。



记得2008年我们刚来新加坡时,因为生活习惯和语言的关系,闹过不少笑话。有一次我去星巴克,点了一杯咖啡之后,帮我点单的小哥,好心问了一句,要不要加点奶油(cream)在上面。当时因为还不适应新加坡口音,我愣是没听懂cream这个词,于是问了一句“那是什么”(What is it?)。那小哥当时就凌乱了,看着我不知如何解释什么是cream。现在想起来还很好笑。





Install Minikube on Ubuntu Server 17.10

I have some experiences with Docker and containers, but never played with Kubernetes before. I started to explore Kubernetes recently as I may need a container orchestration solution in the coming projects. Kubernetes is supported by Azure AKS. Even Docker has announced their support of it. Looks like it is going to be the major container orchestration solution in the market for the coming years.

I started with deploying a local Kubernetes cluster with Minikube on a Ubuntu 17.10 server on Azure. Kubernetes has a document on its site which is about installing the Minikube. But it is very brief. So in this post, I will try to document the step by step procedure both for the future reference of myself and for others who are new to Kubernetes.

Install a Hypervisor

To install Minikube, the first step is to install a hypervisor on the server. On Linux, both VirtualBox and KVM are supported hypervisors. I chose to install KVM and followed the guidance here. The following are steps.

  • Make sure VT-x or AMD-v virtualization is enabled. In Azure, if the VM is based on vCPUs, the virtualization is enabled. To double check, run command egrep -c '(vmx|svm)' /proc/cpuinfo, if the output is 1, the virtualization is enabled.
  • Install the KVM packages with the following command:

[code lang=bash]
sudo apt-get install qemu-kvm libvirt-bin ubuntu-vm-builder bridge-utils

  • Use the following command to add the current user to the libvert group, and then logout and login to make it work. Note, in the guidance the group name is libvirtd, but on Ubuntu 17.10, the name has changed to libvert.

[code lang=bash]
sudo adduser `id -un` libvirt

  • Test if your install has been successful with the following command:

[code lang=bash]
virsh list –all

  • Install virt-manager so that we have a UI to manage VMs

[code lang=bash]
sudo apt-get install virt-manager

Install kubectl

Follow the instruction here to install kubectl. The following are the commands:

[code lang=bash]
curl -LO https://storage.googleapis.com/kubernetes-release/release/$(curl -s https://storage.googleapis.com/kubernetes-release/release/stable.txt)/bin/linux/amd64/kubectl
chmod +x ./kubectl
sudo mv ./kubectl /usr/local/bin/kubectl

Install Minikube

Follow the instruction on the release notes of Minikube to install it. I used the following command:

[code lang=bash]
curl -Lo minikube https://storage.googleapis.com/minikube/releases/v0.25.0/minikube-linux-amd64 && chmod +x minikube && sudo mv minikube /usr/local/bin/

When you finish this step, according to the official document, the installation of Minikube has been completed. But before you can use it, there are several other components which needs to be installed as well.

Install Docker, Docker-Machine, and KVM driver

Minikube can run on natively on the Ubuntu server without a virtual machine. To do so, Docker needs to be installed on the server. Docker-CE has a different way to be installed and Docker has a document for it.

Docker Machine can be installed with the following commands:

[code lang=bash]
curl -L https://github.com/docker/machine/releases/download/v0.13.0/docker-machine-`uname -s`-`uname -m` >/tmp/docker-machine && \
sudo install /tmp/docker-machine /usr/local/bin/docker-machine

Finally, we need to install a VM driver for the docker machine. Kubernetes team ships a KVM2 driver which is supposed to replace the KVM driver created by others. However, I failed to make the Minikube work with the KVM2 driver. There is a bug report for this issue and hope the Kubernetes team will fix it soon.

So I installed the KVM driver with the following command:

[code lang=bash]
curl -LO https://github.com/dhiltgen/docker-machine-kvm/releases/download/v0.10.0/docker-machine-driver-kvm-ubuntu16.04
sudo cp docker-machine-driver-kvm-ubuntu16.04 /usr/local/bin/docker-machine-driver-kvm
sudo chmod +x /usr/local/bin/docker-machine-driver-kvm

Test if Minikube Works

With the completion of all the above steps, we can test the Minikube now.

[code lang=bash]
minikube start –vm-driver kvm

It will create a vm named as minikube in KVM and configure a local Kubernetes cluster based on it. With kubectl, you should be able to see the cluster info and node info.

[code lang=bash]
kubectl cluster-info
kubectl get nodes

With that, you can start to explore Kubernetes.