Steve Spencer's Blog - Docker

DotNetSheff Slides

Thu, 09 Mar 2017 21:07:02 +0000

I presented at DotNetSheff on Tues 7th March

The slides for the two talks are here:

Building Scalable Resilient Web Apps in Azure

Custom ASP.NET MVC app running in a Container on Service Fabric

Sun, 05 Mar 2017 11:26:53 +0000

In an earlier post, I talked about how to create a Docker container on Windows that housed a custom ASP.Net MVC app. What I want to show now is how you can get this container running in Service Fabric.

I created 3 identical virtual machines all capable of running Docker as in my earlier post. Now I needed to make my three VMs into a Service fabric cluster. These two posts explain how:

https://docs.microsoft.com/en-us/azure/service-fabric/service-fabric-get-started

https://docs.microsoft.com/en-us/azure/service-fabric/service-fabric-cluster-standalone-deployment-preparation

My 3 VMs are called sf0, sf1 & sf2 and I needed to put these into my cluster config. I picked the ClusterConfig.Unsecure.MultiMachine config file that comes with the Service Fabric files and changed it to include my 3 VMs, so my nodes look like this:

"nodes": [
{
      "nodeName": "sf0",
      "iPAddress": "sf0",
      "nodeTypeRef": "NodeType0",
      "faultDomain": "fd:/dc1/r0",
      "upgradeDomain": "UD0"
},
{
      "nodeName": "sf1",
      "iPAddress": "sf1",
      "nodeTypeRef": "NodeType0",
      "faultDomain": "fd:/dc2/r0",
      "upgradeDomain": "UD1"
},
{
      "nodeName": "sf2",
      "iPAddress": "sf2",
      "nodeTypeRef": "NodeType0",
      "faultDomain": "fd:/dc3/r0",
      "upgradeDomain": "UD2"
}
],

I then remoted onto one of the machines and ran the following PowerShell:

.\TestConfiguration.ps1 -ClusterConfigFilePath .\ClusterConfig.json

This will check all the machines in the ClusterConfig.json file to see if they are configured correctly and report any errors. I got the following error:

Machine 'sf2' is not reachable on port 445. Check connectivity/open ports. Error: A connection attempt failed because the connected party did not properly respond after a period of time, or established connection failed because connected host has failed to respond 192.168.1.222:445

This meant I needed to open the correct firewall ports on my VM. I got this error for all the machines in the cluster. Once I fixed this and reran the PowerShell, the tests passed which meant I could install Service Fabric on each of the machines as follows:

.\CreateServiceFabricCluster.ps1 -ClusterConfigFilePath .\ClusterConfig.json –AcceptEULA

When this completes successfully you should see something like this:

Your cluster is successfully created! You can connect and manage your cluster using Microsoft Azure Service Fabric Explorer or Powershell. To connect through Powershell, run 'Connect-ServiceFabricCluster

I could connect to Service Fabric Explorer using: http://sf0:19080

Now I have my cluster running I needed to create a Service Fabric App and deploy it to the cluster. Make sure that you have installed the Service Fabric SDK, then run Visual Studio. Create a new Service Fabric project. When the project is created, right click on the services node, Select Add->New Service Fabric Service

Then pick Guest Container and enter the name in your Docker Hub repository where your Docker image resides.

This will add in the necessary files to your service fabric project. If you remember from my earlier post, the website was hosted on port 8000 of the container. We need to tell service fabric about this and also we may want to map this to a different port.

If you open the containers ServiceManifest file

Add an endpoint with the endpoint you want Service Fabric to use to publish the website out

In this example I’m using the same port. If you want to map the port to a different one then changes this to something else e.g. If I wanted to use http://sf0:8080 as the website then I would change the Service Manifest to this:

You also need to tell service fabric about the Container port that is published. This is done in the application manifest file:

This is set to 8000 as that is the port exposed by the Docker container

Now deploy your application to service fabric. It may take a while to initialise your container as it will need to be downloaded from Docker Hub before it will run. Once it is running you should see it as Ready in the Service Fabric Explorer

Custom ASP.NET MVC app running in a Windows Container

Sat, 11 Feb 2017 16:39:36 +0000

With the introduction of Windows Containers on Window Server 2016 and the ability to run containers in Service Fabric I thought it was time to investigate Windows Containers and I wanted to know how to build one that will run a web site using IIS.

As I’m new to containers, although I’ve done a very similar exercise with Docker on Linux, I decided to follow the Windows Quick Start Guide. I hit a few problems early on so I’ve put the steps I followed here:

After opening a PowerShell window as administrator I ran the following commands:

Install-Module -Name DockerMsftProvider -Repository PSGallery –Force – Ran OK
Install-Package -Name docker -ProviderName DockerMsftProvider – Had an error
WARNING: Cannot verify the file SHA256. Deleting the file.
WARNING: C:\Users\ADMINI~1.DEV\AppData\Local\Temp\DockerMsftProvider\Docker-1-12-2-cs2-ws-beta.zip does not exist
Install-Package : Cannot find path 'C:\Users\ADMINI~1.DEV\AppData\Local\Temp\DockerMsftProvider\Docker-1-12-2-cs2-ws-beta.zip' because it does not exist.

Not sure what was causing this to fail but I followed the instructions to manually install (from https://github.com/OneGet/MicrosoftDockerProvider/issues/15)

Start-BitsTransfer -Source https://dockermsft.blob.core.windows.net/dockercontainer/docker-1-12-2-cs2-ws-beta.zip -Destination /docker.zip
Get-FileHash -Path /docker.zip -Algorithm SHA256
mkdir C:\Users\Administrator\AppData\Local\Temp\DockerMsftProvider\
cp .\docker.zip C:\Users\Administrator\AppData\Local\Temp\DockerMsftProvider\
cd C:\Users\Administrator\AppData\Local\Temp\DockerMsftProvider\
cp .\docker.zip Docker-1-12-2-cs2-ws-beta.zip
Install-Package -Name docker -ProviderName DockerMsftProvider -Verbose Restart-Computer –Force

After Rebooting I tried to download and run a sample container

docker run microsoft/dotnet-samples:dotnetapp-nanoserver

but I got the following error

docker : C:\Program Files\Docker\docker.exe: error during connect: Post http://%2F%2F.%2Fpipe%2Fdocker_engine/v1.25/containers/create: open //./pipe/docker_engine: The

system cannot find the file specified..

At line:1 char:1

+ docker run microsoft/dotnet-samples:dotnetapp-nanoserver

+ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

+ CategoryInfo : NotSpecified: (C:\Program File...ile specified..:String) [], RemoteException

+ FullyQualifiedErrorId : NativeCommandError

It turns out that the docker service wasn’t running after the reboot, so open services.msc and find the docker service to start it.

Running the same command again will download the image from docker hub, create a container from it and then run it. As this is a visual container it runs once and then stops.

Every time I do docker run microsoft/dotnet-samples:dotnetapp-nanoserver it creates a new container. What I want to do is to run one that is stopped and view the output on the screen.

For this I needed to start the container I had already created. If you run

docker –ls –a

This will list all the containers that are both running and stopped and you can see from the image below that I had run docker run a number of time. Each time it tried to download the image (which was already downloaded) and then create a new container from it.

docker container start -a 12d382ae0bd6 (-a attached STDOUT so you can see the output)

Now I know how to create and start containers I wanted to build one of my own. This is easier than I first though as there a lots of base templates stored on docker hub and git hub.

https://docs.microsoft.com/en-us/virtualization/windowscontainers/samples#Application-Frameworks

https://hub.docker.com/r/microsoft/

I picked one on docker hub that has IIS and ASP.Net installed already, so all I needed to do after was to add my own website and configure IIS correctly. Using docker pull,

docker pull microsoft/aspnet (see https://hub.docker.com/r/microsoft/aspnet/)

This retrieves the template from Docker Hub and I want to use that template to install my ASP.Net MVC site and configure IIS to serve the pages on port 8000. Following the instructions here (https://docs.microsoft.com/en-us/dotnet/articles/framework/docker/aspnetmvc). I published my MVC site and copied the publish folder to my docker machine. Then I needed to create a Dockerfile recipe to instruct docker what to install in my image. So I created a folder that contained the Dockerfile and also the published website as below

The contents of the Dockerfile are:

# The FROM instruction specifies the base image. You are
# extending the microsoft/aspnet image.
FROM microsoft/aspnet
# Next, this Dockerfile creates a directory for your application
RUN mkdir C:\sdsweb
# configure the new site in IIS.
RUN powershell -NoProfile -Command \
Import-module IISAdministration; \
New-IISSite -Name "sdsweb" -PhysicalPath C:\sdsweb -BindingInformation "*:8000:"
# This instruction tells the container to listen on port 8000.
EXPOSE 8000
# The final instruction copies the site you published earlier into the container.
ADD sdswebsource/ /sdsweb

Now I need to run this to create the image

In PowerShell, I changed directory to the folder containing my Dockerfile, then ran

docker build -t sdsweb .

This has created an image and we need to now get this running as a container

using docker run again

docker run -d -p 8000:8000 --name sdsweb sdsweb

My container is now running and I should be able to view the web pages in my browser on port 8000, but I need to know the IP address first

docker inspect -f "{{ .NetworkSettings.Networks.nat.IPAddress }}" sdsweb

Now I can browser to http://172.17.97.235:8000

I changed the default web page to show the machine name serving the pages under Getting Started. Listing the containers will show the container ID and this matches the machine name displayed on the web page

That’s it running in a container. There are a couple more things I’d like to do before I’ve finished. The first is to make sure that when my Windows Server restarts, then my sdsweb container also starts. At the moment it will not start as I didn’t add a restart parameter when I called docker run. Adding –restart always will cause the container to restart when windows restarts.

docker run -d -p 8000:8000 --name sdsweb --restart always sdsweb

The final thing I want to do is to be able to share this image so I’d like to push it up to docker hub

docker login - enter username and password

docker push recneps/sdsweb

Then to use it on another machine

docker pull recneps/sdsweb

In my next post I am going to look at how I can create a container that can be hosted in Service Fabric