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Windows Container limitations so far

· One min read
  1. Do not support spec.hostAliases in Windows Pod
  2. ClusterFirstWithHostNet is not supported for DNS. Windows treats all names with a ‘.’ as a FQDN and skips PQDN resolution
  3. terminationGracePeriodSeconds is not work

Add File Extension to Windows IIS Container during image build

· 2 min read

Let's say: we need to add json file extension to the containerized IIS.

Dockerfile:

FROM {imageRegistry}/mcr.microsoft.com/dotnet/framework/aspnet:4.8-20200114-windowsservercore-ltsc2019
COPY . /inetpub/wwwroot
WORKDIR /inetpub/wwwroot

RUN C:\windows\system32\inetsrv\appcmd.exe set config "Default Web Site" -section:system.webServer/security/requestFiltering /+"fileExtensions.[fileExtension='json',allowed='True']"

ENV ASPNETCORE_URLS http://+:80
EXPOSE 80/tcp

An error occurs during build docker image:

Step 1/6 : FROM repo.q1lan.k8s:9999/mcr.microsoft.com/dotnet/framework/aspnet:4.8-20200114-windowsservercore-ltsc2019
 ---> a5bc996f06b3
Step 2/6 : COPY . /inetpub/wwwroot
 ---> bdb9536e506a
Step 3/6 : WORKDIR /inetpub/wwwroot
 ---> Running in f7666a9ffd0b
Removing intermediate container f7666a9ffd0b
 ---> c9fe76854f6c
Step 4/6 : RUN C:\windows\system32\inetsrv\appcmd.exe set config "Default Web Site" -section:system.webServer/security/requestFiltering /+"fileExtensions.[fileExtension='json',allowed='True']"
 ---> Running in 1c74d16420c2
Failed to process input: The parameter 'Web' must begin with a / or - (HRESULT=80070057).

Try to escape all double-quotes in Dockerfile:

RUN C:\windows\system32\inetsrv\appcmd.exe set config \"Default Web Site\" -section:system.webServer/security/requestFiltering /+\"fileExtensions.[fileExtension='json',allowed='True']\"

It works like a charm:

Step 1/6 : FROM repo.q1lan.k8s:9999/mcr.microsoft.com/dotnet/framework/aspnet:4.8-20200114-windowsservercore-ltsc2019
 ---> a5bc996f06b3
Step 2/6 : COPY . /inetpub/wwwroot
 ---> 646bbf3d5def
Step 3/6 : WORKDIR /inetpub/wwwroot
 ---> Running in 584471c0524a
Removing intermediate container 584471c0524a
 ---> 54f6a3ade821
Step 4/6 : RUN C:\windows\system32\inetsrv\appcmd.exe set config \"Default Web Site\" -section:system.webServer/security/requestFiltering /+\"fileExtensions.[fileExtension='json',allowed='True']\"
 ---> Running in f84c38da656a
Applied configuration changes to section "system.webServer/security/requestFiltering" for "MACHINE/WEBROOT/APPHOST/Default Web Site" at configuration commit path "MACHINE/WEBROOT/APPHOST/Default Web Site"
Removing intermediate container f84c38da656a
 ---> 7dfffe2d9813
Step 5/6 : ENV ASPNETCORE_URLS http://+:80
 ---> Running in dff81c8282f1
Removing intermediate container dff81c8282f1
 ---> cbd697556dd7
Step 6/6 : EXPOSE 80/tcp
 ---> Running in d10903bec188
Removing intermediate container d10903bec188
...
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