Docker - Increase web.config size

Since we have many IIS rewrites, the web.config file size has exceeded the default 250 KB. We moved all the redirects to separate rewriteMaps configuration but the overall web.config file size has been more than 2.5 MB. In order for the application to work, we went ahead and set the registry changes in Docker images. 

While building the Sitecore CM image, we added few lines in Dockerfile to set the max size. Below lines will increase the web.config max size to 10 MB.

SHELL ["powershell", "-Command", "$ErrorActionPreference = 'Stop'; $ProgressPreference = 'SilentlyContinue';"]

# Set the web.config size to 10MB to support rewriteconfig
RUN New-Item -Path 'HKLM:\SOFTWARE\Wow6432Node\Microsoft\InetStp\Configuration'
RUN New-Item -Path 'HKLM:\SOFTWARE\Microsoft\InetStp\Configuration'
RUN Reg Add HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\Microsoft\InetStp\Configuration /v MaxWebConfigFileSizeInKB /t REG_DWORD /d 10240
RUN Reg Add HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\InetStp\Configuration /v MaxWebConfigFileSizeInKB /t REG_DWORD /d 10240

Update: Dec 2022:

It is recommended to convert multiple RUN statements to multiline. 

Example: 

RUN {cmd1}  \
  && {cmd2} \
  && {cmd3} \