Thinktecture Webinar: Small and secure Docker images for .NET

This repository contains all samples from the webinar held during March 2021.

Iterative approach

During the webinar, we kept on optimizing the Dockerfile starting with the default Dockerfile produced by Visual Studio 2019 or Visual Studio for Mac.

Build

To build a certain Docker image execute the following command:

docker build . -f Dockerfile -t webinar-api:0.0.1

Depending on the iteration, replace Dockerfile and 0.0.1 with the concrete value as shown below:

docker build . -f 2.Dockerfile -t webinar-api:0.0.2

Verification

Each iteration should be verified based on several metrics such as

• Image Size
• Layer Size
• Vulnerabilities
• Sample API functionality

All those metrics can be verified using the following command:

# print all webinar images and their size
docker image ls --format "table {{.Repository}}{{.Tag}}\t{{.Size}}" | grep webinar

TAG="0.0.1"
LOCAL_PORT=8080
CONTAINER_PORT=80
# inspect layer sizes
docker history webinar-api:$TAG

# scan for vulnerabilities
docker scan webinar-api:$TAG

# verify that the api still works
$CONTAINER_ID=$(docker run -d -p $LOCAL_PORT:$CONTAINER_PORT webinar-api:$TAG)
docker logs $CONTAINER_ID
curl -ix GET http://localhost:$LOCAL_PORT/weatherforecast
docker rm -f $CONTAINER_ID