Repository is not signed in docker build

Question

I have the following Dockerfile that uses the latest Ubuntu image pulled from dockerhub:

FROM ubuntu:latest  
RUN apt-get update  && apt-get install -y           


        

Answer 1

Since Docker api v1.25+ ( released: Nov 18, 2019 )

Running command below fixed problem for me:

docker system prune --force

The --force flag stands for non interactive prune.