Unable to create docker container

First, Unable to find image 'docker/whalesay:latest' locally is said when you doesn't specify a tag

A docker image is defined by repo/name:tag

After that, as you can read in https://docs.docker.com/registry/spec/deprecated-schema-v1/, you're downloading an image generated with docker schema v1 (It was generated with a deprecated version of docker), and your docker version uses schema-v2.

So, one possibility should be install a docker previous version which uses schema-v1, but it's not recommended, since it'd worked with deprecated schema images only.

The other possibility is generate image by yourself, using Dockerfile before your docker run command.

Dockerfile https://hub.docker.com/r/docker/whalesay/

FROM ubuntu:14.04

# install cowsay, and move the "default.cow" out of the way so we can overwrite it with "docker.cow"
RUN apt-get update && apt-get install -y cowsay --no-install-recommends && rm -rf /var/lib/apt/lists/* \
    && mv /usr/share/cowsay/cows/default.cow /usr/share/cowsay/cows/orig-default.cow

# "cowsay" installs to /usr/games
ENV PATH $PATH:/usr/games

COPY docker.cow /usr/share/cowsay/cows/
RUN ln -sv /usr/share/cowsay/cows/docker.cow /usr/share/cowsay/cows/default.cow

CMD ["cowsay"]

Put next docker.cow in the same folder than your Dockerfile.

docker.cow

##
## Docker Cow
##
$the_cow = <<EOC;
    $thoughts
     $thoughts
      $thoughts     
                    ##        .            
              ## ## ##       ==            
           ## ## ## ##      ===            
       /""""""""""""""""\___/ ===        
  ~~~ {~~ ~~~~ ~~~ ~~~~ ~~ ~ /  ===- ~~~   
       \\______ o          __/            
        \\    \\        __/             
          \\____\\______/   
EOC

Finally, execute docker build before your docker run command, and docker image will be generated according to schema-v2.

sudo docker build -t docker/whalesay:latest . 
sudo docker run docker/whalesay cowsay Hello-World!

If you edit another file.cow can create your own whalesay docker image. I've created image with name docker/whalesay:latest in order to use your own command, but you can set whatever name you prefer. It's recommended to use your user docker hub repo (if you have it), because docker push are not allowed for you to docker/whalesay:latest.

Image docker.io/docker/whalesay:latest uses outdated schema1 manifest format.you're seeing this error because the updated version hasn't been pushed back to DockerHub.

If you just want to test Docker's functionality as a beginner, You can use hello-world Docker image rather than docker/whalesay.

docker run hello-world

You can either

1. Create your own image
2. Pull an alternative Image of the one you want to pull it Use can user this one:

docker pull chuanwen/cowsay