github.com/guilhermebr/docker@v1.4.2-0.20150428121140-67da055cebca/docs/sources/userguide/level2.md (about) 1 page_title: Docker images test 2 page_description: How to work with Docker images. 3 page_keywords: documentation, docs, the docker guide, docker guide, docker, docker platform, virtualization framework, docker.io, Docker images, Docker image, image management, Docker repos, Docker repositories, docker, docker tag, docker tags, Docker Hub, collaboration 4 5 <a title="back" class="dockerfile back" href="/userguide/dockerimages/#creating-our-own-images">Back</a> 6 7 #Dockerfile tutorial 8 9 ## Test your Dockerfile knowledge - Level 2 10 11 ### Questions: 12 13 <div class="level_questions"> 14 What is the Dockerfile instruction to specify the base image?<br> 15 <input type="text" class="level"> 16 <div style="display:none;" id="level2_error0" class="alert alert-error level_error">The right answer was <code>FROM</code></div><br> 17 Which Dockerfile instruction sets the default command for your image?<br> 18 <input type="text" class="level"> 19 <div style="display:none;" id="level2_error4" class="alert alert-error level_error">The right answer was <code>ENTRYPOINT</code> or <code>CMD</code></div><br> 20 What is the character used to add comments in Dockerfiles?<br> 21 <input type="text" class="level"> 22 <div style="display:none;" id="level2_error3" class="alert alert-error level_error">The right answer was <code>#</code></div><br> 23 Which Dockerfile instruction sets the username to use when running the image?<br> 24 <input type="text" class="level"> 25 <div style="display:none;" id="level2_error5" class="alert alert-error level_error">The right answer was <code>USER</code></div><br> 26 What is the Dockerfile instruction to execute any command on the current image and commit the results?<br> 27 <input type="text" class="level"> 28 <div style="display:none;" id="level2_error1" class="alert alert-error level_error">The right answer was <code>RUN</code></div><br> 29 Which Dockerfile instruction sets ports to be exposed when running the image?<br> 30 <input type="text" class="level"> 31 <div style="display:none;" id="level2_error6" class="alert alert-error level_error">The right answer was <code>EXPOSE</code></div><br> 32 What is the Dockerfile instruction to specify the maintainer of the Dockerfile?<br> 33 <input type="text" class="level"> 34 <div style="display:none;" id="level2_error2" class="alert alert-error level_error">The right answer was <code>MAINTAINER</code></div><br> 35 Which Dockerfile instruction lets you trigger a command as soon as the container starts?<br> 36 <input type="text" class="level"> 37 <div style="display:none;" id="level2_error7" class="alert alert-error level_error">The right answer was <code>ENTRYPOINT</code> or <code>CMD</code></div><br> 38 <p> 39 40 <div class="alert alert-success" id="all_good" style="display:none;">Congratulations, you made no mistake!<br /> 41 Tell the world <a href="https://twitter.com/share" class="twitter-share-button" data-url="http://www.docker.io/learn/dockerfile/level1/" data-text="I just successfully answered questions of the #Dockerfile tutorial Level 1. What's your score?" data-via="docker" >Tweet</a><br /> 42 And try the next challenge: <a href="#fill-the-dockerfile">Fill the Dockerfile</a> 43 </div> 44 <div class="alert alert-error" id="no_good" style="display:none;">Your Dockerfile skills are not yet perfect, try to take the time to read this tutorial again.</div> 45 <div class="alert alert-block" id="some_good" style="display:none;">You're almost there! Read carefully the sections corresponding to your errors, and take the test again!</div> 46 </p> 47 <button class="btn btn-primary" id="check_level2_questions">Check your answers</button> 48 </div> 49 50 ### Fill the Dockerfile 51 <br> 52 Your best friend Roberto Hashioka sent you a Dockerfile, but some parts were lost in the ocean. Can you find the missing parts? 53 <div class="form-inline"> 54 <pre> 55 # Redis 56 # 57 # VERSION 0.42 58 # 59 # use the ubuntu base image provided by dotCloud 60 <input id="from" class="l_fill" type="text"> ub<input id="ubuntu" class="l_fill" type="text"><br> 61 MAINT<input id="maintainer" class="l_fill" type="text"> Ro<input id="roberto" class="l_fill" type="text"> Ha<input id="hashioka" class="l_fill" type="text"> roberto.hashioka@dotcloud.com<br> 62 # make sure the package repository is up to date 63 <input id="run0" class="l_fill" type="text"> echo "deb http://archive.ubuntu.com/ubuntu precise main universe" > /etc/apt/sources.list 64 <input id="run1" class="l_fill" type="text"> apt-get update<br> 65 # install wget (required for redis installation) 66 <input id="run2" class="l_fill" type="text"> apt-get install -y wget<br> 67 # install make (required for redis installation) 68 <input id="run3" class="l_fill" type="text"> apt-get install -y make<br> 69 # install gcc (required for redis installation) 70 RUN apt-get install -y <input id="gcc" class="l_fill" type="text"><br> 71 # install apache2 72 <input id="run4" class="l_fill" type="text"> wget http://download.redis.io/redis-stable.tar.gz 73 <input id="run5" class="l_fill" type="text">tar xvzf redis-stable.tar.gz 74 <input id="run6" class="l_fill" type="text">cd redis-stable && make && make install<br> 75 # launch redis when starting the image 76 <input id="entrypoint" class="l_fill" type="text"> ["redis-server"]<br> 77 # run as user dameon 78 <input id="user" class="l_fill" type="text"> daemon<br> 79 # expose port 6379 80 <input id="expose" class="l_fill" type="text"> 6379 81 </pre> 82 <div class="alert alert-success" id="dockerfile_ok" style="display:none;">Congratulations, you successfully restored Roberto's Dockerfile! You are ready to containerize the world!.<br /> 83 Tell the world! <a href="https://twitter.com/share" class="twitter-share-button" data-url="http://www.docker.io/learn/dockerfile/level2/" data-text="I just successfully completed the 'Dockerfill' challenge of the #Dockerfile tutorial Level 2" data-via="docker" >Tweet</a> 84 </div> 85 <div class="alert alert-error" id="dockerfile_ko" style="display:none;">Wooops, there are one or more errors in the Dockerfile. Try again.</div> 86 <br> 87 <button class="btn btn-primary" id="check_level2_fill">Check the Dockerfile</button></p> 88 </div> 89 90 ## What's next? 91 <p> 92 Thanks for going through our tutorial! We will be posting Level 3 in the future. 93 94 To improve your Dockerfile writing skills even further, visit the <a href="https://docs.docker.com/articles/dockerfile_best-practices/">Dockerfile best practices page</a>. 95 96 <a title="creating our own images" class="btn btn-primary" href="/userguide/dockerimages/#creating-our-own-images">Back to the Docs!</a>