{"id":6851,"date":"2019-10-07T07:45:30","date_gmt":"2019-10-07T07:45:30","guid":{"rendered":"https:\/\/www.devopsschool.com\/blog\/?p=6851"},"modified":"2021-11-16T09:42:04","modified_gmt":"2021-11-16T09:42:04","slug":"docker-interview-questions-and-answer-part-1","status":"publish","type":"post","link":"https:\/\/www.devopsschool.com\/blog\/docker-interview-questions-and-answer-part-1\/","title":{"rendered":"Docker Interview Questions and Answer Part &#8211; 1"},"content":{"rendered":"\n<ul class=\"wp-block-list\"><li>What happens when you run&nbsp;<code>docker run hello-world<\/code>?<\/li><\/ul>\n\n\n<pre class=\"wp-block-code\" aria-describedby=\"shcb-language-1\" data-shcb-language-name=\"JavaScript\" data-shcb-language-slug=\"javascript\"><span><code class=\"hljs language-javascript\">Docker CLI passes your request to Docker daemon.\nDocker daemon downloads the image <span class=\"hljs-keyword\">from<\/span> Docker Hub\nDocker daemon creates a <span class=\"hljs-keyword\">new<\/span> container by using the image it downloaded\nDocker daemon redirects output <span class=\"hljs-keyword\">from<\/span> container to Docker CLI which redirects it to the standard output\n<\/code><\/span><small class=\"shcb-language\" id=\"shcb-language-1\"><span class=\"shcb-language__label\">Code language:<\/span> <span class=\"shcb-language__name\">JavaScript<\/span> <span class=\"shcb-language__paren\">(<\/span><span class=\"shcb-language__slug\">javascript<\/span><span class=\"shcb-language__paren\">)<\/span><\/small><\/pre>\n\n\n<ul class=\"wp-block-list\"><li>How do you run a container?<\/li><li>What do you see when you run&nbsp;<code>docker ps<\/code>?<\/li><li>What&nbsp;<code>docker commit<\/code>&nbsp;does? when will you use it?<\/li><li>Explain what is Dockerfile used for and the content of the following Dockerfile<\/li><\/ul>\n\n\n<pre class=\"wp-block-code\" aria-describedby=\"shcb-language-2\" data-shcb-language-name=\"JavaScript\" data-shcb-language-slug=\"javascript\"><span><code class=\"hljs language-javascript\">FROM registry.access.redhat.com\/rhel7\/rhel\n\nRUN yum -y install httpd &amp;&amp; yum -y update; yum clean all\n\nEXPOSE <span class=\"hljs-number\">80<\/span>\nENTRYPOINT &#91; <span class=\"hljs-string\">\"\/usr\/sbin\/httpd\"<\/span> ]\nCMD &#91; <span class=\"hljs-string\">\"-D\"<\/span>, <span class=\"hljs-string\">\"FOREGROUND\"<\/span> ]\n<\/code><\/span><small class=\"shcb-language\" id=\"shcb-language-2\"><span class=\"shcb-language__label\">Code language:<\/span> <span class=\"shcb-language__name\">JavaScript<\/span> <span class=\"shcb-language__paren\">(<\/span><span class=\"shcb-language__slug\">javascript<\/span><span class=\"shcb-language__paren\">)<\/span><\/small><\/pre>\n\n\n<p>Answer:<\/p>\n\n\n<pre class=\"wp-block-code\" aria-describedby=\"shcb-language-3\" data-shcb-language-name=\"PHP\" data-shcb-language-slug=\"php\"><span><code class=\"hljs language-php\"><span class=\"hljs-keyword\">Use<\/span> <span class=\"hljs-title\">the<\/span> <span class=\"hljs-title\">image<\/span> '<span class=\"hljs-title\">rhel7<\/span>\/<span class=\"hljs-title\">rhel<\/span>' <span class=\"hljs-title\">from<\/span> <span class=\"hljs-title\">the<\/span> <span class=\"hljs-title\">registry<\/span> '<span class=\"hljs-title\">registry<\/span>.<span class=\"hljs-title\">access<\/span>.<span class=\"hljs-title\">redhat<\/span>.<span class=\"hljs-title\">com<\/span>` <span class=\"hljs-title\">to<\/span> <span class=\"hljs-title\">run<\/span> <span class=\"hljs-title\">httpd<\/span>.\n<span class=\"hljs-title\">Befor<\/span> <span class=\"hljs-title\">running<\/span> <span class=\"hljs-title\">it<\/span>, <span class=\"hljs-title\">install<\/span> <span class=\"hljs-title\">the<\/span> <span class=\"hljs-title\">httpd<\/span> <span class=\"hljs-title\">package<\/span>, <span class=\"hljs-title\">update<\/span> <span class=\"hljs-title\">all<\/span> <span class=\"hljs-title\">packages<\/span> <span class=\"hljs-title\">and<\/span> <span class=\"hljs-title\">expose<\/span> <span class=\"hljs-title\">port<\/span> 80.\n<\/code><\/span><small class=\"shcb-language\" id=\"shcb-language-3\"><span class=\"shcb-language__label\">Code language:<\/span> <span class=\"shcb-language__name\">PHP<\/span> <span class=\"shcb-language__paren\">(<\/span><span class=\"shcb-language__slug\">php<\/span><span class=\"shcb-language__paren\">)<\/span><\/small><\/pre>\n\n\n<ul class=\"wp-block-list\"><li>How would you transfer data from one container into another?<\/li><li>What is the difference between ADD and COPY in Dockerfile?<\/li><li>What is the difference between CMD and RUN in Dockerfile?<\/li><li>Explain what is Docker compose and what is it used for<\/li><li>What are the differences between Docker compose, Docker swarm and Kuberenets?<\/li><li>Explain Docker interlock<\/li><li>What is the difference between Docker Hub and Docker cloud?<\/li><\/ul>\n\n\n<pre class=\"wp-block-code\" aria-describedby=\"shcb-language-4\" data-shcb-language-name=\"JavaScript\" data-shcb-language-slug=\"javascript\"><span><code class=\"hljs language-javascript\">Docker Hub is a native Docker registry service which allows you to run pull\nand push commands to install and deploy Docker images <span class=\"hljs-keyword\">from<\/span> the Docker Hub.\n\nDocker Cloud is built on top <span class=\"hljs-keyword\">of<\/span> the Docker Hub so Docker Cloud provides\nyou <span class=\"hljs-keyword\">with<\/span> more options\/features compared to Docker Hub. One example is\nSwarm management which means you can create <span class=\"hljs-keyword\">new<\/span> swarms <span class=\"hljs-keyword\">in<\/span> Docker Cloud.<\/code><\/span><small class=\"shcb-language\" id=\"shcb-language-4\"><span class=\"shcb-language__label\">Code language:<\/span> <span class=\"shcb-language__name\">JavaScript<\/span> <span class=\"shcb-language__paren\">(<\/span><span class=\"shcb-language__slug\">javascript<\/span><span class=\"shcb-language__paren\">)<\/span><\/small><\/pre>\n\n<div class=\"epyt-gallery\" data-currpage=\"1\" id=\"epyt_gallery_84438\"><iframe loading=\"lazy\"  id=\"_ytid_69708\"  width=\"760\" height=\"427\"  data-origwidth=\"760\" data-origheight=\"427\" src=\"https:\/\/www.youtube.com\/embed\/?enablejsapi=1&#038;autoplay=0&#038;cc_load_policy=0&#038;cc_lang_pref=&#038;iv_load_policy=1&#038;loop=0&#038;rel=1&#038;fs=1&#038;playsinline=0&#038;autohide=2&#038;theme=dark&#038;color=red&#038;controls=1&#038;disablekb=0&#038;\" class=\"__youtube_prefs__  no-lazyload\" title=\"YouTube player\"  data-epytgalleryid=\"epyt_gallery_84438\"  allow=\"fullscreen; accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture; web-share\" referrerpolicy=\"strict-origin-when-cross-origin\" allowfullscreen data-no-lazy=\"1\" data-skipgform_ajax_framebjll=\"\"><\/iframe><div class=\"epyt-gallery-list\"><div>Sorry, there was a YouTube error.<\/div><\/div><\/div>","protected":false},"excerpt":{"rendered":"<p>What happens when you run&nbsp;docker run hello-world? How do you run a container? What do you see when you run&nbsp;docker ps? What&nbsp;docker commit&nbsp;does? when will you use it? Explain what&#8230; <\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_joinchat":[],"footnotes":""},"categories":[4862],"tags":[],"class_list":["post-6851","post","type-post","status-publish","format-standard","hentry","category-docker"],"_links":{"self":[{"href":"https:\/\/www.devopsschool.com\/blog\/wp-json\/wp\/v2\/posts\/6851","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.devopsschool.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.devopsschool.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.devopsschool.com\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.devopsschool.com\/blog\/wp-json\/wp\/v2\/comments?post=6851"}],"version-history":[{"count":2,"href":"https:\/\/www.devopsschool.com\/blog\/wp-json\/wp\/v2\/posts\/6851\/revisions"}],"predecessor-version":[{"id":25412,"href":"https:\/\/www.devopsschool.com\/blog\/wp-json\/wp\/v2\/posts\/6851\/revisions\/25412"}],"wp:attachment":[{"href":"https:\/\/www.devopsschool.com\/blog\/wp-json\/wp\/v2\/media?parent=6851"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.devopsschool.com\/blog\/wp-json\/wp\/v2\/categories?post=6851"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.devopsschool.com\/blog\/wp-json\/wp\/v2\/tags?post=6851"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}