![\"run_docker_image\"](\"http:\/\/shijuvarghese.com\/wp-content\/uploads\/2018\/08\/run_docker_image.jpg\")
<\/a><\/p>\nLet us try to run an image named\u00a0\u00a0hello-world<\/em>. If the image is not present in localhost, the application will check in Docker repository and download hello-world container image.<\/p>\n[root@centos9docker ~]#<\/strong> docker run hello-world<\/p>\n===== ===<\/em>
\nUnable to find image ‘hello-world:latest’ locally<\/em>
\nlatest: Pulling from library\/hello-world<\/em>
\nc1ec31eb5944: Pull complete<\/em>
\nDigest: sha256:1408fec50309afee38f3535383f5b09419e6dc0925bc69891e79d84cc4cdcec6<\/em>
\nStatus: Downloaded newer image for hello-world:latest<\/em><\/p>\nHello from Docker!<\/em>
\nThis message shows that your installation appears to be working correctly.<\/em><\/p>\nTo generate this message, Docker took the following steps:<\/em>
\n 1. The Docker client contacted the Docker daemon.<\/em>
\n 2. The Docker daemon pulled the “hello-world” image from the Docker Hub.<\/em>
\n (amd64)<\/em>
\n 3. The Docker daemon created a new container from that image which runs the<\/em>
\n executable that produces the output you are currently reading.<\/em>
\n 4. The Docker daemon streamed that output to the Docker client, which sent it<\/em>
\n to your terminal.<\/em><\/p>\nTo try something more ambitious, you can run an Ubuntu container with:<\/em>
\n $ docker run -it ubuntu bash<\/em><\/p>\n=== ==== ==<\/em><\/p>\nSimilarly, let us download and run a small Ubuntu server, opening it in a console view:<\/p>\n
[root@docker1 ~]# docker run -it\u00a0ubuntu\u00a0<\/strong><\/em><\/p>\nThe command Ctrl+PQ<\/strong> will allow us to exit from the Ubuntu host’s console. However the server will continue to run, and the Ubuntu image will continue to run. Instead, if we type “exit” instead of Ctrl+PQ<\/strong>\u00a0the container will stop and you will get back to the base node’s cli.<\/p>\nTry both the situations and check the status of containers running on the node by issuing the command “docker ps<\/strong>“.<\/p>\nLet us run a container from image ubuntu and list out the directories in it when the container comes up<\/p>\n
[root@docker1 ~]# docker run ubuntu ls<\/strong><\/em><\/p>\n[root@docker1 ~]# docker run ubuntu\u00a0ping google.com<\/strong><\/em><\/p>\nLet us\u00a0list the containers running on the docker. Take a note of the “NAME”<\/strong> field.<\/p>\n[root@docker1 ~]# docker ps<\/strong><\/em><\/p>\n[root@docker1 ~]# docker ps -aq<\/strong><\/em><\/p>\nBelow command will list all containers ever created.<\/p>\n
[root@docker1 ~]# docker ps –all<\/strong><\/em><\/p>\nBelow command will remove an image named hello-world<\/p>\n
[root@docker1 ~]#\u00a0docker rmi -f\u00a0 hello-world\u00a0<\/strong><\/em><\/p>\nThe below command\u00a0will allow us to get back to the container named “thirsty_ptolemy”<\/em> if it is shown as running when the above command was executed.<\/p>\n[root@docker1 ~]# docker attach thirsty_ptolemy<\/strong><\/em><\/p>\nOnce in the container’s console, the command “exit”<\/em> will stop the container, and exit out of its shell. Now the command “docker ps”<\/em> will not display the container named “thirsty_ptolemy”.<\/p>\nroot@bb06e23e73e2:\/# exit<\/strong><\/em><\/p>\nLists the images available in the host<\/p>\n
[root@docker1 ~]# docker images<\/strong><\/em><\/p>\nRemove the “hello-world” image from the host.<\/p>\n
[root@docker1 ~]# docker rmi -f hello-world<\/strong><\/em><\/p>\n************ ***********<\/p>\n
The below is an exerciser to create a small image from a set of files, that will be later used to run as container<\/p>\n
[root@docker1 ~]# mkdir \/sandbox<\/strong><\/em>
\n [root@docker1 ~]# cd \/sandbox<\/strong><\/em>
\n [root@docker1 hello-system]# vi index.js<\/strong><\/em><\/p>\nAdd the below contents between the lines<\/p>\n
===== ====== ====== ===<\/p>\n
var http = require(‘http’);<\/em><\/p>\nconst PORT = 80;<\/em><\/p>\nfunction requestHandler(req, res) {<\/em>
\n res.end(`Hello my ${process.platform}`);<\/em>
\n }<\/em><\/p>\nvar server = http.createServer(requestHandler);<\/em><\/p>\nserver.listen(PORT, function(){<\/em>
\n console.log(`${process.env.NODE_ENV} server listening on port: ${PORT}. CTRL-C to exit.`);<\/em>
\n });<\/em><\/p>\n===== ====== ====== ===<\/p>\n
[root@docker1 hello-system]# vi package.json<\/strong><\/em><\/p>\nThis is copied from :<\/p>\n
https:\/\/github.com\/HermantNET\/hello-system\/blob\/master\/package.json<\/p>\n
===== === ========= ======= ======== ======<\/p>\n
{<\/em>
\n “name”: “hello-system”,<\/em>
\n “version”: “1.0.0”,<\/em>
\n “description”: “Greets the current operating system”,<\/em>
\n “main”: “index.js”,<\/em>
\n “scripts”: {<\/em>
\n “start”: “NODE_ENV=production node index.js”,<\/em>
\n “test”: “echo \\”Error: no test specified\\” && exit 1″<\/em>
\n },<\/em>
\n “repository”: {<\/em>
\n “type”: “git”,<\/em>
\n “url”: “github.com\/hermantnet\/hello-system”<\/em>
\n },<\/em>
\n “author”: “Thomas E Herman Jr”,<\/em>
\n “license”: “ISC”<\/em>
\n }<\/em><\/p>\n===== === ========= ======= ======== ======<\/p>\n
[root@docker1 hello-system]# vi .Dockerfile<\/strong><\/em><\/p>\n=======**=======**===<\/p>\n
FROM node:4-onbuild<\/em>
\n EXPOSE 80<\/em><\/p>\n=======**=======**===<\/p>\n
Now let us build the image, and look for the confirmation message “Successfully tagged hello-system:latest”
\n[root@docker1 hello-system]# docker build -t hello-system -f .\/.Dockerfile .<\/strong><\/em><\/p>\nLet us run the image
\n[root@docker1 hello-system]# docker run -it –rm –name shiju-running-app hello-system<\/strong><\/em>
\nThis should run the image in its console view with the message at the end “production server listening on port: 80. Press CTRL-C to exit.”<\/p>\nPressing CTRL+C should bring you back to your host’s shell prompt.<\/p>\n
On basis of message displayed in the docker’s console view, you may not be able to check the website using “http:\/\/localhost:80”<\/em>, etc.<\/p>\nYou will have to create the container mapping a free port in the base host with the port 80 listened by the container, as shown below:<\/p>\n
[root@docker1 \/]# docker run -it -p 1337:80 –name myContainer hello-system<\/strong><\/em>
\nNow the website can be accessed using “http:\/\/localhost:1337”<\/span><\/em><\/p>\nPressing CTRL+C<\/em> should bring you back to your host’s shell prompt, but the container may be still running though the command “docker ps” wont list this container as running.<\/p>\n[root@docker1 hello-system]# docker ps<\/strong><\/em><\/p>\n[root@docker1 \/]# docker run -it -p 1337:80 –name myContainer hello-system<\/strong><\/em>
\nNote: This may give an error stating the container is running.<\/p>\n <\/p>\n
Below trick will remove the container completely<\/strong><\/p>\n[root@docker1 \/]# docker start myContainer<\/strong><\/em>
\n [root@docker1 \/]# docker rm -f myContainer<\/strong><\/em><\/p>\nThe\u00a0docker run<\/strong> command\u00a0creates<\/strong> a container and\u00a0starts<\/strong> it.\u00a0The command to create a container is\u00a0docker create <image>\u00a0<\/strong>and the command to run it is\u00a0docker start <container ID><\/strong>.<\/p>\nImagine you have changed the content in the “index.js” file to display a webpage “Hello my system Linux”. This will not come into action just by restarting the container. You will have to build a new docker image from the files, or run the following command, binding the folder holding the content to a place where the app will be located.<\/p>\n
[root@docker1]# docker run -it -p 1338:80 -v \/root\/hello-system\/.:\/usr\/src\/app –name myContainer hello-system<\/strong><\/em><\/p>\nCheck the site accessing the base host via port 1338<\/p>\n
<\/p>\n
List all containers hosted in the system, weather running or not:<\/p>\n
[root@docker1 docker]# docker container ls -all<\/strong><\/em><\/p>\n <\/p>\n
Remove a container named myContainer2<\/em><\/p>\n[root@docker1 docker]#\u00a0docker rm -f myContainer2<\/strong><\/em><\/p>\n <\/p>\n","protected":false},"excerpt":{"rendered":"
This tutorial is aimed to teach one how to install Docker in CentOS\u00a09 base host, and to perform basic tasks. Quick Notes: You cannot […]<\/a><\/p>\n<\/div>","protected":false},"author":1,"featured_media":730,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[25,30],"tags":[],"class_list":["post-722","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-docker","category-rhel-9"],"_links":{"self":[{"href":"http:\/\/shijuvarghese.com\/index.php?rest_route=\/wp\/v2\/posts\/722","targetHints":{"allow":["GET"]}}],"collection":[{"href":"http:\/\/shijuvarghese.com\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/shijuvarghese.com\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/shijuvarghese.com\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/shijuvarghese.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=722"}],"version-history":[{"count":30,"href":"http:\/\/shijuvarghese.com\/index.php?rest_route=\/wp\/v2\/posts\/722\/revisions"}],"predecessor-version":[{"id":1618,"href":"http:\/\/shijuvarghese.com\/index.php?rest_route=\/wp\/v2\/posts\/722\/revisions\/1618"}],"wp:featuredmedia":[{"embeddable":true,"href":"http:\/\/shijuvarghese.com\/index.php?rest_route=\/wp\/v2\/media\/730"}],"wp:attachment":[{"href":"http:\/\/shijuvarghese.com\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=722"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/shijuvarghese.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=722"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/shijuvarghese.com\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=722"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}
![\"Container](\"http:\/\/shijuvarghese.com\/wp-content\/uploads\/2018\/08\/container.jpg\")
<\/a><\/p>\n