Docker Run Arguments Example

Docker Compose showed us the advantages of specifying everything in a YAML file as opposed to trying to remember all the arguments we have to pass to docker commands. The Docker package is named lxc-docker (confusingly, since LXC is no longer strictly required). I’d like to run a docker with two volumes mounted inside, from two directory present in the filesystem… how should I do that ? In docker-compose I would have this for example : volumes:. cmd (array of strings) - Custom command to run on the container. Stray whitespace in inspect format could cause errors. In the docker run example above I have not worried about those, so all those configuration options are going to use defaults. In this example, we will use headless Chrome to load our website and perform a simple click on the button we want to test on the site. An image developer can define image defaults related to: detached or foreground running; container identification; network settings; runtime constraints on CPU and memory; With the docker run [OPTIONS] an operator can add to or override the image defaults set by a developer. More often in a larger production environment, you would push to a container registry using jib. Proxy and docker build If you need internet access while building the image you need to pass the environment variables with the --build-arg argument just like you do it with run time environment variables. The environment variables used are the same as those used by the Docker command-line client. My example CMD statement starts foreman , which is adequate for development. 0, the instructions will: Download version v0. Letâ s take an example of the following command in Dock. VMs on MacOS vs. 0 1044 4 ?. xxx -e MS_PORT=7003 samplewls:12. These images are free to use under the Elastic license. Now, you’d also need to tell Docker which container to run. And: If the user specifies arguments to docker run then they will override the default specified in CMD. Start Your Docker Enterprise Hosted Trial Access in minutes. apt-get update should now work and not run into a timeout. For example, the following snippet in Dockerfile. jar Application in a. 19 February 2017 on docker. The parameters object allows users to supply arbitrary command-line options for the docker run command executed by the Mesos. 5, the tag "latest" point to the latest stable release instead of the master branch. Why Docker? 4. This starts Prometheus with a sample configuration and exposes it on port 9090. Docker run –d –p 8080:80 nginx -> Container running inside boot2docker VM To access this web server from host machine,. 2 you would add an entry as. The COMMAND instruction is a way to instruct Docker to run npm install and ng serve. Advanced Docker Compose Configuration We can utilize Docker Compose in new and interesting (and even some unexpected) ways. 148 Build and run the sample locally You can build and run the sample locally with the. sh # located at. If you run a web server (httpd) on a platform whose own character code isn't ISO-8859-1, such as a Mac or an IBM mainframe, then it's the job of the server to convert text documents into ISO-8859-1 code when sending them to the network. Inherited Dockerfiles may unset the entrypoint with ENTRYPOINT []. This means that Docker will take the base image (alpine:3. Using Docker-Compose, we can define a file, containing all the information we passed into the run command. Lorem Ipsum Dolor Docker by Example Ganesh & Hari [email protected] We recommend running this WSGI application with gunicorn. The image being used to create the container is generally specified as : such as ruby:latest. Connect to the instances. To list the containers, run the following command:. Docker also allows operators to simultaneously run and manage apps side-by-side in multiple isolated containers, and it can be used to set up agile software delivery pipelines for faster and more secure shipping. These examples use the directory off the C: drive to avoid any permission conflicts on Windows. Generally we use existing images which is like a template to create new container. The -rm option means that the container will be removed when you Ctrl+D back out of it. Conditions execute in order: • always - Run regardless of Pipeline status • changed - Run if the result of Pipeline has changed from last run • success - Run if Pipeline is successful. The Docker daemon checks to see if it already has a copy of the hello-world container image in its local file system (also called the local container registry). If you start an image, you have a running container of this image. Use the docker-compose build command to build the services specified in the docker-compose. For example, the following would run Neo4j as your current user:. Toggle navigation. py will completely override any SOME_VAR you might have set otherwise for the app. If you need a different browser, Zalenium can redirect your tests to a cloud testing provider (Sauce Labs, BrowserStack, TestingBot, CrossBrowserTesting, LambdaTest). The Docker daemon checks to see if it already has a copy of the hello-world container image in its local file system (also called the local container registry). For example, if port 80 is not available, you can map the landing page to port 8080 using -p 8080:80. You may want to omit CMD entirely and always pass in 0 dev or 1 prod as arguments to the run command. Note that the argument order is different in this case - the image name goes at the end in this command, whereas the shell was at the end in the previous example $ docker run --rm -it --entrypoint /bin/bash myImage You'll now have a shell inside the container that you can use to inspect the contents or run other commands. When a container is run from this image, the url for the GitHub Repo is passed in as environment variable – as well as (optionally) the directory in the repo to run the application from, the name of the file to run and the specific version of the Node runtime to use. A Docker image is a read-only template that defines your container. Docker has almost 4 years now. First Name. You can specify which user to run as by invoking docker with the --user argument. If the docker directory you mapped with the -v option for docker run does not appear on the same path on the host and container then you will need to communicate the mapping to Wing as well, with the Debugger > Advanced > Location Map preference. 6 container whose id is “3464bb547f88” and installed git on top of it. NetworkSettings. This configuration instructs Docker Compose to run three services, each of which corresponds to a Docker container: The prometheus service uses the local prometheus. To do this, we need to run a CMD command. Docker : Writing Your First Dockerfile. Second, is the use of command-line arguments, namely --currency. By now, you should have a really good overview build-time arguments, environment variables, env_files and docker-compose templating with. The docker run command can be used in combination with docker commit to change the command that a container runs. Configure Debugging In order to debug app. In this example, we have a custom shell script which accepts three command line arguments ($1, $2 & $3). Docker tools to easily create and run tests for the PHP-SRC. For security reasons Neo4j will run as the neo4j user inside the container. This guide shows you how to list, stop, and start Docker containers. I would go ahead and remove this if you have it. Save the modified container (while it is still running) to a new image and then you should be able to launch containers using the simpler docker run command as shown # docker run -p8888:8888 sagemath/sagemath:jlabentry sage-jupyterlab Push to OCI Repository. dockerserver Super lightweight & simple RESTFul distributed server for running docker containers on a remote machine(s). You can prepare your filesystem manually, and run the InfluxDB on a Docker container with no initialization scripts. In today’s article, we are going to explore two key Dockerfile instructions that enable us to do just that. Remember that Docker is meant to be one-to-one, container to application, so when building this container it is only natural that we have a command that we want to run that will get our application running in the container. Run a Simple. 4), then execute RUN apk update and then Docker will add the resulting files from that step as another layer on top of the base image. As we've seen in my original tutorial, the simplest example is to run a shell: docker run -ti centos:centos7 /bin/bash So what do we have here? We are running a new container instance with its own TTY (-t) and STDIN (-i), from the CentOS 7 image, with a BASH shell. Create a directory; Directory is required to organize files. args (string) - Extra arguments for docker run on the command line. This Dockerfile uses a build-time argument named RELEASE which has a default value of master. Metadata added as labels - The task adds traceability related metadata to the image in the form of the following labels -. Solution 2. Before running the docker pull command it needs to search the Docker registry for the image to download. A Docker image is the blueprint of Docker containers that contains the application and everything you need to run the application. Here's the layout of my code: esp8266 ├──. Note: This is intended for demonstration purposes only and shouldn’t be used for production or performance/scale testing. Use docker-in-docker executor. Here we’re running the Fedora latest image and then we’re running the logger message. Run a container in interactive mode: #Run a bash shell inside an image $ docker run -it rhel7/rhel bash #Check the release inside a container [[email protected]/]# cat /etc/redhat-release 2. 6, Marathon supports two new keys for docker containers: privileged and parameters. In this short article, I will show you a simple way to run Kafka locally with Docker. Docker Compose showed us the advantages of specifying everything in a YAML file as opposed to trying to remember all the arguments we have to pass to docker commands. Laerte Junior provides a guide to get started creating SQL Server instances in Docker. However, Linux containers require the Docker host to be running a Linux kernel. googleComputeEngineR has a lot of integration with Docker, using it to launch custom pre-made images via the gce_vm_container and gce_vm_template commands. If you don’t use CMD , you always have to pass the command to the argument: docker run -i run_image /usr/local/bin/run. When creating a Docker container, the goal is generally that anyone could simply execute docker run and launch the container. However, this is not representative of how you should run it in production. com -o test-docker. sh script and exists. We do this by running the command docker-compose run, which is similar to its cousin docker run but takes additional arguments for the service (which is web in our case). Followed by various other methods, commands and arguments (or conditions), in return, provide a new image which is to be used for creating docker containers. The extension defines a new runc command for bonobo to run a (local) ETL job within a docker container. The Effect Hook lets you perform side effects in function components:. To do this, you must use the node-red-pi start script in place of node-red. It can be used for example to bind the task to some Maven Phase (package, deploy…). If the specified. The plugin has a Docker-based demo. Remember that Docker is meant to be one-to-one, container to application, so when building this container it is only natural that we have a command that we want to run that will get our application running in the container. Let's explore the differences between the CMD and ENTRYPOINT instructions. sh is the command we want to run in the container—using a shell lets us start interacting with it. If the image already exists, the image is reused. Dockerfile: RUN vs CMD vs ENTRYPOINT. [email protected]:~$ df -h Filesystem Size Used Avail Use% Mounted on udev 30G 0 30G 0% /dev tmpfs 6. As argument to docker run you pass the name or image ID of the Docker image you want to run a container based on. Follow me on Twitter, happy to take your suggestions on topics or improvements /Chris. To enable Docker support, see the Enable Docker section of Using Docker in Cloud Foundry in the Cloud Foundry documentation. docker -v Run Sample docker run Hello-world “docker run” runs a image on docker Some constantly used commands See Docker process docker ps -a Check Docker images docker images Remove Docker images docker rmi 2 e8 2e8 is image id in docker process. They can be used by providing a Dockerfile's content - in various ways - to the docker daemon to build an image. The Python script my_script. 12 (Jun 16, 2017) Label the Docker workspace volume mount shared for SELinux. Once the image has been downloaded, you can now run a container from that image. It work on Windows Server 2016 hosts, but the built-in routing mesh is not supported until the newest Windows Server version 1709, released in October 2017. Availability Installation. Note that the argument order is different in this case - the image name goes at the end in this command, whereas the shell was at the end in the previous example $ docker run --rm -it --entrypoint /bin/bash myImage You'll now have a shell inside the container that you can use to inspect the contents or run other commands. You can define DOCKER_HOST, DOCKER_TLS_HOSTNAME, DOCKER_API_VERSION, DOCKER_CERT_PATH, DOCKER_SSL_VERSION, DOCKER_TLS, DOCKER_TLS_VERIFY and DOCKER_TIMEOUT. xxx -e MS_PORT=7003 samplewls:12. Runtime arguments are passed in when you docker run or start your container: 1 $ docker run [OPTIONS] IMAGE[:TAG|@DIGEST] [COMMAND] [ARG…] They allow you to send variables to your application that will be running in your container as defined in your dockerfile by your CMD or ENTRYPOINT definitions. Containers conflict: IT pros debate Docker bare metal vs. As the operator (the person running a container from the image), you can override that CMD just by specifying a new COMMAND. While Dombrowski’s book is a useful addition to the literature because of the scope of its discussion of ontological arguments—for example, it contains a chapter on Rorty on ontological arguments, and another chapter on John Taylor on ontological arguments—even reviewers sympathetic to process theism have not been persuaded that it makes. To mitigate this and ensure all developers are using the same arguments I switched to docker-compose. Can you try the following one? nvidia-docker run --name digits -d -p 8888:5000 \. In this post we'd like to share our experience in automating big projects start in development, testing, and configuration using docker-compose. You can specify runtime parameters in the Config file the same way you can specify them with the docker run command. The Docker container available on DockerHub is pre-configured to run with gunicorn, and is preferred. This starts Prometheus with a sample configuration and exposes it on port 9090. Now, we want to create a new image snapshot from the container:. In the following example, we use the docker:dind container to run a Docker daemon in a sidecar and give the main container access to the daemon. Despite its popularity, it may be tricky to run it on your development machine- especially if you run Windows. Additional docker run arguments. For example: docker run-d-p 8888:8888-p 4040:4040-p 4041:4041 jupyter/pyspark-notebook; Usage Examples. Preparing our Apps for Docker Compose. To mitigate this and ensure all developers are using the same arguments I switched to docker-compose. A “ Dockerfile ” is another great example on the utility of Docker and analogous to a Makefile. In the case of Docker, the main reason for using the socket is that any user belonging to the docker group can connect to the socket while the Docker daemon itself can run as root. No credit card required. In this example, we are saying to launch the shell , thereby overriding the default CMD instruction for the Docker Image. A guide on Dockerfile to automate building of docker images with examples of docker images, one for to build nodejs web app image and one for nginx server. This guide assumes you have some basic familiarity with Docker and the Docker Command Line. Start Your Docker Enterprise Hosted Trial Access in minutes. Sign in with your Docker ID. compose (boolean) - If true, Vagrant will use docker-compose to manage the lifecycle and configuration of containers. Moreover, we will see the uninstallation process of Docker in Kafka. By now, you should have a really good overview build-time arguments, environment variables, env_files and docker-compose templating with. This post describes how to pass external arguments to R when calling a Rscript with a command line. I use an operating system that has a rolling release, in which kernel updates happen somewhat frequently. "docker run -d -p 8080:8080 -e TOMCAT_PASS="mypass" tutum/tomcat", which can also specified and. You can build Docker images by running “docker build” on these examples. but it just works in the development side not the webserver. Followed by various other methods, commands and arguments (or conditions), in return, provide a new image which is to be used for creating docker containers. sh postgres'. Docker manages these files on behalf of containers. Take note that the docker-compose command is bound to the individual physical host running Docker. To use Docker tasks with Bamboo Windows, run Docker Machine. 2 you would add an entry as. What are Dockerfile Directives. Despite its popularity, it may be tricky to run it on your development machine- especially if you run Windows. To launch a container which will use a volume you have created with docker volume create, add the following argument to the docker run command: -v [volume name]:[container directory] For example, to run a container from the centos image named my-volume-test and map the volume data-volume to the container's /data directory, the command is:. How To Run Custom Script Inside Docker. So I though it's maybe benefitial to write a Step by step setup guide. jar Application in a. The command and arguments that you define cannot be changed after the Pod is created. Compose abstracts all that verbosity away neatly in a "docker-compose. With Docker, you can quickly install download and run the LSST Science Pipelines on any platform without compiling from source. Getting Started with Docker The order of precedence is command line parameters and then environment variables. Hi, I have following Dockerfile where I am trying to call. Before we jump in, let’s understand the basic syntax of the docker run command: docker run [OPTIONS] IMAGE[:TAG] [COMMAND] [ARGS]. Pull Jenkins from the public repo by running: docker pull jenkins/jenkins docker run -p 8080:8080 --name=jenkins-master jenkins/jenkins. The -d option starts the container in the background (detached mode). You can specify runtime parameters in the Config file the same way you can specify them with the docker run command. Jenkins has an “agent” directive, which lets it use docker with pipeline. Docker is designed to run isolated environments in so called containers, without the overhead of virtual machines. Similar to the docker commit command, we can create a new image using the commitCmd method. Docker has almost 4 years now. docker run --rm example/aws-cli If you run this, Docker creates a container from your image, executes the aws command, and then exists. If you pass true as the the first argument, the script will run in. docker run -p 8080:8080 sagemath/sagemath sage -notebook I can map everything across except "-notebook" - does anyone know how to do that? Here is what I have so far, and of course it doesn't work since "-notebook" is not translated over to kubectl correctly:. If you were going to run it in production, you’d want to use external data services for PostgreSQL and Redis, as well as store the GitLab filesystem somewhere that. Docker is a platform for packaging, deploying, and running applications in containers. Docker is an open-source project that provides the tools and ecosystem to build and run applications inside containers. If you run a container using the above Dockerfile, at container start, ab script will get executed with the dummy-url as an argument. #docker help or man docker-run will show you the entire list of command line arguments. 5 release on October 31. Docker and Cgroups. Copy a file from the host machine to the new docker image. Also allows a container to be run as an executable with docker run. Lorem Ipsum Dolor Docker by Example Ganesh & Hari [email protected] In a more realistic example, you will be setting those environment variables inside the container. You can see that when the container starts up, the command portion is interprated to be sh -c 'docker-entrypoint. In the docker run example above I have not worried about those, so all those configuration options are going to use defaults. DOCKER_TLS_VERIFY¶ Verify the host against a CA certificate. The intent of this library is to help any PHP developer to create PHPT tests for the language engine and its core extensions. Use docker-in-docker executor. To generate citations with parenthesis and/or additional content, brackets should be used: e. Connect to the instances. Docker Php Application Example. It lets you do anything the docker command does, but from within Python apps – run containers, manage containers, manage Swarms, etc. Metadata added as labels - The task adds traceability related metadata to the image in the form of the following labels -. Docker defines themselves as: A platform for developers and sysadmins to develop, deploy, and run applications with Introduction Moving towards the world of Dockerization??? Here is the cheat sheet which is going to help you in this journey of containerization and allow you to build and play with Docker Containers. The docker run command uses an image to create a container from scratch to run a specific command in. Docker could, in theory, be used to build a platform to run serverless applications on, but that doesn’t make it serverless. It provides absolutely the same information, as the docker info shell command. This will run a new Redis container via the Docker CLI. Notice that it will lead us into the shell. Hi, I have following Dockerfile where I am trying to call. To detach from the container, you can type the escape sequence Ctrl+P followed by Ctrl+Q. Run SQL Server vNext CTP 1 as a Docker Container on a Mac; Docker installation on Ubuntu Linux. This makes Docker Compose an ideal automation tool for your docker run commands, too. This Docker tutorial will cover everything you need to know to start creating and using containers. For all other tasks we simply hand you back the object that is given to us by docker-java which is a pojo representation of the json handed back by docker. Deploying Go servers with Docker. For more information, and a shell wrapper example, please see the Dockerfile best practices: ENTRYPOINT documentation. Several environment variables must also be passed to the container to allow it to register: MY_LEGAL_NAME - The X500 to use when generating the config. sh postgres'. » parameters - at run time » post - Defines actions to be taken when pipeline or stage completes based on outcome. This is due to using both the -v argument for docker run to mount a volume in the container, and the fact that app. dockerserver Super lightweight & simple RESTFul distributed server for running docker containers on a remote machine(s). For example today it's stuck at 0. note in this example I reserved a range of 65536 UIDs (the numbers in the subuid file are the starting UID and the. In the basic Docker example, we demonstrated how to run GitLab CE in an all-on-one Docker container. For example:. py commands:. Using docker-compose to spawn services and run end-to-end tests is very convenient. This is one way to do it, I will use this example for now but there are other ways to install the node packages. These images can also be used directly with docker run and provide a complete Haskell build environment. Both images run the /bin/echo program. 6 container whose id is “3464bb547f88” and installed git on top of it. You can also use gutter icons and the context menu in the Docker Compose file to control services. We have earlier discussed how to create a docker container & also learned some important commands for managing the containers. A lot of examples (like the prior blog post) will use docker run to start a NAV on Docker container, but there are actually a lot of different ways to start these containers. If you specify CMD , you can override the command specified in the Dockerfile, but not with ENTRYPOINT (see the example in Listing 2 ). It provides absolutely the same information, as the docker info shell command. C:\git\dotnet-docker-samples\aspnetapp>docker inspect -f "{{. Additional docker run arguments. It is a very comprehensive resource. Serving example. Let's create a docker image (node js image) and setup a sample node web app to work with throughout this article:. To point your docker client to the docker daemon inside the VM, use the following command: $ eval $(docker-machine env ) After setting this up, you can run any docker command in your host, and it will execute the command in your RancherOS VM. Use the docker Chef InSpec audit resource to test configuration data for the Docker daemon. 1 as the host IP if you want to run multiple brokers otherwise the brokers won’t be able to communicate. 2019-02-09T00:00:00+00:00 2019-02-09T00:00:00+00:00 http://localhost:4000/2019/02/09/java-11-part2. It currently supports both running a file (with bonobo runc ) or a directory (using bonobo runc ), but not a python module refered as by python dot notation. One drawback is a lack of machine readability in output results. We use the command "docker run" to run a container. Basic Syntax. yml" file and takes the pressure off you to remember the complex tags required for the docker run command. Docker - 'A better way to build apps', as stated on its website, is an open-source platform for building apps and microservices. The docker pull command serves for downloading Docker images from a registry. We will also inject some of our custom HTML for the example. in a docker-compose file). $ docker-compose down. In order to run Kafka, you need a Zookeeper instance and Kafka instance. Passing arguments to the underlying Node. Lorem Ipsum Dolor Docker by Example Ganesh & Hari [email protected] Despite its popularity, it may be tricky to run it on your development machine- especially if you run Windows. Linking is a recent feature added to Docker in the 0. All Prometheus services are available as Docker images on Quay. 0 from GitHub releases page of hacher and unpack. And voila! It works without any problems. • To access exposed ports from host machine, configure port forwarding under NAT in Virtualbox and forward exposed ports to host. This is one way to do it, I will use this example for now but there are other ways to install the node packages. This flag is false by default. In the following example, we use the docker:dind container to run a Docker daemon in a sidecar and give the main container access to the daemon. 2019-02-09T00:00:00+00:00 2019-02-09T00:00:00+00:00 http://localhost:4000/2019/02/09/java-11-part2. The Edit arguments field allows specifying additional options for docker run. To do so, we’ll use the docker run command. Second, is the use of command-line arguments, namely --currency. Docker on Windows 2016 : A simple webserver In our example today we are going to discuss how to create a simple web server (IIS) and run it in a container. To launch a container which will use a volume you have created with docker volume create, add the following argument to the docker run command: -v [volume name]:[container directory] For example, to run a container from the centos image named my-volume-test and map the volume data-volume to the container's /data directory, the command is:. When a Docker image is launched, it exists in a container. The following examples use the configuration settings to illustrate how to write and use docker run commands. Hello world but when container runs as docker run -it John will result in. Docker is a Linux container management toolkit with a "social" aspect, allowing users to publish container images and consume those published by others. Here we’re running the Fedora latest image and then we’re running the logger message. /docker/worker,. Letâ s take an example of the following command in Dock. Docker Swarm enables containers to be managed across different hosts. Example:3 Search Docker Images in its Registry Server With help of 'docker search' command we search the docker. Letâ s take an example of the following command in Dock. If you pass true as the the first argument, the script will run in. The build command takes in some different parameters. If you need a different browser, Zalenium can redirect your tests to a cloud testing provider (Sauce Labs, BrowserStack, TestingBot, CrossBrowserTesting, LambdaTest). A lot of examples (like the prior blog post) will use docker run to start a NAV on Docker container, but there are actually a lot of different ways to start these containers. The -rm option will shut down this container when we’re finished with it. If you run a web server (httpd) on a platform whose own character code isn't ISO-8859-1, such as a Mac or an IBM mainframe, then it's the job of the server to convert text documents into ISO-8859-1 code when sending them to the network. When a container is run from this image, the url for the GitHub Repo is passed in as environment variable – as well as (optionally) the directory in the repo to run the application from, the name of the file to run and the specific version of the Node runtime to use. For each service, you can declare build arguments, which are values available to the image only at build time. Stackify was founded in 2012 with the goal to create an easy to use set of tools for developers to improve their applications. If the specified. when I click run in the VS. They are: DOCKER_HOST¶ The URL to the Docker host. $ docker build -t mydocker. Technically, the command of the build runner is wrapped in a shell script, and this script is executed inside a Docker container with the docker run command. To stop the containers, remove it from Docker and remove the connected networks and volumes from it, we can use the opposite command: $> docker-compose down. This will leave you with a Docker image called that you can deploy and will load your model for serving on startup. When a new task starts, the Amazon ECS container agent pulls the latest version of the specified image and tag for the container to use. io is not maintained by Docker, Inc. The CMD instructions can be however overridden by the docker run subcommand arguments. Some of the elements in this design cannot be used with Kubernetes as is. Example 3: Output arguments. Workflow Server in a Docker container. Thumbsup is published as a Docker image called thumbsupgallery/thumbsup. Step 10: Look at Running Containers. If this is blank, the DOCKER_HOST environment variable will also be read. If you are using docker machine, run the script shipped with the product that sets. This file can be customized to suit your needs and requirements. And, additionally, operators can override nearly all the defaults set by the Docker runtime itself. This makes Docker Compose an ideal automation tool for your docker run commands, too. As you can imagine, running docker run for each of your containers and passing in the command line arguments can become tedious. The --rm option means that the old container is removed afterwards, so it doesn't clutter up your drive. To run the agent to enable the Docker Containerizer, you must launch the agent with “docker” as one of the containerizers option. /docker/web,. Start Your Docker Enterprise Hosted Trial Access in minutes. The docker run command is used to run a Docker container based on a given Docker image. Think of Docker images as a PHP class and a container as an instance of that class. sh # # NOTE: Make sure to verify the contents of the script # you downloaded matches the contents of install. Run a Simple. ENTRYPOINT arguments are always used, while CMD ones can be overwritten by command line arguments provided when Docker container runs. In this case we are running a package update and then installing nginx.