What is a container? Explained in simple terms

Container is a concept that is used in both web design and information technology. However, in each of these fields, it has its own specific meaning. In web design, a container is an element that helps structure and organize content on a page, ensuring its convenient display and responsiveness. In the IT context, a container refers to a virtualization technology that allows you to isolate applications and their dependencies, simplifying the deployment and management of software. Thus, despite the general terminology, the context of the use of the word "container" Design and development experts Alexey Nibo and Egor Yakovishen explain the meaning of the term "container" in simple terms. A container is an element used to organize and structure content on a web page. It allows for the grouping of various elements, such as text, images, and buttons, improving the user interface and making information easier to digest. Proper use of containers in web design promotes better navigation and user interaction, which makes the site more attractive and functional.

Design Director of Atvinty, with expertise in UX/UI design and teaching courses on this topic.

A container is a box

A container is an element that serves to hold other elements. It can be compared to a box that holds various objects. In the context of interface design, a container acts as a "box" in which various objects are placed. It helps organize and structure information, ensuring convenient user interaction with the content. Proper use of containers in web development and interface design improves visual and functional components, and also increases the ease of navigation.

Image: freepik

You can place various components in a container. Containers are universal structures that allow you to organize and manage content. They can include text blocks, images, videos, forms, and other elements, providing flexibility in the design and functionality of a web page. Containers allow content to easily adapt to different devices and screen sizes, improving user experience and SEO. Proper use of containers helps organize information more effectively and improves the user experience.

text,
images,
tables,
cards, and so on.

Containers on the website layout: invisible - when the boundaries are not clearly defined, visible - with clear boundaries: Image, background, frameImage: "Atvinta"

Components in a Container

The content of a box can include one or more components. This can be text only, text with an image, or any other combination. These options allow for flexible content customization depending on user needs and page goals.

A container is an area that configures content to fit a specified format. For example, a container for a product card automatically crops the image to a rectangular shape. Regardless of the original dimensions of the uploaded photo, any elements extending beyond the container will be removed. This allows you to maintain a uniform style for displaying products and improves visual perception on the site.

Prototype and layout of a card with an image in the catalog Image: "Atvinta"

What is a container for?

A website or application page is an extensive A container within which the designer can create smaller elements to form the intended composition. These elements can include text blocks, images, and interactive components, allowing for efficient organization of information and improved user experience. Proper content arrangement on a page contributes not only to aesthetics but also to functionality, which is crucial for successful website promotion in search engines.

This is especially important for elements that are difficult to integrate into the overall design grid. Within a container, a unique ecosystem can be created by setting the necessary parameters for a custom grid. This approach allows for more efficient management of elements, ensuring their optimal placement and interaction with other components.

What to Consider When Creating a Container

The main criterion for choosing a container is the elements that will be placed within it. These elements determine the shape, size, frame, and the need for an accent background, as well as other characteristics of the container. The correct choice of these parameters affects the overall appearance and functionality of the container, which is important for creating a harmonious design.

The process of creating a container on the prototype of the resort website Video: "Atvinta"

In Figma and other graphic editors, the container area is represented as a simple geometric shape. A designer can define any container shape, but a rectangle is most commonly used. Various elements and objects are placed within this container, allowing for organization and structure in the design. Proper use of containers in graphics programs facilitates more efficient management of elements and improves the overall visual balance of the project. Before you begin, carefully plan the placement of elements on the page and determine whether they require a modular grid. Use frames or accent backgrounds to visually highlight content. Pay attention to the font size and color of the text to improve readability and draw attention to important information.

A service station is a specialized institution that provides car repair and maintenance services. The main services offered by a service station include diagnostics, oil changes, engine repair, brake system and suspension, as well as electrical work. High-quality service at a service station not only extends the lifespan of a car but also improves its safety on the road. Choosing a reliable service station is of great importance for car owners, as it provides confidence in the vehicle's proper functioning. Regular visits to the service station for maintenance help avoid serious breakdowns and unexpected repair costs. The service station also offers services to prepare cars for seasonal use, which is especially important in a changing climate.

"Is it working locally for me?"

Masha: Vasya, have you completed the deployment yet? The staging screen displays a white screen.

Vasya: That's strange, everything is functioning correctly on my local machine. Give me some time, I'll figure out the problem.

Vasya noticed that the Node.js version is outdated and needs to be updated.

Masha began to think that it was high time to pack everything into containers. Not only will this help you organize your space, but it will also save you time when moving or cleaning. Packing in containers provides reliable protection for items from damage and dirt. It's also a great way to maintain order and systematization, which is especially important in limited space. Sound familiar? Many of us face similar moments in life, when everyday tasks become a real challenge. We often find ourselves in situations where we need to make quick decisions or cope with unexpected circumstances. It's important to learn to adapt to these challenges and find optimal solutions. Coping with difficulties and finding a way out of difficult situations is what makes us stronger and helps us develop. In today's world, full of change and uncertainty, the ability to quickly adapt is becoming a key skill. How do you handle such situations? Differences in environment settings between the developer's computer and the server are a common cause of problems. In this article, we'll look at what environment settings are and how using containers can help avoid such situations. Containers allow developers to create an isolated environment where they can be confident that their code will run consistently across all systems. This is achieved by packaging all dependencies and settings into a single container, minimizing the risk of incompatibility. Thus, the use of containers promotes more stable and predictable application operation across different environments.

Environment and Dependencies

Code cannot function independently; it always runs within a specific environment. Typically, this is either the developer's computer, where the code is written and debugged, or the server on which it is run. To ensure that code runs correctly and consistently across different environments, it is important to configure all environments in a consistent manner. This will help avoid compatibility issues and improve development efficiency, which is especially important in today's environment, where projects may be developed and tested on multiple platforms. Properly configured environments play a key role in the success of software development. An environment consists of many components that interact with each other. Key elements of the environment include physical, biological, and social aspects. Physical components include climate, geography, and resources. Biological aspects encompass ecosystems, flora, and fauna, as well as their interrelationships. Social components represent the interactions between people, their cultures, and economic systems. All these elements are interconnected and influence the sustainability and development of the environment. Understanding these components is important for the effective management of natural resources and the preservation of ecosystems. The operating system plays a key role in the operation of computers and servers. Developers most often choose Windows or macOS for their workstations, as these systems offer a wide range of tools and a user-friendly interface. Meanwhile, servers typically run various Linux distributions, which ensure high stability, security, and performance. The choice of operating system depends on the specific tasks and requirements of users, making understanding the different platforms an important aspect of the IT field.

A runtime environment is an essential component of programming languages such as Python, Node.js, Go, and PHP. When you enter commands such as python my_script.py or node main.js, your script is executed in this environment. It provides the necessary infrastructure for programs to run, providing access to libraries, interpreters, and other resources needed to execute code. Understanding how the runtime environment works will help you optimize the process of developing and debugging your applications.

Certain libraries are required for an application to function correctly. These libraries provide interaction with network resources, graphics processing, video and audio work, as well as management of encryption and other system functions. Without them, the application will not be able to effectively perform its tasks and provide the required functionality to users.

Configuration files and system settings play a key role in ensuring the stable and efficient operation of software. These files contain important settings that determine the functionality of applications and operating systems. Properly configuring configuration files allows you to optimize performance, ensure security, and set up integration between various systems.

Working with configuration files requires care, as incorrect changes can lead to system failures. Therefore, it is important to understand the structure and format of these files, as well as the potential consequences of changes. Regularly backing up your configuration files will help prevent losses in the event of errors.

Whether you're working with web servers, databases, or operating systems, properly configuring configuration files is key to reliable and secure system operation.

Other applications that need to be running and available include web servers such as nginx, databases including PostgreSQL and MongoDB, and messaging systems such as RabbitMQ and Kafka. These components play a key role in ensuring the efficient operation of modern web applications and systems.

These components of the environment are commonly referred to as dependencies. Dependencies play a key role in the operation of software because they determine which external libraries or modules are required for the application to function correctly. Dependency management allows developers to effectively control the versions of the components used, ensuring stability and compatibility. Proper dependency management also helps simplify the development and testing process, making it more predictable and reliable.

When developing software, it is important to consider not only the availability of required dependencies but also their versions. For example, if Node.js version 16 is installed on one computer and version 18 on another, this could cause code to behave incorrectly or even fail completely. Therefore, to ensure project stability and compatibility, it is recommended to use the same versions of dependencies on all devices. This is especially important when working in a team and deploying applications to different servers. Controlling dependency versions helps avoid unexpected errors and simplifies the development process.

Even if you configure all the settings correctly once, it won't last long. Regular updates and optimization are essential to keeping your system efficient and up-to-date. You should periodically review your settings, adapt them to changes in the environment, and take into account new trends. This will help maintain high results and prevent potential problems in the future.

New developers will join the team, and they will need to prepare the production environment.
Important updates to the operating system or libraries will appear that will need to be installed everywhere.
As the number of product users grows, the need for new servers will arise.

Continuously monitoring the configuration of a growing and changing set of environments becomes an increasingly complex task.

Containers are an excellent solution in this situation. They offer a convenient way to organize and store information, and also allow for effective data management. Using containers simplifies the process of developing and deploying applications, providing isolation and scalability. Choosing containers as a tool for optimizing workflows can significantly improve productivity and simplify resource management.

Containers and Docker

Containers in development are an effective method of packaging code and all its dependencies into a single isolated environment. This approach allows a container to be handed off to another developer or deployed to a server with the assurance that it will run with the same configuration it was created with. This significantly simplifies the process of developing and deploying applications, minimizing issues related to software and environment incompatibility. Using containers allows developers to test and implement changes faster, increasing overall team productivity. Docker is the most common tool for creating and managing containers. The container lifecycle includes several key stages, each of which plays an important role in the management and operation of containerized applications. This process begins with container creation, when the developer defines the necessary dependencies and settings in the image. This is followed by the startup stage, during which the container is initialized and begins performing its specified tasks. After the container has completed its operation, its state may change: it may be stopped, deleted, or remain dormant. It is important to note that effective container lifecycle management helps optimize resource usage and improve application stability.

Containers can also be restarted or updated without requiring extensive downtime, making them an ideal solution for developing and deploying modern applications. Understanding all stages of the container lifecycle helps developers and system administrators better manage infrastructure and ensure high service availability.

The process begins with taking an existing application and creating a container configuration description for it. In Docker, a special file called a Dockerfile is used for this purpose, which is stored in the same folder as the project code. This file contains the instructions needed to build the container image, ensuring its stable operation in various environments. Properly configuring a Dockerfile is a key step in application containerization, as it significantly simplifies deployment and management of the application in cloud and on-premises environments.

An example Dockerfile for a Node.js web application demonstrates how to effectively create a container for your application. Start by choosing a base image, for example, `node:14`, which contains the Node.js runtime. Next, install the required dependencies by copying the `package.json` and `package-lock.json` files to the container and running the `npm install` command. After that, add your source code to the container using the `COPY` command. Make sure your application is listening on the correct port, which should be exposed using the `EXPOSE` instruction. Complete the Dockerfile by specifying the command to run your application, for example, `CMD [«node», «app.js»]`. This simple Dockerfile will create an optimized image for your Node.js application, allowing you to easily deploy it to a containerized environment.

The basis for application development will be the Node.js version 18 image. This image provides a stable and highly efficient environment for executing JavaScript code on the server-side. Node.js 18 offers improved features such as built-in support for ES Modules, an updated streaming engine, and improved performance, making it an ideal choice for building scalable web applications and APIs. Using this image gives you access to the latest updates and security, which is critical to maintaining the reliability of your project. Choosing Node.js 18 as a foundation allows developers to take advantage of the latest technology advancements and streamline their development processes.

Use the official Node.js 18 image to build and deploy applications. This image provides a stable environment for developing and running JavaScript applications on the server-side. Node.js 18 includes the latest updates and performance improvements, making it an ideal choice for modern web developers. Using this image simplifies dependency management and environment setup, promoting more efficient development and faster application deployment.

Setting the /app directory as the working directory is an important step in setting up an environment for developing or deploying applications. This helps organize the project structure and ensure convenient access to the necessary resources. The /app working directory becomes the center for executing commands, managing dependencies, and storing configuration files. Properly setting the working directory promotes more efficient development and simplifies debugging.

WORKDIR /app

The WORKDIR directive is used in the Dockerfile to set the working directory within the container. By specifying WORKDIR /app, you specify that all subsequent commands in the Dockerfile will be executed in the /app directory. This simplifies the project structure and helps avoid confusion with file paths. Proper use of WORKDIR improves the readability of the Dockerfile and makes it more understandable for developers, which facilitates efficient work with containers.

Copying the package.json and package-lock.json files from the project is an important step in ensuring the correct operation of your application. These files contain information about the project's dependencies, versions of the libraries used, and other configuration data.

To successfully copy these files, you must ensure that you are in the root directory of your project. Use the copy commands appropriate for your operating system to move package.json and package-lock.json to the correct location.

Note that package.json manages your project's dependencies and scripts, while package-lock.json locks the versions of installed packages, avoiding conflicts and ensuring build reproducibility. Properly copying these files will help keep your application stable and predictable.

Copying package.json and package-lock.json to the current directory allows you to install all the necessary dependencies for the project. This is an important step in setting up the environment, as these files contain information about packages, their versions, and dependencies. Make sure you are in the root directory of the project before running this command. This will help avoid installation errors and ensure the correct functioning of your application.

Installing dependencies is a key step in software development. This process involves downloading and configuring the necessary libraries and packages that enable your application to function. Properly installing dependencies ensures that all components work together and minimizes the likelihood of errors. For optimal performance of your project, it is important to consider compatible library versions and their up-to-dateness. Use dependency management tools such as npm or pip to simplify the installation and update process. This will allow you to focus on development, without being distracted by issues related to incompatibility or missing packages.

To install the required project dependencies, run the npm install command. This command will download and install all the packages specified in your package.json file. Make sure you have Node.js and npm installed to ensure the command runs correctly. Once the installation is successful, you will be able to run the project and use all its functionality.

Copying the remaining application code is an important step in the development process. This step involves porting and adapting the code, which helps ensure the functionality and integrity of the application. It is important to pay attention to the code structure and to optimize it for improved performance. Properly organizing and copying code not only speeds up the development process but also simplifies subsequent maintenance and updates of the application. It is also recommended to use version control systems to track changes and ensure the ability to roll back to previous versions of the code if necessary.

Copying files and directories in operating systems is an important task, especially for data management and backup purposes. The COPY command allows the user to quickly and efficiently duplicate content from one location to another. It is used both in the Windows command line and in other operating systems, such as Linux, where similar commands can perform the same function. It is important to correctly specify the paths to the source and destination files for the operation to be successful. Proper use of the COPY command helps avoid data loss and simplifies the organization of the file structure, which, in turn, promotes more efficient work with information.

Expanding port 3000 in a container is an important step when setting up applications running in a containerization environment such as Docker. Port 3000 is often used for developing web applications, and its availability inside the container allows for communication between the application and users. To open port 3000, you must use the appropriate commands in the Dockerfile or when starting the container using the Docker CLI. Ensure that the port is forwarded correctly and does not conflict with other services to ensure the smooth operation of your application. Proper port configuration plays a key role in ensuring the security and performance of your container environment.

EXPOSE 3000 is an instruction used in Docker to specify the port that the container will listen on during execution. This port is necessary for communication between the container and the outside world. By specifying EXPOSE 3000, you are indicating that your service running inside the container will be accessible on port 3000. This is important for setting up networking and allowing other services or users to connect to your application using the specified port. This instruction does not open the port, but only documents it, so for actual access, you must use commands such as docker run with parameters that open the desired port. Therefore, properly setting EXPOSE 3000 is a key step in the process of containerizing applications using Docker.

Starting an application is an important stage in the process of using it. To launch successfully, you need to complete several key steps. First, make sure your device meets the application's system requirements. If all conditions are met, locate and run the installation file. Then, follow the on-screen instructions to complete the installation process. After installation, open the application and configure it according to your preferences. Pay attention to updates that can improve the functionality and security of the application. Proper launch of the application ensures its stable operation and efficiency in performing its intended tasks. To launch the application, use the CMD command with the «npm» and «start» parameters. This command initiates the process necessary to start your Node.js application. Make sure all dependencies are installed and the project configuration is correct. Using this command allows you to effectively manage the launch of your application in the Docker environment or other containerized systems. Optimize your project settings to achieve maximum performance and stability at launch.

Once the Dockerfile is ready, we can create a container image using the build command. This command transforms the instructions in a Dockerfile into an executable container image that can be used to deploy an application in an isolated environment. Building an image is a crucial step in the containerization process, ensuring reproducibility and portability of applications. Preparing a Dockerfile and creating a container image are key steps in developing and deploying modern applications using containerization technologies.

To build an application image using Docker, run the docker build command with the -t flag, which allows you to specify the image name. In the example, the image name is set to myapp, and the period at the end points to the current directory, which contains the Dockerfile and all the necessary files for the build. This command allows you to effectively manage the process of developing and deploying applications in containers. Make sure you have Docker installed and are in the correct directory before running the command.

We have a container template named myapp. This is not the container itself, but a base that allows you to launch any number of container instances based on this template.

Let's launch the container from the newly created image. To do this, we'll use a command that creates and runs a new container based on our image. Make sure you're in the correct directory and have the necessary permissions. When running a container, you can specify various parameters, such as the container name, ports to expose, and environment variables. This will allow you to customize the container to your needs and ensure it runs correctly.

Running an application in Docker with port forwarding can be accomplished using a command that binds the container port to the host port. To do this, use the following command: docker run -p 80:3000 myapp. This command will expose port 3000 of the myapp container on port 80 of your host. This allows users to access your application through the standard HTTP port, providing convenient access and improving interaction with the service. Make sure your Docker container is configured correctly and all dependencies are installed for the application to run correctly.

The container has been successfully launched. Note the -p 80:3000 parameter, which redirects incoming requests from port 80 on the host machine to port 3000 inside the container. This allows the application to handle external HTTP requests, providing access to its functionality. Configuring port forwarding is a key aspect of working with containers, as it allows interaction with the application through the standard web port.

Once the container is running, we can monitor logs using the docker logs command and access the container terminal using the docker attach command. These tools allow us to effectively monitor the application's state and perform debugging in real time.

It is possible to run many different containers on a single computer or server. Containerization allows for efficient resource utilization, application isolation, and simplified management. This makes containers an ideal solution for software development, testing, and deployment. Each container operates independently, providing application flexibility and scalability. Using containers on a single device allows you to optimize your infrastructure and improve its efficiency.

Containers allow you to run different applications or their versions, which is especially useful for safely rolling back to a previous version. By default, they provide complete isolation both from the host machine and from each other. If necessary, you can open specific ports and configure communication between containers, which allows for effective collaboration between applications within a single environment.

What else is useful to know about containers

In large projects, the number of containers can reach hundreds, and they are started and stopped automatically. For example, if the load increases or errors occur in some containers, the system automatically restarts them or adds new ones. This automated process of managing and coordinating containers is called orchestration. One of the most popular tools for container orchestration is Kubernetes, which provides efficient resource allocation, scaling, and application lifecycle management. Kubernetes enables developers and operations teams to optimize containerized applications, improving their stability and performance. Container registries play a key role in storing and distributing container images. Docker offers a public repository called Docker Hub, which allows users to upload and share container images. This repository functions similarly to GitHub and is a convenient platform for sharing images. For enterprise and production projects, private registries, such as Amazon Container Registry, are often chosen, providing an additional layer of security and access control to container images. Using container registries streamlines application development and deployment processes, improving team collaboration. Containers play a key role in modern software development. They provide application isolation, allowing developers to build, test, and deploy code in a homogeneous environment. Using containers significantly simplifies the process of managing dependencies and configurations, which in turn increases development efficiency.

With containers, developers can easily scale applications, providing resource flexibility and simplifying their work with cloud platforms. Containers also improve security because applications run in isolated environments, minimizing the risk of vulnerabilities.

Furthermore, containers support the "write once, run anywhere" principle, allowing developers to be confident that their code will run consistently across different platforms. This simplifies teamwork and significantly reduces the time required to deploy and update applications.

As a result, containers become an indispensable tool for developers, enabling them to create higher-quality and reliable applications with less time and resources.

Containers play a vital role in packaging application code and its dependencies in an isolated environment, allowing it to run on any system that supports Docker. This solution eliminates issues associated with configuration differences between local machines and servers, providing confidence that the code will run stably without unexpected errors. Using containers streamlines the development and deployment process, making it more predictable and efficient.

Learn more about design on our Telegram channel. Subscribe to stay up-to-date on current trends and get helpful tips.