Coffee break #29. 7 websites to prepare for a technical interview. What is the difference between Docker and Kubernetes?

7 websites to prepare for a technical interview

Source: FreeCodeCamp The requirements for developers are getting more and more complex. If a few years ago, to get a job, it was enough to show knowledge of algorithms and data structures, now employers are increasingly looking to see candidates with real experience and skills in their team. Many interviewers focus only on the candidate's ability to use full-stack technologies and teamwork skills. Job seekers will benefit greatly from practice in preparing for a technical interview. Many for this purpose pass so-called test interviews. But besides them, there are also specialized online platforms where you can prepare for interviews in the field of software development. In this article, we will introduce you to some of them.

coderbyte

On Coderbyte's website, you can find programming challenges, interview preparation tips, and practice interview videos. Also here you will find a large number of articles and videos on algorithms, front-end and even technologies related to databases. All this will help you prepare for an interview in any direction of development. What is very useful, all problems have solutions. In addition, you can see the solutions of other users. The only caveat is that you are required to know English (as, indeed, on other sites).

Interview Cake

This site is often cited as the best source for interview articles, tips, and technical interview related content. Here you will find a lot of useful tips on how to communicate effectively with interviewers, even if you don't know the right answer.

AlgoExpert

AlgoExpert is one of the useful sites dedicated to coding problems. On this platform, you will find many video tutorials and interview tips. To prepare for the interview as efficiently as possible, site visitors are offered a selection of 100 tasks using a variety of technologies.

Interviewing.io

This site uses its own method for interview preparation. At Interviewing.io, instead of posting content and practical coding tasks, it is proposed to familiarize yourself with a library of real video interviews. As a paid option, you can anonymously complete a trial interview with an engineer for hire. Of course, interviews alone will not be enough for you. You still can’t do without theory and practice in programming, but it’s still a great investment to get objective feedback.

Leetcode

Leetcode is a site with programming tasks. It also offers several courses to prepare for interviews in large IT companies. When it comes to problem solving, the site displays scores from different teams of developers, so you can compare your results with them.

HackerEarth

HackerEarth is well known for its programming contests and hackathons. But not so long ago there was an opportunity to pass a test interview. The site has a large international developer community, so it's a good resource if you're looking for a place to connect with potential employers.

HackerRank

HackerRank was originally known for its recruiting tools. But now, programming tasks and materials for preparing for interviews are available on this resource. Unlike other sites, there is no paid subscription here: all functionality and task library are free. HackerRank will be useful for anyone who is interested in finding a job but is not sure if they are ready to spend money on paid training.

What is the difference between Docker and Kubernetes?

Source: Geekflare No major project can be imagined without virtualization and containerization. Therefore, today we will try to compare the areas and features of using Kubernetes, Docker, as well as the Docker Swarm orchestration tool.

What is Docker?

At first glance, it may seem that developing an application is all about writing reliable code. However, a problem can arise when you need to provide interoperability when working with multiple programming languages ​​on different platforms. And this is where Docker comes to the rescue. This tool helps to control applications both during development and execution. With it, you can manage storage, memory and application rights, ensure a consistent environment on any host, regardless of the type of operating system (*nix or Windows).

Docker Features

• simple and fast setup. Applications are deployed in less time;
• high performance;
• application isolation - Docker uses containers to run them;
• security management.

What is Kubernetes?

Kubernetes is a container management tool that automates deployment. The platform is open source, previously created by Google. Now it is supported by Cloud Native. Kubernetes helps you quickly update applications, manages the workload and scheduling of containers in a cluster, and automates manual processes, including deploying, scaling, and managing applications in a container.

Features of Kubernetes

• automation of manual processes;
• load balancing. Kubernetes is good at keeping things up and running as traffic increases;
• self-healing. The tool restarts unhealthy containers, moves, and also deletes a container that does not match the user's pattern;
• orchestration: users can automatically mount the storage system to their liking.

Comparison of Docker and Kubernetes

Docker and Kubernetes are different technologies. It is not entirely correct to compare them or raise the question of which of them should be given priority. Docker is a container playground and Kubernetes is a container orchestration tool for platforms like Docker. Docker and Kubernetes often work together. Docker is used to isolate applications in containers, while Kubernetes is a scheduler for deployment and scaling.

Similarities between Docker and Kubernetes:

• microservice architecture;
• mostly written in Go, allowing them to be shipped as lightweight binaries;
• both use files in human-readable YAML format.

What to choose: Docker or Kubernetes?

If your work is based on a microservice architecture, use Docker and create a container for each microservice. Kubernetes is a technology that is especially useful when you have a large development staff that needs a serious production environment. For a small project and three or four developers, the overhead can eat up all the benefits.

Applications

Docker:

• if the application is suitable for running in a container;
• the application does not need a graphical interface;
• the application must be deployed sequentially.

Kubernetes:

If the organization is not tied to one cloud provider, then using Kubernetes will be very reasonable. The reason is that it works the same on all systems. That's why it's called vendor independent. Undoubtedly, both technologies develop in parallel and are launched one after the other. Then what makes people think that there is competition between Docker and Kubernetes? The reason for this is Docker Swarm. This is one of the container orchestration tools from Docker Inc.

What is Docker Swarm?

It is an internal container orchestration tool designed to interact with containers running in a Docker environment. It is used for clustering and scheduling, and allows you to manage multiple containers deployed on multiple host machines. The work uses the standard Docker API.

Work principles:

• backward compatibility;
• default security;
• stable and fault-tolerant architecture;
• simple yet dynamic user interface.

Comparison of Kubernetes and Docker Swarm

Deployment:

Kubernetes : Applications can be deployed using a mix of pods and services/microservices. Docker Swarm: Applications can be deployed as services/microservices in a Swarm cluster or using Docker Compose. A YAML file is used to designate generic containers.

Installation:

Kubernetes: installation is completely manual. Getting started requires careful planning. The installation process may differ for different OS and depends on the service provider. Docker Swarm : Installation is quick and easy compared to Kubernetes. It only takes one set of tools to learn how to build environments and configurations on top of it.

Functioning:

Kubernetes: Navigating within the framework and running Kubernetes will require knowledge and understanding of the Docker CLI. Getting started and configured requires a general understanding of the infrastructure. Docker Swarm: Since this is a Docker development, it uses one language to navigate within the structure. This increases the speed of work and provides variability. Docker thus gains a significant usability advantage.

Logging:

Kubernetes: For a clustered service like Elasticsearch/Kibana, Kubernetes supports multiple versions of monitoring and logging. Docker Swarm: Only monitoring with third party applications is supported. For these purposes, Riemann is usually recommended .

Scaling:

Kubernetes: For distributed systems, Kubernetes is the best choice. This sophisticated all-in-one framework provides strong guarantees regarding the state of the cluster and a unified set of APIs. Docker Swarm: unlike Kubernetes, container deployment speed is much faster. On-demand scaling allows fast response times.

Net:

Kubernetes: The network in Kube is flat. All containers can communicate with each other. Kubernetes requires two CIDRs, one for getting an IP address and one for internal services. Docker Swarm supports the ability to independently encrypt user traffic in a container when creating an overlay network.