30+ Docker Interview Questions (ANSWERED) in 2020

30+ Docker Interview Questions (ANSWERED) in 2020

Q1: What is the need for DevOps? What is the need for DevOps?
39 DevOps Interview Questions  DevOps  39  Entry
Answer
Nowadays instead of releasing big sets of features, companies are trying to see if small features can be transported to their customers through a series of release trains. This has many advantages like quick feedback from customers, better quality of software etc. which in turn leads to high customer satisfaction. To achieve this, companies are required to:

Increase deployment frequency
Lower failure rate of new releases
Shortened lead time between fixes
Faster mean time to recovery in the event of new release crashing
DevOps fulfills all these requirements and helps in achieving seamless software delivery.

Interview Coming Up?  Check 39 DevOps Interview Questions
linkedureka.co
Q2: What is Docker? What is Docker?
55 Docker Interview Questions  Docker  55  Entry
Answer
Docker is a containerization platform which packages your application and all its dependencies together in the form of containers so as to ensure that your application works seamlessly in any environment be it development or test or production.
Docker containers, wrap a piece of software in a complete filesystem that contains everything needed to run: code, runtime, system tools, system libraries etc. anything that can be installed on a server.
This guarantees that the software will always run the same, regardless of its environment.
Interview Coming Up?  Check 55 Docker Interview Questions
linkedureka.co
Q3: What are the advantages of DevOps? What are the advantages of DevOps?
39 DevOps Interview Questions  DevOps  39  Junior
Answer
Technical benefits:

Continuous software delivery
Less complex problems to fix
Faster resolution of problems
Business benefits:

Faster delivery of features
More stable operating environments
More time available to add value (rather than fix/maintain)
Interview Coming Up?  Check 39 DevOps Interview Questions
linkedureka.co
👉 See All Questions 
50 CSS Interview Questions  CSS  50 
38 Software Architecture Interview Questions  Software Architecture  38 
81 MongoDB Interview Questions  MongoDB  81 
44 AWS Interview Questions  AWS  44 
72 Ruby on Rails Interview Questions  Ruby on Rails  72 
55 HTML5 Interview Questions  HTML5  55 
164 React Interview Questions  React  164 
39 Questions to Ask Interview Questions  Questions to Ask  39 
39 TypeScript Interview Questions  TypeScript  39 
57 Entity Framework Interview Questions  Entity Framework  57 
30 Data Structures Interview Questions  Data Structures  30 
27 Reactive Programming Interview Questions  Reactive Programming  27 
45 Design Patterns Interview Questions  Design Patterns  45 
116 JavaScript Interview Questions  JavaScript  116 
113 Android Interview Questions  Android  113 
Q4: What is the function of CI (Continuous Integration) server? What is the function of CI (Continuous Integration) server?
39 DevOps Interview Questions  DevOps  39  Junior
Answer
CI server function is to continuously integrate all changes being made and committed to repository by different developers and check for compile errors. It needs to build code several times a day, preferably after every commit so it can detect which commit made the breakage if the breakage happens.

Interview Coming Up?  Check 39 DevOps Interview Questions
linklinoxide.com
Q5: How to build envrionment-agnostic systems with Docker? How to build envrionment-agnostic systems with Docker?
55 Docker Interview Questions  Docker  55  Junior
Answer
There are three main features helping to achieve that:

Volumes
Environment variable injection
Read-only file systems
Interview Coming Up?  Check 55 Docker Interview Questions
linkrafalgolarz.com
👉 See All Questions 
82 PHP Interview Questions  PHP  82 
52 Agile & Scrum Interview Questions  Agile & Scrum  52 
38 Bootstrap Interview Questions  Bootstrap  38 
113 Android Interview Questions  Android  113 
39 Questions to Ask Interview Questions  Questions to Ask  39 
95 Node.js Interview Questions  Node.js  95 
72 Ruby on Rails Interview Questions  Ruby on Rails  72 
58 Web Security Interview Questions  Web Security  58 
66 SOA & REST API Interview Questions  SOA & REST API  66 
41 Vue.js Interview Questions  Vue.js  41 
14 NoSQL Interview Questions  NoSQL  14 
72 React Native Interview Questions  React Native  72 
68 Kotlin Interview Questions  Kotlin  68 
62 AngularJS Interview Questions  AngularJS  62 
Q6: What is the difference between the `COPY` and `ADD` commands in a Dockerfile? What is the difference between the `COPY` and `ADD` commands in a Dockerfile?
55 Docker Interview Questions  Docker  55  Junior
Answer
Although ADD and COPY are functionally similar, generally speaking, COPY is preferred.

That’s because it’s more transparent than ADD. COPY only supports the basic copying of local files into the container, while ADD has some features (like local-only tar extraction and remote URL support) that are not immediately obvious. Consequently, the best use for ADD is local tar file auto-extraction into the image, as in ADD rootfs.tar.xz /.

Interview Coming Up?  Check 55 Docker Interview Questions
linkstackoverflow.com
35 Entity Framework Interview Questions (ANSWERED + .NET Core Updates) For 2020
35 Entity Framework Interview Questions (ANSWERED + .NET Core Updates) For 2020
#Entity Framework 
Q7: What is Docker image? What is Docker image?
55 Docker Interview Questions  Docker  55  Junior
Answer
Docker image is the source of Docker container. In other words, Docker images are used to create containers. Images are created with the build command, and they’ll produce a container when started with run. Images are stored in a Docker registry such as registry.hub.docker.com because they can become quite large, images are designed to be composed of layers of other images, allowing a minimal amount of data to be sent when transferring images over the network.

Interview Coming Up?  Check 55 Docker Interview Questions
linkedureka.co
👉 See All Questions 
55 Docker Interview Questions  Docker  55 
33 ASP.NET MVC Interview Questions  ASP.NET MVC  33 
38 Software Architecture Interview Questions  Software Architecture  38 
45 Design Patterns Interview Questions  Design Patterns  45 
84 Ruby Interview Questions  Ruby  84 
35 LINQ Interview Questions  LINQ  35 
13 UX Design Interview Questions  UX Design  13 
32 Webpack Interview Questions  Webpack  32 
53 OOP Interview Questions  OOP  53 
30 Data Structures Interview Questions  Data Structures  30 
39 Questions to Ask Interview Questions  Questions to Ask  39 
68 Kotlin Interview Questions  Kotlin  68 
66 SOA & REST API Interview Questions  SOA & REST API  66 
Q8: What is Docker container? What is Docker container?
55 Docker Interview Questions  Docker  55  Junior
Answer
Docker containers include the application and all of its dependencies, but share the kernel with other containers, running as isolated processes in user space on the host operating system. Docker containers are not tied to any specific infrastructure: they run on any computer, on any infrastructure, and in any cloud.

Interview Coming Up?  Check 55 Docker Interview Questions
linkedureka.co
Q9: What is Docker hub? What is Docker hub?
55 Docker Interview Questions  Docker  55  Junior
Answer
Docker hub is a cloud-based registry service which allows you to link to code repositories, build your images and test them, stores manually pushed images, and links to Docker cloud so you can deploy images to your hosts. It provides a centralized resource for container image discovery, distribution and change management, user and team collaboration, and workflow automation throughout the development pipeline.

Interview Coming Up?  Check 55 Docker Interview Questions
linkedureka.co
👉 See All Questions 
35 LINQ Interview Questions  LINQ  35 
39 TypeScript Interview Questions  TypeScript  39 
68 Kotlin Interview Questions  Kotlin  68 
44 AWS Interview Questions  AWS  44 
72 Ruby on Rails Interview Questions  Ruby on Rails  72 
42 Blockchain Interview Questions  Blockchain  42 
22 PWA Interview Questions  PWA  22 
52 Agile & Scrum Interview Questions  Agile & Scrum  52 
66 SOA & REST API Interview Questions  SOA & REST API  66 
164 React Interview Questions  React  164 
16 MSMQ Interview Questions  MSMQ  16 
49 Golang Interview Questions  Golang  49 
55 Docker Interview Questions  Docker  55 
Q10: What are the various states that a Docker container can be in at any given point in time? What are the various states that a Docker container can be in at any given point in time?
55 Docker Interview Questions  Docker  55  Junior
Answer
There are four states that a Docker container can be in, at any given point in time. Those states are as given as follows:

Running
Paused
Restarting
Exited
Interview Coming Up?  Check 55 Docker Interview Questions
linkmindmajix.com
Q11: Is there a way to identify the status of a Docker container? Is there a way to identify the status of a Docker container?
55 Docker Interview Questions  Docker  55  Junior
Answer
We can identify the status of a Docker container by running the command

docker ps –a
which will in turn list down all the available docker containers with its corresponding statuses on the host. From there we can easily identify the container of interest to check its status correspondingly.

Interview Coming Up?  Check 55 Docker Interview Questions
linkmindmajix.com
27 Angular 9 Interview Questions (with Ivy UPDATE) for 2020
27 Angular 9 Interview Questions (with Ivy UPDATE) for 2020
#Angular 
👉 See All Questions 
52 Agile & Scrum Interview Questions  Agile & Scrum  52 
112 Behavioral Interview Questions  Behavioral  112 
13 UX Design Interview Questions  UX Design  13 
58 Azure Interview Questions  Azure  58 
38 Bootstrap Interview Questions  Bootstrap  38 
30 Redux Interview Questions  Redux  30 
83 Xamarin Interview Questions  Xamarin  83 
33 ADO.NET Interview Questions  ADO.NET  33 
30 Data Structures Interview Questions  Data Structures  30 
72 Ruby on Rails Interview Questions  Ruby on Rails  72 
33 ASP.NET Web API Interview Questions  ASP.NET Web API  33 
45 Design Patterns Interview Questions  Design Patterns  45 
Q12: What are the most common instructions in Dockerfile? What are the most common instructions in Dockerfile?
55 Docker Interview Questions  Docker  55  Junior
Answer
Some of the common instructions in Dockerfile are as follows:

FROM: We use FROM to set the base image for subsequent instructions. In every valid Dockerfile, FROM is the first instruction.
LABEL: We use LABEL to organize our images as per project, module, licensing etc. We can also use LABEL to help in automation.
In LABEL we specify a key value pair that can be later used for programmatically handling the Dockerfile.
RUN: We use RUN command to execute any instructions in a new layer on top of the current image. With each RUN command we add something on top of the image and use it in subsequent steps in Dockerfile.
CMD: We use CMD command to provide default values of an executing container. In a Dockerfile, if we include multiple CMD commands, then only the last instruction is used.
Interview Coming Up?  Check 55 Docker Interview Questions
linkknowledgepowerhouse.com
Q13: What type of applications - Stateless or Stateful are more suitable for Docker Container? What type of applications - Stateless or Stateful are more suitable for Docker Container?
55 Docker Interview Questions  Docker  55  Junior
Answer
It is preferable to create Stateless application for Docker Container. We can create a container out of our application and take out the configurable state parameters from application. Now we can run same container in Production as well as QA environments with different parameters. This helps in reusing the same Image in different scenarios. Also a stateless application is much easier to scale with Docker Containers than a stateful application.

Interview Coming Up?  Check 55 Docker Interview Questions
linkmindmajix.com
👉 See All Questions 
120 Angular Interview Questions  Angular  120 
51 jQuery Interview Questions  jQuery  51 
55 Docker Interview Questions  Docker  55 
36 T-SQL Interview Questions  T-SQL  36 
27 Reactive Programming Interview Questions  Reactive Programming  27 
33 ASP.NET MVC Interview Questions  ASP.NET MVC  33 
147 Java Interview Questions  Java  147 
112 Behavioral Interview Questions  Behavioral  112 
68 Kotlin Interview Questions  Kotlin  68 
50 CSS Interview Questions  CSS  50 
32 Webpack Interview Questions  Webpack  32 
68 Flutter Interview Questions  Flutter  68 
53 OOP Interview Questions  OOP  53 
56 SQL Interview Questions  SQL  56 
Q14: Explain basic Docker usage workflow Explain basic Docker usage workflow
55 Docker Interview Questions  Docker  55  Mid
Answer
Everything starts with the Dockerfile. The Dockerfile is the source code of the Image.
Once the Dockerfile is created, you build it to create the image of the container. The image is just the "compiled version" of the "source code" which is the Dockerfile.
Once you have the image of the container, you should redistribute it using the registry. The registry is like a git repository -- you can push and pull images.
Next, you can use the image to run containers. A running container is very similar, in many aspects, to a virtual machine (but without the hypervisor).
    +------------+  docker build   +--------------+  docker run -dt   +-----------+  docker exec -it   +------+
    | Dockerfile | --------------> |    Image     | --------------->  | Container | -----------------> | Bash |
    +------------+                 +--------------+                   +-----------+                    +------+
                                     ^
                                     | docker pull
                                     |
                                   +--------------+
                                   |   Registry   |
                                   +--------------+
Interview Coming Up?  Check 55 Docker Interview Questions
linkstackoverflow.com
Q15: What is the difference between Docker Image and Layer? What is the difference between Docker Image and Layer?
55 Docker Interview Questions  Docker  55  Mid
Answer
Image: A Docker image is built up from a series of read-only layers
Layer: Each layer represents an instruction in the image’s Dockerfile.
The below Dockerfile contains four commands, each of which creates a layer.

FROM ubuntu:15.04
COPY . /app
RUN make /app
CMD python /app/app.py
Importantly, each layer is only a set of differences from the layer before it.

Interview Coming Up?  Check 55 Docker Interview Questions
linkstackoverflow.com
👉 See All Questions 
15 JSON Interview Questions  JSON  15 
95 Node.js Interview Questions  Node.js  95 
33 ADO.NET Interview Questions  ADO.NET  33 
51 .NET Core Interview Questions  .NET Core  51 
46 WPF Interview Questions  WPF  46 
53 OOP Interview Questions  OOP  53 
41 Vue.js Interview Questions  Vue.js  41 
66 SOA & REST API Interview Questions  SOA & REST API  66 
38 Software Architecture Interview Questions  Software Architecture  38 
36 Git Interview Questions  Git  36 
83 Xamarin Interview Questions  Xamarin  83 
33 ASP.NET Web API Interview Questions  ASP.NET Web API  33 
26 Code Problems Interview Questions  Code Problems  26 
Q16: What is virtualisation? What is virtualisation?
55 Docker Interview Questions  Docker  55  Mid
Answer
In its conceived form, virtualisation was considered a method of logically dividing mainframes to allow multiple applications to run simultaneously. However, the scenario drastically changed when companies and open source communities were able to provide a method of handling the privileged instructions in one way or another and allow for multiple operating systems to be run simultaneously on a single x86 based system.

The net effect is that virtualization allows you to run two completely different OS on same hardware. Each guest OS goes through all the process of bootstrapping, loading kernel etc. You can have very tight security, for example, guest OS can't get full access to host OS or other guests and mess things up.

The virtualization method can be categorized based on how it mimics hardware to a guest operating system and emulates guest operating environment. Primarily, there are three types of virtualization:

Emulation
Paravirtualization
Container-based virtualization
Interview Coming Up?  Check 55 Docker Interview Questions
linkstackoverflow.com
Guest Voice: Top 10 NodeJS Frameworks For Developers in 2020
Guest Voice: Top 10 NodeJS Frameworks For Developers in 2020
#Node.js 
Q17: What is Hypervisor? What is Hypervisor?
55 Docker Interview Questions  Docker  55  Mid
Answer
The hypervisor handles creating the virtual environment on which the guest virtual machines operate. It supervises the guest systems and makes sure that resources are allocated to the guests as necessary. The hypervisor sits in between the physical machine and virtual machines and provides virtualization services to the virtual machines. To realize it, it intercepts the guest operating system operations on the virtual machines and emulates the operation on the host machine's operating system.

The rapid development of virtualization technologies, primarily in cloud, has driven the use of virtualization further by allowing multiple virtual servers to be created on a single physical server with the help of hypervisors, such as Xen, VMware Player, KVM, etc., and incorporation of hardware support in commodity processors, such as Intel VT and AMD-V.

Interview Coming Up?  Check 55 Docker Interview Questions
linkstackoverflow.com
👉 See All Questions 
24 GraphQL Interview Questions  GraphQL  24 
45 Design Patterns Interview Questions  Design Patterns  45 
68 Kotlin Interview Questions  Kotlin  68 
72 React Native Interview Questions  React Native  72 
16 MSMQ Interview Questions  MSMQ  16 
26 Code Problems Interview Questions  Code Problems  26 
36 T-SQL Interview Questions  T-SQL  36 
57 Entity Framework Interview Questions  Entity Framework  57 
84 Ruby Interview Questions  Ruby  84 
36 Git Interview Questions  Git  36 
50 CSS Interview Questions  CSS  50 
164 React Interview Questions  React  164 
33 ASP.NET Web API Interview Questions  ASP.NET Web API  33 
55 Docker Interview Questions  Docker  55 
Q18: What is Docker Swarm? What is Docker Swarm?
55 Docker Interview Questions  Docker  55  Mid
Answer
Docker Swarm is native clustering for Docker. It turns a pool of Docker hosts into a single, virtual Docker host. Docker Swarm serves the standard Docker API, any tool that already communicates with a Docker daemon can use Swarm to transparently scale to multiple hosts.

Interview Coming Up?  Check 55 Docker Interview Questions
linkedureka.co
Q19: How will you monitor Docker in production? How will you monitor Docker in production?
55 Docker Interview Questions  Docker  55  Mid
Answer
Docker provides tools like docker stats and docker events to monitor Docker in production. We can get reports on important statistics with these commands.

Docker stats: When we call docker stats with a container id, we get the CPU, memory usage etc of a container. It is similar to top command in Linux.
Docker events: Docker events are a command to see the stream of activities that are going on in Docker daemon.
Some of the common Docker events are: attach, commit, die, detach, rename, destroy etc. We can also use various options to limit or filter the events that we are interested in.

Interview Coming Up?  Check 55 Docker Interview Questions
linkknowledgepowerhouse.com
👉 See All Questions 
68 Kotlin Interview Questions  Kotlin  68 
41 XML & XSLT Interview Questions  XML & XSLT  41 
112 C# Interview Questions  C#  112 
68 Flutter Interview Questions  Flutter  68 
41 Vue.js Interview Questions  Vue.js  41 
24 GraphQL Interview Questions  GraphQL  24 
56 SQL Interview Questions  SQL  56 
34 Microservices Interview Questions  Microservices  34 
53 OOP Interview Questions  OOP  53 
52 Agile & Scrum Interview Questions  Agile & Scrum  52 
39 Questions to Ask Interview Questions  Questions to Ask  39 
33 ASP.NET MVC Interview Questions  ASP.NET MVC  33 
60 ASP.NET Interview Questions  ASP.NET  60 
Q20: What is an orphant volume and how to remove it? What is an orphant volume and how to remove it?
55 Docker Interview Questions  Docker  55  Senior
Answer
Join FSC to see Answer to this Interview Question...

Q21: What is Paravirtualization? What is Paravirtualization?
55 Docker Interview Questions  Docker  55  Senior
Answer
Join FSC to see Answer to this Interview Question...

40 Kotlin Interview Questions Android Devs Should Know in 2020
40 Kotlin Interview Questions Android Devs Should Know in 2020
#Kotlin 
👉 See All Questions 
49 Golang Interview Questions  Golang  49 
55 HTML5 Interview Questions  HTML5  55 
113 Android Interview Questions  Android  113 
44 AWS Interview Questions  AWS  44 
58 Azure Interview Questions  Azure  58 
41 Vue.js Interview Questions  Vue.js  41 
60 ASP.NET Interview Questions  ASP.NET  60 
16 MSMQ Interview Questions  MSMQ  16 
36 T-SQL Interview Questions  T-SQL  36 
33 WCF Interview Questions  WCF  33 
39 Questions to Ask Interview Questions  Questions to Ask  39 
82 PHP Interview Questions  PHP  82 
112 Behavioral Interview Questions  Behavioral  112 
34 Microservices Interview Questions  Microservices  34 
Q22: How is Docker different from a virtual machine? How is Docker different from a virtual machine?
55 Docker Interview Questions  Docker  55  Senior
Answer
Join FSC to see Answer to this Interview Question...

Q23: Can you explain dockerfile ONBUILD instruction? Can you explain dockerfile ONBUILD instruction?
55 Docker Interview Questions  Docker  55  Senior
Answer
Join FSC to see Answer to this Interview Question...

👉 See All Questions 
113 Android Interview Questions  Android  113 
33 WCF Interview Questions  WCF  33 
49 Golang Interview Questions  Golang  49 
68 Kotlin Interview Questions  Kotlin  68 
95 Node.js Interview Questions  Node.js  95 
51 jQuery Interview Questions  jQuery  51 
13 UX Design Interview Questions  UX Design  13 
14 NoSQL Interview Questions  NoSQL  14 
15 JSON Interview Questions  JSON  15 
112 C# Interview Questions  C#  112 
41 Vue.js Interview Questions  Vue.js  41 
164 React Interview Questions  React  164 
58 Web Security Interview Questions  Web Security  58 
Q24: Is it good practice to run stateful applications on Docker? What are the scenarios where Docker best fits in? Is it good practice to run stateful applications on Docker? What are the scenarios where Docker best fits in?
55 Docker Interview Questions  Docker  55  Senior
Answer
Join FSC to see Answer to this Interview Question...

Q25: Can you run Docker containers natively on Windows? Can you run Docker containers natively on Windows?
55 Docker Interview Questions  Docker  55  Senior
Answer
Join FSC to see Answer to this Interview Question...

👉 See All Questions 
68 Kotlin Interview Questions  Kotlin  68 
116 JavaScript Interview Questions  JavaScript  116 
53 OOP Interview Questions  OOP  53 
34 Microservices Interview Questions  Microservices  34 
55 HTML5 Interview Questions  HTML5  55 
82 PHP Interview Questions  PHP  82 
46 WPF Interview Questions  WPF  46 
35 LINQ Interview Questions  LINQ  35 
44 AWS Interview Questions  AWS  44 
57 Entity Framework Interview Questions  Entity Framework  57 
96 Python Interview Questions  Python  96 
112 Behavioral Interview Questions  Behavioral  112 
58 Web Security Interview Questions  Web Security  58 
27 Reactive Programming Interview Questions  Reactive Programming  27 
Q26: How does Docker run containers in non-Linux systems? How does Docker run containers in non-Linux systems?
55 Docker Interview Questions  Docker  55  Expert
Answer
Share this post to Unlock Answer to Expert Interview Question...

Share This Post To Unlock Expert Answers!
Top 29+ Advanced Blockchain Interview Questions (ANSWERED)
Top 29+ Advanced Blockchain Interview Questions (ANSWERED)
#Blockchain 
Q27: How containers works at low level? How containers works at low level?
55 Docker Interview Questions  Docker  55  Expert
Answer
Share this post to Unlock Answer to Expert Interview Question...

Share This Post To Unlock Expert Answers!
👉 See All Questions 
35 LINQ Interview Questions  LINQ  35 
22 PWA Interview Questions  PWA  22 
72 React Native Interview Questions  React Native  72 
83 Xamarin Interview Questions  Xamarin  83 
55 HTML5 Interview Questions  HTML5  55 
39 TypeScript Interview Questions  TypeScript  39 
53 OOP Interview Questions  OOP  53 
55 Docker Interview Questions  Docker  55 
46 WPF Interview Questions  WPF  46 
33 WCF Interview Questions  WCF  33 
34 Microservices Interview Questions  Microservices  34 
112 C# Interview Questions  C#  112 
147 Java Interview Questions  Java  147 
Q28: Name some limitations of containers vs VM Name some limitations of containers vs VM
55 Docker Interview Questions  Docker  55  Expert
Answer
Share this post to Unlock Answer to Expert Interview Question...

Share This Post To Unlock Expert Answers!
Q29: How to use Docker with multiple environments? How to use Docker with multiple environments?
55 Docker Interview Questions  Docker  55  Expert
Answer
Share this post to Unlock Answer to Expert Interview Question...

Share This Post To Unlock Expert Answers!
👉 See All Questions 
147 Java Interview Questions  Java  147 
87 Spring Interview Questions  Spring  87 
30 Redux Interview Questions  Redux  30 
33 WCF Interview Questions  WCF  33 
30 Data Structures Interview Questions  Data Structures  30 
53 OOP Interview Questions  OOP  53 
26 Code Problems Interview Questions  Code Problems  26 
24 GraphQL Interview Questions  GraphQL  24 
46 WPF Interview Questions  WPF  46 
22 PWA Interview Questions  PWA  22 
35 LINQ Interview Questions  LINQ  35 
72 Ruby on Rails Interview Questions  Ruby on Rails  72 
Q30: Why Docker compose does not wait for a container to be ready before moving on to start next service in dependency order? Why Docker compose does not wait for a container to be ready before moving on to start next service in dependency order?
55 Docker Interview Questions  Docker  55  Expert
Answer
Share this post to Unlock Answer to Expert Interview Question...