Docker is an open platform for developing, shipping, and running applications. It allows packaging applications into standardized units for software called containers that can run on any infrastructure. The key components of Docker include images, containers, a client-server architecture using Docker Engine, and registries for storing images. Images act as templates for creating containers, which are run-time instances of images. Docker provides portability and isolation of applications using containers.
Learn, Collaborate & Dockerize. Docker is an open platform that helps you build, ship and run applications anytime and anywhere.
Join Docker Jaipur:
Docker Page: events.docker.com/jaipur
Telegram Group: t.me/dockerjaipur
Twitter: @JaipurDocker
Learn, Collaborate & Dockerize. Docker is an open platform that helps you build, ship and run applications anytime and anywhere.
Join Docker Jaipur:
Docker Page: events.docker.com/jaipur
Telegram Group: t.me/dockerjaipur
Twitter: @JaipurDocker
What Is A Docker Container? | Docker Container Tutorial For Beginners| Docker...Simplilearn
This presentation on Docker Container will help you understand what is Docker, the architecture of Docker, what is a Docker Container, how to create a Docker Container, benefits of Docker Container, basic commands of Containers and you will also see a demo on creating Docker Container. Docker is a very lightweight software container and containerization platform. Docker containers provide a way to run software in isolation. It is an open source platform that helps to package an application and its dependencies into a Docker container for the development and deployment of software and a Docker COntainer is a portable executable package which includes applications and their dependencies. With Docker Containers, applications can work efficiently in different computer environments.
Below DevOps tools are explained in this Docker Container presentation:
1. What is Docker?
2. The architecture of Docker?
3. What is a Docker Container?
4. How to create a Docker Container?
5. Benefits of Docker Containers
6. Basic commands of Containers
Simplilearn's DevOps Certification Training Course will prepare you for a career in DevOps, the fast-growing field that bridges the gap between software developers and operations. You’ll become an expert in the principles of continuous development and deployment, automation of configuration management, inter-team collaboration and IT service agility, using modern DevOps tools such as Git, Docker, Jenkins, Puppet and Nagios. DevOps jobs are highly paid and in great demand, so start on your path today.
Why learn DevOps?
Simplilearn’s DevOps training course is designed to help you become a DevOps practitioner and apply the latest in DevOps methodology to automate your software development lifecycle right out of the class. You will master configuration management; continuous integration deployment, delivery and monitoring using DevOps tools such as Git, Docker, Jenkins, Puppet and Nagios in a practical, hands-on and interactive approach. The DevOps training course focuses heavily on the use of Docker containers, a technology that is revolutionizing the way apps are deployed in the cloud today and is a critical skillset to master in the cloud age.
After completing the DevOps training course you will achieve hands-on expertise in various aspects of the DevOps delivery model. The practical learning outcomes of this Devops training course are:
An understanding of DevOps and the modern DevOps toolsets
The ability to automate all aspects of a modern code delivery and deployment pipeline using:
1. Source code management tools
2. Build tools
3. Test automation tools
4. Containerization through Docker
5. Configuration management tools
6. Monitoring tools
DevOps jobs are the third-highest tech role ranked by employer demand on Indeed.com but have the second-highest talent deficit.
Learn more at https://www.simplilearn.com/cloud-computing/devops-practitioner-certification-training
Docker Explained | What Is A Docker Container? | Docker Simplified | Docker T...Edureka!
( ** DevOps Training: https://www.edureka.co/devops ** )
This Docker Explained PPT will explain to you the fundamentals of Docker with a hands-on. Below are the topics covered in the PPT:
Problems Before Docker
Virtualization vs Containerization
What is Docker?
How does Docker work?
Docker Components
Docker Architecture
Docker Compose & Docker Swarm
Hands-On
Docker is the world’s leading software container platform. Developers use Docker to eliminate “works on my machine” problems when collaborating on code with co-workers. Operators use Docker to run and manage apps side-by-side in isolated containers to get better compute density. Enterprises use Docker to build agile software delivery pipelines to ship new features faster, more securely and with confidence for both Linux and Windows Server apps.
Learn More: http://www.collabnix.com
Docker Tutorial For Beginners | What Is Docker And How It Works? | Docker Tut...Simplilearn
This presentation about Docker tutorial will help you understand what is Docker, advantages of Docker, how does Docker work, components of Docker, virtual machine vs Docker, advanced concepts in Docker, basic Docker commands along with a demo. A Docker is an OS-level virtualization software that enables developers and IT administrators to create, deploy and run applications in a Docker container with all their dependencies. It is said to be a very light-weight software container and containerization platform. Docker engine or Docker is a client-server application that builds and executes using Docker components. Rapid deployment, portability, better efficiency, faster configuration, scalability, security are some of the advantages you get by using Docker.
Below topics are explained in this Docker presentation:
1. Virtual machine vs Docker
2. What is Docker?
3. Advantages of Docker
4. How does Docker work?
5. Components of Docker
6. Advanced concepts in Docker
7. Basic Docker commands
Why learn DevOps?
Simplilearn’s DevOps training course is designed to help you become a DevOps practitioner and apply the latest in DevOps methodology to automate your software development lifecycle right out of the class. You will master configuration management; continuous integration deployment, delivery and monitoring using DevOps tools such as Git, Docker, Jenkins, Puppet and Nagios in a practical, hands-on and interactive approach. The DevOps training course focuses heavily on the use of Docker containers, a technology that is revolutionizing the way apps are deployed in the cloud today and is a critical skillset to master in the cloud age.
After completing the DevOps training course you will achieve hands-on expertise in various aspects of the DevOps delivery model. The practical learning outcomes of this Devops training course are:
An understanding of DevOps and the modern DevOps toolsets
The ability to automate all aspects of a modern code delivery and deployment pipeline using:
1. Source code management tools
2. Build tools
3. Test automation tools
4. Containerization through Docker
5. Configuration management tools
6. Monitoring tools
Who should take this course?
DevOps career opportunities are thriving worldwide. DevOps was featured as one of the 11 best jobs in America for 2017, according to CBS News, and data from Payscale.com shows that DevOps Managers earn as much as $122,234 per year, with DevOps engineers making as much as $151,461. DevOps jobs are the third-highest tech role ranked by employer demand on Indeed.com but have the second-highest talent deficit.
This DevOps training course will be of benefit the following professional roles:
1. Software Developers
2. Technical Project Managers
3. Architects
4. Operations Support
5. Deployment engineers
6. IT managers
7. Development managers
You can learn more at https://www.simplilearn.com/cloud-computing/devops-practitioner-certification-training
Docker is the world's leading software containerization platform.
This is a comprehensive introduction to Docker, suitable for delivering in introductory meetups to an audience who does not know about docker.
In case you want to deliver this presentation somewhere, kindly drop me a mail at aditya.konarde@gmail.com
You can contact me at:
Connect with me onLinkedIN: https://www.linkedin.com/in/adityakonarde
Add me on Facebook: https://www.facebook.com/Aditya.Konarde
Tweet to me @aditya_konarde
Short Introduction to Docker. These slides show the basic idea behind the container technology Docker. The slides present the basic features for the daily use with Docker, Docker Compose, Docker Machine and Docker Swarm.
Docker is specially important for DevOps, because it gives Software Developers more control about their dependencies in different environments.
What Is A Docker Container? | Docker Container Tutorial For Beginners| Docker...Simplilearn
This presentation on Docker Container will help you understand what is Docker, the architecture of Docker, what is a Docker Container, how to create a Docker Container, benefits of Docker Container, basic commands of Containers and you will also see a demo on creating Docker Container. Docker is a very lightweight software container and containerization platform. Docker containers provide a way to run software in isolation. It is an open source platform that helps to package an application and its dependencies into a Docker container for the development and deployment of software and a Docker COntainer is a portable executable package which includes applications and their dependencies. With Docker Containers, applications can work efficiently in different computer environments.
Below DevOps tools are explained in this Docker Container presentation:
1. What is Docker?
2. The architecture of Docker?
3. What is a Docker Container?
4. How to create a Docker Container?
5. Benefits of Docker Containers
6. Basic commands of Containers
Simplilearn's DevOps Certification Training Course will prepare you for a career in DevOps, the fast-growing field that bridges the gap between software developers and operations. You’ll become an expert in the principles of continuous development and deployment, automation of configuration management, inter-team collaboration and IT service agility, using modern DevOps tools such as Git, Docker, Jenkins, Puppet and Nagios. DevOps jobs are highly paid and in great demand, so start on your path today.
Why learn DevOps?
Simplilearn’s DevOps training course is designed to help you become a DevOps practitioner and apply the latest in DevOps methodology to automate your software development lifecycle right out of the class. You will master configuration management; continuous integration deployment, delivery and monitoring using DevOps tools such as Git, Docker, Jenkins, Puppet and Nagios in a practical, hands-on and interactive approach. The DevOps training course focuses heavily on the use of Docker containers, a technology that is revolutionizing the way apps are deployed in the cloud today and is a critical skillset to master in the cloud age.
After completing the DevOps training course you will achieve hands-on expertise in various aspects of the DevOps delivery model. The practical learning outcomes of this Devops training course are:
An understanding of DevOps and the modern DevOps toolsets
The ability to automate all aspects of a modern code delivery and deployment pipeline using:
1. Source code management tools
2. Build tools
3. Test automation tools
4. Containerization through Docker
5. Configuration management tools
6. Monitoring tools
DevOps jobs are the third-highest tech role ranked by employer demand on Indeed.com but have the second-highest talent deficit.
Learn more at https://www.simplilearn.com/cloud-computing/devops-practitioner-certification-training
Docker Explained | What Is A Docker Container? | Docker Simplified | Docker T...Edureka!
( ** DevOps Training: https://www.edureka.co/devops ** )
This Docker Explained PPT will explain to you the fundamentals of Docker with a hands-on. Below are the topics covered in the PPT:
Problems Before Docker
Virtualization vs Containerization
What is Docker?
How does Docker work?
Docker Components
Docker Architecture
Docker Compose & Docker Swarm
Hands-On
Docker is the world’s leading software container platform. Developers use Docker to eliminate “works on my machine” problems when collaborating on code with co-workers. Operators use Docker to run and manage apps side-by-side in isolated containers to get better compute density. Enterprises use Docker to build agile software delivery pipelines to ship new features faster, more securely and with confidence for both Linux and Windows Server apps.
Learn More: http://www.collabnix.com
Docker Tutorial For Beginners | What Is Docker And How It Works? | Docker Tut...Simplilearn
This presentation about Docker tutorial will help you understand what is Docker, advantages of Docker, how does Docker work, components of Docker, virtual machine vs Docker, advanced concepts in Docker, basic Docker commands along with a demo. A Docker is an OS-level virtualization software that enables developers and IT administrators to create, deploy and run applications in a Docker container with all their dependencies. It is said to be a very light-weight software container and containerization platform. Docker engine or Docker is a client-server application that builds and executes using Docker components. Rapid deployment, portability, better efficiency, faster configuration, scalability, security are some of the advantages you get by using Docker.
Below topics are explained in this Docker presentation:
1. Virtual machine vs Docker
2. What is Docker?
3. Advantages of Docker
4. How does Docker work?
5. Components of Docker
6. Advanced concepts in Docker
7. Basic Docker commands
Why learn DevOps?
Simplilearn’s DevOps training course is designed to help you become a DevOps practitioner and apply the latest in DevOps methodology to automate your software development lifecycle right out of the class. You will master configuration management; continuous integration deployment, delivery and monitoring using DevOps tools such as Git, Docker, Jenkins, Puppet and Nagios in a practical, hands-on and interactive approach. The DevOps training course focuses heavily on the use of Docker containers, a technology that is revolutionizing the way apps are deployed in the cloud today and is a critical skillset to master in the cloud age.
After completing the DevOps training course you will achieve hands-on expertise in various aspects of the DevOps delivery model. The practical learning outcomes of this Devops training course are:
An understanding of DevOps and the modern DevOps toolsets
The ability to automate all aspects of a modern code delivery and deployment pipeline using:
1. Source code management tools
2. Build tools
3. Test automation tools
4. Containerization through Docker
5. Configuration management tools
6. Monitoring tools
Who should take this course?
DevOps career opportunities are thriving worldwide. DevOps was featured as one of the 11 best jobs in America for 2017, according to CBS News, and data from Payscale.com shows that DevOps Managers earn as much as $122,234 per year, with DevOps engineers making as much as $151,461. DevOps jobs are the third-highest tech role ranked by employer demand on Indeed.com but have the second-highest talent deficit.
This DevOps training course will be of benefit the following professional roles:
1. Software Developers
2. Technical Project Managers
3. Architects
4. Operations Support
5. Deployment engineers
6. IT managers
7. Development managers
You can learn more at https://www.simplilearn.com/cloud-computing/devops-practitioner-certification-training
Docker is the world's leading software containerization platform.
This is a comprehensive introduction to Docker, suitable for delivering in introductory meetups to an audience who does not know about docker.
In case you want to deliver this presentation somewhere, kindly drop me a mail at aditya.konarde@gmail.com
You can contact me at:
Connect with me onLinkedIN: https://www.linkedin.com/in/adityakonarde
Add me on Facebook: https://www.facebook.com/Aditya.Konarde
Tweet to me @aditya_konarde
Short Introduction to Docker. These slides show the basic idea behind the container technology Docker. The slides present the basic features for the daily use with Docker, Docker Compose, Docker Machine and Docker Swarm.
Docker is specially important for DevOps, because it gives Software Developers more control about their dependencies in different environments.
Docker introduction.
References : The Docker Book : Containerization is the new virtualization
http://www.amazon.in/Docker-Book-Containerization-new-virtualization-ebook/dp/B00LRROTI4/ref=sr_1_1?ie=UTF8&qid=1422003961&sr=8-1&keywords=docker+book
Brief overview of the Docker eco system, the paradigm change it brings to development and operations processes. While docker has lots of potential its still working to mature into a viable production system that has proved itself secure, stable, and viable.
Kubernetes Online Training Hyderabad | Docker Online Trainingnavyatejavisualpath
Visualpath is the best educational institute offering top-notch online training for Docker and Kubernetes in Hyderabad. Our program features dynamic live interactive sessions led by industry experts with practical projects that enhance hands-on learning experience. Contact us at +91-9989971070.
Visit: https://www.visualpath.in/DevOps-docker-kubernetes-training.html
Containerization with docker syllabus wise ..
Unit-1 Introduction of Docker Contact Hours: 20
Introduction of Docker
Docker, Containerization, Uses of container Virtualization, Difference between Docker and Virtual Machines Docker Architecture, Features, Components of Docker, Advantages of Docker, Advantages of Containerization over Virtualization
Experiment no. 1.1 1. Install Docker on Linux or windows
2. Using docker CLI with commands.
Installation of Docker
Installation of Docker, Docker Hub, Difference between Docker Image and Container, Containers and shell, Creating Docker images, backing up a Docker Container, Restoring a Docker Container. Deploy, Login, Exit Container. List, Start, Stop and Restart Containers. Deleting Containers.
Experiment no. 1.2 Pulling Docker Images from Docker Hub
Chapter 1.3 Data Volumes and system Management
Creating and mounting data volumes, Defining Volumes in images, Pruning unused resources.
Experiment no. 1.3 Deploying Docker images as Stateless Containers.
Experiment no. 1.4 Managing Containers with the Docker CLI
Unit-2 Docker components Contact Hours: 20
Docker Compose & Docker Swarm Docker Compose and Compose installation, Introduction to Docker Swarm, Create Swarm, Maintain Swarm, Deploy Services to Swarm, Updates to Services, Managing Swarm Services.
Experiment no. 2.1 Understanding the Docker file for Customizing Images
Docker Files Docker Files, Building Files, Public repositories, Private Registry, Building Web server Docker file, instruction commands, Container Linking
Experiment no. 2.1 Building a Custom Docker Image for a Web Application
Experiment no. 2.3 Maintaining State with Docker Volumes
Docker Storage, ring and Kubernetes Contact Hours:20
How to manage data in docker, Types of storage available in docker, Multi Container environment, Docker volumes, Types of Volumes
Working with Docker Compose
Container Network model, Default Bridge Network, User Created Bridge, Host Network, Docker Cloud, Docker Log, Docker Compose, Continuous Integrations tools, Kubernetes architecture, Kubernetes Components, Working of Kubernetes.
Creating a Private Docker Image Repository
Introduction of kubernetes, Comparison of Docker and Kubernetes, Configuration of minikube on linux OS, Installing Kubernetes using the Docker Client Running first app on Kubernetes.
Cleaning Up Old Containers and Docker Images
docker : how to deploy Digital Experience in a container drinking a cup of co...Matteo Bisi
This was my session @ IconUK 2016. We was talking about docker and ibm and giving some tips to use it and build it your own container with ibm social collaboration software
The Axigen Docker image is provided for users to be able to run an Axigen based mail service within a Docker container.
The following services are enabled and mapped as 'exposed' TCP ports in Docker:
§ SMTP (25 - non secure, 465 - TLS)
§ IMAP (143 - non secure, 993 - TLS)
§ POP3 (110 - non secure, 995 - TLS)
§ WEBMAIL (80 - non secure, 443 - TLS)
§ WEBADMIN (9000 - non secure, 9443 - TLS)
CLI (7000 - non secure
Ethnobotany and Ethnopharmacology:
Ethnobotany in herbal drug evaluation,
Impact of Ethnobotany in traditional medicine,
New development in herbals,
Bio-prospecting tools for drug discovery,
Role of Ethnopharmacology in drug evaluation,
Reverse Pharmacology.
The Art Pastor's Guide to Sabbath | Steve ThomasonSteve Thomason
What is the purpose of the Sabbath Law in the Torah. It is interesting to compare how the context of the law shifts from Exodus to Deuteronomy. Who gets to rest, and why?
2024.06.01 Introducing a competency framework for languag learning materials ...Sandy Millin
http://sandymillin.wordpress.com/iateflwebinar2024
Published classroom materials form the basis of syllabuses, drive teacher professional development, and have a potentially huge influence on learners, teachers and education systems. All teachers also create their own materials, whether a few sentences on a blackboard, a highly-structured fully-realised online course, or anything in between. Despite this, the knowledge and skills needed to create effective language learning materials are rarely part of teacher training, and are mostly learnt by trial and error.
Knowledge and skills frameworks, generally called competency frameworks, for ELT teachers, trainers and managers have existed for a few years now. However, until I created one for my MA dissertation, there wasn’t one drawing together what we need to know and do to be able to effectively produce language learning materials.
This webinar will introduce you to my framework, highlighting the key competencies I identified from my research. It will also show how anybody involved in language teaching (any language, not just English!), teacher training, managing schools or developing language learning materials can benefit from using the framework.
Read| The latest issue of The Challenger is here! We are thrilled to announce that our school paper has qualified for the NATIONAL SCHOOLS PRESS CONFERENCE (NSPC) 2024. Thank you for your unwavering support and trust. Dive into the stories that made us stand out!
Operation “Blue Star” is the only event in the history of Independent India where the state went into war with its own people. Even after about 40 years it is not clear if it was culmination of states anger over people of the region, a political game of power or start of dictatorial chapter in the democratic setup.
The people of Punjab felt alienated from main stream due to denial of their just demands during a long democratic struggle since independence. As it happen all over the word, it led to militant struggle with great loss of lives of military, police and civilian personnel. Killing of Indira Gandhi and massacre of innocent Sikhs in Delhi and other India cities was also associated with this movement.
Welcome to TechSoup New Member Orientation and Q&A (May 2024).pdfTechSoup
In this webinar you will learn how your organization can access TechSoup's wide variety of product discount and donation programs. From hardware to software, we'll give you a tour of the tools available to help your nonprofit with productivity, collaboration, financial management, donor tracking, security, and more.
Palestine last event orientationfvgnh .pptxRaedMohamed3
An EFL lesson about the current events in Palestine. It is intended to be for intermediate students who wish to increase their listening skills through a short lesson in power point.
Instructions for Submissions thorugh G- Classroom.pptxJheel Barad
This presentation provides a briefing on how to upload submissions and documents in Google Classroom. It was prepared as part of an orientation for new Sainik School in-service teacher trainees. As a training officer, my goal is to ensure that you are comfortable and proficient with this essential tool for managing assignments and fostering student engagement.
Unit 8 - Information and Communication Technology (Paper I).pdfThiyagu K
This slides describes the basic concepts of ICT, basics of Email, Emerging Technology and Digital Initiatives in Education. This presentations aligns with the UGC Paper I syllabus.
Synthetic Fiber Construction in lab .pptxPavel ( NSTU)
Synthetic fiber production is a fascinating and complex field that blends chemistry, engineering, and environmental science. By understanding these aspects, students can gain a comprehensive view of synthetic fiber production, its impact on society and the environment, and the potential for future innovations. Synthetic fibers play a crucial role in modern society, impacting various aspects of daily life, industry, and the environment. ynthetic fibers are integral to modern life, offering a range of benefits from cost-effectiveness and versatility to innovative applications and performance characteristics. While they pose environmental challenges, ongoing research and development aim to create more sustainable and eco-friendly alternatives. Understanding the importance of synthetic fibers helps in appreciating their role in the economy, industry, and daily life, while also emphasizing the need for sustainable practices and innovation.
2. CONTAINER
• Before going to docker let us know about Container
• Container: A container is a standard unit of software that
packages up code and all its dependencies, so the application
runs quickly and reliably from one computing environment to
another.
• Container images become containers at runtime and in the case
of Docker containers - images become containers when they
run on Docker Engine.
• Available for both Linux and Windows-based applications,@2020 copyright KalKey training
3. CONTAINER IMAGE
• A container image is a self-contained piece of
software that has everything in it needed to
run – code, tools, and resources.
@2020 copyright KalKey training
12. What is docker?
• Docker is an open platform for developing, shipping, and running
applications. Docker enables you to separate your applications from
your infrastructure so you can deliver software quickly.
• With Docker, you can manage your infrastructure in the same ways
you manage your applications. By taking advantage of Docker’s
methodologies for shipping, testing, and deploying code quickly, you
can significantly reduce the delay between writing code and running
it in production.
@2020 copyright KalKey training
13. Docker platform
• Docker provides the ability to package and run an application in a
loosely isolated environment called a container.
• The isolation and security allow you to run many containers
simultaneously on a given host.
• Containers are lightweight because they don’t need the extra load
of a hypervisor but run directly within the host machine’s kernel.
• This means you can run more containers on a given hardware
combination than if you were using virtual machines. You can
even run Docker containers within host machines that are actually
virtual machines
@2020 copyright KalKey training
14. Docker Engine
Docker Engine is a client-server application with these major
components:
• A server which is a type of long-running program called a daemon
process (the dockerd command).
• A REST API which specifies interfaces that programs can use to talk to
the daemon and instruct it what to do.
• A command line interface (CLI) client (the docker command).
@2020 copyright KalKey training
16. Docker architecture
• Docker uses a client-server architecture.
• The Docker client talks to the Docker daemon, which does the heavy
lifting of building, running, and distributing your Docker containers.
• The Docker client and daemon can run on the same system, or you
can connect a Docker client to a remote Docker daemon.
• The Docker client and daemon communicate using a REST API, over
UNIX sockets or a network interface.
@2020 copyright KalKey training
18. Docker registries
• A Docker registry stores Docker images.
• Docker Hub is a public registry that anyone can use, and Docker is
configured to look for images on Docker Hub by default. You can
even run your own private registry.
• When you use the docker pull or docker run commands, the
required images are pulled from your configured registry.
• When you use the docker push command, your image is pushed
to your configured registry.
@2020 copyright KalKey training
19. Docker objects
• When you use Docker, you are creating and using images, containers,
networks, volumes, plugins, and other objects.
@2020 copyright KalKey training
20. Docker images
• An image is a read-only template with instructions for creating a
Docker container. Often, an image is based on another image,
with some additional customization. For example, you may build
an image which is based on the ubuntu image, but installs the
Apache web server and your application, as well as the
configuration details needed to make your application run.
• You might create your own images or you might only use those
created by others and published in a registry. To build your own
image, you create a Dockerfile with a simple syntax for defining
the steps needed to create the image and run it.
@2020 copyright KalKey training
21. Docker CONTAINERS
• A container is a runnable instance of an image. You can create, start,
stop, move, or delete a container using the Docker API or CLI. You
can connect a container to one or more networks, attach storage to
it, or even create a new image based on its current state.
• By default, a container is relatively well isolated from other
containers and its host machine. You can control how isolated a
container’s network, storage, or other underlying subsystems are
from other containers or from the host machine.
• A container is defined by its image as well as any configuration
options you provide to it when you create or start it. When a
container is removed, any changes to its state that are not stored in
persistent storage disappear.
@2020 copyright KalKey training
22. Docker SERVICES
• Services allow you to scale containers across multiple Docker
daemons, which all work together as a swarm with multiple
managers and workers.
• Each member of a swarm is a Docker daemon, and all the
daemons communicate using the Docker API.
• A service allows you to define the desired state, such as the
number of replicas of the service that must be available at any
given time.
@2020 copyright KalKey training