Introduction to Cloud native applications

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Del curso dictado por IBM

A Developer's guide to Node-RED

25 calificaciones

IBM

A Developer's guide to Node-RED

25 calificaciones

>>> By enrolling in this course you agree to the End User License Agreement as set out in the FAQ. Once enrolled you can access the license in the Resources area <<< Rapid application development using agile methodologies and processes are increasingly being used when developing applications. There is pressure on development teams to reduce the time needed to convert an idea into a working solution, be it as part of an innovation workshop or hackathon, a prototype for a new solution idea or main stream development. Developers are looking for new ways to allow them to be more production and innovations, such as Node-RED from the JS Foundation is a technology that allows a developer to rapidly create applications, taking a fraction of the time need coding write code. Node-RED is built on Node.js, so will run anywhere capable of hosting node.js applications, such as small single board computers like the Raspberry Pi or Beaglebone, on your laptop or workstation or in cloud environments, such as the IBM Cloud. Node red allows developers to compose flows using a pallet of nodes, where each node provides prebuilt functionality, that can be connected to other nodes to rapidly construct an application. This course assumes some basic knowledge of Node-RED, so if you have not used Node-RED then you may want to take a look at the Coursera course - A Developer’s Guide to the Internet of Things (https://www.coursera.org/learn/developer-iot/), which provides a beginner look at Node-RED. What you will learn: The course will improve your use of Node-RED. It will introduce some more advanced features available in key nodes, show you how to visualise data using dashboard nodes. It shows you how to create web APIs using Node-RED and how to consume web services and how to make use of different storage technologies within a Node-RED flow. The last section of the course shows how you can extend Node-RED by creating your own nodes. What technology is required to complete the course? The course requires you to have an IBM Cloud account, as some of the assignment work does make use of designated cloud services. You can create a free account on the IBM Cloud and in week 2 of the course we make a promotional code available, which unlocks some additional resources on the IBM Cloud, so you can complete the course without having to provide credit card information or pay for cloud services. If you choose to take this course and earn the Coursera course certificate, you will also earn an IBM digital badge. To find out more about IBM digital badges follow the link https://ibm.biz/badging.

De la lección

Week 1 - Introduction and Review of Node-RED

Welcome to the course. This learning module introduces you to course and the instructors. The module outlines the content covered on the course and gives an introduction to the Internet of Things. It also discusses the requirements needed to complete the course including the hardware, software and details of prerequisite skills required to complete the programming assignments. The module then discusses using Node-RED to create cloud applications and the different options available to customise the Node-RED runtime

Introduction to Cloud native applications7:40

Conoce a los instructores

Brian Innes
Developer Advocate
IBM Digital Business Group
Nick O'Leary
Developer Advocate
IBM Digital Business Group
Maeve O'Reilly
IT Specialist
IBM Watson Internet of Things
John Walicki
Watson IoT Developer Advocate
Watson Internet of Things

Increasingly, applications have been created to run within cloud environments.

For an application to work well in a cloud environment,

there are some additional considerations that need to be taken into account.

You may hear terms such as cloud native and born on the cloud,

which refer to applications that were designed to run on cloud platforms,

versus the more traditional or legacy applications

designed to run in a computer data center.

The design of a cloud native application,

includes much more than the function requirements the application must implement.

It takes into account the developer and automation tooling,

and automation used to implement and manage the application through its entire life cycle.

The migration between different runtime environments,

from dev through test into production,

the automated management of the workload and appropriate scaling

up and down of the application to cope with workload changes,

or the automated management of failures within the cloud infrastructure.

When designing a cloud native application,

there are a set of principles that are often used,

called The twelve-factor app.

These twelve factors, can be used as

guiding principles when designing applications for the cloud.

The original twelve-factor app work,

was completed some time ago,

but they still provide a good set of guidelines today.

I'm going to look at some of the twelve factors,

and discuss options for creating good cloud native applications in Node-RED.

As Node-RED, is a Node.js application using the express framework,

it does adhere to many of the twelve-factors guiding principles.

The version of Node-RED running on the IBM cloud,

has a few modifications from the standard version of Node-RED ,

that allows it to run as a cloud application.

There are a couple of areas you need to be aware of.

where your choice of node,

or the implementation of a flow,

can make the difference between having a well-behaved cloud application,

or an application that's not suitable for running as a cloud application.

Config: an application config,

is everything that is likely to vary between deploys.

With node-RED, it's easy to capture application configuration in a node.

Capturing environment specific configuration,

breaks the ability to use DevOps tooling to

automatically move an application between different environments.

Many nodes understand if they are being deployed in a cloud environment,

and will pick up configuration for bound services using environment variables.

However, many nodes do not.

You should be aware of any configuration you're capturing within a node red flow,

if the target for the application is a cloud environment.

Nodes often allow you to pass configuration properties with the incoming messages.

So it's sometimes possible to still use an environment variable to hold configuration,

and then ensure the configuration is passed from the environment variable into the node.

So no configuration is held within the node configuration.

Processes: execute the application as one or more stateless processes.

A cloud native application should not hold

any state in local memory or on the local file system.

You can use them briefly if needed during the processing of a single request,

but not to persist values between requests.

All state should be held by

a backing service that's available to all running instances of the application.

So it does not matter where a request lands.

All instances of the application should generate the same response.

There are many different storage options available on the IBM cloud,

and in week three,

we'll look at some of the common ones you may want to

use to persist data between requests.

In Node-RED, this does mean,

you need to be aware that currently the flow and

global context objects are in memory stores.

So they should not be used to store state.

The file system nodes are disabled by default in

the IBM cloud deployment of Node-RED using the boilerplate.

But if you decide you want to enable them,

you should be sure that you're not storing state on the local storage,

which could be lost during cloud scaling,

or error handling automated activities.

There is one consideration,

that's not explicitly called out in the twelve-factor app guidelines,

and that is the capability of services to handle

a variable number of clients representing a single application.

For Node-RED , you may need to look,

to verify if the node creator took cloud applications into consideration,

when developing the node.

If you take a social media or a messaging service as an example, will,

every instance of the application connected to the service,

get a copy of every message,

or is the backing service and the implementation of the Node-RED node

enabled to cope with multiple instances of an application,

all being connected and ensuring that only one instance receives each message.

As you move into week four of the course,

it's worth keeping in mind the requirements for

cloud deployment as you learn to develop your own nodes.

There are also a few areas where Node-RED needs to be modified to

make it easier to fit into a cloud native development model.

Code base: The code for an application,

needs to be tracked in a version control system.

While this is true of the Node-RED runtime itself,

which is held in a version control system, the flows are not.

On the IBM cloud,

they are stored in a NoSQL database,

and there's no version control system integration.

Build, release, and run: An application should have

distinct stages to take the codebase stored in the code repository through a build stage,

then onto a release stage or deploy stage,

and then finally, into running.

Again, the Node-RED runtime deployed

within the boilerplate does work within a DevOps toolchain,

and it goes through these stages.

The Node-RED flows do not.

Currently in a scaled environment,

the editor only works against a single running instance.

So when deploying, the changes are only made live to that single instance.

The updated flows are stored in the common NoSQL database.

But there's no mechanism to get all instances

to update their running a flow to the latest version.

Node-RED is still relatively young,

and there is an article on the Node-RED website called, A Roadmap to 1.0,

which sets out the plan to address many of the challenges developers have raised,

and also some of the shortfalls integrating Node-RED

into production environments and cloud environments.

As these new features outlined in the roadmap are implemented,

it will allow Node-RED to be run in

different ways to best suit environment it's running in,

and allow integration into DevOps tooling and processes.

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