What is Cloud Migration?

Cloud migration. What does it mean? Cloud migration is the process of moving digital assets — like data, workloads, IT resources, or applications — to cloud infrastructure. Cloud migration commonly refers to moving tools and data from old, legacy infrastructure or an on-premises* data center to the cloud.

*On-premises is sometimes shortened to “on-prem” and commonly — though incorrectly (from a grammar point-of-view) — called “on-premise.” 

Though "cloud migration" typically refers to moving things from on-premises to the cloud, it can also refer to moving from one cloud to another cloud. A migration may involve moving all or just some assets. It also involves a whole lot of other things. That's why we've complied this guide to cover all things cloud migration.

Looking to learn more about cloud migration? This beginner's guide to cloud migrations covers everything you need to go from knowing nothing about cloud migration to knowing something about migrating to cloud.

We'll start with an explain-it-like-I'm-five intro to cloud basics and take you all the way to cloud migration strategies and migration tools and services in this high-level look at successfully accomplishing cloud migrations. Plus, you'll get handy resources to take you from getting the gist to getting it down pat.

• A Brief Intro to Cloud
• Why Businesses Migrate to the Cloud
• Public, Private, Hybrid, and Multicloud
• SaaS, Paas, and IaaS Service Models
• The Benefits of Cloud Migration
• Cloud Migration Planning
• Cloud Migration Strategy
• Migration Tools + Services
• Common Challenges of Cloud Migration

The cloud — often used as shorthand for “cloud computing” — refers to a pool of computer services accessed over the internet. This pool is accessible on-demand and self-service, giving instant access to services without setup. With the cloud, computers that businesses once had to have on-premises can be stored in massive data centers* around the world.

*“Data center” is a term used to describe the space dedicated to housing computer systems and their necessary accouterments.

Unlike a server* room or server closet, the computer-systems-storing units you might find behind a (hopefully) locked door in any given office, data centers are dedicated primarily to housing computer equipment. They're normally huge and designed specifically for the express purpose of keeping a ton of tech running in optimal conditions.

*"Tap the brakes. What are servers?" you may be asking. Servers are basically heavy-duty computers designed to run all the time and typically dedicated to a single task, like storing, sending, or processing data.

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These data centers are managed by companies focused on running data centers, reducing the need for local IT resources — computers, that is, not people. (You’ll still probably want some people, particularly people who know how to use cloud.)

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These computer services don’t actually exist in the sky, of course. (You probably knew that, but just in case . . . ) The name “cloud” actually comes from the symbol used in conceptual network diagrams from the 1970s. 

The cloud is sometimes used interchangeably with the term “internet,” but, technically, the cloud isn’t the internet. Rather, the cloud uses the internet to deliver resources. But when people are doing things on the internet, they’re probably using cloud services — from checking Gmail to uploading a dog pics to Instagram to streaming Adam Sandler movies on Netflix.

So, what can you do with the cloud? Almost anything you can do with a computer or a server is available as a service in the cloud.

Services vary in complexity, from storing the digital pieces that compose a webpage to employing beefy hardware to perform resource-intensive tasks, like using artificial intelligence (A.I.) and machine learning (M.L.) to analyze business data for insights.

The reasons businesses migrate to the cloud are plentiful and varied. But one big reason is that working in the cloud gives you access to virtually limitless computer resources. 

An easy thought exercise is to think of this nearly bottomless pool of computing power and storage a bit like electricity. Sure, you could produce electricity on your own by running a generator, but the upfront cost for the hardware is expensive. Then, you’ve got to keep it running, which requires a level of expertise and time spent on ongoing maintenance. And if it goes down, you’re out of luck — unless you’ve really splurged and have a second generator just sitting around ready to go at a moment’s notice.

But like the way you (probably) consume electricity, if you and others around you all need electricity, it makes more sense to outsource the setup and day-to-day management of electricity production. Then, you and all your neighbors who need electricity can tap into electricity with the flip of a switch. You’re free to use what you need and pay for only what you use. Got a bunch of people coming to visit for a holiday? You can have all the electricity they need, no problem. The electricity company has you covered. They focus on delivering you electricity quickly and efficiently, so you’re free to focus on what you need to do. (If analogies aren’t your thing, just re-read the last two paragraphs and replace “electricity” with “cloud.”) 

The plain and simple of it is this: Cloud abstracts and serves up IT on tap. You get servers and computer services without the need to buy, maintain, and manage hardware or dedicate employees to the low-level admin work that comes with that.

If you think about cloud like a utility (like electricity), you're basically thinking about public cloud, which is just one type of cloud deployment model. But what’s the difference between public and private cloud? And what’s hybrid cloud? Funny you ask.

• With public cloud, services are owned and run by a third-party vendor (called a cloud service provider) over the public internet. These services can be free or available as pay-per-use to anyone who wishes to use or buy them. The advantages of public cloud are huge, which might explain why it’s the most common type of deployment.
• Examples of public clouds include Amazon Web Services (AWS), Microsoft Azure, Google Cloud Platform (GCP), Alibaba Cloud, IBM Cloud, and Oracle Cloud. 
• The advantages of public cloud include 24/7 uptime, the ability to only pay for what you use (which can result in cost savings), scalability, and simplified infrastructure management — meaning setup is simple and there’s no need to buy and manage on-premises infrastructure. 

• With private cloud, cloud resources are used and owned solely by one organization. That makes this approach desirable by governmental and financial industries that seek maximum control or customization. The private cloud may be located in a data center on-site or hosted by a provider in a remote location. 
• Private cloud providers include Hewlett Packard Enterprise (HPE), Dell, IBM, Oracle, and some familiar names from the public cloud provider space, including AWS, Google, and Microsoft.

• Hybrid cloud combines elements of private and public cloud and allows resources to move between the two. Hybrid cloud works well for organizations that need an element of private cloud (for example, regulation requirements around sensitive data) but still want access to public cloud and its big benefits.
• Like private cloud, this model takes some real IT skill and may require the use of on-site hardware, cutting back on some of the cost benefits of public cloud. It also adds another layer of complexity to the equation.

• Multicloud is the use of multiple cloud services in a single environment. This can mean, for example, a mix of public and private clouds or using a mix of public cloud providers to reduce reliance on a single provider or to realize the benefits of more than one provider.
• Multicloud is the most popular cloud strategy among enterprises.
• How’s multicloud different than hybrid cloud? Multicloud refers to using multiple services (like services from AWS and Azure), while hybrid cloud refers to using multiple deployment models (like using public and private cloud).

What’s the difference between SaaS, PaaS, and IaaS? They’re three different kinds of cloud service models, cloud service categories, or the types of cloud computing — all just different terms for the same three funny-looking acronyms. Whatever you want to call them, understanding these is a solid step to wrapping your head around what cloud can do.

“aaS” stands for “as a service.” In its simplest form, this means moving that piece of the tech stack to the cloud. For example, software as a service means moving software that would typically reside on a computer to the cloud.

• Software as a Service, or SaaS, is software provided over the internet. Nothing is installed on a local computer, tablet, or phone; no one is needed to manage things like patches or updates. It just works.
• Examples of SaaS include Dropbox, Salesforce, the G Suite apps (like Gmail), and Microsoft 365. 
• Want to talk the talk without making an A-A-S of yourself? When said aloud, SaaS is either spelled out (S-A-A-S) or pronounced “sass.”

• PaaS, or Platform as a Service, is a software building ground for developers. Just BYO applications and data. PaaS provides a blank slate in the cloud that lets the developers create, deploy, and scale applications without having to sweat things like infrastructure, storage, or operating systems. 
• Examples of PaaS include AWS Elastic Beanstalk, OpenShift, and Google App Engine. 
• How do you say Paas? When said aloud, PaaS is either spelled out (P-A-A-S) or pronounced “paz” or “pass.”

• Infrastructure as a Service, or IaaS, means moving infrastructure into the cloud.  (Think: renting a server in the cloud.) Your cloud provider owns the hardware and is responsible for managing and maintaining it, so you don’t have to worry about any maintenance.
• Examples of IaaS include AWS, Microsoft Azure, Google Cloud Platform, Rackspace, and DigitalOcean.
• How do you pronounce IaaS? When said aloud, IaaS is most commonly spelled out (I-A-A-S) — though it is sometimes pronounced “eye-azz.”

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At a basic level, the benefits of cloud are often around efficiency, achieving the maximum results with minimal expense. For organizations that pull off a successful cloud migration, the rewards reaped can include increased scalability, lower costs, and security. 

For simplicity’s sake, we’ll focus specifically on public cloud benefits, though some of these benefits apply to other cloud deployment models, too. Here are seven big benefits of migrating to the cloud.

Cloud allows for improved scalability, giving organizations the ability to almost instantaneously add or take away resources on an as-needed basis or to match demand. Elasticity goes hand in hand with scalability and refers to the ability to quickly expand or decrease computer processing, memory, and storage resources (data storage optimization) to meet changing demands without concerning yourself with cloud capacity planning. Elasticity enables scalability.

Think about it this way: An influx of users can eat up a server’s resources. With traditional self-hosted hardware, requests would then be denied. But the cloud has a practically infinite set of resources. That means servers can scale up to handle the rush without a hitch.

The process of scaling can be done automatically (called autoscaling), based on, for example, the time of day or the amount of processor resources being used.

Cloud gives you the ability to only pay for the resources you use. (Think: taking an Uber instead of buying a car.) This gives you access to resources that would cost way too much time and money to keep up yourself, which ties back into scalability. 

A traditional IT approach to scaling up is costly. It takes planning; it can take months, requires hardware at a big upfront cost, electricity to keep it all operating and cool, and skilled IT staff capable of getting (and keeping) it all up and running. With cloud, that’s all done nearly instantly by your cloud provider.

But where cloud scalability really leaves on-prem scalability in the dust is around decreasing resources. Traditional IT infrastructure can require having enough resources to handle peak demand. (For example, a retailer having to pay for the data center resources to be ready for a rush of Black Friday shoppers, even though they’re not half as busy the other 364 days of the year.) Cloud infrastructure can scale up and down with the peaks and valleys of a year, month, day, or hour. 

Keep in mind, an organization’s cloud spend can get out of control without the proper planning and execution, and cloud isn’t inherently a money-saving move if done improperly. It does however undoubtedly allow an organization to . . . 

Cloud shifts tech systems from a capital expenditure (CapEx) to an operating expenditure (OpEx) — or from an investment in something you hold onto for a few years that will depreciate in value (like a bunch of expensive hardware gathering cobwebs) to a regular, ongoing cost for running the business (like paying for internet). That’s great news for businesses that like to hang onto as much cash as possible. (You can talk to your finance department to confirm, but that’s probably anywhere anyone works.)

Agility can mean a couple of different things around the cloud. “Cloud agility” is often used to describe the ability to quickly develop, test, and launch business applications. But cloud also gives you the agility to respond quickly as needs change. 

Even small businesses get access to the same powerful tools that the biggest enterprises use. New services can be accessed with a few mouse clicks, so when a new need, challenge, or opportunity arises, it’s possible to respond immediately.

And cloud can also make it easier for organizations with multiple offices — eliminating the need to set up infrastructure in each location. Just turn on the power and the internet and your people are ready to go. It also makes it possible for your workforce to suddenly switch to, say, working from home (looking at you, 2020).

The big cloud service providers run a worldwide, world-class network of facilities packed with cutting-edge tech. This ensures everything from keeping network latency low to delivering near unparalleled data backup and disaster recovery. No matter where the people who need access to your tools are, the cloud typically brings them closer.

Most cloud providers are big companies with big companies relying on them. That’s why they go out of the way to consider security and compliance, which includes staying on top of updates and trends that will ensure your sensitive data is safe in the cloud.

Public cloud providers typically bring to the table policies, tech, and controls that are a huge step up from the average organization’s security practices. This is paired with considerations for almost any industry-specific compliance needs.

Plus, keeping data in the cloud rather than on your hard drive can also keep data from getting compromised if a device is stolen or misplaced.

Maintaining computer hardware and software is a full-time job. Literally. With public cloud, you don’t have to have employees spending time dedicated to the tedious maintenance of equipment that doesn’t directly contribute to business objectives. Your cloud service provider ensures the infrastructure is in place, so your tech wizards can focus on driving business outcomes.

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Without the right strategy, you can hurt your chances of achieving your desired cloud benefits. There are many common mistakes when companies go cloud, and a botched migration can mean hampered performance and increased costs. It's regularly reported that more than half of companies don't see the cloud benefits they expected. This is commonly due to faults in migration strategy and a lack of the necessary cloud talent.

If you’re looking for a guide to cloud migrations, here are the three fundamentals to consider no matter what type of cloud and what cloud service models you’ll use:

1. What you’re moving 
2. Why you’re moving it
3. How you’re going to do it

At a more detailed level, it’s all about figuring out the migration process and giving plenty of thought to planning.

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Ideally, you won’t be winging it when migrating to the cloud. Keep tabs on what’s done and what’s next to ensure all the moving pieces end up where they should. Need a cloud migration template? Here some steps to include on your cloud migration checklist.

Why are you moving to the cloud? This calls for a formal business case! It’s important for leadership to be clear on the purpose of the migration — and set aggressive goals to drive the organization forward. This includes creating a baseline of your current IT infrastructure and forming some cloud migration key performance indicators (KPIs). These will make it possible to measure your cloud migration success.

Take stock of what’s in your environment, noting any interdependencies, then figure out what you’ll migrate first and how you’ll migrate it. Look at which applications can be moved as they are, which ones will need some (or A LOT of) reworking, and what tools are out there to simplify migration of those trickier workloads. Pick your cloud deployment models and the various tools and services out there (see below). You’ll ideally want to figure out ROI (return on investment) for things you’ll be migrating and how long that might take to achieve. 

Time to roll those sleeves up and get your hands cloudy. When you’re ready to start migrating, it’s typically best to start with something not overly complex or business-critical. With any luck, that quick win will boost excitement and teach you some things along the way. 

Applications should be designed, migrated, and validated using one of the migration strategies covered below. After making the move, you’ll want to test everything out and decommission your old systems. This can mean running two environments for a time, but you can keep this time in limbo from lasting too long by ensuring your cloud leaders are ready to confirm all systems are go and are able to measure your cloud success.

As you migrate applications, keep hammering away to figure out your new operating model, turn off those legacy systems, and keep pushing forward.

There are three basic types or patterns of cloud migration. In the order below, they run from easiest and fastest (with some drawbacks) to more difficult (with bigger benefits). 

1. Lift and shift
2. Move and improve
3. Rip and replace

Let’s dig in a bit more into the types of cloud migration strategies and the pros and cons of each.

What are the advantages of a lift and shift (also called “rehosting) approach? It’s quick and requires minimal refactoring. But (and this is a big but) the downsides of lift-and-shift include the fact that you may miss out on benefits you'd see if going cloud native because you’re performing the bare minimum changes needed. This means you could end up paying for the speed and the ease of your migration in the long run — at least when compared to a more thorough approach.

Lift-and-shift can be used for simple, low-impact workloads, particularly by organizations that are still far from cloud maturity. If your current setup includes loads of virtual machines, it’s relatively straightforward. There are even products from vendors that claim to help you automate your migration (but doing the process manually can be a great learning exercise). The good news is even if you've hastily made a lift-and-shift, applications are easier to rework and optimize once they’re running in cloud.

The move-and-improve (or replatforming) approach to migration includes making some modern updates to your application — like, say, introducing scaling or automation — without throwing the whole thing out. This happy-medium approach can seem like the superior option at a glance, but it can result in migrations where you keep all your technical debt and get none of the cloud-native benefits.

This approach (also called refactoring or re-architecting) means rebuilding your workload from scratch to be “cloud-native.” It takes an investment in time and skills development (particularly reskilling and upskilling your existing talent), but it pays out with the maximum benefits available in the cloud. 

While every organization and workload is unique, if the reason for moving to the cloud is to take advantage of its awesome benefits and capabilities, embracing cloud-native design principles should be your approach. This means taking the time to plan and do things right: ensuring your people have the necessary skills to make the move and refactoring your code.

• Repurchasing — Got a legacy application that won’t easily move to the cloud? Buy a new product that’s already there.

• Retiring — After looking over everything in your environment, you’re likely to discover there are things you can axe without consequences. DO it. Saves money, improve security, and give your people one less tool they have to learn to use.

• Retaining — See something you’re not quite ready to retire but also aren’t ready to move to the cloud? Revisit it later. It's not procrastination. There are times where it may make sense to just keep things as they are. (After all, as we've covered, moving to the cloud just for the sake of moving to the cloud can keep you from realizing the benefits it can offer.)

• Cloud-to-cloud migrations — This involves moving from one cloud to another, like from AWS to Azure.

• Reverse cloud migrations — This migration away from the cloud to an on-site data center is also called cloud repatriation, de-clouding, or unclouding.

Which tool is used for cloud migration? Well, there's more than one...much more! Big public cloud providers like AWS, GCP, and Azure want you to move to their slice of the cloud (go figure), so they throw plenty of tools your way to make migrations as pain-free as possible.

Of course, they’re also happy to take your money if you want to just throw it their way. Cost savings are a potential benefit of moving to cloud, but cloud costs can also easily get out of control. That’s why it’s important to use all the tools at your disposal to plan for what you need and adjust processes. Things that worked fine on-premises can be costly mistakes in the cloud.

Cloud cost calculators can help you sneak a peek at the cost of your setup before making the move. Check out the one your public cloud provider offers. Examples include the AWS Pricing Calculator, the Azure Pricing Calculator, and the (equally surprisingly named) Google Cloud Pricing Calculator.

Other tools to check out early on include (for AWS) AWS Trusted Advisor and (for Azure) Microsoft Azure Advisor. These give you real-time guidance around cloud best practices and can also help with cost optimization, as well as security and performance.

What cloud migration tools does Amazon Web Services (AWS) offer? If you’re looking for Amazon cloud migration services, the cloud juggernaut has a range of solutions — including plenty of free ones — to help you kick off your migration.

• AWS Migration Hub — What is AWS Migration Hub? It lets you track the progress of migrations across AWS solutions, helping you pick the right tools, track metrics, and more.
• AWS Application Delivery Service — Plan for your migration by letting AWS review your on-prem data setup. Collected data is encrypted and accessible from the Migration Hub.
• AWS Server Migration Service — This service makes it easy and quick to move workloads to AWS, particularly when dealing with large-scale server migrations.
• AWS Database Migration Service — Easily and securely move your databases to AWS. Bonus: The source database remains functional throughout the migration, minimizing downtime.
• CloudEndure Migration — This automated lift-and-shift solution is free for 90 days.

There are also several tools for migrating data and files, including AWS Snowball, AWS Snowball Edge, AWS Snowmobile, AWS DataSync, and AWS Transfer for SFTP. You can get more details on these and other services from AWS. You can also skill-up more generally with Amazon and their services through a certification.

Need Azure cloud migration tools? Azure offers plenty of resources, including tools, tutorials, and videos. (We also have a few tips for those looking to migrate servers to Azure.)

• Azure Migrate — Microsoft’s built-in migration service serves as a central hub for tools, progress tracking, insights, and guidance to plan and successfully migrate to the cloud. Most other tools covered below are integrated into this central dashboard.
• Azure Migrate: Server Assessment and Server Migration — These tools let you assess and migrate servers to Azure, including physical servers and VMware, Hyper-V, public cloud, and other VMs.
• Data Migration Assistant — DMA helps locate compatibility issues that could derail your migration. It points out unsupported features, new features, and helps you plot a proper path for database migration.
• Azure Database Migration Service — Migrate on-prem databases to Azure VMs.
• Azure Data Box — Move large amounts of offline data to the Azure cloud. 
• Movere — This SaaS platform was acquired by Microsoft in 2019. It’s a discovery solution that increases business intelligence to see and control environments across.

If you want to skill up more generally in Azure, perhaps try a certification?

GCP has two different paths for simplifying cloud migration planning. The first (and newer option) is called Google Cloud Rapid Assessment & Migration Program (RAMP), which the company describes as a “holistic, end-to-end migration program.” The second option is The Google Cloud Adoption Framework (a whitepaper you can download) and the 15-minute Cloud Maturity Assessment.

Ready to start migrating to the cloud that Google built? The company has its own laundry list of migration services.

• Transfer Service — Execute large-scale data transfers from online and on-premises sources to Google Cloud Storage.
• Transfer Appliance — For offline bulk data migration, Transfer Appliance lets you securely capture, ship, and upload data using 100TB or 480TB models.
• Migrate for Anthos — Migrate and modernize existing workloads to containers.
• Migrate for Compute Engine — Get enterprise applications running in Google Cloud while data migrates in the background. Validate, run, and migrate applications without reworking them.
• BigQuery Data Transfer Service — Let your analytics team set the foundation for a BigQuery data warehouse and schedule and automate data transfers from your SaaS applications.

Other Google Cloud migration tools can be viewed on Google’s migration center site. And if you want to level up more generally with GCP, perhaps try a certification?

Anticipating potential issues is a key part of your cloud migration strategy. What are some common cloud migration challenges?

• Managing costs — Cloud can deliver cost savings, but determining the cost of cloud can be tricky. Cloud expenses can be easy to underestimate. Don’t just consider the costs of migrating but also the cost of migration services, the potential need for increased bandwidth, and future recurring expenses. (Proper planning and cloud cost optimization help here big time.)
  
• Complexity — Public cloud is generally easier to manage, but it can get complex (and fast if you start introducing hybrid cloud elements). Your talent needs to be capable of managing your cloud and understand the effort needed for a successful migration.
  
• Dependencies — Application dependencies get complicated real quick and bring migrations to a screeching halt. Cloud provider discovery tools can ensure you’ve got them all in sight.
  
• Legacy applications — Some applications are a nightmare to get to the cloud. This is where evaluating why you’re moving what you’re moving becomes crucial. Decide what you’ll keep as-is, what needs to be rebuilt, and what might be worth repurchasing.
  
• Databases — Getting massive amounts of data to the cloud can take time. To help, some providers offer options for physically copying your data to provided hardware that you then ship off.
  
• Stakeholder support — You want leadership committed to the long game when it comes to cloud. This is where forming a Cloud Center of Excellence really pays off. 

• Building cloud fluency — A central cloud team doesn’t scale. Cloud fluency ensures your entire organization is on the same page, so you don’t have a small pool of cloud pros overburdened as cloud translators. A Cloud Guru's 2020 State of Cloud Learning Report has more info on how organizations are pursuing cloud learning.

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Also, here are a few more resources you might find useful!

Getting a cloud certification can be a great help, and you've got pathways for each platform.

• Amazon cloud certification pathways
• Microsoft Azure certification pathways
• Google Cloud certification pathways

Other useful resources on migrating to cloud:

• 6 People You Need on Your Cloud Migration Dream Team
• Pro tips for architecting sustainable systems on AWS
• Cloud Migration: Ask The Experts
• Cloud Migration Patterns That Really Work
• AWS Cloud Migration Journey: Upskilling Your Architects