Cloud is now firmly mainstream, with roughly 94% of enterprises using cloud services and a growing majority running over half of their workloads in the cloud. Worldwide end-user spending on public cloud was forecasted to reach roughly $723 billion in 2025, underlining just how critical cloud has become to a business’ strategy.
Yet despite this investment, cloud migration challenges remain stubbornly persistent. One major study found that organisations spend on average 14% more on migration than planned and 38% of migrations are delayed by more than a quarter, driven by complexity, poor planning and skills gaps. Another widely cited report notes that 84% of organisations struggle to manage cloud spend effectively.
This guide explores the most common cloud migration challenges, why they occur and how to design a migration strategy, tooling approach and operating model that gives you a much higher chance of success. It also demonstrates how CACI’s cloud, engineering and implementation services can support your journey.
What is cloud migration and why is it so challenging?
Cloud migration is the process of moving applications, data, workloads and underlying infrastructure from on-premises or legacy environments into cloud platforms. It can also include moving between clouds or from one cloud service model to another.
Types of cloud migration
Understanding the main migration patterns is a useful starting point for setting expectations:
- Rehost (lift-and-shift): Moving workloads with minimal changes.
- Replatform: Making modest optimisations (e.g. managed databases) during migration.
- Refactor: Re-architecting applications to use cloud-native services.
- Rebuild: Rewriting systems from scratch for the cloud.
- Replace: Retiring legacy apps in favour of SaaS solutions.
Most organisations end up using a mix of these approaches across workloads.
Complex deployment models
Modern estates typically combine:
- Public cloud for scale and agility
- Private cloud for specific compliance or performance needs
- Hybrid cloud spanning on-prem and cloud
- Multi-cloud using several providers.
Gartner expects 90% of organisations to adopt hybrid cloud by 2027, reflecting the reality that few businesses are “all in” on a single environment. More choice is valuable, but it amplifies governance, integration and cost-management challenges.
Cloud benefits versus migration risks
The benefits of cloud are well documented: agility, scalability, resilience, innovation, access to AI services and more. IDC’s overview of cloud market trends highlights how cloud is now the foundation for data, automation and AI use cases.
However, without a structured approach, migrations can lead to:
- Higher-than-expected operating costs
- Outages and performance issues
- Security gaps and compliance risk
- Stalled programmes and change fatigue.
This is where understanding the main cloud migration challenges becomes essential.
Most substantial cloud migration challenges (by phase)
Grouping cloud migration challenges by phase of the journey helps you anticipate issues before they derail your programme.
1. Strategy & business alignment challenges
No clear business case
Many migrations begin with a general desire to “move to the cloud” without defining measurable success criteria. Are you aiming for reduced costs, faster product delivery, better resilience, improved security or all the above?
Lift-and-shift by default
Under pressure to move quickly, organisations often default to lift-and-shift. While appropriate in some cases, this often leads to increased cloud costs and disappointed stakeholders once workloads land in an environment they were not designed for.
Misaligned stakeholders
Finance wants predictable spend, IT wants stability and business units want new features tomorrow. Without a shared roadmap and governance model, priorities can easily clash.
How to mitigate these challenges
- Define a clear business case with KPIs (e.g. target cost savings, uptime, deployment frequency)
- Involve IT, finance and business leaders from the outset
- Use a structured migration framework and consider partnering with specialists such as CACI’s cloud, engineering and implementation services to co-create your strategy.
2. Discovery & assessment challenges
Poor application and dependency visibility
It is not uncommon for organisations to start migration planning and then discover that they do not have a complete, up-to-date inventory of applications, databases, integrations and dependencies. Missing a single critical dependency can cause outages when workloads are moved.
Legacy constraints
Older platforms, bespoke middleware and tightly coupled integrations obfuscate cloud migration. Some systems may be out of vendor support or lack documentation.
Underestimating integration complexity
Hybrid and multi-cloud architectures must integrate cleanly with on-prem systems and SaaS applications. Underestimating integration can lead to brittle connections and security gaps.
How to mitigate these challenges
- Use automated discovery and assessment tools to build a realistic view of your estate
- Map dependencies visually and prioritise high-blast-radius systems
- Classify workloads using a structured model (retain, retire, rehost, re-platform, refactor, replace)
- Consider a Platform Migration approach with expert support, such as CACI’s dedicated Platform Migration service.
3. Architecture & technical challenges
Choosing the right architecture
The breadth of cloud services is both a blessing and a curse. Teams must choose between virtual machines, containers, serverless, managed databases, message queues, data lakes and more, often with incomplete information and tight deadlines.
Performance and latency issues
Network design, data placement and application architecture all influence latency and throughput. Poor decisions in these areas can degrade customer experience and internal system performance.
Vendor lock-in
Leveraging cloud-native services maximises value but may also increase dependence on specific providers. Regulatory and data-sovereignty discussions, particularly in the UK and EU, are causing many organisations to carefully consider portability and digital sovereignty strategies.
How to mitigate these challenges
- Define reference architectures and guardrails early
- Run performance tests in pilot migrations
- Make conscious choices about where you accept lock-in for higher value and where you prefer portability.
4. Cloud migration security challenges
Security is consistently cited as one of the top cloud migration challenges. Government and industry bodies emphasise that cloud— used correctly— can be more secure than on-prem infrastructure. The UK government’s Cloud First policy and accompanying guidance stress the importance of security-by-design, shared responsibility and robust governance.
Identity and access management (IAM)
Misconfigured IAM, overly broad privileges and lack of role-based access control are a major root cause of cloud incidents.
Data protection
Sensitive data must be encrypted in transit and at rest, with careful key management and robust backup and recovery procedures.
Compliance and shared responsibility
Regulated sectors must demonstrate compliance with standards and regulations in a model where security responsibilities are split between provider and customer.
How to mitigate these challenges
- Establish an IAM strategy with least-privilege access and strong authentication
- Implement encryption, key management and robust logging from day one
- Use security posture-management tools and align with public guidance such as the UK cloud guide for the public sector
- Build security into your cloud platform as part of solution implementation rather than as an afterthought.
5. Data & integration challenges
Moving large volumes of data
Migrating terabytes or petabytes of data without impacting operations requires careful planning. Complex cutover plans, bulk transfer tools and synchronisation mechanisms are often needed.
Data quality and consistency
Inconsistent schemas, duplication and poor data governance can lead to mistrust in analytics and operational systems post-migration.
Integrating cloud with on-prem and SaaS
APIs, message queues and integration platforms must be carefully designed to avoid fragile, tightly coupled connections.
How to mitigate these challenges
- Treat data migration as a dedicated workstream
- Clean and reconcile data before moving it
- Design integration patterns (e.g. event-driven architectures) aligned to your target operating model
- Draw on lessons from real-world programmes like CACI’s case study on HMCTS Court Store and Bench’s move to AWS.
6. Cost, governance & FinOps challenges
Cloud is often sold as a route to lower costs, but the reality is more nuanced. In 2025, 84% of organisations struggled to manage cloud spend and cost optimisation remains a top priority year after year.
Bill shock and opaque spend
Without robust tagging, budgeting and monitoring, costs can escalate quickly. Bursty workloads, test environments left running and underused instances are common culprits.
Weak financial governance
Traditional budgeting models are not always suited to variable, usage-based pricing. Cloud makes it easy to spend money, but not to spend wisely.
Unclear total cost of ownership
Many organisations underestimate the ongoing cost of running cloud environments, including observability, security, data transfer and platform teams.
How to mitigate these challenges
- Adopt FinOps principles early, not after migration. A growing number of organisations are doing this specifically to tackle cloud waste and align spend to business value
- Tag resources consistently to enable accurate cost allocation
- Use budgets, alerts and dashboards to track spend against KPIs
- Consider getting external support from cloud specialists such as CACI’s Cloud Services to design your governance model.
7. People, skills & operating model challenges
Skills gaps
Cloud-native, DevOps and automation skills are in high demand. Internal teams may lack experience in designing and operating cloud platforms at scale.
Operating model friction
Existing ITIL-style processes and siloed teams do not always translate well to cloud environments, where continuous delivery and shared ownership are essential.
Cultural change
Cloud is not just a technology shift, but a cultural one. Teams must embrace new ways of working, from infrastructure-as-code to platform teams and product-centric delivery.
How to mitigate these challenges
- Create a Cloud Centre of Excellence (CCoE) to set standards and share best practice
- Invest in training and hands-on enablement
- Partner with experienced providers to accelerate learning, as described in CACI’s article on the actual experience of cloud migration for business.
How to build a cloud migration strategy that avoids these challenges
A structured cloud migration strategy is your best defence against these pitfalls.
Step 1: Define business outcomes and KPIs
Start with the “why”:
- Cost optimisation (e.g. target percentage reduction in run-rate costs)
- Improved resilience (e.g. RPO/RTO targets, availability SLAs)
- Faster time-to-market (e.g. release frequency, lead time for changes)
Better customer and employee experience.
Step 2: Assess your current
- Catalogue applications, services, databases and integrations
- Classify each workload by business criticality, technical complexity and risk
- Identify “quick wins” and high-risk areas needing more design work.
Step 3: Plan migration waves
Avoid trying to move everything at once. Instead:
- Group workloads into waves with clear objectives
- Start with lower-risk, high-learning systems
- Use pilot migrations to refine patterns and tooling.
Step 4: Design your target cloud architecture
Make conscious choices about:
- Compute models (VMs, containers, serverless)
- Data platforms (managed databases, data lakes, warehouses)
- Networking and connectivity (VPNs, private links, SD-WAN)
- Platform services for security, observability and CI/CD.
Step 5: Embed security and governance upfront
- Define IAM, logging, monitoring and compliance controls before migration
- Align with recognised guidance such as the UK government’s cloud technology collection
- Treat “platform hardening” as a prerequisite for production workloads.
Step 6: Establish a cloud operating model
Clarify:
- Who owns the central platform
- How product and application teams consume it
- How changes are tested, deployed and supported.
This operating model is where the concept of a cloud-appropriate strategy (rather than “cloud at all costs”) really takes shape.
Step 7: Plan for continuous optimisation
Cloud migration is not a one-off event. After cutover, you should:
- Right-size resources and use auto-scaling
- Tune performance and storage tiers
- Modernise where there is clear value
- Review costs and security posture regularly.
Cloud migration tools, platforms & frameworks
Choosing the right tools reduces risk and effort at each stage of migration.
Discovery, assessment & dependency mapping
- Infrastructure discovery tools and CMDBs
- Application performance monitoring (APM) platforms
- Dependency mapping and visualisation tools.
Data migration & synchronisation
- Cloud-native database migration services
- ETL/ELT tools for structured data movement
- Bulk transfer technologies for large datasets.
Application migration & modernisation
- Containerisation and orchestration tools
- Refactoring accelerators and code analysis tools
- CI/CD platforms to support new deployment models.
Security, compliance & governance
- Cloud security posture management (CSPM) and policy-as-code
- Identity and access management, secrets management and HSMs
- SIEM and threat-detection tooling.
Observability, performance & FinOps (H3)
- Monitoring, logging and tracing platforms
- Cost-management and optimisation tools aligned with FinOps practices.
The specific mix will depend on your chosen cloud providers and operating model, but the categories remain consistent.
Cloud migration best practices
This checklist outlines a practical reference throughout your programme:
Pre-migration
- Business case and KPIs agreed
- Application inventory and dependency maps completed
- Migration patterns decided per workload (rehost/replatform/refactor/etc.)
- Security and governance baselines designed
- Cost management and tagging strategy defined.
During migration
- Workloads migrated in waves, with rollback plans
- Performance and resilience tested in each wave
- Security controls verified before go-live
- Costs monitored against forecasts.
Post-migration
- Workloads rightsized and tuned
- Modernisation opportunities assessed
- Security posture and compliance reviewed regularly
- KPIs tracked and reported to stakeholders.
Measuring cloud migration success: KPIs & metrics
You cannot improve what you do not measure. Useful KPIs include:
Technical
- Availability and uptime
- Latency and response times
- Error rates and incident frequency.
Financial
- Monthly cloud run-rate vs baseline
- Cost per transaction or per user
- Savings from rightsizing or modernisation initiatives.
Business
- Release frequency and deployment lead times
- Time-to-market for new features
- Customer satisfaction or NPS impact.
Security
- Number of critical vulnerabilities
- Mean time to detect (MTTD) and mean time to remediate (MTTR)
- Compliance audit findings.
These metrics help you demonstrate whether your cloud migration is delivering on its promises or whether strategy and execution need to be re-thought.
Turning cloud migration challenges into an advantages with CACI
Cloud has moved from a novelty to a business necessity, but the real differentiator is how effectively your organisation navigates cloud migration challenges: strategy, security, cost, people and operations.
With the right roadmap, tools and operating model, you can turn those challenges into an advantages: more resilient services, faster innovation and a technology foundation ready for AI and future growth.
If you are ready to move from theory to practice, explore CACI’s Cloud, Engineering & Implementation Services and our dedicated Platform Migration and Solution Implementation offerings. You can also learn from real projects in our article on the actual experience of cloud migration for business.