Virtualisation vs Containerisation: Key Differences

In the domain of Computing, Virtualisation and Containerisation are transformative technologies which play a pivotal role in how IT resources are managed and utilised. However, there are subtle differences between Virtualisation vs Containersation, making them unique.    

Virtualisation is a well-established technology that creates a virtual instance of physical hardware, allowing multiple Operating Systems (OS) to run concurrently on a single physical machine. On the other hand, Containerisation is a relatively newer technology that focuses on the application level.     

Understanding their distinct characteristics and applications is crucial for making informed IT infrastructure and software development decisions. So, let’s get started. Read this blog to learn more about Virtualisation vs. Containerisation, its nuances, features, and more! 

Table of Contents 

1) What is Virtualisation? 

2) What is Containerisation? 

3) Differences Between Virtualisation and Containerisation 

   a) Isolation 

   b) Varied operating systems  

   c) Guest support 

   d) Deployment 

   e) Enduring virtual storage 

   f) Network Virtualisation 

   g) Virtual load balancing 

   h) Application lifecycle 

   i) Portability 

   j) Persistent storage 

4) Conclusion 

What is Virtualisation? 

Virtualisation is a transformative technology that fundamentally alters how Computing resources are utilised and managed. It involves creating virtual versions of physical hardware components, such as servers, storage devices, network resources, and even entire operating systems. This is achieved using a software layer called a hypervisor.  

The hypervisor acts as a platform for running multiple Virtual Machines (VMs), each functioning independently with its Operating System (OS) and applications. These VMs are abstracted from the underlying physical hardware, allowing them to share the same physical resources. This separation provides several key benefits:  

a) Resource Efficiency: Virtualisation maximises the utilisation of physical resources, reducing the need for multiple physical machines. It enables better scaling and management of resources, as virtual environments can be adjusted without material hardware changes. 

b) Isolation and Security: Each VM operates in isolation, ensuring that processes in one VM do not impact others. This isolation enhances security, as a problem in one VM doesn't compromise the others. 

c) Flexibility and Scalability: It offers remarkable flexibility. New VMs can be quickly created, modified, or deleted, enabling scalable solutions for varying workloads. 

d) Cost Reduction: By reducing the need for physical hardware, Virtualisation lowers hardware costs, energy consumption, and the physical space needed for servers. 

e) Disaster Recovery and Testing: It simplifies backup and disaster recovery processes. VMs can be easily replicated or moved to different servers, and their isolated nature makes them ideal for testing new applications or system updates without risk to the primary system.
 

What is Containerisation? 

Containerisation focuses on encapsulating an application and its dependencies into a container. Unlike traditional Virtualisation, which virtualises the entire operating system, Containerisation virtualises only the application layer. This means that containers share the host system's operating system kernel but run in isolated user spaces, known as containers.   

The critical component of Containerisation is the container engine, with Docker being the most prominent example. This engine enables the creation, execution, and management of containers. Each container is an isolated environment containing the application's libraries, binaries, configuration files, and other necessary components. This encapsulation ensures that the application runs consistently across different Computing environments. 

Differences Between Virtualisation and Containerisation 

The distinctions between Virtualisation and Containerisation are essential in understanding modern IT infrastructure and software deployment strategies. Each technology offers unique benefits and caters to different needs in Computing. Let’s see how: 

1) Isolation 

Isolation in Virtualisation and Containerisation is fundamental for security, resource management, and performance. In Virtualisation, isolation is achieved at the hardware level. Each Virtual Machine (VM) runs its own operating system, completely segregated from others on the same host. This provides strong security as activities in one VM do not affect others. 

On the contrary, Containerisation, while offering a degree of isolation, does so at the application level. Containers share the host's operating system kernel but operate in isolated user spaces. This setup provides a lightweight form of isolation, ensuring that applications do not interfere with each other. However, it might not offer the same level of security as Virtualisation, particularly in environments with high-security demands. 

2) Varied Operating Systems 

Virtualisation excels in environments requiring varied operating systems. Each VM in a virtualised environment can run a different operating system, allowing for a diverse ecosystem where Windows, Linux, and other OS can coexist on the same physical hardware. This flexibility is crucial for testing across different OS, legacy system support, or specific software requirements that rely on certain operating systems.  

Containerisation, on the other hand, is less flexible regarding operating system diversity. Containers share the host's OS kernel, restricting them to the OS type of the host. While containers can run different distributions of the same kernel (e.g., other Linux distributions), they cannot cross the boundaries of entirely different operating systems. This limitation is generally acceptable for most modern applications but can be restrictive for OS-level diversity scenarios. 

3) Guest Support 

Guest support refers to the ability of a system to host and manage different operating environments. In Virtualisation, each VM is a separate computer capable of hosting a complete and independent operating system. This ability is essential for running applications compatible with only specific OS or testing applications across different environments.  

Containerisation, in contrast, supports only the application layer. Containers encapsulate the application and its dependencies but not an entire operating system. This model is particularly effective for microservices architecture and cloud-native applications, focusing on lightweight, efficient deployment rather than full-fledged OS support. 

4) Deployment 

Deployment efficiency is a critical differentiator between Virtualisation and Containerisation. Virtualisation involves setting up and managing entire operating systems within VMs, which can be resource-intensive and time-consuming. While offering more control and flexibility, this approach is less agile than Containerisation.   

Containerisation, on the other hand, streamlines deployment by encapsulating the application and its immediate environment, excluding the entire OS. This makes containers much lighter and faster to deploy, especially beneficial in agile and DevOps environments where speed and efficiency are paramount. The lightweight nature of containers also allows for rapid scaling and responsiveness to changing demands. 

5) Enduring Virtual Storage 

Enduring virtual storage in Virtualisation is handled through virtual disks, which provide persistent storage solutions for VMs. These virtual disks are managed independently of the underlying physical storage, allowing data management, migration, and backup flexibility.   

In Containerisation, enduring storage is more challenging due to the temporary nature of containers. Since containers are designed to be transient, any data stored within them is lost when the container is stopped or deleted. Therefore, containerised environments often rely on external solutions, like Cloud or network-attached storage, to ensure data persistence. 

6) Network Virtualisation 

Network Virtualisation in a VM environment involves creating virtual networks, including switches, routers, firewalls, and other networking components. This capability allows for the creation of complex, segmented networks that provide enhanced security and traffic management among VMs.   

On the other hand, Containerisation generally utilises simpler networking models. While containers can be configured to communicate with each other and with external networks, they typically rely on the host system's networking capabilities. Advanced orchestration tools like Kubernetes can manage more complex networking requirements in containerised environments but generally do not offer the same network customisation and control as VM-based network Virtualisation. 

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7) Virtual Load Balancing 

Virtual load balancing in a virtualised environment involves distributing workloads across multiple VMs to optimise resource utilisation and application performance. This can be crucial in large-scale deployments where traffic management and high availability are critical.  

Meanwhile, container orchestration platforms often manage load balancing in containerised environments. These platforms can dynamically distribute container workloads to maintain optimal performance. While generally simpler than VM-based load balancing solutions, container load balancers are highly effective for lightweight, dynamic workloads typical in containerised environments. 

8) Application Lifecycle 

The application lifecycle in virtualised environments tends to be longer and more static. VMs are suited for applications that require stable, long-term environments with infrequent changes. This is particularly relevant for legacy applications or environments prioritising stability and longevity over rapid iteration.  

Meanwhile, Containerisation is aligned with modern application development practices like Continuous Integration and Continuous Deployment (CI/CD). Containers support a more dynamic application lifecycle, allowing rapid updates, testing, and deployment. This agility makes containers ideal for development environments where speed and flexibility are essential. 

9) Portability 

Portability in Virtualisation allows entire VMs and their Operating Systems and applications to be easily moved from one physical server to another. This is particularly useful for disaster recovery, migration, or load balancing across servers.   

Containerisation, on the other hand, offers portability at the application level. Containers can be moved easily across different environments (development, testing, production) or Cloud platforms without any modification. This portability ensures consistency in application performance and behaviour across various infrastructures. 

10) Persistent Storage 

Virtualisation typically achieves this through virtual disks, which are durable storage for VMs. These virtual disks persist data even when VMs are shut down or moved between hosts, ensuring data longevity and integrity. On the other hand, for Containerisation, achieving persistent storage is more challenging, as containers are inherently ephemeral. Solutions often involve external storage systems, such as Network-Attached Storage (NAS) or Cloud-based storage services, which are mounted to containers to ensure data persists beyond the container's lifecycle. This approach is essential for applications that require data retention, such as databases or file storage systems, operating within containerised environments. 

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Conclusion 

Understanding the differences between Virtualisation vs Containerisation is crucial in making informed decisions in IT infrastructure and application deployment. Virtualisation offers robust isolation and flexibility in OS environments, and Containerisation is ideal for microservices, Cloud-native applications, and environments with frequent updates and deployments. Both technologies have transformed the IT industry, which offers unique benefits and efficiencies. 

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