Limitations of Virtual Machines and Servers?

1. Startup & Shutdown Times:

  • VMs generally take longer to start up and shut down compared to containers, which can impact the speed of deployment and scaling.
  • This delay can be a bottleneck in environments requiring rapid provisioning and de-provisioning of resources.

2. Dynamic Resource Allocation is Complex:

  • VMs rely on hypervisors(such as VMware ESXi, Microsoft Hyper-V) to manage and allocate resources like CPU, memory and storage. This adds complexity because the hypervisor needs to handle various resource demands and ensure fare distribution. (Earlier we would need to Shutdown the VM for changing the allocated resources but now this can be done on a running instance as well but it still needs input/human intervention and its complex)
  • Automatic Scaling & Descaling is not possible.

3. Inefficient Resource Utilization:

  • VMs may not always utilize the underlying hardware efficiently. Idle VMs still consume resources, as resources assigned to VMs are utilized by OS(like kernel services, other services), rest is used by actual application.
  • Over-provisioning of resources to ensure performance can also result in underutilized hardware.

4. Resource Contention:

  • Multiple VMs running on a single physical server can lead to resource contention, where VMs compete for CPU, memory and I/O resources.
  • Leads to performance degradation especially under heavy workloads.

5. Less VM's Spin up

  • Number of VMs that can be spined is more compared to Physical Servers but less compared with Containers.

Why Containers are the Heroes?

1. Efficiency and Speed:

  • Containers are lightweight and start up much faster than traditional VMs. The efficiency allows for rapid deployment and scaling of applications.

2. Consistency Across Environments:

  • Containers encapsulate an application and its dependencies, ensuring that it runs consistently across different environments, from development to production.

3. Resource Optimization

  • Containers share the host system's kernel, which reduces overhead and allows for better utilization of system resources compared to VMs.

4. Portability:

  • Containers can run on any system that supports the container runtime, making it easy to move applications between different environments and cloud providers.

5. Microservices Architecture

  • Containers are ideal for microservices architecture, where applications are broken down into smaller, manageable services that can be developed, deployed and scaled independently.

6. Simplified Management:

  • Tools like Kubernetes have made it easier to manage, orchestrate, and scale containerized applications, further enhancing their appeal.