Mesh expansion is a crucial concept in the realm of containerization and orchestration. It refers to the process of adding non-Kubernetes services to a network mesh. This allows for the integration of services running outside the Kubernetes cluster into the service mesh, thereby expanding the mesh's capabilities. This article will delve into the intricacies of mesh expansion, its history, use cases, and specific examples.
Understanding mesh expansion requires a firm grasp of containerization and orchestration. Containerization is a lightweight alternative to full machine virtualization that involves encapsulating an application in a container with its own operating environment. On the other hand, orchestration is the automated configuration, coordination, and management of computer systems and services. Together, they form the backbone of modern software deployment and scaling strategies.
Definition of Key Terms
Before delving into the specifics of mesh expansion, it is essential to define some key terms related to containerization and orchestration. These terms form the foundation of understanding the concept of mesh expansion.
Firstly, a 'container' is a standard unit of software that packages up code and all its dependencies so the application runs quickly and reliably from one computing environment to another. A Docker container image is a lightweight, standalone, executable package that includes everything needed to run a piece of software, including the system tools, system libraries, settings, and runtime.
Docker
Docker is an open-source platform that automates the deployment, scaling, and management of applications. It uses containerization to package an application and its dependencies into a virtual container that can run on any Linux server. This helps enable flexibility and portability on where the application can run, whether on-premises, public cloud, private cloud, bare metal, etc.
Docker provides the ability to package and run an application in a loosely isolated environment called a container. The isolation and security allow you to run many containers simultaneously on a given host. Containers are lightweight because they don’t need the extra load of a hypervisor, but run directly within the host machine’s kernel.
Kubernetes
Kubernetes, also known as K8s, is an open-source platform designed to automate deploying, scaling, and operating application containers. It groups containers that make up an application into logical units for easy management and discovery. Kubernetes provides a framework to run distributed systems resiliently, scaling and recovering as needed.
Kubernetes services, deployments, and pods are all part of the orchestration framework. Services maintain network connectivity and load balancing across a set of pods. Deployments manage the desired state of an application, ensuring that the environment is always in the specified state. Pods are the smallest deployable units of computing that can be created and managed in Kubernetes.
Understanding Mesh Expansion
Mesh expansion is a feature of service meshes like Istio that allows the inclusion of services running outside of a Kubernetes cluster into the service mesh. This is done by installing sidecar proxies on the VMs running these services, which then become part of the mesh and can communicate with other services in the mesh.
The primary purpose of mesh expansion is to enable seamless communication between services, regardless of where they are running. This is particularly useful for organizations that have a mix of services running in Kubernetes and on traditional VMs. With mesh expansion, they can manage all their services as if they were part of a single, unified network.
Service Mesh
A service mesh is a dedicated infrastructure layer for handling service-to-service communication. It's responsible for the reliable delivery of requests through the complex topology of services that comprise a modern, cloud-native application. In practice, the service mesh provides every service instance with a network proxy instance.
The service mesh abstracts the complexity of managing microservices and the network communication between them. The proxies form a mesh network that handles service discovery, load balancing, failure recovery, metrics, and monitoring. A service mesh also often has more complex operational requirements, like A/B testing, canary releases, rate limiting, access control, and end-to-end authentication.
Istio
Istio is an open-source service mesh that layers transparently onto existing distributed applications. It is also a platform, including APIs that let it integrate into any logging platform, or telemetry or policy system. Istio's diverse feature set lets you successfully, and efficiently, run a distributed microservice architecture, and provides a uniform way to secure, connect, and monitor microservices.
Istio provides several vital services consistently across a mesh network such as load balancing, service-to-service authentication, and monitoring without requiring changes in the service code. Istio gives you the tools needed to observe, control, and secure the traffic within your network, and, when used in conjunction with a platform like Kubernetes, can also manage traffic between your network and the outside world.
History of Mesh Expansion
The concept of mesh expansion has its roots in the evolution of distributed systems and the need for more efficient and scalable methods of managing communication between services. As organizations began to adopt microservices architectures, they faced challenges in managing the increasing complexity of service-to-service communication. This led to the development of service meshes, which provided a dedicated infrastructure layer for handling this communication.
However, as organizations continued to evolve and adopt hybrid cloud strategies, they needed a way to manage communication between services running in different environments. This led to the development of mesh expansion, which extended the capabilities of the service mesh to include services running outside the Kubernetes cluster. The first major service mesh to introduce this feature was Istio, which added it in version 0.8, released in May 2018.
Use Cases of Mesh Expansion
Mesh expansion has a wide range of use cases, particularly for organizations that have a mix of services running in Kubernetes and on traditional VMs. By enabling these services to communicate seamlessly, mesh expansion can help organizations achieve greater operational efficiency and agility.
One common use case for mesh expansion is in migrating applications to a microservices architecture. If an organization has a legacy application running on a VM that it wants to break down into microservices running in a Kubernetes cluster, it can use mesh expansion to ensure that the services can communicate with each other during the migration process.
Hybrid Cloud Strategies
Mesh expansion is particularly useful for organizations implementing hybrid cloud strategies. In a hybrid cloud environment, an organization's data and applications are spread across different cloud environments, including public clouds, private clouds, and on-premises data centers. Mesh expansion allows these disparate services to communicate with each other as if they were part of a single, unified network.
This can greatly simplify the management of hybrid cloud environments, as it eliminates the need for complex networking configurations to enable communication between services. It also provides a consistent way to apply policies and security measures across all services, regardless of where they are running.
Multi-Cloud Strategies
Similarly, mesh expansion can also be beneficial for organizations implementing multi-cloud strategies. In a multi-cloud environment, an organization uses multiple cloud services from different providers to meet its IT needs. This can provide benefits in terms of cost savings, performance optimization, and risk mitigation.
However, managing communication between services running in different clouds can be complex. Mesh expansion can simplify this by enabling all services to communicate with each other as if they were part of a single network. This can make it easier to manage and monitor the entire multi-cloud environment.
Examples of Mesh Expansion
Several organizations have successfully implemented mesh expansion to improve their operational efficiency and agility. One such example is Auto Trader UK, a leading digital automotive marketplace. Auto Trader used Istio's mesh expansion feature to integrate its Kubernetes-based microservices with its legacy applications running on VMs.
This allowed Auto Trader to manage all its services as if they were part of a single, unified network, greatly simplifying its operational processes. It also enabled Auto Trader to apply consistent policies and security measures across all its services, improving its overall security posture.
Financial Services
Another example can be found in the financial services industry, where mesh expansion is being used to enable seamless communication between services running in different environments. For instance, a bank might have some of its services running in a private cloud for security reasons, while others run in a public cloud for scalability.
By using mesh expansion, the bank can ensure that all its services can communicate with each other seamlessly, regardless of where they are running. This can greatly simplify the bank's operational processes and improve its ability to deliver high-quality services to its customers.
Healthcare
Mesh expansion is also being used in the healthcare industry to enable seamless communication between services running in different environments. For example, a hospital might have some of its services running in a private cloud for security and compliance reasons, while others run in a public cloud for scalability and cost-efficiency.
By using mesh expansion, the hospital can ensure that all its services can communicate with each other seamlessly, regardless of where they are running. This can greatly simplify the hospital's operational processes and improve its ability to deliver high-quality care to its patients.
Conclusion
Mesh expansion is a powerful tool for managing communication between services running in different environments. By enabling these services to communicate as if they were part of a single, unified network, mesh expansion can greatly simplify operational processes and improve operational efficiency and agility.
Whether you're migrating applications to a microservices architecture, implementing a hybrid or multi-cloud strategy, or simply trying to manage communication between services running in different environments, mesh expansion can provide significant benefits. As with any technology, it's important to understand the specifics of how it works and how it can be used to meet your specific needs.