Service Mesh vs API Gateway

As organizations continue to adopt microservices architecture, managing the communication between these services becomes a challenge. This is where Service Mesh and API gateway come into play. Both serve as essential tools in managing microservices communication, but they differ in their approach and functionality.

So, what is a Service Mesh?

A Service Mesh is a dedicated infrastructure layer designed to manage and monitor service-to-service communication within a microservices architecture. It provides a way to manage, control and secure service-to-service communication using a set of lightweight proxies deployed alongside the services themselves.

Deploying a Service Mesh:

1. Install Istio on Kubernetes

istioctl install

Documentation: https://istio.io/latest/docs/setup/install/kubernetes/

2. Create a new namespace and label it for automatic sidecar injection:

kubectl create namespace my-namespace
kubectl label namespace my-namespace istio-injection=enabled

Documentation: https://istio.io/latest/docs/setup/additional-setup/sidecar-injection/#automatic-sidecar-injection

3. Deploy a sample application and service:

kubectl apply -f <sample_app.yaml>
kubectl apply -f <sample_service.yaml>

Managing a Service Mesh:

1. View the status of the mesh components:

istioctl version
istioctl analyze

Documentation: https://istio.io/latest/docs/ops/diagnostic-tools/istioctl/

2. View the traffic flow and metrics:

istioctl dashboard

On the other hand, an API gateway is an essential part of an organization’s API infrastructure. It is responsible for managing and controlling access to APIs by external clients or applications. It provides a centralized point of entry for API requests, handles authentication, and enforces API policies.

Deploying an API Gateway:

1. Install Kong Ingress Controller on Kubernetes:

helm repo add kong https://charts.konghq.com
helm install kong/kong --generate-name

Documentation: https://docs.konghq.com/kubernetes-ingress-controller/2.3.x/deployment/installation/

2. Create a KongPlugin for authentication:

kubectl apply -f <kong_auth_plugin.yaml>

Documentation: https://docs.konghq.com/kubernetes-ingress-controller/2.3.x/guides/plugins/custom-plugins/

3. Deploy an Ingress resource to expose the service:

kubectl apply -f <ingress.yaml>

Documentation: https://kubernetes.io/docs/concepts/services-networking/ingress/

Managing an API Gateway:

1. View the KongAdmin dashboard:

kubectl port-forward service/<kong-admin-service-name> <local-port>:<remote-port>

Documentation: https://docs.konghq.com/kubernetes-ingress-controller/2.3.x/guides/expose-admin-api/

2. View the KongProxy metrics:

kubectl port-forward service/<kong-proxy-service-name> <local-port>:<remote-port>

Documentation: https://docs.konghq.com/kubernetes-ingress-controller/2.3.x/guides/expose-metrics/

While both service mesh and API gateway share some similarities, there are key differences between them.

1. Communication

A service mesh manages communication between services within a microservices architecture, while an API gateway is responsible for managing communication between external clients and the APIs. Service mesh is focused on east-west traffic (between services), while API gateway focuses on north-south traffic (between external clients and APIs).

2. Functionality

Service mesh is more focused on service-to-service communication, providing features such as service discovery, load balancing, traffic routing, and service-level security. In contrast, API gateway is more focused on managing external access to APIs, providing features such as API authentication, rate limiting, and API transformation.

3. Deployment

Service mesh proxies are deployed alongside the services themselves, providing a dedicated infrastructure layer for managing service-to-service communication. API gateways, on the other hand, are typically deployed as a separate layer in the infrastructure, providing a centralized point of entry for API requests.

So, which is better?

The answer to this question depends on the specific needs of your organization. If you are focused on managing service-to-service communication within a microservices architecture, then service mesh is the better choice. Service mesh provides a dedicated infrastructure layer for managing and securing communication between services, providing features such as service discovery, load balancing, and traffic routing.

If your organization is more focused on managing external access to APIs, then API gateway is the better choice. API gateway provides a centralized point of entry for API requests, handling authentication, rate limiting, and API transformation.

In conclusion, both service mesh and API gateway play important roles in managing microservices communication. Service mesh is focused on east-west traffic within a microservices architecture, while API gateway is focused on north-south traffic between external clients and APIs. Choosing the right tool depends on your organization’s specific needs and priorities.