Kubernetes, often abbreviated as K8s, is an open-source container orchestration platform that automates the deployment, scaling, and management of containerized applications. Here are some key aspects of Kubernetes:
- Containers and Pods: Kubernetes manages applications that are packaged in containers—primarily Docker containers. Containers within Kubernetes are grouped into units called Pods. A Pod is the smallest deployable unit in Kubernetes and can contain one or more containers that share storage/network resources and a specification on how to run the containers.
- Scalability and Load Balancing: Kubernetes can scale applications up or down as required by adding or removing Pods based on the current load, ensuring that applications can handle varying loads efficiently.
- Automated Rollouts and Rollbacks: It allows for automated deployments and updates to applications without downtime, and can automatically roll back to a previous version if a new version fails its checks.
- Service Discovery and Load Balancing: Kubernetes can expose a container to the internet or other containers in the Kubernetes cluster using DNS names or IP addresses. It can also load balance traffic to ensure deployments are stable and performant.
- Self-healing: Kubernetes restarts containers that fail, replaces and reschedules containers when nodes die, kills containers that don't respond to user-defined health checks, and doesn't advertise them to clients until they are ready to serve.
How Kubernetes Relates to Terraform
Kubernetes and Terraform can be used together to provide a powerful combination for managing complex deployments. Here’s how they relate:
- Infrastructure Management: Terraform can be used to set up the underlying infrastructure that Kubernetes runs on. This includes provisioning the network, storage, and compute resources required for a Kubernetes cluster on any supported cloud platform (like AWS, GCP, Azure).
- Cluster Configuration and Management: After Terraform has been used to provision the physical resources, Kubernetes takes over to manage the containerized applications that run on that infrastructure. Kubernetes handles the runtime, scaling, and management aspects of the containers.
- Complementary Tools: While Terraform is great for setting up and changing the infrastructure with a high level of control and predictability, Kubernetes excels at managing the operational aspects of container orchestration within that infrastructure.
Using both together, developers and operations teams can automate and manage infrastructure and application deployment, from the physical layers up to the application layer, in a consistent and reproducible way. This makes the combination of Kubernetes and Terraform particularly powerful for cloud-native development and operations.
