Container orchestration automates the deployment, management, scaling, and networking of containers. Enterprises that need to deploy and manage hundreds or thousands of LinuxⓇ containers and hosts can benefit from container orchestration.
Container orchestration can be used in any environment where you use containers. It can help you to deploy the same application across different environments without needing to redesign it. And microservices in containers make it easier to orchestrate services, including storage, networking, and security.
Containers give your microservice-based apps an ideal application deployment unit and self-contained execution environment. They make it possible to run multiple parts of an app independently in microservices, on the same hardware, with much greater control over individual pieces and life cycles.
Managing the lifecycle of containers with orchestration also supports DevOps teams who integrate it into CI/CD workflows. Along with application programming interfaces (APIs) and DevOps teams, containerized microservices are the foundation for cloud-native applications.
What is container orchestration used for?
Use container orchestration to automate and manage tasks such as:
- Provisioning and deployment
- Configuration and scheduling
- Resource allocation
- Container availability
- Scaling or removing containers based on balancing workloads across your infrastructure
- Load balancing and traffic routing
- Monitoring container health
- Configuring applications based on the container in which they will run
- Keeping interactions between containers secure
Container orchestration tools
Container orchestration tools provide a framework for managing containers and microservices architecture at scale. There are many container orchestration tools that can be used for container lifecycle management. Some popular options are Kubernetes, Docker Swarm, and Apache Mesos.
Kubernetes is an open source container orchestration tool that was originally developed and designed by engineers at Google. Google donated the Kubernetes project to the newly formed Cloud Native Computing Foundation in 2015.
Kubernetes orchestration allows you to build application services that span multiple containers, schedule containers across a cluster, scale those containers, and manage their health over time.
Kubernetes eliminates many of the manual processes involved in deploying and scaling containerized applications. You can cluster together groups of hosts, either physical or virtual machines, running Linux containers, and Kubernetes gives you the platform to easily and efficiently manage those clusters.
More broadly, it helps you fully implement and rely on a container-based infrastructure in production environments.
These clusters can span hosts across public, private, or hybrid clouds. For this reason, Kubernetes is an ideal platform for hosting cloud-native apps that require rapid scaling.
Kubernetes also assists with workload portability and load balancing by letting you move applications without redesigning them.
Main components of Kubernetes:
- Cluster: A group of nodes, with at least one master node and several worker nodes.
- Master: The machine that controls Kubernetes nodes. This is where all task assignments originate.
- Kubelet: This service runs on nodes and reads the container manifests and ensures the defined containers are started and running.
- Pod: A group of one or more containers deployed to a single node. All containers in a pod share an IP address, IPC, hostname, and other resources.
How does container orchestration work?
When you use a container orchestration tool, such as Kubernetes, you will describe the configuration of an application using either a YAML or JSON file. The configuration file tells the configuration management tool where to find the container images, how to establish a network, and where to store logs.
When deploying a new container, the container management tool automatically schedules the deployment to a cluster and finds the right host, taking into account any defined requirements or restrictions. The orchestration tool then manages the container’s lifecycle based on the specifications that were determined in the compose file.
Container orchestration can be used in any environment that runs containers, including on-premise servers and public cloud or private cloud environments.
Source : Container Orchestration