What is Container Orchestration?
Container orchestration refers to a process that deals with managing the lifecycles of containers in large, dynamic environments. It’s a tool that schedules the workload of individuated containers within many clusters, for applications based on microservices. A process of virtualization, it essentially separates and organizes services and applications at the base operating level. Orchestration is not a hypervisor since the containers are not separate from the rest of the architecture. It shares the same resources and kernel of the operating system.
Containerization has emerged as a new way for software organizations to build and maintain complex applications. Organizations that have adopted microservices in their businesses are using container platforms for application management and packaging.
The Problem It Solves
Scalability is the problem that containerization resolves when facing operational challenges in utilizing containers effectively. The problem begins when there are many containers and services to manage simultaneously. Their organization becomes complicated and cumbersome. Container orchestration solves that problem by offering practical methods for automating the management, deployment, scaling, networking, and availability of containers.
Microservices use containerization to deliver more scalable and agile applications. This tool gives companies complete access to a specific set of resources, either in the host’s physical or virtual operating system. It’s why containerization platforms have become one of the most sought-after tools for digital transformation.
Software teams in large organizations find container orchestration a highly effective way to control and to automate a series of tasks, including;
- Container Provisioning
- Container Deployment
- Container redundancy and availability
- Removing or scaling up containers to spread the load evenly across the host’s system.
- Allocating resources between containers
- Monitoring the health of containers and hosts
- Configuring an application in relation to specific containers which are using them
- Balancing service discovery load between containers
- Assisting in the movement of containers from one host to another if resources are limited or if a host expires
To explain how containerization works we need to look at the deployment of microservices. Microservices employ containerization to deliver tiny, single-function modules. They work together to produce more scalable and agile applications. This inter-functionality of smaller components (containers) is so advantageous that you do not have to build or deploy a completely new version of your software each time you update or scale a function. It saves time, resources, and allows for flexibility that monolithic architecture cannot provide.
How Does Container Orchestration Work?
There are a host of container orchestration tools available on the market currently with Docker swarm and Kubernetes commanding the largest user-bases in the community.
Software teams use container orchestration tools to scribe the configuration of their applications. Depending on the nature of the orchestration tool being used, the file could be in a JSON or YAML format. These configuration files are responsible for directing the orchestration tool towards the location of container images. Information on other functions that the configuration file is responsible for includes establishing networking between containers, mounting storage volumes, and the location for storing logs for the particular container.
Replicated groups of containers deploy onto the hosts. The container orchestration tool subsequently schedules the deployment, once it’s time to deploy a container into a cluster. It then searches for an appropriate host to place the container, based on constraints such as CPU or memory availability. The organization of containers happens according to labels, Metadata, and their proximity to other hosts.
The orchestration tool manages the container’s lifecycle once it’s running on the host. IT follows specifications laid out by the software team in the container’s definition file. Orchestration tools are increasingly popular due to their versatility. They can work in any environment which supports containers. Thus, they support both traditional on-premise servers and public cloud instances, running on services such as Microsoft Azure or Amazon Web Services.
What Are Containers Used For?
Making deployment of repetitive tasks and jobs easier: Containers assist or support one or several similar processes that are run in the background, i.e. batch jobs or ETL functions.
Giving enhanced support to the microservices architecture: Microservices and distributed applications are effortlessly deployed and easily isolated or scaled by implementing single container building blocks.
Lifting and shifting: Containers can ‘Lift and Shift’, which means to migrate existing applications into modern and upgraded environments.
Creating and developing new container-native apps: This aspect underlines most of the benefits of using containers, such as refactoring, which is more intensive and beneficial than ‘lift-and-shift migration’. You can also isolate test environments for new updates for existing applications.
Giving DevOps more support for (CI/CD): Container technology allows for streamlined building, testing, and deployment from the same container images and assists DevOps to achieve continuous integration and deployment.
Benefits of Containerized Orchestration Tools
Container orchestration tools, once implemented, can provide many benefits in terms of productivity, security, and portability. Below are the main advantages of containerization.
- Enhances productivity: Container orchestration has simplified installation, decreasing the number of dependency errors.
- Deployments are faster and simple: Container orchestration tools are user-friendly, allowing quick creation of new containerized applications to address increasing traffic.
- Lower overhead: Containers take up lesser system resources when you compare to hardware virtual-machine or traditional environments. Why? Operating system images are not included.
- Improvement in security: Container orchestration tools allow users to share specific resources safely, without risking security. Web application security is further enhanced by application isolation, which separates each application’s process into separate containers.
- Increase in Portability: Container orchestration allows users to scale applications with a single command. It only provides scale specific functions which do not affect the entire application.
- Immutability: Container orchestration can encourage the development of distributed systems, adhering to the principles of immutable infrastructure, which cannot be affected by user modifications.
Container Orchestration Tools: Kubernetes vs. Docker Swarm
Kubernetes and Docker are the two current market leaders in building and managing containers.
Docker, when first became available, became synonymous with containerization. It’s a runtime environment that creates and builds software inside containers. According to Statista, over 50% of IT leaders reported using Docker container technology in their companies last year. Kubernetes is a container orchestrator. It recognizes multiple container runtime environments, such as Docker.
To understand the differences between Kubernetes and Docker Swarm, we should examine it more closely. Each has its own sets of merits and disadvantages, which makes the task of choosing between one of them, a tough one. Indeed, both the technologies differ in some fundamental ways, as evidenced below:
|Points of Difference||Kubernetes||Docker Swarm|
|Container Setup||Docker Compose or Docker CLI cannot define containers. Kubernetes instead uses its own YAML, client definitions, and API. These differ from standard docker equivalents.||The Docker Swarm API offers much of the same functionality of Dockers, although it does not recognize all of Docker’s commands.|
|High Availability||Pods are distributed among nodes, offering high availability as it tolerates the failure of an application. Load balancing services detect unhealthy pods and destroys them.||Docker Swarm also offers high availability as the services can replicate via swarm nodes. The entire cluster is managed by Docker Swarm’s Swarm manager nodes, which also handle the resources of worker nodes.|
|Load Balancing||In most instances, an ingress is necessary for load balancing purposes.||A DNS element inside Swarm nodes can distribute incoming requests to a service name. These services can run on ports defined by the user, or be assigned automatically.|
|Scalability||Since Kubernetes has a comprehensive and complex framework, it tends to provide strong guarantees about a unified set of APIs as well as the cluster state. This setup slows downscaling and deployment.||Docker Swarm is Deploys containers much faster, allowing faster reaction times for achieving scalability.|
|Application Definition||Applications deploy in Kubernetes via a combination of microservices, pods, and deployments.||Applications deploy either as microservices or series in a swarm cluster. Docker-compose helps in installing the application.|
|Networking||Kubernetes has a flat networking model. This setup allows all pods to interact with each other according to network specifications. To do so, it implements as an overlay.||As a node joins a swarm cluster, an overlay network will generate. This overlay network covers every host in the docker swarm, along with a host-only docker bridge network.|
Which Containerization Tool to Use?
Container orchestration tools are still fledgling and constantly evolving technologies. Users should make their decision after looking at a variety of factors such as architecture, flexibility, high availability needs, and learning curve. Besides the two popular tools, Kubernetes and Docker Swarm, there are also a host of other third-party tools and software associated with them both, which allow for continuous deployment.
Kubernetes currently stands as the clear standard when it comes to container orchestration. Many cloud service providers as Google and Microsoft have started offering “Kubernetes-as-a-service” options. Yet, if you’re starting and running a smaller deployment without a lot to scale, then Docker Swarm is the way to go. Read our in-depth article on the key differences between Kubernetes vs Docker Swarm.
To get support with your container development and CI/CD pipeline, or find out how advanced container orchestration can enhance your microservices, connect with one of our experts to explore your options today.