Traditional software application development depended upon a mirroring of all conditions across launch environments including the supporting hardware structure and configuration, the operating system, and the asset files. Even slight variations between the development environment and the launch environment can result in application error or failure. This model of software development and launch created needless complexity, taxing limited server resources. The development and implementation of Kubernetes has eliminated most of these issues, smoothing out the path from development and testing to launch and implementation. Understanding the role of Kubernetes in your application development is essential if you are to avoid many of these application development and launch issues.
The Movement to Cloud Native Services
“Cloud Native” services involves structuring and moving teams and utilized technology away from on-premise to ubiquitous architectures in order to manage complexity and increase velocity responsiveness. For most companies today, the movement to Cloud Native services is not a one-and-done but an incremental change in deployment. The primary driver behind movement to Cloud Native services is not where the technology industry is today, but where it is going to be in the next few years. The key benefit of Cloud Native services is a reduction in problem-solving drudgery and system downtime. Cloud Native services solve for these issues with self-healing and self-managing infrastructure. Cloud Native services support better tooling by building new systems on top of existing systems, thus reducing size, resource demands, and complexity.
Understanding the Structure of Kubernetes
A Kubernetes structure is comprised of pods, containers, and clusters. It is a way of managing and organizing a large volume of application-dependent information. Pods are a physical machine, which provide the environmental variables governing containers. A pod is a collection of containers which run inside a node. A collection of nodes, pods, and containers is called a cluster. Other components include the following:
- ReplicaSets are the number of identical pods running. ReplicaSets ensure that the set of identical pods running remains consistent. ReplicaSets can bring new pods online if existing pods drop off.
- Secrets are stores of non-public information such as tokens, certificates, and passwords that can be attached to pods at runtime to ensure sensitive data can be stored in the cluster securely.
- Deployments manage rollbacks or rollouts as they are made. This is done behind the scenes so that the application continues running successfully while changes are implemented. Deployments make use of ReplicaSets to achieve this perpetual functioning.
- DaemonSets ensure that a copy of the configured software is running on every pod. DaemonSets provide a way to guarantee that a specific copy of the software is running on all given clusters within the configuration. As clusters grow or shrink, DaemonSets spread the specially labeled pods across all nodes.
- Ingresses serve to route traffic to and from specific clusters while providing a single Secure Socket Layer (SSL) endpoint for all the applications. SSL is the computing protocol that ensures the security of data, encrypting information sent across the internet.
Other less common elements of a Kubernetes Structure are CronJobs and CRDs.
How does Kubernetes Work?
Software applications usually contain three elements: the language runtime, libraries, and the original source code. In turn, libraries normally rely on external shared library components conjoined to the operating system of the machine in use. When libraries differ from pod to pod, applications fail or glitch. This dependency is the root cause of most application launch failures.
It is important that programmers can package applications to be shared with others. The default container runtime engine is called Docker. A container runtime is an executable that launches and manages container images. Container runtimes are responsible for all the components of a container that aren’t actively running the program itself. Docker enables programmers to package and push remote registry components where they can later be accessed by other users, thus solving for component dependency issues. Containers are like virtual machines, except that they exhibit more relaxed isolation properties, sharing the operating system across multiple applications. In this way, containers are set free or decoupled from underlying infrastructure. This allows them to become portable across different cloud and OS distributions.
By way of illustration, creators who design documents in Adobe In-Design must package all the elements of those documents before sharing them with the printing house. This includes fonts, color schematics, layer transparency, and graphic elements. Without any one of these elements, a printing house would be unable to render the document exactly as designed by the creator.
In the same way, container images work by bundling all the necessary elements and dependencies into a single artifact. This information is stored in a root filesystem. The container image functions as a manifest of the components necessary to run an application. Container images stack, with each layer inheriting and modifying the layers that come before it.
Kubernetes is a way of bundling and deploying applications. In a production environment, it is essential that all components are available to all users. Kubernetes ensures an accurate manifest, even as it manages and auto-scales resources, while self-correcting for errors.
Several software companies run platforms that allow for clear mapping and observability of your Kubernetes structure. These enable greater data analysis essential as practices of storage and launch move from on-premise to hybrid and eventually to cloud and SaaS providers. While there are a host of Kubernetes observability software options, New Relic and Wavefront are two of the most popular.
In the coming years, cloud-based application launch and data management will almost completely replace on-premise development. Adopting a Kubernetes structure provides the environment essential to this migration, ensuring a coherent development and consistent launch of native applications.