API Machinery, Chaos and Dishwashers, with Lucas Käldström
Feb 20, 2024
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Lucas Käldström discusses Kubernetes API machinery, Chaos, Entropy, and even Dishwashers in an insightful chat. The podcast also covers Weaveworks shutdown, KubeAdmiral release, and Strimzi joining CNCF Incubator. The intersection of Control Theory and Kubernetes, managing JSON Objects, API Version complexities, and reflections on technology analogies are also explored.
Kubernetes acts like a control system to minimize chaos and bring order to server infrastructure, API machinery is the software framework for control theory ensuring communication between client and server, Operators in Kubernetes provide a novel programming model for controlling and managing specific infrastructure within Kubernetes
Deep dives
Kubernetes as a Control System
Lucas discusses how Kubernetes acts like a control system to minimize chaos and bring order to server infrastructure. He draws an analogy between Kubernetes and a dishwasher, highlighting how both minimize chaos in their respective domains. He explains that the API machinery in Kubernetes is the software framework for control theory, ensuring communication and common understanding between client and server. Lucas also emphasizes the importance of measuring stability in a system and continually driving towards the desired state.
Operators and Novel Programming Model
Lucas highlights the significance of operators in Kubernetes and their role as a novel programming model. He explains how operators provide a way to control and manage specific types of infrastructure within Kubernetes, taking application semantics into account. These operators offer a declarative approach, allowing users to specify the end state and enabling continuous synchronization with the desired state. Lucas discusses the continuous checking and reconciliation loop of operators, emphasizing the importance of stability and minimizing failures in a system.
API Machinery and Promise Theory
The discussion delves into the concept of API machinery in Kubernetes and its connection to promise theory. Lucas explains that API machinery ensures a common language and understanding between client and server, facilitating effective communication. He mentions the KCP project, which showcases Kubernetes without core resources, demonstrating the separation of the lower-level API machinery from container-specific functionalities. Lucas also touches on promise theory, highlighting how Kubernetes promises to manage and maintain the desired state of deployed resources.
API Machinery and its Role in Kubernetes
API Machinery in Kubernetes is responsible for handling the encoding, decoding, and conversion between different versions of API objects. It ensures that the communication between humans and computers is clear and accurate. The API Machinery documentation provides insights into the structure and design of Kubernetes YAML, helping users understand how the various components and fields should be structured.
Long-Term Support and the Complexity of Upgrades
Long-term support (LTS) in Kubernetes is a topic of contention within the community. While LTS offers extended support for non-supported upstream Kubernetes versions, it comes at a higher cost. Some cloud providers offer LTS for their managed Kubernetes offerings, charging more for out-of-support versions. Upgrades in Kubernetes can be complex due to the need to support old APIs and schema versions, as well as ensuring compatibility between storage versions and migrations. The decision to opt for LTS or upgrade to newer versions involves a trade-off between cost, ease, and the need for support.
Lucas Käldström is a CNCF Ambassador, Kubernetes contributor and expert. Lucas Co-led SIG cluster lifecycle, ported Kubernetes to ARM and shepherded kubeadm from inception to GA. Today Lucas runs three meetup groups in Finland, studies at Aalto University, and, when time allows, contributes to cloud native software as a contractor.
We chatted about Kubernetes API machinery, Chaos, Entropy, and Dishwashers.
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