Documentation
TL;DR
Cartographer is a Supply Chain Choreographer for Kubernetes. It enables App Operators to create supply chains, pre-approved paths that standardize how multiple app teams deliver applications to end users. Cartographer enables this within the Kubernetes ecosystem, allowing supply chains to be composed of resources from an organization’s existing toolchains (e.g. Jenkins).
Each pre-approved supply chain creates a paved road to production, orchestrating test, build, scan, deploy. Developers are freed to focus on delivering value to their users while App Operators retain the peace of mind that all code in production has passed through every step of an approved workflow.
Cartographer Design and Philosophy
Cartographer allows users to define every step that an application must go through to reach production. Users achieve this with the Supply Chain abstraction, see Spec Reference.
The supply chain consists of resources that are specified via Templates. A template acts as a wrapper for a Kubernetes resource, allowing Cartographer to integrate each well known tool into a cohesive whole. There are four types of templates:
Contrary to many other Kubernetes native workflow tools that already exist in the market, Cartographer does not “run” any of the objects themselves. Instead, it leverages the controller pattern at the heart of Kubernetes. Cartographer creates an object on the cluster and the controller responsible for that resource type carries out its control loop. Cartographer monitors the outcome of this work and captures the outputs. Cartographer then applies these outputs in the following templates in the supply chain. In this manner, a declarative chain of Kubernetes resources is created.
The simplest explanation of Kubernetes' control loops is that an object is created with a desired state and a controller moves the cluster closer to the desired state. For most Kubernetes objects, this pattern this includes the ability of an actor to update the desired state (to update the spec of an object), and have the controller move the cluster toward the new desired state. But not all Kubernetes resources are updatable; this class of immutable resources includes resources of the CI/CD tool Tekton. Cartographer enables coordination of these resources with its immutable pattern: rather than updating an object and monitoring for its new outputs, Cartographer creates a new immutable object and reads the outputs of the new object.
While the supply chain is operator facing, Cartographer also provides an abstraction for developers called workloads. Workloads allow developers to create application specifications such as the location of their repository, environment variables and service claims.
By design, supply chains can be reused by many workloads. This allows an operator to specify the steps in the path to production a single time, and for developers to specify their applications independently but for each to use the same path to production. The intent is that developers are able to focus on providing value for their users and can reach production quickly and easily, while providing peace of mind for app operators, who are ensured that each application has passed through the steps of the path to production that they’ve defined.
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