Configure Keptn via the new Helm umbrella chart

In the dynamic world of cloud-native and microservices, installation and continuous upgrades of distributed systems is a priority. Embarking on a journey into the world of containerized applications often leads us into a labyrinth of configuration and deployment intricacies. Amidst this complexity, Helm charts emerge as the guiding light, streamlining the orchestration of Kubernetes-based applications.

In this article, we're delving into the topic of Helm charts, in particular Umbrella charts - an approach that simplifies the deployment and maintenance of microservice application architectures. Let's uncover how these consolidated charts pave the way for smoother deployments, enhance scalability, and bring harmony to the orchestration of complex Kubernetes environments.

What is Helm?

Helm is a powerful package manager for Kubernetes. It simplifies and streamlines the deployment and management of applications on Kubernetes clusters. It acts as a tool for defining, installing, and upgrading complex Kubernetes applications using pre-configured templates called charts. These charts encapsulate all the necessary Kubernetes resources and configuration files needed to deploy an application, making it easier for developers and operators to manage applications consistently across different environments. Helm's ability to package, version, and share applications as charts facilitates collaboration and standardization within the Kubernetes ecosystem, significantly improving the efficiency of deploying and maintaining containerized applications. The basic configuration mechanism for deployments is a values.yaml file which contains all the configuration options with the default values for the given software.

What is Keptn?

Keptn is a CNCF project for continuous delivery and automated operations. It helps developers and platform engineering teams automate deployment, monitoring, and management of applications running in cloud environments. Keptn works with standard deployment software like ArgoCD or Flux, consolidating metrics, observability, and analysis for all the microservices that comprise your deployed software as well as providing checks and executables that can run before and/or after the deployment.

It also comprises multiple components with different feature sets as well as different installation and upgrade requirements so proper configuration can be cumbersome for people unfamiliar with Helm charts.

Keptn uses the Helm umbrella charts to manage multiple sub-charts (one sub-chart per component) as a single entity. This concept provides us the opportunity to install and manage each Keptn component as a fully independent microservice, but additionally also as a complete toolkit.

In Keptn, just use a single values.yaml file to configure both the global umbrella chart parameters that apply to all components, and each individual sub-chart's parameters. Each individual Keptn component has all the possible helm configuration parameters documented in the Keptn repository.

In the individual sub-charts, we can set parameters such as image tag, imagePullPolicy or annotations. Additionally, global parameters which affect all the sub-charts can be set, like the global image registry or global annotations. These options are documented here.

Note that setting the values for individual components overrides the global ones. For example, if the same annotation option is configured for the global chart and the component, the component value is favored.

Installation of Keptn with default values

Let's look at a real-life example of a clean installation of Keptn using umbrella charts. For basic installation of all components with the use of default values for configuration parameters you need to execute the following commands:

helm repo add keptn https://charts.lifecycle.keptn.sh 
helm repo update 
helm upgrade --install keptn keptn/keptn -n keptn-system --create-namespace

You can see that it's not necessary to create a custom "values.yaml" file when using the default values. Keptn will be installed with all the components (metrics-operator, lifecycle-operator, cert-manager), with default Helm values set for each of them.

Installation of Keptn with custom values

Let's now look at a use-case, where we want to use only Keptn metrics and therefore do not need to install the lifecycle-operator, which provides functionality for Observability and/or Release Lifecycle Management. Additionally to metrics-operator, we need to install keptn-cert-manager, which will provide certificates webhooks present in the metrics-operator. For this all, we need to create a values.yaml file with the following content:

certManager:
  enabled: true
  image: # using custom image registry and tag to the cert-manager
  registry: "myCustomRegistry"
  tag: v0.0.0

lifecycleOperator:
  enabled: false # installation of lifecycle-operator is disabled

metricsOperator:
  replicas: 3 # installing 3 replicas of metrics-operator
  annotations: # setting custom annotations for metrics-operator
  myMetricsKey: metricsValue1
  image: # using the latest image of the metrics-operator
  tag: latest

global:
  commonAnnotations: # setting common annotations for all installed component
  myGlobalKey: globalValue1
  myMetricsKey: globalValue2

This values.yaml file disables the lifecycle-operator and it sets the used image registry and tag of the cert-manager. tag, annotations and replicas are set for the metrics-operator. These parameters are configuring each installed component via their sub-charts. Also, we configure the global annotations for all installed components (metrics-operator and cert-manager only, since lifecycle-operator is disabled). Note that the myMetricsKey annotation is set to different values in global parameters (globalValue2) and in metrics-operator sub-chart parameters (metricsValue1). Here the annotation defined in the metrics-operator component configuration will be used.

When the values.yaml file is ready, we use it to install Keptn with the following commands:

helm repo add keptn https://charts.lifecycle.keptn.sh 
helm repo update 
helm upgrade --install keptn keptn/keptn -n keptn-system --create-namespace --values=values.yaml

More information about the installation and upgrade options can be found in the official Keptn documentation and in the linked Helm values documentation.

Summary

Let's sum up what we have seen. We started with a brief description of Keptn, Helm and Umbrella charts. Next, we described how the installation of Keptn components can be customized with Helm values that are under the aegis of the Helm umbrella chart. In the end, we went through an example of the configurable parameters of individual components or global values and how the custom values.yaml file can be used for installation.