Kubernetes Patterns - Examples
Installation instructions for the example prerequisites are summarised in INSTALL. By default, you need access to a vanilla Kubernetes installation, like Minikube. If addons are required, the example description explains this additional requirement.
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All example are categorised according to the Book’s patterns category. Each of the examples is contained in an extra directory per pattern and is self-contained. 
- Predictable Demands
Our sample random generator dealing with hard requirements on ConfigMap and PersistentVolumeClaims as well as with resource limits.
- Declarative Deployment
Rolling and fixed update of the random generator Deployment from version 1.0 to 2.0.
- Health Probe
Liveness and Readiness probes for the random generator.
- Managed Lifecycle
preStophooks demonstrated with the random generator application.
- Automated Placement
Example with node selector, pod and node affinity, taint and tolerations demonstrated.
- Batch Job
Generate thousands of random numbers into a file with a batch job
- Periodic Job
Reuses the Batch Job example, but runs it periodically at a configured schedule
- Daemon Service
Sample maintenance script for maintenance jobs on every node of a cluster
- Singleton Service
Example of a PodDisruptionBudget for controlling voluntary disruptions
- Stateful Service
StatefulSet example for our random-generator
- Service Discovery
Various ways how to access our random-generator REST service
- Self Awareness
Using the Downward API for setting environment variables and mount resource fields as files with the random-generator service.
- Init Container
Initialize a HTTP server’s HTML source from a remote git repository
Git polling example for a sidecar
Adapter for exporting timing information from the sample random-generator application in a Prometheus format
Ambassador for moving on the log of the random-generator
- EnvVar Configuration
A simple example of how to use environment variables literally and from ConfigMaps and Secrets for our random-generator service.
- Configuration Resource
Example how to configure the random-generator Spring Boot application with a ConfigMap
- Immutable Configuration
Several examples of how to use immutable configuration containers for application configuration. This includes examples for the plain Docker case and for Kubernetes.
- Configuration Template
Example how to use a template configuration
standalone.xmlwhich is processed with a template processed and filled with data from ConfigMap before a Wildfly server is started.
Simple, pure shell based controller which watches ConfigMap resources for changes and restarts Pods by using a label selector provided as annotation. An additional example controller exposes an Ingress route when it detects an
exposeServicelabel attached to the service.
Operator based on the ConfigMap watch controller and introduces a CRD ConfigWatcher which connects a ConfigMap with a set of Pods to restart in case of a config change.
- Elastic Scale
Horizontal and vertical scaling examples with the random-generator Service [*]
- Image Builder
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