k8spatterns/mini-http-server repository overview

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= Kubernetes Patterns - Examples

image:https://i.creativecommons.org/l/by/4.0/88x31.png[Creative⁠ Commons License, role="right", link="https://creativecommons.org/licenses/by/4.0/⁠"]

This GitHub project contains the examples from Kubernetes Patterns - Reusable Elements for Designing Cloud-Native Applications http://hyperurl.co/kubernetes-patterns[book⁠] by https://github.com/bibryam[Bilgin⁠ Ibryam] and https://github.com/rhuss[Roland⁠ Huß]

Installation instructions for the example prerequisites are summarised in link:INSTALL.adoc[INSTALL]. By default, you need access to a vanilla Kubernetes installation, like Minikube. If addons are required, the example description explains this additional requirement.

For feedback, issues or questions in general, please use the https://github.com/bibryam/k8spatterns/issues[issue⁠ tracker] to open issues. Also, we love contributions like spelling fixes, bug fixes, improvements, ... Please open Pull Requests, we are happy to review them!

== Patterns

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. footnote:[Examples marked with an "*" are functional but still, lack the full instruction set for running the examples. If you feel adventurous, please try out the provided resource files yourself. Happy to take also PRs, did we already mention that we love contributions? ;)]

=== Foundational Patterns

link:foundational/PredictableDemands/README.adoc[Predictable Demands]:: Our sample random generator dealing with hard requirements on ConfigMap and PersistentVolumeClaims as well as with resource limits. link:foundational/DeclarativeDeployment/README.adoc[Declarative Deployment]:: Rolling and fixed update of the random generator Deployment from version 1.0 to 2.0. link:foundational/HealthProbe/README.adoc[Health Probe]:: Liveness and Readiness probes for the random generator. link:foundational/ManagedLifecycle/README.adoc[Managed Lifecycle]:: postStart and preStop hooks demonstrated with the random generator application. link:foundational/AutomatedPlacement/README.adoc[Automated Placement]:: Example with node selector, pod and node affinity, taint and tolerations demonstrated.

=== Behavorial Patterns

link:behavorial/BatchJob/README.adoc[Batch Job]:: Generate thousands of random numbers into a file with a batch job link:behavorial/PeriodicJob/README.adoc[Periodic Job]:: Reuses the link:behavorial/BatchJob/README.adoc[Batch Job] example, but runs it periodically at a configured schedule link:behavorial/DaemonService/README.adoc[Daemon Service]:: Sample maintenance script for maintenance jobs on every node of a cluster link:behavorial/SingletonService/README.adoc[Singleton Service]:: Example of a PodDisruptionBudget for controlling voluntary disruptions link:behavorial/StatefulService/README.adoc[Stateful Service]:: StatefulSet example for our random-generator link:behavorial/ServiceDiscovery/README.adoc[Service Discovery]:: Various ways how to access our random-generator REST service link:behavorial/SelfAwareness/README.adoc[Self Awareness]:: Using the Downward API for setting environment variables and mount resource fields as files with the random-generator service.

=== Structural Patterns

link:structural/InitContainer/README.adoc[Init Container]:: Initialize a HTTP server's HTML source from a remote git repository link:structural/Sidecar/README.adoc[Sidecar]:: Git polling example for a sidecar link:structural/Adapter/README.adoc[Adapter]:: Adapter for exporting timing information from the sample random-generator application in a Prometheus format link:structural/Ambassador/README.adoc[Ambassador]:: Ambassador for moving on the log of the random-generator

=== Configuration Patterns

link:configuration/EnvVarConfiguration/README.adoc[EnvVar Configuration]:: A simple example of how to use environment variables literally and from ConfigMaps and Secrets for our random-generator service. link:configuration/ConfigurationResource/README.adoc[Configuration Resource]:: Example how to configure the random-generator Spring Boot application with a ConfigMap link:configuration/ImmutableConfiguration/README.adoc[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. link:configuration/ConfigurationTemplate/README.adoc[Configuration Template]:: Example how to use a template configuration standalone.xml which is processed with a template processed and filled with data from ConfigMap before a Wildfly server is started.

=== Advanced Patterns

link:advanced/Controller/README.adoc[Controller]:: Simple, pure shell based controller which watches ConfigMap resources for changes and restarts Pods by using a label selector provided as annotation. An additional link:advanced/Controller/expose-controller/README.adoc[example controller] exposes an Ingress route when it detects an exposeService label attached to the service. link:advanced/Operator/README.adoc[Operator]:: Operator based on the ConfigMap watch link:advanced/Controller/README.adoc[controller] and introduces a CRD ConfigWatcher which connects a ConfigMap with a set of Pods to restart in case of a config change. link:advanced/ElasticScale/README.adoc[Elastic Scale]:: Horizontal and vertical scaling examples with the random-generator Service [*] link:advanced/ImageBuilder/README.adoc[Image Builder]:: Setup a link:advanced/ImageBuilder/openshift/README.adoc[chained build] on OpenShift and use link:advanced/ImageBuilder/knative/README.adoc[Knative build] for doing builds within the cluster.

This work is licensed under a https://creativecommons.org/licenses/by/4.0/[Creative⁠ Commons Attribution 4.0 International License]