k8s-configmap-watcher

Archival Note

⚠️ This repo (and the corresponding container image) is unmaintained. Please use https://github.com/kiwigrid/k8s-sidecar instead which is a maintained drop-in replacement.

What?

This is a docker container intended to run inside a kubernetes cluster to collect config maps with a specified label and store the included files in an local folder. It can also send a html request to a specified URL after a configmap change. The main target is to be run as a sidecar container to supply an application with information from the cluster. The contained Go programm is working with the Kubernetes API 1.10

How?

Run the container created by this repo together you application in an single pod with a shared volume. Specify which label should be monitored and where the files should be stored. By adding additional env variables the container can send a html request to specified URL.

Features

• Extract files from config maps
• Filter based on label
• Update on change of configmap

Usage

Example for a simple deployment can be found in example.yaml. Depending on the cluster setup you have to grant yourself admin rights first: kubectl create clusterrolebinding cluster-admin-binding --clusterrole cluster-admin --user $(gcloud config get-value account)

Configuration Environment Variables

• LABEL

  • description: Label that should be used for filtering
  • required: true
  • type: string

• FOLDER

  • description: Folder where the files should be placed
  • required: true
  • type: string

• NAMESPACE

  • description: If specified, the sidecar will search for config-maps inside this namespace. Otherwise the namespace in which the sidecar is running will be used. It's also possible to specify ALL to search in all namespaces.
  • required: false
  • type: string

• METHOD

  • description: If METHOD is set with LIST, the sidecar will just list config-maps and exit. Default is watch.
  • required: false
  • type: string

• REQ_URL

  • description: URL to which send a request after a configmap got reloaded
  • required: false
  • type: URI

• REQ_METHOD

  • description: Request method GET(default) or POST
  • required: false
  • type: string

• REQ_PAYLOAD

  • description: If you use POST you can also provide json payload
  • required: false
  • type: json