Injecting configurations from files

In its purest, and probably the most common form, a ConfigMap takes a single file. For example, we can create one from the cm/prometheus-conf.yml file:

kubectl create cm my-config \
    --from-file=cm/prometheus-conf.yml

We created a ConfigMap (cm) called my-config. The data of the map is the content of the cm/prometheus-conf.yml file.

Let's describe it, and see what we'll get.

kubectl describe cm my-config  

The output is as follows:

Name:         my-config 
Namespace:    default 
Labels:       <none> 
Annotations:  <none> 
 
Data 
==== 
prometheus-conf.yml: 
---- 
global: 
  scrape_interval:     15s 
 
scrape_configs: 
  - job_name: Prometheus 
    metrics_path: /prometheus/metrics 
    static_configs: 
      - targets: 
        - localhost:9090 
 
Events:  <none> 

The important part is located below Data. We can...