Passing Configuration Data to a Kubernetes Container

One of these applications is a simple Nginx web server. This server is used as part of a secure backend application, and the company would like it to be configured to use HTTP basic authentication.

This will require an htpasswd file as well as a custom Nginx config file. In order to deploy this Nginx server to the cluster with good configuration practices, you will need to load the custom Nginx configuration from a ConfigMap (this already exists) and use a Secret to store the htpasswd data.

Create a Pod with a container running the nginx:1.19.1 image. Supply a custom Nginx configuration using a ConfigMap, and populate an htpasswd file using a Secret.

Generate an htpasswd file:

htpasswd -c .htpasswd user

View the file’s contents:

cat .htpasswd

Create a Secret containing the htpasswd data:

kubectl create secret generic nginx-htpasswd --from-file .htpasswd

Delete the .htpasswd file:

rm .htpasswd

Create the Nginx Pod

Create pod.yml:

apiVersion: v1
kind: Pod
metadata:
  name: nginx
spec:
  containers:
  - name: nginx
    image: nginx:1.19.1
    ports:
    - containerPort: 80
    volumeMounts:
    - name: config-volume
      mountPath: /etc/nginx
    - name: htpasswd-volume
      mountPath: /etc/nginx/conf
  volumes:
  - name: config-volume
    configMap:
      name: nginx-config
  - name: htpasswd-volume
    secret:
      secretName: nginx-htpasswd

View the existing ConfigMap:

kubectl get cm

we need to create the configMap for nginx-config:-

apiVersion: v1
kind: ConfigMap
metadata:
  name: nginx-config
data:
 nginx.conf: |
   user  nginx;
    worker_processes  1;

    error_log  /var/log/nginx/error.log warn;
    pid        /var/run/nginx.pid;

     events {
       worker_connections  1024;
      }
     http {
      server {
        listen       80;
        listen  [::]:80;
        server_name  localhost;
        location / {
            root   /usr/share/nginx/html;
            index  index.html index.htm;
        }
        auth_basic "Secure Site";
        auth_basic_user_file conf/.htpasswd;
      }
     }

Get more info about nginx-config:

kubectl describe cm nginx-config

Apply the pod

kubectl apply -f pod.yml

Within the existing busybox pod, without using credentials, verify everything is working:

kubectl exec busybox -- curl <NGINX_POD_IP>

We’ll see HTML for the 401 Authorization Required page — but this is a good thing, as it means our setup is working as expected.

curl: (6) Couldn't resolve host 'user'
  % Total    % Received % Xferd  Average Speed   Time    Time     Time  Current
                                 Dload  Upload   Total   Spent    Left  Speed
100   179  100   179    0     0  62174      0 --:--:-- --:--:-- --:--:-- 89500
<html>
<head><title>401 Authorization Required</title></head>
<body>
<center><h1>401 Authorization Required</h1></center>
<hr><center>nginx/1.19.1</center>
</body>
</html>

Run the same command again using credentials (including the password you created at the beginning of the lab) to verify everything is working:

kubectl exec busybox -- curl -u user:<PASSWORD> <NGINX_POD_IP>
  % Total    % Received % Xferd  Average Speed   Time    Time     Time  Current
                                 Dload  Upload   Total   Spent    Left  Speed
100   612  100   612    0     0  48846      0 --:--:-- --:--:-- --:--:-- 51000
<!DOCTYPE html>
<html>
<head>
<title>Welcome to nginx!</title>
<style>
    body {
        width: 35em;
        margin: 0 auto;        font-family: Tahoma, Verdana, Arial, sans-serif;
    }
</style>
</head>
<body>
<h1>Welcome to nginx!</h1>
<p>If you see this page, the nginx web server is successfully installed and
working. Further configuration is required.</p>

<p>For online documentation and support please refer to
<a href="http://nginx.org/">nginx.org</a>.<br/>
Commercial support is available at
<a href="http://nginx.com/">nginx.com</a>.</p>

<p><em>Thank you for using nginx.</em></p>
</body>
</html>

Cheers

Osama

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