Lab 12: Smoke Test

Info

This is a fork of the original "Kubernetes the hard way" originally written by Kelsey Hightower (GitHub: kelseyhightower). Unlike the original, which bases itself on Debian-like distributions for the ARM64 architecture, this fork targets Enterprise Linux distributions such as Rocky Linux, which runs on x86_64 architecture.

In this lab, you will complete tasks to ensure your Kubernetes cluster functions correctly.

Data Encryption

In this section, you will verify the ability to encrypt secret data at rest.

Create a generic secret:

kubectl create secret generic kubernetes-the-hard-way \
  --from-literal="mykey=mydata"

Print a hexdump of the kubernetes-the-hard-way secret stored in etcd:

ssh root@server \
    'etcdctl get /registry/secrets/default/kubernetes-the-hard-way | hexdump -C'

00000000  2f 72 65 67 69 73 74 72  79 2f 73 65 63 72 65 74  |/registry/secret|
00000010  73 2f 64 65 66 61 75 6c  74 2f 6b 75 62 65 72 6e  |s/default/kubern|
00000020  65 74 65 73 2d 74 68 65  2d 68 61 72 64 2d 77 61  |etes-the-hard-wa|
00000030  79 0a 6b 38 73 3a 65 6e  63 3a 61 65 73 63 62 63  |y.k8s:enc:aescbc|
00000040  3a 76 31 3a 6b 65 79 31  3a 67 64 d4 64 d9 6c eb  |:v1:key1:gd.d.l.|
00000050  f3 a9 80 8c 82 a0 f3 50  e6 eb 02 cb a6 65 8b 51  |.......P.....e.Q|
00000060  0a 03 2f ef 4a a8 d9 7d  62 f5 68 27 74 1c 6d 88  |../.J..}b.h't.m.|
00000070  ee 89 39 8d c9 e4 c6 2c  9c 3f 55 3b eb 79 2c 55  |..9....,.?U;.y,U|
00000080  d9 47 ec 77 84 0b 6e b1  ab 58 41 22 1e c3 7c 00  |.G.w..n..XA"..|.|
00000090  92 ad ad d0 97 55 f4 d5  b6 1e 6d 57 fb 2f 7c 36  |.....U....mW./|6|
000000a0  f5 6a 45 5e a7 a4 70 52  1d 9d 00 61 14 cd f3 92  |.jE^..pR...a....|
000000b0  9a 05 57 dd cf 41 1c 74  0c a7 2c ac 64 f5 79 51  |..W..A.t..,.d.yQ|
000000c0  e6 5c 16 e1 a9 5e da 00  91 d0 f5 77 e2 32 8f a2  |.\...^.....w.2..|
000000d0  9a c3 26 50 f2 a0 f8 f9  95 09 20 29 f1 7c 7a 7d  |..&P...... ).|z}|
000000e0  4f 82 0b 78 43 28 91 a1  56 ee 66 90 fb ac 26 8c  |O..xC(..V.f...&.|
000000f0  a3 b4 b2 ed 2d 0a d3 54  d1 10 89 a4 c3 dd b6 2d  |....-..T.......-|
00000100  b9 d7 98 bb db c4 0d f2  96 5a 57 8b 01 2e 97 43  |.........ZW....C|
00000110  ea 9c 8b cf cc 9b 80 cd  02 c8 c5 a4 e7 bf 62 73  |..............bs|
00000120  e6 6b e8 c2 cf 34 50 2b  e0 3c 66 a2 29 4f 08 0c  |.k...4P+.<f.)O..|
00000130  65 99 e4 9f 40 4f d9 94  eb 40 bd 3a 01 77 95 2b  |e...@O...@.:.w.+|
00000140  c9 20 ea a8 73 d9 19 2d  d8 00 9b da 3e 55 3e 82  |. ..s..-....>U>.|
00000150  80 3a 39 d5 08 f9 6c de  6b 0a                    |.:9...l.k.|
0000015a

You need to prefix the etcd key with k8s:enc:aescbc:v1:key1, which indicates using the aescbc provider to encrypt the data with the key1 encryption key.

Deployments

In this section, you will verify the ability to create and manage Deployments.

Create a deployment for the nginx web server:

kubectl create deployment nginx \
  --image=nginx:latest

List the pod created by the nginx deployment:

kubectl get pods -l app=nginx

NAME                     READY   STATUS    RESTARTS   AGE
nginx-54c98b4f84-dfwl9   1/1     Running   0          71s

Port Forwarding

In this section, you will verify the ability to access applications remotely using port forwarding.

Retrieve the full name of the nginx pod:

POD_NAME=$(kubectl get pods -l app=nginx \
  -o jsonpath="{.items[0].metadata.name}")

Forward port 8080 on your local machine to port 80 of the nginx pod:

kubectl port-forward $POD_NAME 8080:80

Forwarding from 127.0.0.1:8080 -> 80
Forwarding from [::1]:8080 -> 80

In a new terminal, make an HTTP request with the forwarding address:

curl --head http://127.0.0.1:8080

HTTP/1.1 200 OK
Server: nginx/1.27.4
Date: Tue, 04 Mar 2025 01:30:20 GMT
Content-Type: text/html
Content-Length: 615
Last-Modified: Wed, 05 Feb 2025 11:06:32 GMT
Connection: keep-alive
ETag: "67a34638-267"
Accept-Ranges: bytes

Switch back to the previous terminal and stop the port forwarding to the nginx pod by typing Ctrl+C:

Forwarding from 127.0.0.1:8080 -> 80
Forwarding from [::1]:8080 -> 80
Handling connection for 8080
^C

Logs

In this section, you will verify the ability to retrieve container logs.

Print the nginx pod logs:

kubectl logs $POD_NAME

...<OUTPUT TRUNCATED>...
127.0.0.1 - - [04/Mar/2025:01:30:20 +0000] "HEAD / HTTP/1.1" 200 0 "-" "curl/7.76.1" "-"

Exec

In this section, you will verify the ability to execute commands in a container.

Print the nginx version by executing the nginx -v command in the nginx container:

kubectl exec -ti $POD_NAME -- nginx -v

nginx version: nginx/1.27.4   

Services

In this section, you will verify the ability to expose applications with a Service.

Expose the nginx deployment using a NodePort service:

kubectl expose deployment nginx \
  --port 80 --type NodePort

You cannot use the LoadBalancer service type because your cluster is not configured with cloud provider integration. This tutorial does not cover setting up cloud provider integration.

Retrieve the node port assigned to the nginx service:

NODE_PORT=$(kubectl get svc nginx \
  --output=jsonpath='{range .spec.ports[0]}{.nodePort}')

Make an HTTP request with the IP address and the nginx node port:

curl -I http://node-0:${NODE_PORT}

HTTP/1.1 200 OK
Server: nginx/1.27.4
Date: Tue, 04 Mar 2025 01:40:20 GMT
Content-Type: text/html
Content-Length: 615
Last-Modified: Wed, 05 Feb 2025 11:06:32 GMT
Connection: keep-alive
ETag: "67a34638-267"
Accept-Ranges: bytes

Next: Cleaning Up

Author: Wale Soyinka

Contributors: Steven Spencer, Ganna Zhyrnova