Kubernetes - Secrets

Kubernetes Secrets let you store and manage sensitive information, such as passwords, OAuth tokens, and ssh keys. Storing confidential information in a Secret is safer and more flexible than putting it verbatim in a Pod definition or in a container image

Secrets same as ConfigMap sensitive data( password Authtoken ssh keys)

1. Secrets to store the confidential data

2. Secrets use by default base64 algorithm to encode the data

3. Secrets are mapped to pod where these are decoded on Pod level

4. It stores the data in Key-Value pair 

5. from file and from literal

6. Data should not be more than 1 MB

7. you can store the data from text files 

8. Secret data is stored in etcd database

LAB

# 1. Creating Secret using Kubectl & Consuming it from "volumes" inside Pod

1a. Creating secret using "Kubectl":

------------------------------------

echo -n 'admin' > username.txt

echo -n 'pa$$w00rd' > password.txt

kubectl create secret generic nginx-secret-vol --from-file=username.txt --from-file=password.txt

# rm -f username.txt password.txt

kubectl get secrets

kubectl describe secrets nginx-secret-vol

1b. Consuming "nginx-secret-vol" from "volumes" inside Pod

#nginx-pod-secret-vol.yaml

apiVersion: v1

kind: Pod

metadata:

  name: nginx-pod-secret-vol

spec:

  containers:

  - name: nginx-container

    image: nginx

    volumeMounts:

    - name: test-vol

      mountPath: "/etc/confidential"

      readOnly: true

  volumes:

  - name: test-vol

    secret:

      secretName: nginx-secret-vol

1c. Create | Display | Validate:

--------------------------------

Create

kubectl create -f nginx-pod-secret-vol.yaml

Display

kubectl get po

kubectl get secrets

kubectl describe pod nginx-pod-secret-vol

 Validate from "inside" the pod

kubectl exec nginx-pod-secret-vol -it /bin/sh

cd /etc/confidential

ls 

cat username.txt

cat password.txt

exit

(OR)

Validate from "outside" the pod

kubectl exec nginx-pod-secret-vol ls /etc/confidential

kubectl exec nginx-pod-secret-vol cat /etc/confidential/username.txt

kubectl exec nginx-pod-secret-vol cat /etc/confidential/password.txt

2. Creating Secret "manually" using YAML file & Consuming it from "environment variables" inside Pod

Creating Secret using YAML file:

-------------------------------------

# Encoding secret

echo -n 'admin' | base64

echo -n 'pa$$w00rd' | base64

# YAML file

# redis-secret-env.yaml

apiVersion: v1

kind: Secret

metadata:

  name: redis-secret-env

type: Opaque

data:

  username: YWRtaW4=

  password: cGEkJHcwMHJk

kubectl create -f redis-secret-env.yaml

kubectl get secret

kubectl describe secret redis-secret-env

2b. Consuming “redis-secret-env” secret from “Environment Variables” inside pod

# redis-pod-secret-env.yaml

apiVersion: v1

kind: Pod

metadata:

  name: redis-pod-secret-env

spec:

  containers:

  - name: redis-container

    image: redis

    env:

      - name: SECRET_USERNAME

        valueFrom:

          secretKeyRef:

            name: redis-secret-env

            key: username

      - name: SECRET_PASSWORD

        valueFrom:

          secretKeyRef:

            name: redis-secret-env

            key: password

  restartPolicy: Never

2c. Create | Display | Validate:

# Create

kubectl create -f  redis-pod-secret-env.yaml

# Display

kubectl get pods

kubectl get secrets

kubectl describe pod redis-pod-secret-env

# Validate from "inside" the pod

kubectl exec redis-pod-secret-env -it /bin/sh

env | grep  SECRET

exit

(OR)

# Validate from "outside" the pod

kubectl exec redis-pod-secret-env env | grep SECRET

***************************************************************************

#Decode the secrets

kubectl get secret redis-secret-env -o yaml

echo 'cGEkJHcwMHJk' | base64 --decode

*************************************************************************************************************************************************

3. Cleanup

# Delete secrets

kubectl delete secrets nginx-secret-vol redis-secret-env

# Delete pods

kubectl delete pods nginx-pod-secret-vol redis-pod-secret-env

# Validate

kubectl get pods

kubectl get secrets

kuberenetes-pull-image-from-private Registry

References

https://kubernetes.io/docs/concepts/configuration/secret/