Kubernetes is an open-source container orchestration system that provides a scalable and highly available platform for deploying, managing, and scaling containerized applications. One of the key features of Kubernetes is its ability to securely manage sensitive data, such as passwords, API keys, and TLS certificates, using Kubernetes secrets.
In this article, we’ll explore what Kubernetes secrets are, how they work, and how to use them to securely manage sensitive data in your applications.
What are Kubernetes Secrets ?
In Kubernetes, a secret is an object that stores a small amount of sensitive data, such as a password, token, or key. Secrets are designed to be used by applications that run in a Kubernetes cluster to access sensitive information without exposing it in the container image or configuration files.
Kubernetes secrets are stored in etcd, a distributed key-value store that is used by Kubernetes to store cluster state. Secrets are encrypted at rest using a default encryption provider that is enabled by default in Kubernetes 1.13 or later.
How do Kubernetes Secrets work ?
Kubernetes secrets are similar to Kubernetes ConfigMaps, which are used to store non-sensitive configuration data, such as environment variables or command-line arguments. However, secrets are more secure because they are encrypted at rest and only mounted into a container’s filesystem as a volume when needed.
When you create a secret in Kubernetes, you can choose to store the data as plain text, base64-encoded data, or a reference to a key in a Kubernetes Key Management System (KMS) provider. To use a secret in your application, you need to create a Kubernetes Pod that references the secret and mounts it as a volume in the container’s filesystem.
For example, suppose you want to store a password for a MySQL database in a Kubernetes secret. You can create the secret using the kubectl command-line tool as follows:
kubectl create secret generic mysql-pass --from-literal=password=MyPa$$w0rd
This command creates a new Kubernetes secret called “mysql-pass” that stores a password “MyPa$$w0rd”. To use this secret in a Pod that runs a MySQL container, you can add the following YAML configuration to your Kubernetes manifest file:
apiVersion: v1
kind: Pod
metadata:
name: mysql-pod
spec:
containers:
- name: mysql
image: mysql:latest
env:
- name: MYSQL_PASSWORD
valueFrom:
secretKeyRef:
name: mysql-pass
key: password
volumeMounts:
- name: mysql-pass
mountPath: /etc/mysql/password
readOnly: true
volumes:
- name: mysql-pass
secret:
secretName: mysql-pass
This configuration creates a new Pod called “mysql-pod” that runs a MySQL container. The Pod references the “mysql-pass” secret using the “secretKeyRef” field in the “valueFrom” section of the container’s environment variable. The secret is also mounted as a volume in the container’s filesystem at “/etc/mysql/password”.
When the Pod is created, Kubernetes mounts the secret as a volume into the container’s filesystem decrypts the data, and makes it available to the MySQL container as an environment variable.
Conclusion
Kubernetes secrets provide a secure way to store and manage sensitive data in your applications running in a Kubernetes cluster. By using secrets, you can avoid exposing sensitive data in your container images or configuration files, and reduce the risk of data breaches or unauthorized access.
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