Kubernetes Secrets

What are Kubernetes Secrets? Don't worry. This article has got that covered. In this article, you will learn about Kubernetes Secrets, their types, and how to create secrets. By the end of this article, you will clearly understand Kubernetes Secrets. No, wait. Let's start.

Kubernetes assists developers in managing and scaling applications across distributed environments in an efficient manner. The significance of managing sensitive data such as passwords, tokens, and API credentials is growing. To interact with any form of confidential credentials, privileged access must be obtained. Kubernetes Secrets is an extensive tool for managing and safeguarding sensitive data in the Kubernetes environment

Kubernetes Secrets - Table of Contents:

What are Kubernetes Secrets?

Secrets are Kubernetes objects that allow for the secure storage and administration of sensitive data within a Kubernetes cluster. This data might include authentication credentials, tokens, SSL certificates, etc. This information might be included in a Pod specification or a container image. When you use a Secret, you avoid having secret data in your application code. Secrets are base64-encoded by default but not encrypted; hence, managing access permissions for these objects is crucial.

When creating Secrets, use immutable: true to make them immutable. Preventing modifications to the Secret data after it has been created. Immutability safeguards a Secret from unintentional or undesired updates that could cause application disruptions.

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Types of Kubernetes Secrets

There are several types of Kubernetes Secrets. These are discussed below:

  • Opaque Secrets:

Opaque Secrets are the most common type of Kubernetes Secret. They are used to store arbitrary user-defined data. The information saved in an Opaque Secret is base64-encoded but not encrypted. These Secrets are excellent for dealing with simple values such as passwords, API keys, and certificates.

  • Service Account Secrets: 

Kubernetes automatically creates Service Account Secrets when creating a Service Account. These Secrets provide tokens for pods to authenticate with the Kubernetes API and perform various actions on behalf of the Service Account. Service Account Secrets are not intended to store arbitrary data but to support internal Kubernetes operations.

  • TLS Secrets:

TLS Secrets store private keys and certificates for securing communication between services in the cluster. These Secrets are essential for setting up secure communication through HTTPS or other encrypted protocols.

  • Docker-registry Secrets:

Docker-registry Secrets securely authenticate Kubernetes when retrieving private container images from external container registries. The login credentials required to access the container registry are stored in these Secrets.

  • Basic authentication Secret:

This Secret type stores credentials required for basic authentication. At least one of the keys mentioned below must be included while creating a basic authentication Secret:

username: the user name for authentication

password: the password or token for authentication

  • Bootstrap token Secrets:

During the node bootstrap process, you can utilize this Secret type to store bootstrap token data. In the kube-system namespace, you normally create a bootstrap token Secret and name it <bootstrap-token-token-id>..

  • SSH authentication Secrets:

This is used to store data in SSH authentication. When utilizing SSH authentication, you must specify an ssh-private key-value pair as the SSH credential in the data field.

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How to Create Kubernetes Secrets?

Secrets can be created in many ways to store and handle sensitive data. The following are the primary methods for developing Kubernetes Secrets:

Use kubectl to create Secrets:

There are two ways to create Secrets using Kubectl. These are as follows:

  1. Creating secrets using kubectl through a file using the --from-file=<filename> tag.
  2. Creating secrets using kubectl through a file using the --from-literal=<key>=<value> tag.

In this article, we will use the file method.

We must encode the sensitive data (e.g., username and password) before creating a secret. Use the echo command with base64. Change <your-username> and <your-password> with your real values..

Step 1: 

Provide the Secret data from a file in any directory of your choice. With the following command, create files to store the fictitious user credentials:

The "-n" in the preceding command ensures that no newlines are included at the end of the text. This is important because when kubectl reads the file and converts the content into a base64 string, it will encode the extra newline character.

Step 2: 

After running the above commands, use the "cat" command to verify your file, as given below.

Step 3:

Now use the kubectl command as shown below to create Secrets using the file:

Step 4:

Run the following command to verify that a secret has been created

Use configuration files to create Secrets:

Step 1: 

Before creating a secret, you must first determine how to add the Secret data to the data and/or stringData fields.

The secret data must be encrypted using Base64, utilizing the data field. Use the following command to encode the secret into base64:

Copy the output value, as you will need it later.

Step 2: 

Now create a secret-v1.yaml file and add the following configuration.

Step 3:

Create a Secret by running the following command:

Related Article - What is Kubernetes?

Use kustomize to create Secrets:

Follow the steps below to create secrets using Kustomize:

Step 1: 

Create a new file using the following command:

Step 2:

Now create a kustomization.yaml file. Define a secretGenerator in that file to refer to one of the following:

  • Files containing the secret data,
  • Environment variable (.env),
  • the unencrypted literal form of the secret data values.

Step 3:

Generate the Secret in the same directory as the file with the following kubectl command:

Frequently Asked Questions (FAQs)

1. How does Kubernetes distribute credentials securely?

Kubernetes distributes credentials through its secret management system. Secrets are stored in encryption and mounted into pods, allowing secure access without sharing any sensitive information.

2. Should I use Kubernetes secrets?

Secrets store information in the form of API and ensure data protection through encryption. Although using Secrets doesn’t remove the need to carefully handle sensitive information. It can still give more control on the information you are exposing.

3. Where are secret objects stored in Kubernetes?

Secret objects are stored in etcd. They are unencrypted by default, and you need to configure encryption of Secret data in etcd. They are encoded at rest, ensuring security.

4. Why do we need a centralized Kubernetes security management solution?

A centralized Kubernetes security management system provides a unified view of Kubernetes security. It ensures consistency across different clusters and helps in the management of Secrets without any chance of misconfiguration.

5. How do I encode a string in Kubernetes?

To encode a string, use the command: echo -n "your_string" | base64. Apply this command in Kubernetes YAML and access it in pods as an environment variable.

Related Article - Kubernetes Interview Questions


Secrets in Kubernetes are a dependable and adaptable approach for protecting sensitive data within containerized systems. Developers and administrators may secure sensitive data from unauthorized access and maintain higher security by following best practices. Remember, while Secrets provide further security, they are not a replacement for a complete safety strategy and should be used with other security measures.

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Last updated: 14 Dec 2023
About Author

Kalla Saikumar is a technology expert and is currently working as a Marketing Analyst at MindMajix. Write articles on multiple platforms such as Tableau, PowerBi, Business Analysis, SQL Server, MySQL, Oracle, and other courses. And you can join him on LinkedIn and Twitter.

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