How to Manage Kubernetes Secrets ?

Last Updated : 29 May, 2024

Most applications deployed through Kubernetes require access to databases, services, and other resources located externally. The easiest way to manage the login information necessary to access those resources is by using Kubernetes secrets. Secrets help organize and distribute sensitive information across a cluster.

What are Kubernetes Secrets?

A Kubernetes secret is an object storing sensitive pieces of data such as usernames, passwords, tokens, and keys. Secrets are created by the system during an app installation or by users whenever they need to store sensitive information and make it available to a pod.

If passwords, tokens, or keys were simply part of a pod definition or container image, they could be accidentally exposed during Kubernetes operations. Therefore, the most important function of the secret is to prevent accidental exposure of the information stored in it while at the same time making it available wherever the user needs it.

Types of Secrets

Kubernetes supports several types of Secrets, each designed to handle different use cases and data formats. When creating a Secret, you can specify its type using the type field of the Secret resource, or certain equivalent kubectl command line flags. Kubernetes provides several built-in types for some common usage scenarios. Here are the common types of Kubernetes Secrets:

1. Opaque Secrets

The most adaptable kind of Kubernetes secrets are known as opaque secrets, and they can hold any type of data in the form of key-value pairs. Given due to their flexibility, they are ideal for safely storing an array of private data, such as configuration files, API keys, and passwords. In a Kubernetes cluster, you can make sure that sensitive data is safe and easily accessible by your apps through the use of Opaque Secrets.

Opaque Secrets

2. Service Account Tokens

Every pod has a Service Account connected to it. The pod mounts a token automatically so that it can authenticate with the Kubernetes API server. This approach provides proper resource management and access control inside the cluster by enabling secure communication between the pod and the API server.

Service Account Tokens

3. Docker Registry Secrets

Docker Registry Secrets are employed to store login information for private Docker registries in an encrypted way. Kubernetes can access private container images from these registries without revealing private information because to these secrets.

Docker Registry Secrets

4. SSH Secrets

SSH keys are handled and kept safely inside your infrastructure with the help of SSH Secrets. These secrets of trade enable safe access to servers and services, ensuring that confidential data remains protected and accessible by approved people or systems only. Organizations may enhance their security posture, expedite key management processes, and maintain current best practices through the use of SSH Secrets.

SSH Secrets

5. TLS Secrets

Kubernetes utilizes TLS Secrets for conserving private keys and SSL/TLS certificates safely. By providing the required access and encryption credentials, they allow services within the cluster to interact securely. These secrets of trade ensure secure custody and access of sensitive data while maintaining security and compliance best practices.

TLS Secrets

These examples demonstrate how to create different types of Kubernetes secrets. You can adapt them to your specific use cases, ensuring secure handling of sensitive information within your Kubernetes deployments.

Create and Managing Kubernetes Secrets

Step 1: Creating Secret

You can create secrets manually or use the 'kubectl create secret' command to create them. The create secret command can create secrets from string literals, or files containing the values. If we have our database credentials loaded into files named username.txt and password.txt, then we could load them into the cluster’s secret store with the following command.

kubectl create secret generic db-credentials --fromfile=./username.txt --from-file=./password.txt

This command creates a secret named 'db-credentials' in the secret store. The system should respond with a secret “db-credentials” created response.

Creating Secret Once you have created the secret object, you can add it to the container as volume attached to the pod, or you can load the values into environment variables when initializing a new container in the pod. Let’s look at an example configuration that includes the secrets as a volume on the pod.

Secret Config File

Assuming that you used the original file names to load the database credentials into the secrets object and attached the secrets into a volume named secrets, the credentials could now be accessed at /etc/secrets/username and /etc/secrets/password.

Step 2: Decoding Secret

To view the data stored in a Secret, you can use the 'kubectl get secret' command with the --output flag set to jsonpath.

kubectl get secret my-secret --output jsonpath='{.data}'

You can check if the Secret is created or not by giving below command.

kubectl get secrets

This command will show us the list of secrets-their names, type and number of data values.

kubectl get secrets

Step 3: Updating Secret

To update an existing Secret, you can use the 'kubectl create secret' command again. If you want to update the existing Secret in-place, you can use the 'kubectl patch' command.

kubectl patch secret my-secret

Step 4: Deleting Secret

You can delete a Secret using the 'kubectl delete secret' command followed by the Secret name.

kubectl delete secret my-secret

Step 5: Edit the Secret

By using the below command we can interactively edit the secrets in the Kubernetes.

kubectl edit secret <secret-name>

By following these steps, you can effectively control the Kubernetes Secrets in your cluster.

How Secure are Kubernetes Secrets?

Kubernetes Secrets offer a moderate level of security by provide the dedicated mechanism to store and manage the important data like passwords, tokens, and keys. However, their security is not absolute and depends on several factors:

Base64 Encoding: Secrets are store the data as base64-encode the strings, which is not true encryption. This encode the intended for smooth of transmission rather than security.
Encryption at Rest: Kubernetes supports encryption of Secrets at rest, but it must be explicitly configure. Without this, Secrets are stored in plain text in etcd.
Access Control: Correctly configure the Role-Based Access Control (RBAC) policies is important to ensure that only authorized users and services can access Secrets.
Network Security: Securing network communications within the cluster, such as using TLS, helps protect Secrets from being intercepted during transmission.
Audit Logging: Enabling and regularly review the audit logs helps detect unauthorized access to Secrets.

Best Practices for Managing Kubernetes Secrets

Keys, passwords, tokens, and other configuration information are instances of secrets which require to be kept safely. The Secrets need to remain safe regardless of the unlikely circumstance that our Kubernetes cluster gets compromised. These methods will assist us in preserving Kubernetes Secrets:

Encrypt Data in Transit and at Rest: By default, Kubernetes does not safely transmit or store secrets. Consequently, having a structure that employs end-to-end encryption using TLS to encrypt secrets in transit and a solution that stores secrets encrypted are essential.
Use a centralized Secrets store for easy management: Securing secrets becomes hard when we store them in various places. This is particularly so if we need to handle secrets in multiple clusters or if we use an assortment of private and public key pairs. Unauthorized users have an expanded threat surface since Secrets are spread across many locations in the lack of a centralized Secrets management system.
Encrypt etcd data: The encryption of Secrets before storing them is one technique for improving the security of etcd data. To store our keys and Secrets, we need to use an encryption service provider, such a Key Management Service (KMS). Particularly, when a cluster is built, most of managed Kubernetes providers encrypt overall etcd Secrets storage by default, which helps to the safety of our etcd data.
Have an Audit Log: Discovering your secret activity is an excellent item. An audit record gives you visibility to a breach and aids in your evaluation of the circumstances, allowing you to figure out whether the compromise was intentional, identify the affected location, and take additional investigative actions.

What are immutable Kubernetes Secrets, and what are the benefits?

Immutable Kubernetes Secrets are Secrets that cannot be changed once they are created.

Benefits:

Increased Security: Prevents either accidentally or intentionally modifications to important information.
Stability: Ensures that accidental adjustments won't have an effect on applications that depending on these Secrets.
Improved Performance: Reduces updates and related operations, thereby reduces the load on the API server.

You have to set the immutable field in the Secret manifest to true in order to create an immutable Secret. As a case study, examine the following:

apiVersion: v1
kind: Secret
metadata:
  name: my-secret
immutable: true
data:
  username: bXktdXNlcm5hbWU=
  password: bXktcGFzc3dvcmQ=

Updating and Rotating Secrets

Maintaining the security of your systems and applications needs periodic updates and cycling of secrets. Passwords, cryptographic keys, and API tokens all examples of secrets that need to be updated and rotated frequently to reduce the potential for unauthorized access and security lapses. Here are some crucial variables and suggested processes:

1. Updating Secrets:

Purpose: When it becomes necessary to implement modifications to the private information kept in a secret, updating secrets is required. Password, API key, certificate, and other secret data changes are instances of this.
Process: Typically, changing a secret calls for producing a new version of the secret with the modified data. To take advantage of the most current version of the secret, you may have to update your services or programs once the new version has been installed.
Example: You create a new version of the secret with the updated password and update the applications to use the new secret if you need to change the password for a database connection which is stored in the secret.

2. Rotating Secrets:

Purpose: For the purpose to mitigate the impact of potential security breaches, rotating secrets is a proactive security solution that involves constantly altering sensitive information. This is crucial for minimizing the length of time that credentials or keys are accessible.
Process: Creating a new version of a secret with new credentials or keys while keeping the previous version of it active for a transitional period is referred to as rotating secrets. Applications can be upgraded to use the latest version and previous versions may be removed.
Example: You can create a new version with a new API key if you rotate an API key which is kept in a secret. After a transition period, the old version of the application disappears and the new one has been updated to use it.

Best Practices for Updating and Rotating Secrets:

Automation: Regarding consistency and to avoid mistakes made by humans, use automation technologies to make simpler to update and cycle secrets.
Regular Schedule: Establish a regular schedule for secret rotation to maintain a proactive security posture.
Audit Logging: Employ audit logging for keeping track of changes made to secrets, exposing the persona and timing of these changes.
Versioning: Employ the versioning instruments of secret management to keep record of past modifications and quickly reverse them if needed.

Examples of Kubernetes Secrets in Real-World Scenarios

Here are some examples of how Kubernetes Secrets can be used in real-world scenarios:

Docker registry credentials: To be able to obtain private Docker images, cluster nodes require credentials. It is feasible to archive these registry usernames and passwords in a Secret that is only available to the node Kubernetes daemons.
Cloud metadata: Instead of utilizing command line arguments or pod arrangements, Secrets may be employed to provide sensitive metadata, like access keys for cloud providers, to pods.
API Keys and Tokens: Applications frequently require API keys or tokens for authentication when connecting with external APIs or services. Taking these credentials out of source code or configuration files makes handling and cycling them easier since they are kept in Kubernetes Secrets.
SSL/TLS Certificates: Applications often require SSL/TLS certificates for secure communication. Kubernetes Secrets can store these certificates, making it easy to manage and update them without the need to redeploy the entire application.
Git credentials: Git usernames & tokens can be maintained as Secret for the sole purpose of cloning private git repositories inside of pods. This prohibits pod setups from hardcoding git credentials.
Configuration Files: Some applications use configuration files that contain sensitive information. Kubernetes Secrets can be mounted as files in the application's containers, allowing secure access to sensitive configuration data without exposing it in environment variables.
Database Credentials: Various services in a microservices architecture might have to set up links with databases. Passwords, usernames, and database connection strings may all be securely stored with Kubernetes Secrets. This ensures that environment variables or configuration files do not contain sensitive data.
Encryption Keys: Sensitive data has been protected for apps that require encryption by maintaining encryption keys in Kubernetes Secrets. For data to be secured either in transit or at rest, this is important.

What are the limitations of Kubernetes Secrets?

Base64 Encoding: Base64-encoded strings are employed to hold secrets; nevertheless, this sort of encryption is not really secure and is frequently broken.
Encryption at Rest: Secrets encryption at rest need to be manually enabled and is not enabled by convention.
Access Control Complexity: Using RBAC to handle fine-grained access control can be challenging and prone to blunders.
Memory Storage: The nodes' memory includes secrets that could be available in the event if a node is compromised.
No Versioning: Versioning is not fully enabled in Kubernetes Secrets, making it more difficult to trace changes and roll things back when needed.

Conclusion

Careful monitoring of Kubernetes secrets is required for upholding strong safety protocols in a cluster environment. Utilizing encryption, access control techniques, periodic rotation, and monitoring tools are crucial for safeguarding Kubernetes secrets. By prioritizing proper secret management, organizations may significantly reduce the risk of hacking and improve the overall integrity of their Kubernetes the system.