When Should You Use Secrets Instead of ConfigMaps in Kubernetes?

When we choose between Secrets and ConfigMaps in Kubernetes, we must know the difference. Secrets help us handle sensitive information like passwords, tokens, and SSH keys. On the other hand, ConfigMaps are for regular configuration data that is not sensitive. We should use Secrets when we want to keep data private and safe. They give more protection than ConfigMaps. For general settings that don’t need extra security, we can use ConfigMaps.

In this article, we will look at when to use Secrets instead of ConfigMaps in Kubernetes. We will explain what Secrets and ConfigMaps are, and why they matter. We will also show how to protect sensitive data with Kubernetes Secrets. Then we will talk about when to pick ConfigMaps for data that is not sensitive. Finally, we will cover how to access these resources in your Pods. We will also answer some common questions to help clear up any confusion on this topic.

  • When to use Secrets instead of ConfigMaps in Kubernetes
  • What are Secrets in Kubernetes and why they are important
  • What are ConfigMaps in Kubernetes and when to use them
  • How to protect sensitive data with Kubernetes Secrets
  • When to pick ConfigMaps for non-sensitive data
  • How to access Secrets and ConfigMaps in your Pods
  • Common questions about Secrets and ConfigMaps

What Are Secrets in Kubernetes and Why Use Them

Kubernetes Secrets help us store and manage sensitive information. This includes things like passwords, OAuth tokens, SSH keys, and other private data. Unlike ConfigMaps, which hold non-sensitive data in key-value pairs, Secrets keep sensitive information safe. They make sure this data is not shown directly in our application code or config files.

Key Features of Kubernetes Secrets:

  • Base64 Encoding: Secrets are saved in base64 encoding. This makes the sensitive data less visible.
  • Access Control: Kubernetes has Role-Based Access Control (RBAC). It limits who can see Secrets. Only authorized users or applications can access them.
  • Integration: We can easily add Secrets into Pods. We can use them as environment variables or mount them as files in a volume.

Creating a Secret

We can create a Secret using a YAML file or from the command line. Here is an example of making a Secret with a YAML file:

apiVersion: v1
kind: Secret
metadata:
  name: my-secret
type: Opaque
data:
  username: dXNlcm5hbWU=  # base64 encoded value of "username"
  password: cGFzc3dvcmQ=  # base64 encoded value of "password"

To create the Secret from the command line:

kubectl create secret generic my-secret --from-literal=username=myusername --from-literal=password=mypassword

Accessing Secrets in a Pod

We can access Secrets in Pods as environment variables or as files in a volume. Here is how to access them as environment variables:

apiVersion: v1
kind: Pod
metadata:
  name: my-pod
spec:
  containers:
    - name: my-container
      image: my-image
      env:
        - name: USERNAME
          valueFrom:
            secretKeyRef:
              name: my-secret
              key: username
        - name: PASSWORD
          valueFrom:
            secretKeyRef:
              name: my-secret
              key: password

Why Use Secrets?

  • Security: Using Secrets keeps sensitive information apart from application code. This lowers the risk of accidental exposure.
  • Dynamic Updates: We can change Secrets without redeploying Pods. This makes it easier to manage sensitive data.
  • Compliance: Using Secrets helps us follow rules for handling sensitive information. It gives controlled access.

For more details on how to manage Secrets safely in Kubernetes, we can check this guide on managing secrets in Kubernetes.

What Are ConfigMaps in Kubernetes and When to Use Them

ConfigMaps in Kubernetes help us store non-sensitive configuration data in key-value pairs. They let us separate configuration from image content. This makes our containerized apps more portable. ConfigMaps can keep settings like environment variables, command-line arguments, and configuration files.

When to Use ConfigMaps

  1. Non-Sensitive Data: We should use ConfigMaps for configuration data that is not sensitive. For example:

    • Application settings like URLs and feature flags.
    • Configuration files such as application.properties.
    • Environment variables that do not contain secrets.

  2. Dynamic Configuration: ConfigMaps let us update settings without needing to rebuild container images. We can change ConfigMaps, and running pods will see these changes.

  3. Multiple Data Sources: If our application needs different configuration sources, ConfigMaps can combine these settings.

Creating a ConfigMap

We can create a ConfigMap from literal values, files, or directories. Here are some ways to do this:

From Literal Values:

kubectl create configmap my-config --from-literal=key1=value1 --from-literal=key2=value2

From a File:

kubectl create configmap my-config --from-file=path/to/config.file

From a Directory:

kubectl create configmap my-config --from-file=path/to/directory/

Using ConfigMaps in Pods

To use ConfigMaps in our Pods, we can reference them in environment variables or mount them as volumes.

Using as Environment Variables:

apiVersion: v1
kind: Pod
metadata:
  name: mypod
spec:
  containers:
  - name: mycontainer
    image: myimage
    env:
    - name: MY_CONFIG
      valueFrom:
        configMapKeyRef:
          name: my-config
          key: key1

Mounting as a Volume:

apiVersion: v1
kind: Pod
metadata:
  name: mypod
spec:
  containers:
  - name: mycontainer
    image: myimage
    volumeMounts:
    - name: config-volume
      mountPath: /etc/config
  volumes:
  - name: config-volume
    configMap:
      name: my-config

Limitations

  • ConfigMaps are not good for sensitive information. For sensitive data like passwords or tokens, we should use Kubernetes Secrets.
  • They can only be 1MB in size.

For more details on managing configurations in Kubernetes, we can check out how to manage application configuration in Kubernetes.

How to Secure Sensitive Data with Kubernetes Secrets

Kubernetes Secrets help us store and manage sensitive data. This can be passwords, OAuth tokens, SSH keys, and more. Using Secrets keeps this data safe. Only authorized pods can access it. Let’s see how we can secure sensitive data with Kubernetes Secrets.

Creating a Secret

We can create a Secret using a YAML file or directly with kubectl. Here is an example of making a Secret from simple values:

kubectl create secret generic my-secret \
  --from-literal=username='admin' \
  --from-literal=password='P@ssw0rd'

We can also create a Secret from a file like this:

kubectl create secret generic my-secret --from-file=path/to/your/file

Storing Secrets in YAML

We can define a Secret in a YAML file like this:

apiVersion: v1
kind: Secret
metadata:
  name: my-secret
type: Opaque
data:
  username: YWRtaW4=  # Base64 encoded
  password: UEBzc3cwcmQ=  # Base64 encoded

To use this Secret, we run:

kubectl apply -f secret.yaml

Accessing Secrets in Pods

We can mount Secrets as volumes in pods or use them as environment variables. Here is how we do both:

Mounting as a Volume:

apiVersion: v1
kind: Pod
metadata:
  name: secret-volume-pod
spec:
  containers:
  - name: my-container
    image: my-image
    volumeMounts:
    - name: secret-volume
      mountPath: /etc/secret
  volumes:
  - name: secret-volume
    secret:
      secretName: my-secret

Using as Environment Variables:

apiVersion: v1
kind: Pod
metadata:
  name: secret-env-pod
spec:
  containers:
  - name: my-container
    image: my-image
    env:
    - name: DATABASE_USER
      valueFrom:
        secretKeyRef:
          name: my-secret
          key: username
    - name: DATABASE_PASSWORD
      valueFrom:
        secretKeyRef:
          name: my-secret
          key: password

Best Practices for Using Secrets

  • Limit Access: We should use Role-Based Access Control (RBAC) to control who can see or change Secrets.
  • Avoid Hardcoding: We must not hardcode Secrets in our application code. Instead, access them through environment variables or mounted volumes.
  • Use Encryption: We can turn on etcd encryption to keep Secrets safe when stored.
  • Audit Access: It is good to regularly check who accesses Secrets to keep everything secure.

For more information on managing sensitive data in Kubernetes, check out this article on managing secrets securely.

When to Choose ConfigMaps for Non-Sensitive Configuration Data

ConfigMaps in Kubernetes help us manage non-sensitive configuration data that our applications need to run. They are great for storing settings, environment variables, and files that do not have sensitive info. Here are some situations when we can use ConfigMaps:

  • Application Configuration: Use them to store settings like feature flags, logging levels, and application URLs.
  • Non-Sensitive Data: We can use ConfigMaps for data that does not need encryption, like static config files and non-sensitive JSON or YAML data.

Example of Creating a ConfigMap

We can create a ConfigMap using a YAML file or by using the command line. Here is a simple example with a YAML file:

apiVersion: v1
kind: ConfigMap
metadata:
  name: app-config
data:
  LOG_LEVEL: "debug"
  FEATURE_FLAG: "true"
  APP_URL: "http://example.com"

To create this ConfigMap, save the above content to a file called configmap.yaml. Then we can apply it with:

kubectl apply -f configmap.yaml

Accessing ConfigMap Data in Pods

We can access ConfigMap data in our pods as environment variables or mount them as files. Here is how to use them as environment variables in a deployment:

apiVersion: apps/v1
kind: Deployment
metadata:
  name: my-app
spec:
  replicas: 1
  selector:
    matchLabels:
      app: my-app
  template:
    metadata:
      labels:
        app: my-app
    spec:
      containers:
      - name: app-container
        image: my-app-image
        env:
        - name: LOG_LEVEL
          valueFrom:
            configMapKeyRef:
              name: app-config
              key: LOG_LEVEL

ConfigMaps vs. Secrets

We should use ConfigMaps when the data is not sensitive. For sensitive data like passwords, tokens, and API keys, we must use Kubernetes Secrets. This way, we keep sensitive info safe.

For more info on managing application configuration in Kubernetes, check out how to manage application configuration in Kubernetes.

How to Access Secrets and ConfigMaps in Your Pods

In Kubernetes, we can access Secrets and ConfigMaps in our Pods using environment variables or mounted volumes. This helps our applications use sensitive and non-sensitive settings easily.

Accessing Secrets

To access Kubernetes Secrets, we define them in our Pod specification. Here is how we can use both environment variables and volume mounts:

Using Environment Variables:

We can pass Secrets as environment variables in our Pod specification:

apiVersion: v1
kind: Pod
metadata:
  name: secret-example
spec:
  containers:
  - name: myapp
    image: myapp:latest
    env:
    - name: MY_SECRET
      valueFrom:
        secretKeyRef:
          name: my-secret
          key: secret-key

Using Volumes:

We can also mount the Secret as a volume:

apiVersion: v1
kind: Pod
metadata:
  name: secret-volume-example
spec:
  containers:
  - name: myapp
    image: myapp:latest
    volumeMounts:
    - name: secret-volume
      mountPath: /etc/secret
  volumes:
  - name: secret-volume
    secret:
      secretName: my-secret

Accessing ConfigMaps

ConfigMaps can also be accessed in a similar way. Here is how we define them in our Pods:

Using Environment Variables:

We can define ConfigMaps as environment variables:

apiVersion: v1
kind: Pod
metadata:
  name: configmap-example
spec:
  containers:
  - name: myapp
    image: myapp:latest
    env:
    - name: MY_CONFIG
      valueFrom:
        configMapKeyRef:
          name: my-configmap
          key: config-key

Using Volumes:

Mounting a ConfigMap as a volume is simple:

apiVersion: v1
kind: Pod
metadata:
  name: configmap-volume-example
spec:
  containers:
  - name: myapp
    image: myapp:latest
    volumeMounts:
    - name: config-volume
      mountPath: /etc/config
  volumes:
  - name: config-volume
    configMap:
      name: my-configmap

Using these methods, we can manage and access both Secrets and ConfigMaps in our Kubernetes Pods. This allows our applications to work with the right settings safely.

For more details on managing Secrets in Kubernetes, we can check this guide.

Frequently Asked Questions

1. When should we use Kubernetes Secrets instead of ConfigMaps?

We should use Kubernetes Secrets to store sensitive information like passwords, OAuth tokens, and SSH keys. This helps to keep them safe. ConfigMaps are for non-sensitive data. By using Secrets, we can avoid exposing sensitive data and improve security for our Kubernetes applications.

2. How do we create a Kubernetes Secret?

We can create a Kubernetes Secret using the kubectl command line tool. We can make a Secret from literal values, files, or directories. For example, to create a Secret from a literal value, we can run this command:

kubectl create secret generic my-secret --from-literal=password='my-secret-password'

This command makes a new Secret called my-secret with the password we provided.

3. What are the differences between Kubernetes Secrets and ConfigMaps?

The main difference between Kubernetes Secrets and ConfigMaps is the kind of data they hold. Secrets are for sensitive info while ConfigMaps are for non-sensitive data. Also, Secrets use base64 encoding to protect sensitive data. ConfigMaps store data in plain text. Knowing when to use one or the other is important for keeping our Kubernetes applications safe.

4. How can we access Secrets and ConfigMaps in our Kubernetes Pods?

We can access Secrets and ConfigMaps in our Pods by using environment variables or by mounting them as volumes. To set an environment variable from a Secret, we write it in our Pod’s YAML file like this:

env:
  - name: MY_SECRET
    valueFrom:
      secretKeyRef:
        name: my-secret
        key: password

For ConfigMaps, we do it almost the same way but use configMapKeyRef. This helps our applications get configuration data easily.

5. What are the best practices for managing Secrets in Kubernetes?

To manage Secrets well in Kubernetes, we should keep them safe and limit access using Role-Based Access Control (RBAC). We should also change Secrets regularly and think about using external secret management tools for better security. Plus, we should not hardcode Secrets in our application code. It is better to use environment variables or mounted volumes to access them.

For more information on Kubernetes Secrets, we can check out how to manage secrets in Kubernetes securely.