External secret management integration in Kubernetes - Step-by-Step Execution

Process Flow - External secret management integration

Define Secret in External Manager

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Configure Kubernetes External Secrets

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Kubernetes External Secrets Controller Fetches Secret

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Secret Created/Updated in Kubernetes

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Pod Uses Kubernetes Secret

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Application Accesses Secret

This flow shows how an external secret is defined outside Kubernetes, then fetched and synced into Kubernetes as a secret, which pods can then use.

Execution Sample

Kubernetes

apiVersion: kubernetes-client.io/v1
kind: ExternalSecret
metadata:
  name: my-secret
spec:
  backendType: secretsManager
  data:
  - key: prod/db-password
    name: password

This ExternalSecret resource tells Kubernetes to fetch the 'prod/db-password' from AWS Secrets Manager and create a Kubernetes secret with the key 'password'.

Process Table

Step	Action	Resource Involved	Result	Notes
1	Define secret in AWS Secrets Manager	AWS Secrets Manager	Secret 'prod/db-password' created	External secret stored securely outside Kubernetes
2	Create ExternalSecret resource in Kubernetes	Kubernetes ExternalSecret	ExternalSecret resource 'my-secret' created	Specifies which external secret to fetch
3	External Secrets Controller polls AWS	External Secrets Controller	Fetches 'prod/db-password' value	Controller runs inside Kubernetes cluster
4	Controller creates Kubernetes Secret	Kubernetes Secret	Secret 'my-secret' created with key 'password'	Secret synced from external manager
5	Pod references Kubernetes Secret	Pod spec	Pod mounts or env uses secret 'my-secret'	Application can access secret securely
6	Application reads secret	Application container	Secret value available at runtime	Used for DB connection or API keys
7	Secret updated externally	AWS Secrets Manager	Secret value changed	External secret updated
8	Controller detects change	External Secrets Controller	Updates Kubernetes Secret	Sync keeps secrets current
9	Pod uses updated secret	Pod	Application uses new secret value	No pod restart needed if mounted properly

💡 Secret synced and available in Kubernetes; application can securely use external secrets.

Status Tracker

Variable	Start	After Step 3	After Step 4	After Step 8	Final
External Secret Value	undefined	fetched 'prod/db-password' value	stored in Kubernetes Secret 'my-secret'	updated with new external value	current secret value in Kubernetes

Key Moments - 3 Insights

Why doesn't the application access the external secret directly?

The application accesses the Kubernetes Secret, not the external manager directly, because Kubernetes manages secrets securely inside the cluster and provides standard ways for pods to consume them. See execution_table steps 4 and 5.

How does the Kubernetes Secret stay updated when the external secret changes?

The External Secrets Controller continuously polls or watches the external secret and updates the Kubernetes Secret when changes occur, as shown in execution_table steps 7 and 8.

What happens if the External Secrets Controller is not running?

If the controller is not running, Kubernetes Secrets won't be created or updated from external sources, so pods may have stale or missing secrets. This is implied between steps 3 and 4.

Visual Quiz - 3 Questions

Look at the execution table, at which step does Kubernetes create the secret from the external value?

A Step 3

B Step 4

C Step 5

D Step 6

💡 Hint

Check the 'Result' column for when the Kubernetes Secret 'my-secret' is created.

According to the variable tracker, what is the state of the external secret value after step 8?

A Undefined

B Fetched but not stored

C Updated with new external value

D Deleted

💡 Hint

Look at the 'After Step 8' column for 'External Secret Value'.

If the External Secrets Controller stops running, what will happen to the Kubernetes Secret?

A It will stay but not update with external changes

B It will be deleted immediately

C It will update automatically

D Pods will crash

💡 Hint

Refer to key_moments about controller role and execution_table steps 3-4.

Concept Snapshot

External Secret Management Integration in Kubernetes:
- Define secrets in external manager (e.g., AWS Secrets Manager).
- Create ExternalSecret resource in Kubernetes specifying external keys.
- External Secrets Controller fetches and syncs secrets into Kubernetes Secrets.
- Pods consume Kubernetes Secrets as environment variables or volumes.
- Controller keeps secrets updated automatically without pod restarts.

Full Transcript

External secret management integration in Kubernetes involves storing secrets securely outside the cluster, such as in AWS Secrets Manager. You create an ExternalSecret resource in Kubernetes that tells the External Secrets Controller which external secrets to fetch. The controller runs inside the cluster, fetches the secret values, and creates or updates Kubernetes Secrets accordingly. Pods then use these Kubernetes Secrets to access sensitive data like passwords or API keys. When the external secret changes, the controller detects the update and syncs the new value into Kubernetes Secrets, keeping applications up to date without manual intervention. This process ensures secrets are managed securely and efficiently across systems.