Managing Swarm Secrets

This post will cover topic related to ‘Managing Swarm Secrets’ with multiple docker command examples and different scenerios. So this will help you to understand the command docker and options available in it. Also this post will explain you how to use docker command.

Docker Swarm allows for secure management of secrets, crucial for deploying and managing applications securely. Swarm secrets enable you to store sensitive information, such as passwords or API keys, securely within the Swarm, ensuring that only services that have explicit access can retrieve them.

Example 1: Creating a Swarm secret
To create a new secret named `db_password` in Docker Swarm:

$ echo "mydatabasepassword" | docker secret create db_password -

This command creates a new secret named `db_password` using the value “mydatabasepassword”. To verify the secret exists:

$ docker secret inspect db_password

Example 2: Listing all Swarm secrets
To list all the secrets currently stored in the Swarm:

$ docker secret ls

This command provides a list of all secrets with their IDs and creation dates.

Example 3: Using a secret in a service
Deploying a service with a secret, where `myapp` is the service and `db_password` is the secret:

$ docker service create --name myapp --secret db_password myimage

This command deploys a service named `myapp` using `myimage` and injects the `db_password` secret into the service.

Example 4: Updating a secret
Updating the value of an existing secret `db_password`:

$ echo "newpassword" | docker secret update --secret-id db_password -

This updates the `db_password` secret with a new value “newpassword”.

Example 5: Removing a secret
Removing the secret `db_password` from the Swarm:

$ docker secret rm db_password

This command deletes the `db_password` secret from the Swarm.

Example 6: Inspecting a specific secret
Inspecting details of the `db_password` secret:

$ docker secret inspect db_password

This command displays detailed information about the `db_password` secret, including its metadata.

Example 7: Granting service access to a secret
Granting a service access to the `db_password` secret:

$ docker service update --secret-add source=db_password,target=db_password myapp

This command updates the `myapp` service to include access to the `db_password` secret.

Example 8: Revoking service access to a secret
Removing access to the `db_password` secret from the `myapp` service:

$ docker service update --secret-rm db_password myapp

This command removes access to the `db_password` secret from the `myapp` service.

Example 9: Using secrets in Docker stack files
Specifying a secret `db_password` in a Docker Compose file:

version: '3.7'
services:
  myapp:
    image: myimage
    secrets:
      - db_password
secrets:
  db_password:
    external: true
    name: db_password
    

This Docker Compose file defines a service `myapp` that uses the `db_password` secret.

Example 10: Rotating secrets
Rotating the value of the `db_password` secret:

$ echo "newpassword" | docker secret create --secret-id db_password -

This command creates a new version of the `db_password` secret with a new value “newpassword”, effectively rotating the secret.

To verify whether the above commands executed successfully, you can use Docker commands like `docker secret ls`, `docker secret inspect `, or `docker service inspect ` to check if the secrets were created, updated, or removed as expected.

Also check similar articles.

Managing Swarm Nodes
Managing Swarm Configurations
Managing Docker Image Trust
Managing Docker System
Managing Docker Plugins