Securing sensitive application data (secrets)

Sometimes, our application needs to hold sensitive information. This can be credentials or tokens to log in to a database or service. Storing this sensitive information in the image itself is something to be avoided. Here, Kubernetes provides us with a solution in the construct of secrets.

Secrets give us a way to store sensitive information without including plaintext versions in our resource definition files. Secrets can be mounted to the pods that need them and then accessed within the pod as files with the secret values as content. Alternatively, you can also expose the secrets via environment variables.

Note

Given that Kubernetes still relies on plaintext etcd storage, you may want to explore integration with more mature secrets vaults, such as Vault from Hashicorp. There is even a GitHub project for integration: https://github.com/Boostport/kubernetes-vault.

We can easily create a secret either with YAML or on the command line. Secrets do need...