Vault as the Secrets Backend Overview

By default, Consul Helm chart will expect that any credentials it needs are stored as Kubernetes secrets. As of Consul 1.11 and Consul Helm chart v0.38.0, we integrate more natively with Vault making it easier to use Consul Helm chart with Vault as the secrets storage backend.

Secrets Overview

By default, Consul on Kubernetes leverages Kubernetes secrets which are base64 encoded and unencrypted. In addition, the following limitations exist with managing sensitive data within Kubernetes secrets:

There are no lease or time-to-live properties associated with these secrets.
Kubernetes can only manage resources, such as secrets, within a cluster boundary. If you have sets of clusters, the resources across them need to be managed separately.

By leveraging Vault as a secrets backend for Consul on Kubernetes, you can now manage and store Consul related secrets within a centralized Vault cluster to use across one or many Consul on Kubernetes datacenters.

Secrets stored in the Vault KV Secrets Engine

The following secrets can be stored in Vault KV secrets engine, which is meant to handle arbitrary secrets:

ACL Bootstrap token
ACL Partition token
ACL Replication token
Enterprise license
Gossip encryption key
Snapshot Agent config

Secrets generated and managed by the Vault PKI Engine

The following TLS certificates and keys can be generated and managed by the Vault PKI Engine, which is meant to handle things like certificate expiration and rotation:

Server TLS credentials
Service Mesh and Consul client TLS credentials

Requirements

Vault 1.9+ and Vault-k8s 0.14+ is required.
Vault must be installed and accessible to the Consul on Kubernetes installation.
global.tls.enableAutoencrypt=true is required if TLS is enabled for the Consul installation when using the Vault secrets backend.
The Vault installation must have been initialized, unsealed and the KV2 and PKI secrets engines and the Kubernetes Auth Method enabled.

Next Steps

The Vault integration with Consul on Kubernetes has two aspects or phases:

Systems Integration - Configure Vault and Consul on Kubernetes systems to leverage Vault as the secrets store.
Data Integration - Configure specific secrets to be stored and retrieved from Vault for use with Consul on Kubernetes.

As a next step, please proceed to Systems Integration overview to understand how to first setup Vault and Consul on Kubernetes to leverage Vault as a secrets backend.