Implementing Secrets Management with Vault

When to Use

• When applications store database passwords, API keys, or certificates in environment variables or config files
• When migrating from static long-lived credentials to dynamic short-lived secrets
• When Kubernetes workloads need secure access to database credentials or cloud provider APIs
• When compliance requirements mandate centralized credential management with audit logging
• When CI/CD pipelines contain hardcoded secrets that represent supply chain risk

Do not use for AWS-only environments where AWS Secrets Manager suffices without multi-cloud requirements, for application-level encryption logic (though Vault Transit can help), or for identity federation (see managing-cloud-identity-with-okta).

Prerequisites

• HashiCorp Vault server deployed in HA mode (Consul or Raft storage backend)
• TLS certificates for Vault listener endpoints
• Vault Enterprise license for namespaces, Sentinel policies, and replication (optional)
• Kubernetes cluster with Vault Agent Injector or CSI provider for workload integration

Workflow

Step 1: Deploy Vault in High Availability Mode

Deploy Vault using Integrated Storage (Raft) for HA without external dependencies. Configure TLS, audit logging, and auto-unseal using a cloud KMS.

# vault-config.hcl
storage "raft" {
  path    = "/opt/vault/data"
  node_id = "vault-node-1"

  retry_join {
    leader_api_addr = "https://vault-node-2.internal:8200"
  }
  retry_join {
    leader_api_addr = "https://vault-node-3.internal:8200"
  }
}

listener "tcp" {
  address     = "0.0.0.0:8200"
  tls_cert_file = "/opt/vault/tls/vault.crt"
  tls_key_file  = "/opt/vault/tls/vault.key"
}

seal "awskms" {
  region     = "us-east-1"
  kms_key_id = "alias/vault-unseal-key"
}

api_addr      = "https://vault-node-1.internal:8200"
cluster_addr  = "https://vault-node-1.internal:8201"

telemetry {
  prometheus_retention_time = "30s"
  disable_hostname         = true
}

# Initialize Vault
vault operator init -key-shares=5 -key-threshold=3

# Enable audit logging
vault audit enable file file_path=/var/log/vault/audit.log

# Enable syslog audit for SIEM integration
vault audit enable syslog tag="vault" facility="AUTH"

Step 2: Configure Authentication Methods

Enable authentication backends for human operators, applications, and CI/CD pipelines. Use AppRole for machine authentication and OIDC for human access.

# Enable OIDC auth for human users via Okta
vault auth enable oidc
vault write auth/oidc/config \
  oidc_discovery_url="https://company.okta.com/oauth2/default" \
  oidc_client_id="vault-client-id" \
  oidc_client_secret="vault-client-secret" \
  default_role="default"

# Enable AppRole for application authentication
vault auth enable approle
vault write auth/approle/role/web-app \
  secret_id_ttl=10m \
  token_num_uses=10 \
  token_ttl=20m \
  token_max_ttl=30m \
  secret_id_num_uses=1 \
  token_policies="web-app-policy"

# Enable Kubernetes auth for pod-based access
vault auth enable kubernetes
vault write auth/kubernetes/config \
  kubernetes_host="https://kubernetes.default.svc:443" \
  token_reviewer_jwt=@/var/run/secrets/kubernetes.io/serviceaccount/token \
  kubernetes_ca_cert=@/var/run/secrets/kubernetes.io/serviceaccount/ca.crt

Step 3: Enable Dynamic Secret Engines

Configure database secret engines to generate short-lived credentials on demand. Each credential set has a TTL and is automatically revoked when it expires.

# Enable database secrets engine for PostgreSQL
vault secrets enable database
vault write database/config/production-db \
  plugin_name=postgresql-database-plugin \
  allowed_roles="readonly,readwrite" \
  connection_url="postgresql://{{username}}:{{password}}@db.internal:5432/production?sslmode=require" \
  username="vault_admin" \
  password="initial-password"

# Rotate the root credentials so Vault manages them exclusively
vault write -force database/rotate-root/production-db

# Create a readonly role with 1-hour TTL
vault write database/roles/readonly \
  db_name=production-db \
  creation_statements="CREATE ROLE \"{{name}}\" WITH LOGIN PASSWORD '{{password}}' VALID UNTIL '{{expiration}}'; GRANT SELECT ON ALL TABLES IN SCHEMA public TO \"{{name}}\";" \
  revocation_statements="REVOKE ALL ON ALL TABLES IN SCHEMA public FROM \"{{name}}\"; DROP ROLE IF EXISTS \"{{name}}\";" \
  default_ttl="1h" \
  max_ttl="24h"


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