Key Manager Backend Configuration

Overview

The Key Manager (Barbican) secret store backend determines how secret payloads are encrypted and where ciphertext is stored. Xloud Key Manager supports five backend types — from a software-only AES plugin for development, to hardware HSMs, external KMIP servers, HashiCorp Vault, and Dogtag KRA for enterprise deployments. Configuration is managed through XDeploy; changing the backend after secrets exist requires a migration operation.

Administrator Access Required — This operation requires the admin role. Contact your Xloud administrator if you do not have sufficient permissions.

Supported Backends

Backend	Plugin Name	External System	Best For
Simple Crypto	`simple_crypto`	None — DB-stored encrypted blobs	Development, non-HSM deployments
PKCS#11 HSM	`p11_crypto`	Hardware Security Module (Thales, nCipher, Utimaco, ATOS)	FIPS 140-2 / production HSM
KMIP	`kmip_plugin`	Any OASIS KMIP server (Thales, SafeNet, Vormetric, IBM)	Enterprise KMS integration
HashiCorp Vault	`vault_plugin`	HashiCorp Vault (self-hosted or HCP)	Cloud-native secrets management
Dogtag KRA	`dogtag_plugin`	Red Hat Certificate System / FreeIPA	Software-HSM without hardware

View Current Backend

The active backend is visible in the XDeploy configuration panel under Key Manager → Secret Store. Verify the API is operational:

Verify Key Manager API

openstack secret list --limit 1

Backend Configuration Reference

Simple Crypto
PKCS#11 HSM
KMIP
HashiCorp Vault
Dogtag KRA

Software-based AES-256 encryption. The Key Encryption Key (KEK) is base64-encoded and stored in barbican.conf. Secrets are encrypted at rest in the Barbican database.

barbican.conf

[secretstore]
enabled_secretstore_plugins = store_crypto
enabled_crypto_plugins = simple_crypto

[simple_crypto_plugin]
# 32-byte base64-encoded key encryption key
kek = dGhpcnR5X3R3b19ieXRlX2tleWtleWtleWtleWs=

Parameter	Description
`kek`	32-byte AES key, base64-encoded — protects all project KEKs

The kek value is stored in plaintext in barbican.conf. Any host compromise exposes all secrets. This backend is suitable only for development and testing environments. Use PKCS#11, KMIP, or Vault for production.

Stores the Master KEK and HMAC signing key inside a hardware HSM. Per-project KEKs are wrapped by the MKEK and signed with HMAC before being stored in the database. Supports Thales Luna, nCipher nShield, ATOS Bull, and Utimaco HSMs.

barbican.conf

[secretstore]
enabled_secretstore_plugins = store_crypto
enabled_crypto_plugins = p11_crypto

[p11_crypto_plugin]
library_path = /usr/lib/libCryptoki2_64.so
token_labels = barbican_token
login = <hsm-partition-pin>
mkek_label = barbican_mkek
mkek_length = 32
hmac_label = barbican_hmac
encryption_mechanism = CKM_AES_CBC
hmac_mechanism = CKM_SHA256_HMAC
key_wrap_mechanism = CKM_AES_KEY_WRAP_KWP
pkek_length = 32
pkek_cache_ttl = 900
pkek_cache_limit = 100

Parameter	Description
`library_path`	Path to HSM vendor’s PKCS#11 `.so` shared library
`token_labels`	Label identifying the HSM token
`login`	HSM partition PIN
`mkek_label`	Label of the Master KEK inside the HSM
`hmac_label`	Label of the HMAC signing key inside the HSM (must differ from `mkek_label`)
`encryption_mechanism`	Encryption cipher, e.g. `CKM_AES_CBC`
`hmac_mechanism`	HMAC algorithm, e.g. `CKM_SHA256_HMAC`
`key_wrap_mechanism`	Project KEK wrapping algorithm
`pkek_cache_ttl`	Unwrapped project KEK cache lifetime (seconds)

Generate master keys on first deployment:

Generate MKEK and HMAC keys on HSM

barbican-manage hsm gen_mkek --label barbican_mkek
barbican-manage hsm gen_hmac --label barbican_hmac

mkek_label and hmac_label must be different values. Identical labels cause authentication failures.

Secrets are stored directly on the external KMIP device — Barbican’s database holds only a reference/locator. Supports mutual TLS authentication. Compatible with any OASIS KMIP-compliant server.

barbican.conf

[secretstore]
enabled_secretstore_plugins = kmip_plugin

[kmip_plugin]
host = kmip.internal.<your-domain>
port = 5696
keyfile = /etc/barbican/certs/client.key
certfile = /etc/barbican/certs/client.crt
ca_certs = /etc/barbican/certs/ca.crt
# Optional: username/password if required by the KMIP device
username = barbican-svc
password = <kmip-password>

Parameter	Description
`host`	KMIP server hostname or IP
`port`	KMIP port (default `5696`)
`keyfile`	Client TLS private key path
`certfile`	Client TLS certificate path
`ca_certs`	CA certificate for server validation
`username`	KMIP authentication username (optional)
`password`	KMIP authentication password (optional)

Client certificates and private keys must be readable only by the barbican service user (chmod 0400). Store them on an encrypted volume.

Secrets are stored in Vault’s KV secrets engine. Barbican authenticates using either a root token (development) or AppRole (production). The Vault server can be self-hosted or HCP Vault.

barbican.conf

[secretstore]
enabled_secretstore_plugins = vault_plugin

[vault_plugin]
vault_url = https://vault.internal.<your-domain>:8200
use_ssl = true
ssl_ca_crt_file = /etc/barbican/certs/vault-ca.crt
# Production: use AppRole (recommended)
approle_role_id = <vault-role-id>
approle_secret_id = <vault-secret-id>
kv_mountpoint = secret
# Development only (not recommended for production):
# root_token_id = <vault-root-token>

Parameter	Description
`vault_url`	Vault server address
`use_ssl`	Enable TLS for Vault communication
`ssl_ca_crt_file`	CA certificate for Vault TLS verification
`approle_role_id`	AppRole role ID (recommended for production)
`approle_secret_id`	AppRole secret ID paired with role ID
`kv_mountpoint`	KV secrets engine mount point (default: `secret`)
`root_token_id`	Root token auth — development only

Use AppRole authentication in production. Root token auth works but is not rotatable and grants full Vault access. AppRole provides scoped, rotatable credentials.

Integrates with Red Hat Certificate System’s Key Recovery Authority. Secrets are stored in the KRA with master keys held in an NSS certificate database (software) or HSM. Supports optional FreeIPA integration.

barbican.conf

[secretstore]
enabled_secretstore_plugins = dogtag_plugin

[dogtag_plugin]
dogtag_host = kra.internal.<your-domain>
dogtag_port = 8443
pem_path = /etc/barbican/kra_admin_cert.pem
nss_db_path = /etc/barbican/alias
nss_password = <nss-db-password>

Parameter	Description
`dogtag_host`	KRA server hostname
`dogtag_port`	KRA server port (default `8443`)
`pem_path`	KRA admin certificate PEM file path
`nss_db_path`	NSS certificate database directory
`nss_password`	NSS database password

Dogtag is the only backend offering software-HSM security (NSS database) without requiring physical HSM hardware. It is the recommended middle ground between Simple Crypto (no hardware) and PKCS#11 (requires HSM).

Multi-Backend Deployments

Deploy multiple backends simultaneously — e.g., KMIP as the global default with Vault available for specific projects.

barbican.conf — multi-backend example

[secretstore]
enable_multiple_secret_stores = True
stores_lookup_suffix = software, kmip, vault

[secretstore:software]
secret_store_plugin = store_crypto
crypto_plugin = simple_crypto

[secretstore:kmip]
secret_store_plugin = kmip_plugin
global_default = True

[secretstore:vault]
secret_store_plugin = vault_plugin

Rule	Description
`enable_multiple_secret_stores = True`	Activates multi-backend mode
`stores_lookup_suffix`	Comma-separated list — each maps to a `[secretstore:SUFFIX]` section
`global_default = True`	Exactly one backend must have this — handles secrets with no project preference
`enabled_secretstore_plugins`	Ignored when multi-backend mode is active

When switching from single-backend to multi-backend, keep the existing backend configuration as the global_default to maintain access to existing secrets.

Apply Backend Configuration

Deploy Key Manager configuration via XDeploy

xavs-ansible deploy -t barbican

Verify the service is healthy after deployment

openstack secret list --limit 1

Next Steps

Secret Stores

Configure multiple backends and assign preferred stores to projects

Security

Protect master keys, audit secret access, and certificate management

Architecture

Understand Key Manager service topology and secret lifecycle

Admin Troubleshooting

Diagnose backend connectivity and startup failures

Core Services

Other Services

Key Manager Backend Configuration

Overview

Supported Backends

View Current Backend

Backend Configuration Reference

Multi-Backend Deployments

Apply Backend Configuration

Next Steps

Secret Stores

Security

Architecture

Admin Troubleshooting

Core Services

Other Services

​Overview

​Supported Backends

​View Current Backend

​Backend Configuration Reference

​Multi-Backend Deployments

​Apply Backend Configuration

​Next Steps

Secret Stores

Security

Architecture

Admin Troubleshooting

Overview

Supported Backends

View Current Backend

Backend Configuration Reference

Multi-Backend Deployments

Apply Backend Configuration

Next Steps