AAP + Vault SSH Integration

Dynamically signed SSH credentials replacing static key management.

Architecture

AAP Job → AppRole Auth → Vault SSH CA → Signed Certificate → Target Host

1. AAP authenticates to Vault via AppRole
2. AAP credential plugin submits SSH key for signing
3. Vault SSH CA signs certificate (2hr TTL)
4. AAP uses signed cert for SSH access

Quick Start

1. Vault Configuration (Terraform)

# Enable SSH secrets engine
resource "vault_mount" "ssh" {
  path = "ssh"
  type = "ssh"
}

resource "vault_ssh_secret_backend_ca" "ssh" {
  backend              = vault_mount.ssh.path
  generate_signing_key = true
}

# AppRole for AAP
resource "vault_approle_auth_backend_role" "aap" {
  backend        = "approle"
  role_name      = var.tenant
  token_policies = ["aap-ssh"]
}

# SSH signing role
resource "vault_ssh_secret_backend_role" "aap" {
  backend                 = vault_mount.ssh.path
  name                    = var.tenant
  key_type                = "ca"
  allow_user_certificates = true
  default_user            = "aap"
  allowed_users           = "aap,ansible"
  ttl                     = "7200"
  default_extensions      = { "permit-pty" = "" }
}

Full Terraform config: See references/vault-config.md

2. AAP Credential Setup (Ansible)

# Vault SSH credential
- name: Create Vault SSH Credential
  ansible.controller.credential:
    name: "vault_ssh_{{ tenant }}"
    credential_type: "HashiCorp Vault Signed SSH"
    inputs:
      url: "{{ vault_url }}"
      role_id: "{{ role_id }}"
      secret_id: "{{ secret_id }}"
      default_auth_path: "approle"

# Machine credential linked to Vault
- name: Create Machine Credential
  ansible.controller.credential:
    name: "machine_{{ tenant }}"
    credential_type: "Machine"
    inputs:
      username: "aap"
  register: machine_cred

- name: Link to Vault Source
  ansible.controller.credential_input_source:
    input_field_name: "ssh_public_key_data"
    target_credential: "{{ machine_cred.id }}"
    source_credential: "vault_ssh_{{ tenant }}"
    metadata:
      role: "{{ tenant }}"
      secret_path: "ssh"

Full AAP config: See references/aap-config.md

3. Golden Image (Packer + Ansible)

Target hosts must trust Vault's SSH CA:

- name: Download Vault SSH CA
  ansible.builtin.get_url:
    url: "{{ vault_url }}/v1/ssh/public_key"
    headers:
      X-Vault-Namespace: "{{ vault_namespace }}"
    dest: /etc/ssh/trusted-user-ca-keys.pem

- name: Configure SSH CA Trust
  ansible.builtin.lineinfile:
    path: /etc/ssh/sshd_config
    line: "TrustedUserCAKeys /etc/ssh/trusted-user-ca-keys.pem"
  notify: Restart SSH

Full image config: See references/golden-image.md

Multi-Tenancy

Map tenants across both platforms:

| AAP | Vault | |-----|-------| | Organization | Namespace | | Credential | AppRole + SSH Role | | Team | Entity/Group |

Policy templating for dynamic paths:

path "ssh/sign/{{identity.entity.name}}" {
  capabilities = ["read", "update"]
}

Credential Rotation

Self-Rotation (Recommended)

AAP job rotates its own secret_id daily:

# Vault policy allowing self-rotation
path "auth/approle/role/{{ tenant }}/secret-id" {
  capabilities = ["update"]
}

Schedule AAP job template to run rotation playbook.

Troubleshooting

| Issue | Check | |-------|-------| | Auth failure | Verify role_id/secret_id, check namespace | | Signing failure | Verify allowed_users includes target user | | SSH rejected | Verify TrustedUserCAKeys on target, check CA fingerprint | | Certificate expired | Check TTL settings (default 2hr) |

References

• references/vault-config.md - Complete Terraform for Vault SSH + AppRole
• references/aap-config.md - Complete Ansible for AAP credentials
• references/golden-image.md - Packer/Ansible for target host images