KodeKloud Notes

This guide walks through issuing TLS certificates with the Vault PKI Secrets Engine. We assume you already have a root and intermediate CA configured. For a complete PKI setup, refer to the HashiCorp Learn Portal.

Preconfigured PKI Setup

In this demo environment:

A root CA is mounted at pki-root.
An intermediate CA is mounted at pki.
- We generated a CSR on pki, signed it with pki-root, and then imported the signed certificate back into pki.

Now that the intermediate CA is ready to issue certificates, let’s proceed.

Note

This tutorial skips the initial CA bootstrap. Every organization’s PKI topology differs.
If you need to configure a root or intermediate CA, see the Vault PKI Quickstart.

1. Retrieve the Issuer ID

The intermediate CA’s issuer ID (UUID) is required when creating roles:

vault read -field=default pki/config/issuers

Example output:

330c1480-6be3-3312-93f9-1ef2e4e28429

Save this UUID for your role definition.

2. Create a Role

Define a role named webapp that issues certificates for hcvop.com and its subdomains, with a maximum TTL of 24 hours:

vault write pki/roles/webapp \
  issuer_ref="330c1480-6be3-3312-93f9-1ef2e4e28429" \
  allowed_domains="hcvop.com" \
  allow_subdomains=true \
  max_ttl="24h"

If successful, Vault returns:

Success! Data written to: pki/roles/webapp

CLI Commands Summary

Action	Command	Description
Read issuer ID	`vault read -field=default pki/config/issuers`	Retrieve your intermediate CA’s UUID
Create issuance role	`vault write pki/roles/webapp …`	Configure `webapp` role for SANs

3. Issue a Certificate

Request a certificate for training.hcvop.com using the webapp role:

vault write pki/issue/webapp common_name="training.hcvop.com"

Vault responds with the certificate bundle:

Key              Value
---              -----
certificate      -----BEGIN CERTIFICATE-----
                 MIIDnjCCAoagAwIBAgIUbgbDr7a5Mq...  
                 -----END CERTIFICATE-----
issuing_ca       -----BEGIN CERTIFICATE-----
                 MIIDnjCCoAgAwIBAgIUbgrD7a5Mq...  
                 -----END CERTIFICATE-----
ca_chain         -----BEGIN CERTIFICATE-----
                 MIIDMjCCAhKgAwIBAgIUfns1tob...  
                 -----END CERTIFICATE-----
private_key      -----BEGIN RSA PRIVATE KEY-----
                 MIICXQIBAAKCAQEA/3FLC3UyH47G1tG...  
                 -----END RSA PRIVATE KEY-----
private_key_type rsa
serial_number    16:6b:25:b5:6c:07:d3:38...

Warning

This is the only time Vault returns the private key.
Ensure you store private_key securely—Vault will not expose it again.

4. Using the Vault UI

All of the above operations can also be performed in the Vault web interface.

4.1 Roles List

The image shows a web interface for HashiCorp Vault, specifically the PKI secrets engine, displaying a list of roles with one entry labeled "webapp."

4.2 Issue a Certificate

In the UI form:

Common Name: e.g., certification.hcvop.com
Format: PEM, DER, or PEM bundle
Subject Alternative Names: DNS SANs, IP SANs
TTL: e.g., 72h

The image shows a web interface for issuing a certificate, with fields for common name, format, and subject alternative names (SANs). There are options to generate or cancel the certificate request.

After clicking Generate, the UI displays your certificate and warns you to copy the private key immediately.

4.3 Role Configuration Details

You can view or edit the role’s settings:

The image shows a web interface displaying configuration details for a certificate or security settings, including fields like "Issuer ref," "Signature bits," and "TTL." The interface is part of a tool or application related to security management.

4.4 Certificate Listings

Under Certificates, Vault lists all issued certs with their serial numbers. You can inspect or revoke them here.

The image shows a web interface for HashiCorp Vault, displaying a list of certificates under the "pki" section. The interface includes options for roles, certificates, and configuration.

Summary

Define roles with vault write pki/roles/... to control domain scope and TTL.
Issue certs with vault write pki/issue/..., capturing the private key immediately.
You can perform all tasks via the CLI or the Vault UI.

Watch Video

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Demo PKI Secrets Engine