PKI secrets engine - quick start - root CA setup

This document provides a brief overview of setting up an OpenBao PKI Secrets Engine with a Root CA certificate.

Mount the backend

The first step to using the PKI backend is to mount it. Unlike the kv backend, the pki backend is not mounted by default.

$ bao secrets enable pki
Successfully mounted 'pki' at 'pki'!

Configure a CA certificate

Next, OpenBao must be configured with a CA certificate and associated private key. We'll take advantage of the backend's self-signed root generation support, but OpenBao also supports generating an intermediate CA (with a CSR for signing) or setting a PEM-encoded certificate and private key bundle directly into the backend.

Generally you'll want a root certificate to only be used to sign CA intermediate certificates, but for this example we'll proceed as if you will issue certificates directly from the root. As it's a root, we'll want to set a long maximum life time for the certificate; since it honors the maximum mount TTL, first we adjust that:

$ bao secrets tune -max-lease-ttl=87600h pki
Successfully tuned mount 'pki'!

That sets the maximum TTL for secrets issued from the mount to 10 years. (Note that roles can further restrict the maximum TTL.)

Now, we generate our root certificate:

$ bao write pki/root/generate/internal common_name=myopenbao.com ttl=87600h
Key             Value
---             -----
certificate     -----BEGIN CERTIFICATE-----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-----END CERTIFICATE-----
expiration      1828121029
issuing_ca      -----BEGIN CERTIFICATE-----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-----END CERTIFICATE-----
serial_number   26:aa:f0:ff:d1:03:65:ba:78:0c:4c:5a:2e:38:74:bd:20:07:c8:18

The returned certificate is purely informational; it and its private key are safely stored in the backend mount.

Set URL configuration

Generated certificates can have the CRL location and the location of the issuing certificate encoded. These values must be set manually and typically to FQDN associated to the OpenBao server, but can be changed at any time.

$ bao write pki/config/urls issuing_certificates="http://openbao.example.com:8200/v1/pki/ca" crl_distribution_points="http://openbao.example.com:8200/v1/pki/crl"
Success! Data written to: pki/ca/urls

Configure a role

The next step is to configure a role. A role is a logical name that maps to a policy used to generate those credentials. For example, let's create an "example-dot-com" role:

$ bao write pki/roles/example-dot-com \
    allowed_domains=example.com \
    allow_subdomains=true max_ttl=72h
Success! Data written to: pki/roles/example-dot-com

Issue certificates

By writing to the roles/example-dot-com path we are defining the example-dot-com role. To generate a new certificate, we simply write to the issue endpoint with that role name: OpenBao is now configured to create and manage certificates!

$ bao write pki/issue/example-dot-com \
    common_name=blah.example.com
Key                 Value
---                 -----
certificate         -----BEGIN CERTIFICATE-----
MIIDvzCCAqegAwIBAgIUWQuvpMpA2ym36EoiYyf3Os5UeIowDQYJKoZIhvcNAQEL
BQAwFjEUMBIGA1UEAxMLbXl2YXVsdC5jb20wHhcNMTcxMjA4MTkyNDA1WhcNMTcx
MjExMTkyNDM1WjAbMRkwFwYDVQQDExBibGFoLmV4YW1wbGUuY29tMIIBIjANBgkq
hkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEA1CU93lVgcLXGPxRGTRT3GM5wqytCo7Z6
gjfoHyKoPCAqjRdjsYgp1FMvumNQKjUat5KTtr2fypbOnAURDCh4bN/omcj7eAqt
ldJ8mf8CtKUaaJ1kp3R6RRFY/u96BnmKUG8G7oDeEDsKlXuEuRcNbGlGF8DaM/O1
HFa57cM/8yFB26Nj5wBoG5Om6ee5+W+14Qee8AB6OJbsf883Z+zvhJTaB0QM4ZUq
uAMoMVEutWhdI5EFm5OjtMeMu2U+iJl2XqqgQ/JmLRjRdMn1qd9TzTaVSnjoZ97s
jHK444Px1m45einLqKUJ+Ia2ljXYkkItJj9Ut6ZSAP9fHlAtX84W3QIDAQABo4H/
MIH8MA4GA1UdDwEB/wQEAwIDqDAdBgNVHSUEFjAUBggrBgEFBQcDAQYIKwYBBQUH
AwIwHQYDVR0OBBYEFH/YdObW6T94U0zuU5hBfTfU5pt1MB8GA1UdIwQYMBaAFECK
dYM4gDbMkxRZA2wR4f/yNhQUMDsGCCsGAQUFBwEBBC8wLTArBggrBgEFBQcwAoYf
aHR0cDovLzEyNy4wLjAuMTo4MjAwL3YxL3BraS9jYTAbBgNVHREEFDASghBibGFo
LmV4YW1wbGUuY29tMDEGA1UdHwQqMCgwJqAkoCKGIGh0dHA6Ly8xMjcuMC4wLjE6
ODIwMC92MS9wa2kvY3JsMA0GCSqGSIb3DQEBCwUAA4IBAQCDXbHV68VayweB2tkb
KDdCaveaTULjCeJUnm9UT/6C0YqC/RxTAjdKFrilK49elOA3rAtEL6dmsDP2yH25
ptqi2iU+y99HhZgu0zkS/p8elYN3+l+0O7pOxayYXBkFf5t0TlEWSTb7cW+Etz/c
MvSqx6vVvspSjB0PsA3eBq0caZnUJv2u/TEiUe7PPY0UmrZxp/R/P/kE54yI3nWN
4Cwto6yUwScOPbVR1d3hE2KU2toiVkEoOk17UyXWTokbG8rG0KLj99zu7my+Fyre
sjV5nWGDSMZODEsGxHOC+JgNAC1z3n14/InFNOsHICnA5AnJzQdSQQjvcZHN2NyW
+t4f
-----END CERTIFICATE-----
issuing_ca          -----BEGIN CERTIFICATE-----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-----END CERTIFICATE-----
private_key         -----BEGIN RSA PRIVATE KEY-----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-----END RSA PRIVATE KEY-----
private_key_type    rsa
serial_number       59:0b:af:a4:ca:40:db:29:b7:e8:4a:22:63:27:f7:3a:ce:54:78:8a

OpenBao has now generated a new set of credentials using the example-dot-com role configuration. Here we see the dynamically generated private key and certificate.

Using ACLs, it is possible to restrict using the pki backend such that trusted operators can manage the role definitions, and both users and applications are restricted in the credentials they are allowed to read.

If you get stuck at any time, simply run bao path-help pki or with a subpath for interactive help output.

API

The PKI secrets engine has a full HTTP API. Please see the PKI secrets engine API for more details.