Add OpenStack deploy provider

deployhooks.md

@@ -579,4 +579,39 @@ Certificate should now show up in "Control Panel" -> "Security" -> "Certificates
 Use your browser to sign in with the admin account you want to use. When entering the OTP code, check the "Save this device" checkbox and continue. Get the device ID from the cookie `did` (Left click on the lock to the left side of the URL -> Cookies and Copy the content of the `did` cookie). Set the environment variable to the cookie value:
 ```sh
 export SYNO_DID=A1Bjk...
-```
+```
+
+## 21. Deploy the cert to OpenStack Barbican
+
+This provider supports [OpenStack Barbican](https://docs.openstack.org/barbican)
+secret manager.
+
+Report any issues to https://github.com/acmesh-official/acme.sh/issues/3056
+
+This provider requires the OpenStack Client (python-openstackclient) and
+Barbican client (python-barbicanclient) be installed and available in your path.
+
+It also requires you use Keystone V3 credentials, which can be either password or
+application credentials provided as environment variables.
+
+You will most likely want to source your OpenStack RC file to set your environment variables:
+
+```
+. openrc.sh
+```
+or manually like:
+```
+export OS_AUTH_URL=https://keystone.example.com:5000/
+export OS_USERNAME=<username>
+export OS_PASSWORD=<password>
+export OS_PROJECT_NAME=<project name>
+export OS_PROJECT_DOMAIN_NAME=Default
+export OS_USER_DOMAIN_NAME=Default
+```
+
+To deploy a cert:
+```
+acme.sh --deploy -d example.com --deploy-hook openstack
+```
+
+Your OpenStack credentials will be saved to `~/.acme.sh/account.conf`.