Deploying with SSL

TripleO supports deploying with SSL on the public OpenStack endpoints as well as deploying SSL in the internal network for most services.

This document will focus on deployments using network isolation. For more details on deploying that way, see Configuring Network Isolation

Undercloud SSL

To enable SSL with an automatically generated certificate, you must set the generate_service_certificate option in undercloud.conf to True. This will generate a certificate in /etc/pki/tls/certs with a file name that follows the following pattern:


This will be a PEM file in a format that HAProxy can understand (see the HAProxy documentation for more information on this).

Stable Branch

As of the Rocky release, the default is to have TLS enabled through this option.

This option for auto-generating certificates uses Certmonger to request and keep track of the certificate. So you will see a certificate with the ID of undercloud-haproxy-public-cert in certmonger (you can check this by using the sudo getcert list command). Note that this also implies that certmonger will manage the certificate’s lifecycle, so when it needs renewing, certmonger will do that for you.

The default is to use Certmonger’s local CA. So using this option has the side-effect of extracting Certmonger’s local CA to a PEM file that is located in the following path:


This certificate will then be added to the trusted CA chain, since this is needed to be able to use the undercloud’s endpoints with that certificate.

Stable Branch

As of the Rocky release, the default is for TripleO pass this CA certificate to overcloud nodes so it’ll be trusted.


If you need to access the undercloud from outside the node, the aforementioned file is the one you need to add to your trust store. So for RHEL-based systems you need to copy cm-local-ca.pem into /etc/pki/ca-trust/source/anchors/ and subsequently run the command update-ca-trust extract. This will add that CA to your trust store.

However, it is possible to not use certmonger’s local CA. For instance, one can use FreeIPA as the CA by setting the option certificate_generation_ca in undercloud.conf to have ‘IPA’ as the value. This requires the undercloud host to be enrolled as a FreeIPA client, and to define a haproxy/<undercloud FQDN>@<KERBEROS DOMAIN> service in FreeIPA. We also need to set the option service_principal to the relevant value in undercloud.conf. Finally, we need to set the public endpoints to use FQDNs instead of IP addresses, which will also then use an FQDN for the certificate.

To enable an FQDN for the certificate we set the undercloud_public_vip to the desired hostname in undercloud.conf. This will in turn also set the keystone endpoints to relevant values.

Note that the generate_service_certificate option doesn’t take into account the undercloud_service_certificate option and will have precedence over it.

To enable SSL on the undercloud with a pre-created certificate, you must set the undercloud_service_certificate option in undercloud.conf to an appropriate certificate file. Important: The certificate file’s Common Name must be set to the value of undercloud_public_vip in undercloud.conf.

If you do not have a trusted CA signed certificate file, you can alternatively generate a self-signed certificate file using the following command:

openssl genrsa -out privkey.pem 2048

The next command will prompt for some identification details. Most of these don’t matter, but make sure the Common Name entered matches the value of undercloud_public_vip in undercloud.conf:

openssl req -new -x509 -key privkey.pem -out cacert.pem -days 365

Combine the two files into one for HAProxy to use. The order of the files in this command matters, so do not change it:

cat cacert.pem privkey.pem > undercloud.pem

Move the file to a more appropriate location and set the SELinux context:

sudo mkdir /etc/pki/instack-certs
sudo cp undercloud.pem /etc/pki/instack-certs
sudo semanage fcontext -a -t etc_t "/etc/pki/instack-certs(/.*)?"
sudo restorecon -R /etc/pki/instack-certs

undercloud_service_certificate should then be set to /etc/pki/instack-certs/undercloud.pem.

Add the self-signed CA certificate to the undercloud system’s trusted certificate store:

sudo cp cacert.pem /etc/pki/ca-trust/source/anchors/
sudo update-ca-trust extract


If you’re using a self-signed or autogenerated certificate for the undercloud, the overcloud nodes will need to trust it. So the contents of the certificate need to be set in the CAMap as described in “Getting the overcloud to trust CAs” section.

Overcloud SSL

Certificate and Public VIP Configuration

The public VIP of the deployed overcloud needs to be predictable in order for the SSL certificate to be configured properly. There are two options for configuring the certificate:

  1. The certificate’s Common Name can be set to the IP of the public VIP. In this case, the Common Name must match exactly. If the public VIP is, the certificate’s Common Name must also be Wild cards will not work.

  2. The overcloud endpoints can be configured to point at a DNS name. In this case, the certificate’s Common Name must be valid for the FQDN of the overcloud endpoints. Wild cards should work fine. Note that this option also requires pre-configuration of the specified DNS server with the appropriate FQDN and public VIP.

In either case, the public VIP must be explicitly specified as part of the deployment configuration. This can be done by passing an environment file like the following:

    PublicVirtualFixedIPs: [{'ip_address':''}]


If network isolation is not in use, the ControlFixedIPs parameter should be set instead.

The selected IP should fall in the specified allocation range for the public network.

Certificate Details

Self-Signed SSL

It is not recommended that the self-signed certificate is trusted; So for this purpose, having a self-signed CA certificate is a better choice. In this case we will trust the self-signed CA certificate, and not the leaf certificate that will be used for the public VIP; This leaf certificate, however, will be signed by the self-signed CA.

For the self-signed case, just the predictable public VIP method will be documented, as DNS configuration is outside the scope of this document.

Generate a private key:

openssl genrsa -out overcloud-ca-privkey.pem 2048

Generate a self-signed CA certificate. This command will prompt for some identifying information. Most of the fields don’t matter, and the CN should not be the same as the one we’ll give the leaf certificate. You can choose a CN for this such as “TripleO CA”:

openssl req -new -x509 -key overcloud-ca-privkey.pem \
     -out overcloud-cacert.pem -days 365

Add the self-signed CA certificate to the undercloud’s trusted certificate store. Adding this file to the overcloud nodes will be discussed later:

sudo cp overcloud-cacert.pem /etc/pki/ca-trust/source/anchors/
sudo update-ca-trust extract

This certificate location needs to be added to the enabled-tls.yaml file with the parameter PublicTLSCAFile like so:

    PublicTLSCAFile: '/etc/pki/ca-trust/source/anchors/overcloud-cacert.pem'

PublicTLSCAFile ensures the CA Certificate will be added to the clouds.yaml file for the cacert parameter.

Generate the leaf certificate request and key that will be used for the public VIP. To do this, we will create two files for the certificate request. First, we create the server.csr.cnf:

default_bits = 2048
prompt = no
default_md = sha256
distinguished_name = dn

Create v3.ext:

keyUsage = digitalSignature, nonRepudiation, keyEncipherment, dataEncipherment
subjectAltName = @alt_names

Create the Key:

openssl req -new -sha256 -nodes -out server.csr \
-newkey rsa:2048 -keyout server-key.pem \
-config <( cat server.csr.cnf )

Create the certificate:

openssl x509 -req -in server.csr \
-CA overcloud-cacert.pem \
-CAkey overcloud-ca-privkey.pem \
-CAcreateserial -out server-cert.pem \
-days 500 -sha256 -extfile v3.ext

The following is a list of which files generated in the previous steps map to which parameters in the SSL environment files:

overcloud-cacert.pem: SSLRootCertificate
server-key.pem: SSLKey
server-cert.pem: SSLCertificate

The contents of the private key and certificate files must be provided to Heat as part of the deployment command. To do this, there is a sample environment file in tripleo-heat-templates with fields for the file contents.

It is generally recommended that the original copy of tripleo-heat-templates in /usr/share/openstack-tripleo-heat-templates not be altered, since it could be overwritten by a package update at any time. Instead, make a copy of the templates:

cp -r /usr/share/openstack-tripleo-heat-templates ~/ssl-heat-templates

Then edit the enable-tls.yaml environment file. If using the location from the previous command, the correct file would be in ~/ssl-heat-templates/environments/ssl/enable-tls.yaml. Insert the contents of the private key and certificate files in their respective locations.

Stable Branch

In the Pike release the SSL environment files in the top-level environments directory were deprecated and moved to the ssl subdirectory as shown in the example paths. For Ocata and older the paths will still need to refer to the top-level environments. The filenames are all the same, but the ssl directory must be removed from the path.


The certificate and key will be multi-line values, and all of the lines must be indented to the same level.

An abbreviated version of how the file should look:

    SSLCertificate: |
      -----BEGIN CERTIFICATE-----
      -----END CERTIFICATE-----
[rest of file snipped]

SSLKey should look similar, except with the value of the private key.

SSLIntermediateCertificate can be set in the same way if the certificate signer uses an intermediate certificate. Note that the | character must be added as in the other values to indicate that this is a multi-line value.

When using a self-signed certificate or a signer whose certificate is not in the default trust store on the overcloud image it will be necessary to inject the certificate as part of the deploy process. This can be done with the environment file ~/ssl-heat-templates/environments/ssl/inject-trust-anchor.yaml. Insert the contents of the signer’s root CA certificate in the appropriate location, in a similar fashion to what was done for the certificate and key above.

Self-Signed SSL

Injecting the root CA certificate is required for self-signed SSL. The correct value to use is the contents of the overcloud-cacert.pem file.

DNS Endpoint Configuration

When deploying with DNS endpoint addresses, two additional parameters must be passed in a Heat environment file. These are CloudName and DnsServers. To do so, create a new file named something like cloudname.yaml:


Replace the values with ones appropriate for the target environment. Note that the configured DNS server(s) must have an entry for the configured CloudName that matches the public VIP.

In addition, when a DNS endpoint is being used, make sure to pass the tls-endpoints-public-dns.yaml environment to your deploy command. See the examples below.

Deploying an SSL Environment

The enable-tls.yaml file must always be passed to use SSL on the public endpoints. Depending on the specific configuration, additional files will also be needed. Examples of the necessary parameters for different scenarios follow.

IP-based certificate:

-e ~/ssl-heat-templates/environments/ssl/enable-tls.yaml -e ~/ssl-heat-templates/environments/ssl/tls-endpoints-public-ip.yaml

Self-signed IP-based certificate:

-e ~/ssl-heat-templates/environments/ssl/enable-tls.yaml -e ~/ssl-heat-templates/environments/ssl/tls-endpoints-public-ip.yaml -e ~/ssl-heat-templates/environments/ssl/inject-trust-anchor.yaml

DNS-based certificate:

-e ~/ssl-heat-templates/environments/ssl/enable-tls.yaml -e ~/ssl-heat-templates/environments/ssl/tls-endpoints-public-dns.yaml -e ~/cloudname.yaml

Self-signed DNS-based certificate:

-e ~/ssl-heat-templates/environments/ssl/enable-tls.yaml -e ~/ssl-heat-templates/environments/ssl/tls-endpoints-public-dns.yaml -e ~/cloudname.yaml -e ~/ssl-heat-templates/environments/ssl/inject-trust-anchor.yaml

It is also possible to get all your certificates from a CA. For this you need to include the environments/services/haproxy-public-tls-certmonger.yaml environment file.

Getting the overcloud to trust CAs

As mentioned above, it is possible to get the overcloud to trust a CA by using the ~/ssl-heat-templates/environments/ssl/inject-trust-anchor.yaml environment and adding the necessary details there. However, that environment has the restriction that it will only allow you to inject one CA. However, the file ~/ssl-heat-templates/environments/ssl/inject-trust-anchor-hiera.yaml is an alternative that actually supports as many CA certificates as you need.


This is only available since Newton. Older versions of TripleO don’t support this.

This file is a template of how you should fill the CAMap parameter which is passed via parameter defaults. It looks like this:

    content: |
      The content of the CA cert goes here
    content: |
      The content of the CA cert goes here

where first-ca-name and second-ca-name will generate the files first-ca-name.pem and second-ca-name.pem respectively. These files will be stored in the /etc/pki/ca-trust/source/anchors/ directory in each node of the overcloud and will be added to the trusted certificate chain of each of the nodes. You must be careful that the content is a block string in yaml and is in PEM format.

Stable Branch

As of Rocky, the undercloud now defaults to using TLS through the autogenerated certificate. If you’re upgrading your undercloud and had the generate_service_certificate, it also automatically passes the CA certificate via the CAMap parameter.


In some cases, such as when using Ceph, the overcloud needs to trust the undercloud’s CA certificate. If you’re using the default CA in the undercloud, and autogenerated your certificates, you’ll need to copy the contents of /etc/pki/ca-trust/source/anchors/cm-local-ca.pem into the aforementioned CAMap parameter.