Chapter 9. Enabling SSL/TLS on the Overcloud

The signing host is the host that generates new certificates and signs them with a certificate authority. If you have never created SSL certificates on the chosen signing host, you might need to initialize the host so that it can sign new certificates.

The /etc/pki/CA/index.txt file stores records of all signed certificates. Check if this file exists. If it does not exist, create an empty file:

$ sudo touch /etc/pki/CA/index.txt

The /etc/pki/CA/serial file identifies the next serial number to use for the next certificate to sign. Check if this file exists. If it does not exist, create a new file with a new starting value:

$ echo '1000' | sudo tee /etc/pki/CA/serial

Normally you sign your SSL/TLS certificates with an external certificate authority. In some situations, you might aim to use your own certificate authority. For example, you might aim to have an internal-only certificate authority.

For example, generate a key and certificate pair to act as the certificate authority:

$ openssl genrsa -out ca.key.pem 4096
$ openssl req  -key ca.key.pem -new -x509 -days 7300 -extensions v3_ca -out ca.crt.pem

The openssl req command asks for certain details about your authority. Enter these details.

This creates a certificate authority file called ca.crt.pem.

For any external clients aiming to communicate using SSL/TLS, copy the certificate authority file to each client that requires access your Red Hat OpenStack Platform environment. Once copied to the client, run the following command on the client to add it to the certificate authority trust bundle:

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

For example, the undercloud requires a copy of the certificate authority file so that it can communicate with the overcloud endpoints during creation.

Run the following commands to generate the SSL/TLS key (server.key.pem), which we use at different points to generate our undercloud or overcloud certificates:

$ openssl genrsa -out server.key.pem 2048

This next procedure creates a certificate signing request for the overcloud. Copy the default OpenSSL configuration file for customization.

$ cp /etc/pki/tls/openssl.cnf .

Edit the custom openssl.cnf file and set SSL parameters to use for the overcloud. An example of the types of parameters to modify include:

[req]
distinguished_name = req_distinguished_name
req_extensions = v3_req

[req_distinguished_name]
countryName = Country Name (2 letter code)
countryName_default = AU
stateOrProvinceName = State or Province Name (full name)
stateOrProvinceName_default = Queensland
localityName = Locality Name (eg, city)
localityName_default = Brisbane
organizationalUnitName = Organizational Unit Name (eg, section)
organizationalUnitName_default = Red Hat
commonName = Common Name
commonName_default = 10.0.0.1
commonName_max = 64

[ v3_req ]
# Extensions to add to a certificate request
basicConstraints = CA:FALSE
keyUsage = nonRepudiation, digitalSignature, keyEncipherment
subjectAltName = @alt_names

[alt_names]
IP.1 = 10.0.0.1
DNS.1 = 10.0.0.1
DNS.2 = myovercloud.example.com

Set the commonName_default to one of the following:

Include the same Public API IP address as an IP entry and a DNS entry in the alt_names section. If also using DNS, include the hostname for the server as DNS entries in the same section. For more information about openssl.cnf, run man openssl.cnf.

Run the following command to generate certificate signing request (server.csr.pem):

$ openssl req -config openssl.cnf -key server.key.pem -new -out server.csr.pem

Make sure to include the SSL/TLS key you created in Section 9.4, “Creating an SSL/TLS Key” for the -key option.

Use the server.csr.pem file to create the SSL/TLS certificate in the next section.

The following command creates a certificate for your undercloud or overcloud:

$ sudo openssl ca -config openssl.cnf -extensions v3_req -days 3650 -in server.csr.pem -out server.crt.pem -cert ca.crt.pem -keyfile ca.key.pem

This command uses:

This results in a certificate named server.crt.pem. Use this certificate in conjunction with the SSL/TLS key from Section 9.4, “Creating an SSL/TLS Key” to enable SSL/TLS.

Copy the enable-tls.yaml environment file from the Heat template collection:

$ cp -r /usr/share/openstack-tripleo-heat-templates/environments/enable-tls.yaml ~/templates/.

Edit this file and make the following changes for these parameters:

If the certificate signer is not in the default trust store on the overcloud image, you must inject the certificate authority into the overcloud image. Copy the inject-trust-anchor.yaml environment file from the heat template collection:

$ cp -r /usr/share/openstack-tripleo-heat-templates/environments/inject-trust-anchor.yaml ~/templates/.

Edit this file and make the following changes for these parameters:

If using a DNS hostname to access the overcloud through SSL/TLS, create a new environment file (~/templates/cloudname.yaml) to define the hostname of the overcloud’s endpoints. Use the following parameters:

An example of the contents for this file:

parameter_defaults:
  CloudName: overcloud.example.com
  DnsServers: ["10.0.0.254"]

The deployment command (openstack overcloud deploy) uses the -e option to add environment files. Add the environment files from this section in the following order:

For example:

$ openstack overcloud deploy --templates [...] -e /home/stack/templates/enable-tls.yaml -e ~/templates/cloudname.yaml -e ~/templates/inject-trust-anchor.yaml -e /usr/share/openstack-tripleo-heat-templates/environments/tls-endpoints-public-dns.yaml

If you need to update certificates in the future:

Once the new certificate content is in place, rerun your deployment command. For example:

$ openstack overcloud deploy --templates [...] -e /home/stack/templates/enable-tls.yaml -e ~/templates/cloudname.yaml -e ~/templates/inject-trust-anchor.yaml -e /usr/share/openstack-tripleo-heat-templates/environments/tls-endpoints-public-dns.yaml