Octavia Certificate Configuration Guide

This document is intended for Octavia administrators setting up certificate authorities for the two-way TLS authentication used in Octavia for command and control of Amphora.

This guide does not apply to the configuration of TERMINATED_TLS listeners on load balancers. See the Load Balancing Cookbook for instructions on creating TERMINATED_TLS listeners.

Two-way TLS Authentication in Octavia

The Octavia controller processes communicate with the Amphora over a TLS connection much like an HTTPS connection to a website. However, Octavia validates that both sides are trusted by doing a two-way TLS authentication.

Note

This is a simplification of the full TLS handshake process. See the TLS 1.3 RFC 8446 for the full handshake.

Phase One

When a controller process, such as the Octavia worker process, connects to an Amphora, the Amphora will present its server certificate to the controller. The controller will then validate it against the server Certificate Authority (CA) certificate stored on the controller. If the presented certificate is validated against the server CA certificate, the connection goes into phase two of the two-way TLS authentication.

Phase Two

Once phase one is complete, the controller will present its client certificate to the Amphora. The Amphora will then validate the certificate against the client CA certificate stored inside the Amphora. If this certificate is successfully validated, the rest of the TLS handshake will continue to establish the secure communication channel between the controller and the Amphora.

Certificate Lifecycles

The server certificates are uniquely generated for each amphora by the controller using the server certificate authority certificates and keys. These server certificates are automatically rotated by the Octavia housekeeping controller process as they near expiration.

The client certificates are used for the Octavia controller processes. These are managed by the operator and due to their use on the control plane of the cloud, typically have a long lifetime.

See the Operator Maintenance Guide for more information about the certificate lifecycles.

Creating the Certificate Authorities

As discussed above, this configuration uses two certificate authorities; one for the server certificates, and one for the client certificates.

Note

Technically Octavia can be run using just one certificate authority by using it to issue certificates for both roles. However, this weakens the security as a server certificate from an amphora could be used to impersonate a controller. We recommend you use two certificate authorities for all deployments outside of testing.

For this document we are going to setup simple OpenSSL based certificate authorities. However, any standards compliant certificate authority software can be used to create the required certificates.

  1. Create a working directory for the certificate authorities. Make sure to set the proper permissions on this directory such that others cannot access the private keys, random bits, etc. being generated here.

    $ mkdir certs
$ chmod 700 certs
$ cd certs

  2. Create the OpenSSL configuration file. This can be shared between the two certificate authorities.

    $ vi openssl.cnf

    # OpenSSL root CA configuration file.

[ ca ]
# `man ca`
default_ca = CA_default

[ CA_default ]
# Directory and file locations.
dir               = ./
certs             = $dir/certs
crl_dir           = $dir/crl
new_certs_dir     = $dir/newcerts
database          = $dir/index.txt
serial            = $dir/serial
RANDFILE          = $dir/private/.rand

# The root key and root certificate.
private_key       = $dir/private/ca.key.pem
certificate       = $dir/certs/ca.cert.pem

# For certificate revocation lists.
crlnumber         = $dir/crlnumber
crl               = $dir/crl/ca.crl.pem
crl_extensions    = crl_ext
default_crl_days  = 30

# SHA-1 is deprecated, so use SHA-2 instead.
default_md        = sha256

name_opt          = ca_default
cert_opt          = ca_default
default_days      = 3650
preserve          = no
policy            = policy_strict

[ policy_strict ]
# The root CA should only sign intermediate certificates that match.
# See the POLICY FORMAT section of `man ca`.
countryName             = match
stateOrProvinceName     = match
organizationName        = match
organizationalUnitName  = optional
commonName              = supplied
emailAddress            = optional

[ req ]
# Options for the `req` tool (`man req`).
default_bits        = 2048
distinguished_name  = req_distinguished_name
string_mask         = utf8only

# SHA-1 is deprecated, so use SHA-2 instead.
default_md          = sha256

# Extension to add when the -x509 option is used.
x509_extensions     = v3_ca

[ req_distinguished_name ]
# See <https://en.wikipedia.org/wiki/Certificate_signing_request>.
countryName                     = Country Name (2 letter code)
stateOrProvinceName             = State or Province Name
localityName                    = Locality Name
0.organizationName              = Organization Name
organizationalUnitName          = Organizational Unit Name
commonName                      = Common Name
emailAddress                    = Email Address

# Optionally, specify some defaults.
countryName_default             = US
stateOrProvinceName_default     = Oregon
localityName_default            =
0.organizationName_default      = OpenStack
organizationalUnitName_default  = Octavia
emailAddress_default            =
commonName_default              = example.org

[ v3_ca ]
# Extensions for a typical CA (`man x509v3_config`).
subjectKeyIdentifier = hash
authorityKeyIdentifier = keyid:always,issuer
basicConstraints = critical, CA:true
keyUsage = critical, digitalSignature, cRLSign, keyCertSign

[ usr_cert ]
# Extensions for client certificates (`man x509v3_config`).
basicConstraints = CA:FALSE
nsCertType = client, email
nsComment = "OpenSSL Generated Client Certificate"
subjectKeyIdentifier = hash
authorityKeyIdentifier = keyid,issuer
keyUsage = critical, nonRepudiation, digitalSignature, keyEncipherment
extendedKeyUsage = clientAuth, emailProtection

[ server_cert ]
# Extensions for server certificates (`man x509v3_config`).
basicConstraints = CA:FALSE
nsCertType = server
nsComment = "OpenSSL Generated Server Certificate"
subjectKeyIdentifier = hash
authorityKeyIdentifier = keyid,issuer:always
keyUsage = critical, digitalSignature, keyEncipherment
extendedKeyUsage = serverAuth

[ crl_ext ]
# Extension for CRLs (`man x509v3_config`).
authorityKeyIdentifier=keyid:always

  3. Make any locally required configuration changes to the openssl.cnf. Some settings to consider are:

    • The default certificate lifetime is 10 years.

    • The default bit length is 2048.

  4. Make directories for the two certificate authorities.

    $ mkdir client_ca
$ mkdir server_ca

  5. Starting with the server certificate authority, prepare the CA.

    $ cd server_ca
$ mkdir certs crl newcerts private
$ chmod 700 private
$ touch index.txt
$ echo 1000 > serial

  6. Create the server CA key.

    • You will need to specify a passphrase to protect the key file.

    $ openssl genpkey -algorithm RSA -out private/ca.key.pem -aes-128-cbc -pkeyopt rsa_keygen_bits:4096
$ chmod 400 private/ca.key.pem

  7. Create the server CA certificate.

    • You will need to specify the passphrase used in step 6.

    • You will also be asked to provide details for the certificate. These are up to you and should be appropriate for your organization.

    • You may want to mention this is the server CA in the common name field.

    • Since this is the CA certificate, you might want to give it a very long lifetime, such as twenty years shown in this example command.

    $ openssl req -config ../openssl.cnf -key private/ca.key.pem -new -x509 -days 7300 -sha256 -extensions v3_ca -out certs/ca.cert.pem

  8. Moving to the client certificate authority, prepare the CA.

    $ cd ../client_ca
$ mkdir certs crl csr newcerts private
$ chmod 700 private
$ touch index.txt
$ echo 1000 > serial

  9. Create the client CA key.

    • You will need to specify a passphrase to protect the key file.

    $ openssl genpkey -algorithm RSA -out private/ca.key.pem -aes-128-cbc -pkeyopt rsa_keygen_bits:4096
$ chmod 400 private/ca.key.pem

  10. Create the client CA certificate.

    • You will need to specify the passphrase used in step 9.

    • You will also be asked to provide details for the certificate. These are up to you and should be appropriate for your organization.

    • You may want to mention this is the client CA in the common name field.

    • Since this is the CA certificate, you might want to give it a very long lifetime, such as twenty years shown in this example command.

    $ openssl req -config ../openssl.cnf -key private/ca.key.pem -new -x509 -days 7300 -sha256 -extensions v3_ca -out certs/ca.cert.pem

  11. Create a key for the client certificate to use.

    • You can create one certificate and key to be used by all of the controllers or you can create a unique certificate and key for each controller.

    • You will need to specify a passphrase to protect the key file.

    $ openssl genpkey -algorithm RSA -out private/ca.key.pem -aes-128-cbc -pkeyopt rsa_keygen_bits:2048

  12. Create the certificate request for the client certificate used on the controllers.

    • You will need to specify the passphrase used in step 11.

    • You will also be asked to provide details for the certificate. These are up to you and should be appropriate for your organization.

    • You must fill in the common name field.

    • You may want to mention this is the client certificate in the common name field, or the individual controller information.

    $ openssl req -config ../openssl.cnf -new -sha256 -key private/client.key.pem -out csr/client.csr.pem

  13. Sign the client certificate request.

    • You will need to specify the CA passphrase used in step 9.

    • Since this certificate is used on the control plane, you might want to give it a very long lifetime, such as twenty years shown in this example command.

    $ openssl ca -config ../openssl.cnf -extensions usr_cert -days 7300 -notext -md sha256 -in csr/client.csr.pem -out certs/client.cert.pem

  14. Create a concatenated client certificate and key file.

    • You will need to specify the CA passphrase used in step 11.

    $ openssl rsa -in private/client.key.pem -out private/client.cert-and-key.pem
$ cat certs/client.cert.pem >> private/client.cert-and-key.pem

Configuring Octavia

In this section we will configure Octavia to use the certificates and keys created during the Creating the Certificate Authorities section.

  1. Copy the required files over to your Octavia controllers.

    • Only the Octavia worker, health manager, and housekeeping processes will need access to these files.

    • The first command should return you to the “certs” directory created in step 1 of the Creating the Certificate Authorities section.

    • These commands assume you are running the octavia processes under the “octavia” user.

    • Note, some of these steps should be run with “sudo” and are indicated by the “#” prefix.

    $ cd ..
# mkdir /etc/octavia/certs
# chmod 700 /etc/octavia/certs
# cp server_ca/private/ca.key.pem /etc/octavia/certs/server_ca.key.pem
# chmod 700 /etc/octavia/certs/server_ca.key.pem
# cp server_ca/certs/ca.cert.pem /etc/octavia/certs/server_ca.cert.pem
# cp client_ca/certs/ca.cert.pem /etc/octavia/certs/client_ca.cert.pem
# cp client_ca/private/client.cert-and-key.pem /etc/octavia/certs/client.cert-and-key.pem
# chmod 700 /etc/octavia/certs/client.cert-and-key.pem
# chown -R octavia.octavia /etc/octavia/certs

  2. Configure the [certificates] section of the octavia.conf file.

    • Only the Octavia worker, health manager, and housekeeping processes will need these settings.

    • The “<server CA passphrase>” should be replaced with the passphrase that was used in step 6 of the Creating the Certificate Authorities section.

    [certificates]
cert_generator = local_cert_generator
ca_certificate = /etc/octavia/certs/server_ca.cert.pem
ca_private_key = /etc/octavia/certs/server_ca.key.pem
ca_private_key_passphrase = <server CA key passphrase>

  3. Configure the [controller_worker] section of the octavia.conf file.

    • Only the Octavia worker, health manager, and housekeeping processes will need these settings.

    [controller_worker]
client_ca = /etc/octavia/certs/client_ca.cert.pem

  4. Configure the [haproxy_amphora] section of the octavia.conf file.

    • Only the Octavia worker, health manager, and housekeeping processes will need these settings.

    [haproxy_amphora]
client_cert = /etc/octavia/certs/client.cert-and-key.pem
server_ca = /etc/octavia/certs/server_ca.cert.pem

  5. Start the controller processes.

    # systemctl start octavia-worker
# systemctl start octavia-healthmanager
# systemctl start octavia-housekeeping