Chapter 10. Configuring Custom Certificates
10.1. Overview
Administrators can configure custom serving certificates for the public host names of the OpenShift Container Platform API and web console. This can be done during an advanced installation or configured after installation.
10.2. Configuring a Certificate Chain
If a certificate chain is used, then all certificates must be manually concatenated into a single named certificate file. These certificates must be placed in the following order:
- OpenShift Container Platform master host certificate
- Intermediate CA certificate
- Root CA certificate
- Third party certificate
To create this certificate chain, concatenate the certificates into a common file. You must run this command for each certificate and ensure that they are in the previously defined order.
$ cat <certificate>.pem >> ca-chain.cert.pem
10.3. Configuring Custom Certificates During Installation
During advanced installations, custom certificates can be configured using the openshift_master_named_certificates
and openshift_master_overwrite_named_certificates
parameters, which are configurable in the inventory file. More details are available about configuring custom certificates with Ansible.
Custom Certificate Configuration Parameters
openshift_master_overwrite_named_certificates=true 1 openshift_master_named_certificates=[{"certfile": "/path/on/host/to/crt-file", "keyfile": "/path/on/host/to/key-file", "names": ["public-master-host.com"], "cafile": "/path/on/host/to/ca-file"}] 2 openshift_hosted_router_certificate={"certfile": "/path/on/host/to/app-crt-file", "keyfile": "/path/on/host/to/app-key-file", "cafile": "/path/on/host/to/app-ca-file"} 3
- 1
- If you provide a value for the
openshift_master_named_certificates
parameter, set this parameter totrue
. - 2
- Provisions a master API certificate.
- 3
- Provisions a router wildcard certificate.
Example parameters for a master API certificate:
openshift_master_overwrite_named_certificates=true openshift_master_named_certificates=[{"names": ["master.148.251.233.173.nip.io"], "certfile": "/home/cloud-user/master-bundle.cert.pem", "keyfile": "/home/cloud-user/master.148.251.233.173.nip.io.key.pem" ]
Example parameters for a router wildcard certificate:
openshift_hosted_router_certificate={"certfile": "/home/cloud-user/star-apps.148.251.233.173.nip.io.cert.pem", "keyfile": "/home/cloud-user/star-apps.148.251.233.173.nip.io.key.pem", "cafile": "/home/cloud-user/ca-chain.cert.pem"}
10.4. Configuring Custom Certificates for the Web Console or CLI
You can specify custom certificates for the web console and for the CLI through the servingInfo
section of the master configuration file:
-
The
servingInfo.namedCertificates
section serves up custom certificates for the web console. -
The
servingInfo
section serves up custom certificates for the CLI and other API calls.
You can configure multiple certificates this way, and each certificate can be associated with multiple host names, multiple routers, or the OpenShift Container Platform image registry.
A default certificate must be configured in the servingInfo.certFile
and servingInfo.keyFile
configuration sections in addition to namedCertificates
.
The namedCertificates
section should be configured only for the host name associated with the masterPublicURL
and oauthConfig.assetPublicURL
settings in the /etc/origin/master/master-config.yaml file. Using a custom serving certificate for the host name associated with the masterURL
will result in TLS errors as infrastructure components will attempt to contact the master API using the internal masterURL
host.
Custom Certificates Configuration
servingInfo: logoutURL: "" masterPublicURL: https://openshift.example.com:8443 publicURL: https://openshift.example.com:8443/console/ bindAddress: 0.0.0.0:8443 bindNetwork: tcp4 certFile: master.server.crt 1 clientCA: "" keyFile: master.server.key 2 maxRequestsInFlight: 0 requestTimeoutSeconds: 0 namedCertificates: - certFile: wildcard.example.com.crt 3 keyFile: wildcard.example.com.key 4 names: - "openshift.example.com" metricsPublicURL: "https://metrics.os.example.com/hawkular/metrics"
The openshift_master_cluster_public_hostname
and openshift_master_cluster_hostname
parameters in the Ansible inventory file, by default /etc/ansible/hosts
, must be different. If they are the same, the named certificates will fail and you will need to re-install them.
# Native HA with External LB VIPs openshift_master_cluster_hostname=internal.paas.example.com openshift_master_cluster_public_hostname=external.paas.example.com
For more information on using DNS with OpenShift Container Platform, see the DNS installation prerequisites.
This approach allows you to take advantage of the self-signed certificates generated by OpenShift Container Platform and add custom trusted certificates to individual components as needed.
Note that the internal infrastructure certificates remain self-signed, which might be perceived as bad practice by some security or PKI teams. However, any risk here is minimal, as the only clients that trust these certificates are other components within the cluster. All external users and systems use custom trusted certificates.
Relative paths are resolved based on the location of the master configuration file. Restart the server to pick up the configuration changes.
10.5. Configuring a Custom Master Host Certificate
In order to facilitate trusted connections with external users of OpenShift Container Platform, you can provision a named certificate that matches the domain name provided in the openshift_master_cluster_public_hostname
paramater in the Ansible inventory file, by default /etc/ansible/hosts
.
You must place this certificate in a directory accessible to Ansible and add the path in the Ansible inventory file, as follows:
openshift_master_named_certificates=[{"certfile": "/path/to/console.ocp-c1.myorg.com.crt", "keyfile": "/path/to/console.ocp-c1.myorg.com.key", "names": ["console.ocp-c1.myorg.com"]}]
Where the parameter values are:
- certfile is the path to the file that contains the OpenShift Container Platform custom master API certificate.
- keyfile is the path to the file that contains the OpenShift Container Platform custom master API certificate key.
- names is the cluster public hostname.
The file paths must be local to the system where Ansible runs. Certificates are copied to master hosts and are deployed within the /etc/origin/master directory.
When securing the registry, add the service hostnames and IP addresses to the server certificate for the registry. The Subject Alternative Names (SAN) must contain the following.
Two service hostnames:
docker-registry.default.svc.cluster.local docker-registry.default.svc
Service IP address.
For example:
172.30.252.46
Use the following command to get the Docker registry service IP address:
oc get service docker-registry --template='{{.spec.clusterIP}}'
Public hostname.
docker-registry-default.apps.example.com
Use the following command to get the Docker registry public hostname:
oc get route docker-registry --template '{{.spec.host}}'
For example, the server certificate should contain SAN details similar to the following:
X509v3 Subject Alternative Name: DNS:docker-registry-public.openshift.com, DNS:docker-registry.default.svc, DNS:docker-registry.default.svc.cluster.local, DNS:172.30.2.98, IP Address:172.30.2.98
10.6. Configuring a Custom Wildcard Certificate for the Default Router
You can configure the OpenShift Container Platform default router with a default wildcard certificate. A default wildcard certificate provides a convenient way for applications that are deployed in OpenShift Container Platform to use default encryption without needing custom certificates.
Default wildcard certificates are recommended for non-production environments only.
To configure a default wildcard certificate, provision a certificate that is valid for *.<app_domain>
, where <app_domain>
is the value of openshift_master_default_subdomain
in the Ansible inventory file, by default /etc/ansible/hosts
. Once provisioned, place the certificate, key, and ca certificate files on your Ansible host, and add the following line to your Ansible inventory file.
openshift_hosted_router_certificate={"certfile": "/path/to/apps.c1-ocp.myorg.com.crt", "keyfile": "/path/to/apps.c1-ocp.myorg.com.key", "cafile": "/path/to/apps.c1-ocp.myorg.com.ca.crt"}
For example:
openshift_hosted_router_certificate={"certfile": "/home/cloud-user/star-apps.148.251.233.173.nip.io.cert.pem", "keyfile": "/home/cloud-user/star-apps.148.251.233.173.nip.io.key.pem", "cafile": "/home/cloud-user/ca-chain.cert.pem"}
Where the parameter values are:
- certfile is the path to the file that contains the OpenShift Container Platform router wildcard certificate.
- keyfile is the path to the file that contains the OpenShift Container Platform router wildcard certificate key.
- cafile is the path to the file that contains the root CA for this key and certificate. If an intermediate CA is in use, the file should contain both the intermediate and root CA.
If these certificate files are new to your OpenShift Container Platform cluster, run the Ansible deploy_router.yml playbook to add these files to the OpenShift Container Platform configuration files. The playbook adds the certificate files to the /etc/origin/master/ directory.
# ansible-playbook [-i /path/to/inventory] \ /usr/share/ansible/openshift-ansible/playbooks/openshift-hosted/deploy_router.yml
If the certificates are not new, for example, you want to change existing certificates or replace expired certificates, run the following playbook:
ansible-playbook /usr/share/ansible/openshift-ansible/playbooks/redeploy-certificates.yml
For this playbook to run, the certificate names must not change. If the certificate names change, rerun the Ansible deploy_cluster.yml playbook as if the certificates were new.
10.7. Configuring a Custom Certificate for the Image Registry
The OpenShift Container Platform image registry is an internal service that facilitates builds and deployments. Most of the communication with the registry is handled by internal components in OpenShift Container Platform. As such, you should not need to replace the certificate used by the registry service itself.
However, by default, the registry uses routes to allow external systems and users to do pulls and pushes of images. You can use a re-encrypt route with a custom certificate that is presented to external users instead of using the internal, self-signed certificate.
To configure this, add the following lines of code to the [OSEv3:vars] section of the Ansible inventory file, by default /etc/ansible/hosts file. Specify the certificates to use with the registry route.
openshift_hosted_registry_routehost=registry.apps.c1-ocp.myorg.com 1 openshift_hosted_registry_routecertificates={"certfile": "/path/to/registry.apps.c1-ocp.myorg.com.crt", "keyfile": "/path/to/registry.apps.c1-ocp.myorg.com.key", "cafile": "/path/to/registry.apps.c1-ocp.myorg.com-ca.crt"} 2 openshift_hosted_registry_routetermination=reencrypt 3
- 1
- The host name of the registry.
- 2
- The locations of the cacert, cert, and key files.
- certfile is the path to the file that contains the OpenShift Container Platform registry certificate.
- keyfile is the path to the file that contains the OpenShift Container Platform registry certificate key.
- cafile is the path to the file that contains the root CA for this key and certificate. If an intermediate CA is in use, the file should contain both the intermediate and root CA.
- 3
- Specify where encryption is performed:
-
Set to
reencrypt
with a re-encrypt route to terminate encryption at the edge router and re-encrypt it with a new certificate supplied by the destination. -
Set to
passthrough
to terminate encryption at the destination. The destination is responsible for decrypting traffic.
-
Set to
10.8. Configuring a Custom Certificate for a Load Balancer
If your OpenShift Container Platform cluster uses the default load balancer or an enterprise-level load balancer, you can use custom certificates to make the web console and API available externally using a publicly-signed custom certificate. leaving the existing internal certificates for the internal endpoints.
To configure OpenShift Container Platform to use custom certificates in this way:
Edit the
servingInfo
section of the master configuration file:servingInfo: logoutURL: "" masterPublicURL: https://openshift.example.com:8443 publicURL: https://openshift.example.com:8443/console/ bindAddress: 0.0.0.0:8443 bindNetwork: tcp4 certFile: master.server.crt clientCA: "" keyFile: master.server.key maxRequestsInFlight: 0 requestTimeoutSeconds: 0 namedCertificates: - certFile: wildcard.example.com.crt 1 keyFile: wildcard.example.com.key 2 names: - "openshift.example.com" metricsPublicURL: "https://metrics.os.example.com/hawkular/metrics"
NoteConfigure the
namedCertificates
section for only the host name associated with themasterPublicURL
andoauthConfig.assetPublicURL
settings. Using a custom serving certificate for the host name associated with themasterURL
causes in TLS errors as infrastructure components attempt to contact the master API using the internal masterURL host.Specify the
openshift_master_cluster_public_hostname
andopenshift_master_cluster_hostname
paramaters in the Ansible inventory file, by default /etc/ansible/hosts. These values must be different. If they are the same, the named certificates will fail.# Native HA with External LB VIPs openshift_master_cluster_hostname=paas.example.com 1 openshift_master_cluster_public_hostname=public.paas.example.com 2
For information specific to your load balancer environment, refer to the OpenShift Container Platform Reference Architecture for your provider and Custom Certificate SSL Termination (Production).
10.9. Retrofit Custom Certificates into a Cluster
You can retrofit custom master and custom router certificates into an existing OpenShift Container Platform cluster by editing the the Ansible inventory file, by default /etc/ansible/hosts, and running a playbook.
10.9.1. Retrofit Custom Master Certificates into a Cluster
To retrofit custom certificates:
-
Edit the Ansible inventory file to set the
openshift_master_overwrite_named_certificates=true
. Specify the path to the certificate using the
openshift_master_named_certificates
parameter.openshift_master_overwrite_named_certificates=true openshift_master_named_certificates=[{"certfile": "/path/on/host/to/crt-file", "keyfile": "/path/on/host/to/key-file", "names": ["public-master-host.com"], "cafile": "/path/on/host/to/ca-file"}] 1
- 1
- Path to a master API certificate.
Run the following playbook:
ansible-playbook /usr/share/ansible/openshift-ansible/playbooks/redeploy-certificates.yml
10.9.2. Retrofit Custom Router Certificates into a Cluster
To retrofit custom router certificates:
-
Edit the Ansible inventory file to set the
openshift_master_overwrite_named_certificates=true
. Specify the path to the certificate using the
openshift_hosted_router_certificate
parameter.openshift_master_overwrite_named_certificates=true openshift_hosted_router_certificate={"certfile": "/path/on/host/to/app-crt-file", "keyfile": "/path/on/host/to/app-key-file", "cafile": "/path/on/host/to/app-ca-file"} 1
- 1
- Path to a router wildcard certificate.
Run the following playbook:
ansible-playbook /usr/share/ansible/openshift-ansible/playbooks/openshift-hosted/redeploy-router-certificates.yml
10.10. Using Custom Certificates with Other Components
For information on how other components, such as Logging & Metrics, use custom certificates, see Certificate Management.