Chapter 32. Configuring a custom PKI
Chapter 32. Configuring a custom PKI Some platform components, such as the web console, use Routes for communication and must trust other components' certificates to interact with them. If you are using a custom public key infrastructure (PKI), you must configure it so its privately signed CA certificates are recognized across the cluster. You can leverage the Proxy API to add cluster-wide trusted CA certificates. You must do this either during installation or at runtime. During installation , configure the cluster-wide proxy . You must define your privately signed CA certificates in the install-config.yaml file's additionalTrustBundle setting. The installation program generates a ConfigMap that is named user-ca-bundle that contains the additional CA certificates you defined. The Cluster Network Operator then creates a trusted-ca-bundle ConfigMap that merges these CA certificates with the Red Hat Enterprise Linux CoreOS (RHCOS) trust bundle; this ConfigMap is referenced in the Proxy object's trustedCA field. At runtime , modify the default Proxy object to include your privately signed CA certificates (part of cluster's proxy enablement workflow). This involves creating a ConfigMap that contains the privately signed CA certificates that should be trusted by the cluster, and then modifying the proxy resource with the trustedCA referencing the privately signed certificates' ConfigMap. Note The installer configuration's additionalTrustBundle field and the proxy resource's trustedCA field are used to manage the cluster-wide trust bundle; additionalTrustBundle is used at install time and the proxy's trustedCA is used at runtime. The trustedCA field is a reference to a ConfigMap containing the custom certificate and key pair used by the cluster component. 32.1. Configuring the cluster-wide proxy during installation Production environments can deny direct access to the internet and instead have an HTTP or HTTPS proxy available. You can configure a new OpenShift Container Platform cluster to use a proxy by configuring the proxy settings in the install-config.yaml file. Prerequisites You reviewed the sites that your cluster requires access to and determined whether any of them need to bypass the proxy. By default, all cluster egress traffic is proxied, including calls to hosting cloud provider APIs. You added sites to the Proxy object's spec.noProxy field to bypass the proxy if necessary. Note The Proxy object status.noProxy field is populated with the values of the networking.machineNetwork[].cidr , networking.clusterNetwork[].cidr , and networking.serviceNetwork[] fields from your installation configuration. For installations on Amazon Web Services (AWS), Google Cloud Platform (GCP), Microsoft Azure, and Red Hat OpenStack Platform (RHOSP), the Proxy object status.noProxy field is also populated with the instance metadata endpoint ( 169.254.169.254 ). Procedure Edit your install-config.yaml file and add the proxy settings. For example: apiVersion: v1 baseDomain: my.domain.com proxy: httpProxy: http://<username>:<pswd>@<ip>:<port> 1 httpsProxy: https://<username>:<pswd>@<ip>:<port> 2 noProxy: ec2.<aws_region>.amazonaws.com,elasticloadbalancing.<aws_region>.amazonaws.com,s3.<aws_region>.amazonaws.com 3 additionalTrustBundle: | 4 -----BEGIN CERTIFICATE----- <MY_TRUSTED_CA_CERT> -----END CERTIFICATE----- additionalTrustBundlePolicy: <policy_to_add_additionalTrustBundle> 5 1 A proxy URL to use for creating HTTP connections outside the cluster. The URL scheme must be http . 2 A proxy URL to use for creating HTTPS connections outside the cluster. 3 A comma-separated list of destination domain names, IP addresses, or other network CIDRs to exclude from proxying. Preface a domain with . to match subdomains only. For example, .y.com matches x.y.com , but not y.com . Use * to bypass the proxy for all destinations. If you have added the Amazon EC2 , Elastic Load Balancing , and S3 VPC endpoints to your VPC, you must add these endpoints to the noProxy field. 4 If provided, the installation program generates a config map that is named user-ca-bundle in the openshift-config namespace that contains one or more additional CA certificates that are required for proxying HTTPS connections. The Cluster Network Operator then creates a trusted-ca-bundle config map that merges these contents with the Red Hat Enterprise Linux CoreOS (RHCOS) trust bundle, and this config map is referenced in the trustedCA field of the Proxy object. The additionalTrustBundle field is required unless the proxy's identity certificate is signed by an authority from the RHCOS trust bundle. 5 Optional: The policy to determine the configuration of the Proxy object to reference the user-ca-bundle config map in the trustedCA field. The allowed values are Proxyonly and Always . Use Proxyonly to reference the user-ca-bundle config map only when http/https proxy is configured. Use Always to always reference the user-ca-bundle config map. The default value is Proxyonly . Note The installation program does not support the proxy readinessEndpoints field. Note If the installer times out, restart and then complete the deployment by using the wait-for command of the installer. For example: USD ./openshift-install wait-for install-complete --log-level debug Save the file and reference it when installing OpenShift Container Platform. The installation program creates a cluster-wide proxy that is named cluster that uses the proxy settings in the provided install-config.yaml file. If no proxy settings are provided, a cluster Proxy object is still created, but it will have a nil spec . Note Only the Proxy object named cluster is supported, and no additional proxies can be created. 32.2. Enabling the cluster-wide proxy The Proxy object is used to manage the cluster-wide egress proxy. When a cluster is installed or upgraded without the proxy configured, a Proxy object is still generated but it will have a nil spec . For example: apiVersion: config.openshift.io/v1 kind: Proxy metadata: name: cluster spec: trustedCA: name: "" status: A cluster administrator can configure the proxy for OpenShift Container Platform by modifying this cluster Proxy object. Note Only the Proxy object named cluster is supported, and no additional proxies can be created. Warning Enabling the cluster-wide proxy causes the Machine Config Operator (MCO) to trigger node reboot. Prerequisites Cluster administrator permissions OpenShift Container Platform oc CLI tool installed Procedure Create a config map that contains any additional CA certificates required for proxying HTTPS connections. Note You can skip this step if the proxy's identity certificate is signed by an authority from the RHCOS trust bundle. Create a file called user-ca-bundle.yaml with the following contents, and provide the values of your PEM-encoded certificates: apiVersion: v1 data: ca-bundle.crt: | 1 <MY_PEM_ENCODED_CERTS> 2 kind: ConfigMap metadata: name: user-ca-bundle 3 namespace: openshift-config 4 1 This data key must be named ca-bundle.crt . 2 One or more PEM-encoded X.509 certificates used to sign the proxy's identity certificate. 3 The config map name that will be referenced from the Proxy object. 4 The config map must be in the openshift-config namespace. Create the config map from this file: USD oc create -f user-ca-bundle.yaml Use the oc edit command to modify the Proxy object: USD oc edit proxy/cluster Configure the necessary fields for the proxy: apiVersion: config.openshift.io/v1 kind: Proxy metadata: name: cluster spec: httpProxy: http://<username>:<pswd>@<ip>:<port> 1 httpsProxy: https://<username>:<pswd>@<ip>:<port> 2 noProxy: example.com 3 readinessEndpoints: - http://www.google.com 4 - https://www.google.com trustedCA: name: user-ca-bundle 5 1 A proxy URL to use for creating HTTP connections outside the cluster. The URL scheme must be http . 2 A proxy URL to use for creating HTTPS connections outside the cluster. The URL scheme must be either http or https . Specify a URL for the proxy that supports the URL scheme. For example, most proxies will report an error if they are configured to use https but they only support http . This failure message may not propagate to the logs and can appear to be a network connection failure instead. If using a proxy that listens for https connections from the cluster, you may need to configure the cluster to accept the CAs and certificates that the proxy uses. 3 A comma-separated list of destination domain names, domains, IP addresses (or other network CIDRs), and port numbers to exclude proxying. Note Port numbers are only supported when configuring IPv6 addresses. Port numbers are not supported when configuring IPv4 addresses. Preface a domain with . to match subdomains only. For example, .y.com matches x.y.com , but not y.com . Use * to bypass proxy for all destinations. If you scale up workers that are not included in the network defined by the networking.machineNetwork[].cidr field from the installation configuration, you must add them to this list to prevent connection issues. This field is ignored if neither the httpProxy or httpsProxy fields are set. 4 One or more URLs external to the cluster to use to perform a readiness check before writing the httpProxy and httpsProxy values to status. 5 A reference to the config map in the openshift-config namespace that contains additional CA certificates required for proxying HTTPS connections. Note that the config map must already exist before referencing it here. This field is required unless the proxy's identity certificate is signed by an authority from the RHCOS trust bundle. Save the file to apply the changes. 32.3. Certificate injection using Operators Once your custom CA certificate is added to the cluster via ConfigMap, the Cluster Network Operator merges the user-provided and system CA certificates into a single bundle and injects the merged bundle into the Operator requesting the trust bundle injection. Important After adding a config.openshift.io/inject-trusted-cabundle="true" label to the config map, existing data in it is deleted. The Cluster Network Operator takes ownership of a config map and only accepts ca-bundle as data. You must use a separate config map to store service-ca.crt by using the service.beta.openshift.io/inject-cabundle=true annotation or a similar configuration. Adding a config.openshift.io/inject-trusted-cabundle="true" label and service.beta.openshift.io/inject-cabundle=true annotation on the same config map can cause issues. Operators request this injection by creating an empty ConfigMap with the following label: config.openshift.io/inject-trusted-cabundle="true" An example of the empty ConfigMap: apiVersion: v1 data: {} kind: ConfigMap metadata: labels: config.openshift.io/inject-trusted-cabundle: "true" name: ca-inject 1 namespace: apache 1 Specifies the empty ConfigMap name. The Operator mounts this ConfigMap into the container's local trust store. Note Adding a trusted CA certificate is only needed if the certificate is not included in the Red Hat Enterprise Linux CoreOS (RHCOS) trust bundle. Certificate injection is not limited to Operators. The Cluster Network Operator injects certificates across any namespace when an empty ConfigMap is created with the config.openshift.io/inject-trusted-cabundle=true label. The ConfigMap can reside in any namespace, but the ConfigMap must be mounted as a volume to each container within a pod that requires a custom CA. For example: apiVersion: apps/v1 kind: Deployment metadata: name: my-example-custom-ca-deployment namespace: my-example-custom-ca-ns spec: ... spec: ... containers: - name: my-container-that-needs-custom-ca volumeMounts: - name: trusted-ca mountPath: /etc/pki/ca-trust/extracted/pem readOnly: true volumes: - name: trusted-ca configMap: name: ca-inject items: - key: ca-bundle.crt 1 path: tls-ca-bundle.pem 2 1 ca-bundle.crt is required as the ConfigMap key. 2 tls-ca-bundle.pem is required as the ConfigMap path.
apiVersion: v1 baseDomain: my.domain.com proxy: httpProxy: http://<username>:<pswd>@<ip>:<port> 1 httpsProxy: https://<username>:<pswd>@<ip>:<port> 2 noProxy: ec2.<aws_region>.amazonaws.com,elasticloadbalancing.<aws_region>.amazonaws.com,s3.<aws_region>.amazonaws.com 3 additionalTrustBundle: | 4 -----BEGIN CERTIFICATE----- <MY_TRUSTED_CA_CERT> -----END CERTIFICATE----- additionalTrustBundlePolicy: <policy_to_add_additionalTrustBundle> 5 ./openshift-install wait-for install-complete --log-level debug apiVersion: config.openshift.io/v1 kind: Proxy metadata: name: cluster spec: trustedCA: name: "" status: apiVersion: v1 data: ca-bundle.crt: | 1 <MY_PEM_ENCODED_CERTS> 2 kind: ConfigMap metadata: name: user-ca-bundle 3 namespace: openshift-config 4 oc create -f user-ca-bundle.yaml oc edit proxy/cluster apiVersion: config.openshift.io/v1 kind: Proxy metadata: name: cluster spec: httpProxy: http://<username>:<pswd>@<ip>:<port> 1 httpsProxy: https://<username>:<pswd>@<ip>:<port> 2 noProxy: example.com 3 readinessEndpoints: - http://www.google.com 4 - https://www.google.com trustedCA: name: user-ca-bundle 5 config.openshift.io/inject-trusted-cabundle="true" apiVersion: v1 data: {} kind: ConfigMap metadata: labels: config.openshift.io/inject-trusted-cabundle: "true" name: ca-inject 1 namespace: apache apiVersion: apps/v1 kind: Deployment metadata: name: my-example-custom-ca-deployment namespace: my-example-custom-ca-ns spec: spec: containers: - name: my-container-that-needs-custom-ca volumeMounts: - name: trusted-ca mountPath: /etc/pki/ca-trust/extracted/pem readOnly: true volumes: - name: trusted-ca configMap: name: ca-inject items: - key: ca-bundle.crt 1 path: tls-ca-bundle.pem 2