demos

OCP 4 Image Mangement - Demos

There are a handful of things which can be demoed to show high-level configuration and functionality:

• Configuration and common options
• Access from outside the OpenShift cluster
• Metrics

Registry configuration and common options

To view the operator configuration, use the command oc get -o yaml configs.imageregistry.operator.openshift.io/instance -n openshift-image-registry.

[you@bastion ~]$ oc get -o yaml configs.imageregistry.operator.openshift.io/instance -n openshift-image-registry
apiVersion: imageregistry.operator.openshift.io/v1
kind: Config
metadata:
    [...]
spec:
    httpSecret: 20cb9a6ffNotAvaLIdSecREt3978cc6ec806e
    logging: 2
    managementState: Managed
    proxy: {}
    replicas: 1
    requests:
    read: {}
    write: {}
    storage:
    s3:
        bucket: image-registry--babcd3c9183b44a1aa1c24ff8c9e53f3-564e780d33981
        region: us-east-1
status:
    conditions:
    - lastTransitionTime: 2019-02-18T16:16:00Z
    message: Deployment has minimum availability
    status: "True"
    type: Available
    [...]
    generations: null
    internalRegistryHostname: image-registry.openshift-image-registry.svc:5000
    observedGeneration: 1
    readyReplicas: 0
    storage:
    s3:
        bucket: image-registry--babcd3c9183b44a1aa1c24ff8c9e53f3-564e780d33981
        region: us-east-1
    storageManaged: true
    version: ""

The data in the spec section contains configuration information which has been added by the operator or administrator during the course of deployment and/or execution.

The data in the status section reflects the current status of the registry. This includes status condition changes, the number of replicas which exist, the type of storage being used and its real-time configuration.

Some interesting highlights of the configuration include:

• spec.logging - Set to a value from 0 (lowest) to 3 (highest) to indicate how verbose the logs should be.
• spec.replicas - The number of replicas which should be deployed.
• spec.storage.s3 - Allows the customization of certain aspects of the S3 bucket and storage properties being used. S3 is currently the only supported storage type.

Accessing the registry externally

The image registry operator does not create a route by default. The registry is accessible internally using the service name image-registry on the standard port 5000. There are two options for enabling access to the registry from outside the OpenShift cluster:

1. Create the default route

   When specified, the operator will create a default route for the registry with the name default-route-openshift-image-registry.<domain name>. To request this route be created, edit the configuration using the below command:

   oc patch configs.imageregistry.operator.openshift.io/instance -n openshift-image-registry --type merge --patch '{ "spec": { "defaultRoute": true } }'

   After modifying the operator configuration, the route is created:

   [you@bastion ~]$ oc get route -n openshift-image-registry
   NAME            HOST/PORT                                                                        PATH   SERVICES         PORT    TERMINATION   WILDCARD
   default-route   default-route-openshift-image-registry.apps.cluster-a407.a407.ocp4.opentlc.com          image-registry   <all>   reencrypt        None

2. Create one or more routes defined by the administrator

   If you want to use custom route names, you can provide one or more as a part of the configuration as well. To create non-default routes, we need to supply three pieces of data:

   • A name

   • The hostname desired

   • A secret with the certificate information

     The secret must have three items in it: the certificate, the key, and the CA certificate.

     apiVersion: v1
     kind: Secret
     metadata:
       name: route-certificate
       namespace: openshift-image-registry
     data:
       tls.crt: <certificate>
       tls.key: <key>
       tls.cacrt: <ca_certificate>
     type: Opaque

   Once the secret has been created, modifying the configuration can be done via patch:

   oc patch configs.imageregistry.operator.openshift.io/instance -n openshift-image-registry --type merge --patch '
     {
       "spec": {
          "routes": [
             {
               "name": "registry",
               "hostname": "registry.yourdomain.tld",
               "secret": "route-certificate"
             }
           ]
        }
     }'

   Here is the result of the route being created:

   [you@bastion ~]$ oc get route
   NAME            HOST/PORT                                                                        PATH   SERVICES         PORT    TERMINATION   WILDCARD
   registry        registry.apps.cluster-a407.a407.ocp4.opentlc.com                                        image-registry   <all>   reencrypt     None

Registry metrics

Metrics are configured to be collected by the operator and accessible from the Prometheus endpoint of your OpenShift cluster. To view the Prometheus dashboard, you can click the link at Monitoring -> Metrics or retrieve the route using the command oc get route prometheus-k8s -n openshift-monitoring. Using Prometheus' native interface, we can create simple charts to view the status. You will want to use Grafana to create more robust dashboards for monitoring the state and health of your registry deployment in a production environment.

In the Promethus UI, select the "Graph" option at the top, and again in the ensuing sub-tab.

From here, we can find the metrics which pertain to the image registry. All of the metrics are in the Prometheus' namespace imagemetrics, so if we begin typing that value into the box, the avaialble metrics will be shown:

Select a metric, in this case we've used imageregistry_http_request_duration_seconds, then press the "Execute" button. The result will be a graph showing the last hour's worth of values for that metric.

Note: There are three lines in the above image because the values are plotted as quantiles, specifically the 50th, 90th, and 99th.