Chapter 4. Viewing application composition by using the Topology view

• You have logged in to the web console.
• You have the appropriate roles and permissions in a project to create applications and other workloads in OpenShift Container Platform.
• You have created and deployed an application on OpenShift Container Platform using the Developer perspective.
• You are in the Developer perspective.

• Use the Find by name field to find the required components. Search results may appear outside of the visible area; click Fit to Screen from the lower-left toolbar to resize the Topology view to show all components.

• Use the Display Options drop-down list to configure the Topology view of the various application groupings. The options are available depending on the types of components deployed in the project:

  • Expand group

    • Virtual Machines: Toggle to show or hide the virtual machines.
    • Application Groupings: Clear to condense the application groups into cards with an overview of an application group and alerts associated with it.
    • Helm Releases: Clear to condense the components deployed as Helm Release into cards with an overview of a given release.
    • Knative Services: Clear to condense the Knative Service components into cards with an overview of a given component.
    • Operator Groupings: Clear to condense the components deployed with an Operator into cards with an overview of the given group.

  • Show elements based on Pod Count or Labels

    • Pod Count: Select to show the number of pods of a component in the component icon.
    • Labels: Toggle to show or hide the component labels.

• Click Open URL ( ) to see your application exposed by the route on a public URL.

• Click Edit Source code to access your source code and modify it.

  Note

  This feature is available only when you create applications using the From Git, From Catalog, and the From Dockerfile options.

• Hover your cursor over the lower left icon on the pod to see the name of the latest build and its status. The status of the application build is indicated as New ( ), Pending ( ), Running ( ), Completed ( ), Failed ( ), and Canceled ( ).

• The status or phase of the pod is indicated by different colors and tooltips as:

  • Running ( ): The pod is bound to a node and all of the containers are created. At least one container is still running or is in the process of starting or restarting.
  • Not Ready ( ): The pods which are running multiple containers, not all containers are ready.
  • Warning( ): Containers in pods are being terminated, however termination did not succeed. Some containers may be other states.
  • Failed( ): All containers in the pod terminated but least one container has terminated in failure. That is, the container either exited with non-zero status or was terminated by the system.
  • Pending( ): The pod is accepted by the Kubernetes cluster, but one or more of the containers has not been set up and made ready to run. This includes time a pod spends waiting to be scheduled as well as the time spent downloading container images over the network.
  • Succeeded( ): All containers in the pod terminated successfully and will not be restarted.
  • Terminating( ): When a pod is being deleted, it is shown as Terminating by some kubectl commands. Terminating status is not one of the pod phases. A pod is granted a graceful termination period, which defaults to 30 seconds.
  • Unknown( ): The state of the pod could not be obtained. This phase typically occurs due to an error in communicating with the node where the pod should be running.

• After you create an application and an image is deployed, the status is shown as Pending. After the application is built, it is displayed as Running.

  Figure 4.1. Application topology

  

  The application resource name is appended with indicators for the different types of resource objects as follows:

  • CJ: CronJob
  • D: Deployment
  • DC: DeploymentConfig
  • DS: DaemonSet
  • J: Job
  • P: Pod
  • SS: StatefulSet

  • (Knative): A serverless application

    Note

    Serverless applications take some time to load and display on the Graph view. When you deploy a serverless application, it first creates a service resource and then a revision. After that, it is deployed and displayed on the Graph view. If it is the only workload, you might be redirected to the Add page. After the revision is deployed, the serverless application is displayed on the Graph view.

• Click on the component node to see the Overview panel to the right. Use the Details tab to:

  • Scale your pods using the up and down arrows to increase or decrease the number of instances of the application manually. For serverless applications, the pods are automatically scaled down to zero when idle and scaled up depending on the channel traffic.
  • Check the Labels, Annotations, and Status of the application.

• Click the Resources tab to:

  • See the list of all the pods, view their status, access logs, and click on the pod to see the pod details.
  • See the builds, their status, access logs, and start a new build if needed.
  • See the services and routes used by the component.

  For serverless applications, the Resources tab provides information on the revision, routes, and the configurations used for that component.

Prerequisites

• You have created and deployed minimum two or more components on OpenShift Container Platform using the Developer perspective.

Procedure

• To add a service to the existing application group, press Shift+ drag it to the existing application group. Dragging a component and adding it to an application group adds the required labels to the component.

  Figure 4.4. Application grouping