Summary of "Red Hat Certified OpenShift Administrator Course 05 - Using Openshift CLI OC Client"

Summary of "Red Hat Certified OpenShift Administrator Course 05 - Using OpenShift CLI oc Client"

This video provides a detailed tutorial on using the OpenShift CLI client (oc) to manage and interact with an OpenShift cluster. It emphasizes the power and flexibility of the CLI for automation and cluster management compared to the web GUI.

Main Ideas and Concepts

• Introduction to OpenShift CLI (oc): The CLI is a powerful tool to manage OpenShift clusters, enabling automation and execution of administrative tasks beyond what the GUI offers.
• Downloading and Installing the oc Client:
  • Two main ways to download the oc CLI:
    1. From the OpenShift Web Console under the help/question mark → Command Line Tools.
    2. From the official Red Hat website under product downloads.
  • After downloading, extract the binary files (oc and kubectl).
  • Copy the binaries to /usr/bin for easy access.
  • Verify installation by running oc version and kubectl version.
• Logging into the OpenShift Cluster:
  • Use oc login with username, password, and cluster IP.
  • Switch between projects using oc project <project-name>.
  • Get cluster info with oc cluster-info.
  • Use oc get --raw /apis to see API versions available in the cluster.
• Cluster Operators and Status:
  • Use oc get clusteroperators to check cluster operator status.
  • Healthy operators indicate a healthy cluster.
• Basic oc Commands Overview:
  • oc login - login to the cluster.
  • oc new-project - create a new project.
  • oc new-app - create an application.
  • oc status - view current project status.
  • oc project - switch projects.
  • oc get - list resources.
  • oc describe - detailed info about a resource.
  • oc edit - edit live resources.
  • oc label - add labels to resources.
  • oc expose - expose services or pods.
• Working with Pods:
  • oc get pods lists pods.
  • Use -o wide to get detailed info like IP, node, endpoints.
  • Use -o yaml or -o json to get pod details in YAML or JSON format.
  • Use oc explain pod to get schema and field explanations for pod definition files.
  • Modify pod definitions and apply changes using oc apply -f <file>.
  • Create pods from YAML files and verify changes with oc get pods.
• Namespaces and Resource Filtering:
  • Use -n <namespace> or --namespace=<namespace> to specify namespaces.
  • Use oc get pods --all-namespaces to see pods across all namespaces.
  • Filter resources by labels using oc get pods -l key=value.
  • Use selectors to filter resources by labels.
• Deleting Resources:
  • Delete pods or other resources using oc delete pod <pod-name>.
• Labels and Selectors:
  • Labels can be added to pods or resources for identification.
  • Use selectors to query resources based on labels.
• Resource Groups and Short Names:
  • Resources belong to API groups (e.g., core group).
  • Short names exist for resources (e.g., svc for service) to simplify commands.

Detailed Methodology / Instructions

• Download and install oc CLI:
  1. Log into OpenShift Web Console → Help → Command Line Tools → Download Linux version.
  2. Or download from Red Hat official site → OpenShift client tools.
  3. Extract downloaded archive.
  4. Copy oc and kubectl binaries to /usr/bin using sudo cp.
  5. Verify installation with oc version.
• Login to cluster:

  oc login https://<cluster-ip> -u <username> -p <password>

• Switch projects:

  oc project <project-name>

• Check cluster info:

  oc cluster-info
  oc get clusteroperators

• List pods and resources:

  oc get pods
  oc get pods -o wide
  oc get pods -n <namespace>
  oc get pods --all-namespaces

• View resource details:

  oc describe pod <pod-name>
  oc get pod <pod-name> -o yaml
  oc get pod <pod-name> -o json

• Explain resource fields:

  oc explain pod

Category

Educational

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