第 1 章 OpenShift CLI (oc)


1.1. Getting started with the CLI

1.1.1. About the CLI

With the OpenShift Container Platform command-line interface (CLI), you can create applications and manage OpenShift Container Platform projects from a terminal. The CLI is ideal in situations where you:

  • work directly with project source code.
  • script OpenShift Container Platform operations.
  • are restricted by bandwidth resources and can not use the web console.

1.1.2. Installing the CLI

You can install the OpenShift CLI (oc) either by downloading the binary or by using an RPM.

1.1.2.1. Installing the CLI by downloading the binary

You can install the OpenShift CLI (oc) in order to interact with OpenShift Container Platform from a command-line interface. You can install oc on Linux, Windows, or macOS.

重要

If you installed an earlier version of oc, you cannot use it to complete all of the commands in OpenShift Container Platform 4.5. Download and install the new version of oc.

1.1.2.1.1. Installing the CLI on Linux

You can install the OpenShift CLI (oc) binary on Linux by using the following procedure.

Procedure

  1. Navigate to the Infrastructure Provider page on the Red Hat OpenShift Cluster Manager site.
  2. Select your infrastructure provider, and, if applicable, your installation type.
  3. In the Command line interface section, select Linux from the drop-down menu and click Download command-line tools.
  4. Unpack the archive:

    $ tar xvzf <file>
  5. Place the oc binary in a directory that is on your PATH.

    To check your PATH, execute the following command:

    $ echo $PATH

After you install the CLI, it is available using the oc command:

$ oc <command>
1.1.2.1.2. Installing the CLI on Windows

You can install the OpenShift CLI (oc) binary on Windows by using the following procedure.

Procedure

  1. Navigate to the Infrastructure Provider page on the Red Hat OpenShift Cluster Manager site.
  2. Select your infrastructure provider, and, if applicable, your installation type.
  3. In the Command line interface section, select Windows from the drop-down menu and click Download command-line tools.
  4. Unzip the archive with a ZIP program.
  5. Move the oc binary to a directory that is on your PATH.

    To check your PATH, open the command prompt and execute the following command:

    C:\> path

After you install the CLI, it is available using the oc command:

C:\> oc <command>
1.1.2.1.3. Installing the CLI on macOS

You can install the OpenShift CLI (oc) binary on macOS by using the following procedure.

Procedure

  1. Navigate to the Infrastructure Provider page on the Red Hat OpenShift Cluster Manager site.
  2. Select your infrastructure provider, and, if applicable, your installation type.
  3. In the Command line interface section, select MacOS from the drop-down menu and click Download command-line tools.
  4. Unpack and unzip the archive.
  5. Move the oc binary to a directory on your PATH.

    To check your PATH, open a terminal and execute the following command:

    $ echo $PATH

After you install the CLI, it is available using the oc command:

$ oc <command>

1.1.2.2. Installing the CLI by using an RPM

For Red Hat Enterprise Linux (RHEL), you can install the OpenShift CLI (oc) as an RPM if you have an active OpenShift Container Platform subscription on your Red Hat account.

Prerequisites

  • Must have root or sudo privileges.

Procedure

  1. Register with Red Hat Subscription Manager:

    # subscription-manager register
  2. Pull the latest subscription data:

    # subscription-manager refresh
  3. List the available subscriptions:

    # subscription-manager list --available --matches '*OpenShift*'
  4. In the output for the previous command, find the pool ID for an OpenShift Container Platform subscription and attach the subscription to the registered system:

    # subscription-manager attach --pool=<pool_id>
  5. Enable the repositories required by OpenShift Container Platform 4.5.

    • For Red Hat Enterprise Linux 8:

      # subscription-manager repos --enable="rhocp-4.5-for-rhel-8-x86_64-rpms"
    • For Red Hat Enterprise Linux 7:

      # subscription-manager repos --enable="rhel-7-server-ose-4.5-rpms"
  6. Install the openshift-clients package:

    # yum install openshift-clients

After you install the CLI, it is available using the oc command:

$ oc <command>

1.1.3. Logging in to the CLI

You can log in to the oc CLI to access and manage your cluster.

Prerequisites

  • You must have access to an OpenShift Container Platform cluster.
  • You must have installed the CLI.
注意

To access a cluster that is accessible only over an HTTP proxy server, you can set the HTTP_PROXY, HTTPS_PROXY and NO_PROXY variables. These environment variables are respected by the oc CLI so that all communication with the cluster goes through the HTTP proxy.

Procedure

  • Log in to the CLI using the oc login command and enter the required information when prompted.

    $ oc login

    Example output

    Server [https://localhost:8443]: https://openshift.example.com:6443 1
    The server uses a certificate signed by an unknown authority.
    You can bypass the certificate check, but any data you send to the server could be intercepted by others.
    Use insecure connections? (y/n): y 2
    
    Authentication required for https://openshift.example.com:6443 (openshift)
    Username: user1 3
    Password: 4
    Login successful.
    
    You don't have any projects. You can try to create a new project, by running
    
        oc new-project <projectname>
    
    Welcome! See 'oc help' to get started.

    1
    Enter the OpenShift Container Platform server URL.
    2
    Enter whether to use insecure connections.
    3
    Enter the user name to log in as.
    4
    Enter the user’s password.

You can now create a project or issue other commands for managing your cluster.

1.1.4. Using the CLI

Review the following sections to learn how to complete common tasks using the CLI.

1.1.4.1. Creating a project

Use the oc new-project command to create a new project.

$ oc new-project my-project

Example output

Now using project "my-project" on server "https://openshift.example.com:6443".

1.1.4.2. Creating a new app

Use the oc new-app command to create a new application.

$ oc new-app https://github.com/sclorg/cakephp-ex

Example output

--> Found image 40de956 (9 days old) in imagestream "openshift/php" under tag "7.2" for "php"

...

    Run 'oc status' to view your app.

1.1.4.3. Viewing pods

Use the oc get pods command to view the pods for the current project.

$ oc get pods -o wide

Example output

NAME                  READY   STATUS      RESTARTS   AGE     IP            NODE                           NOMINATED NODE
cakephp-ex-1-build    0/1     Completed   0          5m45s   10.131.0.10   ip-10-0-141-74.ec2.internal    <none>
cakephp-ex-1-deploy   0/1     Completed   0          3m44s   10.129.2.9    ip-10-0-147-65.ec2.internal    <none>
cakephp-ex-1-ktz97    1/1     Running     0          3m33s   10.128.2.11   ip-10-0-168-105.ec2.internal   <none>

1.1.4.4. Viewing pod logs

Use the oc logs command to view logs for a particular pod.

$ oc logs cakephp-ex-1-deploy

Example output

--> Scaling cakephp-ex-1 to 1
--> Success

1.1.4.5. Viewing the current project

Use the oc project command to view the current project.

$ oc project

Example output

Using project "my-project" on server "https://openshift.example.com:6443".

1.1.4.6. Viewing the status for the current project

Use the oc status command to view information about the current project, such as services, deployments, and build configs.

$ oc status

Example output

In project my-project on server https://openshift.example.com:6443

svc/cakephp-ex - 172.30.236.80 ports 8080, 8443
  dc/cakephp-ex deploys istag/cakephp-ex:latest <-
    bc/cakephp-ex source builds https://github.com/sclorg/cakephp-ex on openshift/php:7.2
    deployment #1 deployed 2 minutes ago - 1 pod

3 infos identified, use 'oc status --suggest' to see details.

1.1.4.7. Listing supported API resources

Use the oc api-resources command to view the list of supported API resources on the server.

$ oc api-resources

Example output

NAME                                  SHORTNAMES       APIGROUP                              NAMESPACED   KIND
bindings                                                                                     true         Binding
componentstatuses                     cs                                                     false        ComponentStatus
configmaps                            cm                                                     true         ConfigMap
...

1.1.5. Getting help

You can get help with CLI commands and OpenShift Container Platform resources in the following ways.

  • Use oc help to get a list and description of all available CLI commands:

    Example: Get general help for the CLI

    $ oc help

    Example output

    OpenShift Client
    
    This client helps you develop, build, deploy, and run your applications on any OpenShift or Kubernetes compatible
    platform. It also includes the administrative commands for managing a cluster under the 'adm' subcommand.
    
    Usage:
      oc [flags]
    
    Basic Commands:
      login           Log in to a server
      new-project     Request a new project
      new-app         Create a new application
    
    ...

  • Use the --help flag to get help about a specific CLI command:

    Example: Get help for the oc create command

    $ oc create --help

    Example output

    Create a resource by filename or stdin
    
    JSON and YAML formats are accepted.
    
    Usage:
      oc create -f FILENAME [flags]
    
    ...

  • Use the oc explain command to view the description and fields for a particular resource:

    Example: View documentation for the Pod resource

    $ oc explain pods

    Example output

    KIND:     Pod
    VERSION:  v1
    
    DESCRIPTION:
         Pod is a collection of containers that can run on a host. This resource is
         created by clients and scheduled onto hosts.
    
    FIELDS:
       apiVersion	<string>
         APIVersion defines the versioned schema of this representation of an
         object. Servers should convert recognized schemas to the latest internal
         value, and may reject unrecognized values. More info:
         https://git.k8s.io/community/contributors/devel/api-conventions.md#resources
    
    ...

1.1.6. Logging out of the CLI

You can log out the CLI to end your current session.

  • Use the oc logout command.

    $ oc logout

    Example output

    Logged "user1" out on "https://openshift.example.com"

This deletes the saved authentication token from the server and removes it from your configuration file.

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