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Chapter 2. OpenShift CLI (oc)

2.1. Getting started with the OpenShift CLI
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2.1.1. About the OpenShift CLI
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With the OpenShift CLI (oc), you can create applications and manage OpenShift Container Platform projects from a terminal. The OpenShift CLI is ideal in the following situations:

  • Working directly with project source code
  • Scripting OpenShift Container Platform operations
  • Managing projects while restricted by bandwidth resources and the web console is unavailable

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

2.1.2.1. Installing the OpenShift CLI by downloading the binary
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You can install the OpenShift CLI (oc) to interact with OpenShift Container Platform from a command-line interface. You can install oc on Linux, Windows, or macOS.

Important

If you installed an earlier version of oc, you cannot use it to complete all of the commands in OpenShift Container Platform 4.15. Download and install the new version of oc.

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

Procedure

  1. Navigate to the OpenShift Container Platform downloads page on the Red Hat Customer Portal.
  2. Select the architecture from the Product Variant drop-down list.
  3. Select the appropriate version from the Version drop-down list.
  4. Click Download Now next to the OpenShift v4.15 Linux Clients entry and save the file.

  5. Unpack the archive: 

    $ tar xvf <file>

  6. Place the oc binary in a directory that is on your PATH.

    To check your PATH, execute the following command: 

    $ echo $PATH

Verification

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

    $ oc <command>
2.1.2.1.2. Installing the OpenShift CLI on Windows
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You can install the OpenShift CLI (oc) binary on Windows by using the following procedure.

Procedure

  1. Navigate to the OpenShift Container Platform downloads page on the Red Hat Customer Portal.
  2. Select the appropriate version from the Version drop-down list.
  3. Click Download Now next to the OpenShift v4.15 Windows Client entry and save the file.
  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

Verification

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

    C:\> oc <command>
2.1.2.1.3. Installing the OpenShift CLI on macOS
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You can install the OpenShift CLI (oc) binary on macOS by using the following procedure.

Procedure

  1. Navigate to the OpenShift Container Platform downloads page on the Red Hat Customer Portal.
  2. Select the appropriate version from the Version drop-down list.

  3. Click Download Now next to the OpenShift v4.15 macOS Clients entry and save the file.

    Note

    For macOS arm64, choose the OpenShift v4.15 macOS arm64 Client entry.

  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

Verification

  • Verify your installation by using an oc command: 

    $ oc <command>

2.1.2.2. Installing the OpenShift CLI by using the web console
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You can install the OpenShift CLI (oc) to interact with OpenShift Container Platform from a web console. You can install oc on Linux, Windows, or macOS.

Important

If you installed an earlier version of oc, you cannot use it to complete all of the commands in OpenShift Container Platform 4.15. Download and install the new version of oc.

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

Procedure

  1. From the web console, click ?.

    click question mark

  2. Click Command Line Tools.

    CLI list
  3. Select appropriate oc binary for your Linux platform, and then click Download oc for Linux.
  4. Save the file.

  5. Unpack the archive. 

    $ tar xvf <file>

  6. Move the oc binary to a directory that is on your PATH.

    To check your PATH, execute the following command: 

    $ echo $PATH

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

$ oc <command>
2.1.2.2.2. Installing the OpenShift CLI on Windows using the web console
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You can install the OpenShift CLI (oc) binary on Windows by using the following procedure.

Procedure

  1. From the web console, click ?.

    click question mark

  2. Click Command Line Tools.

    CLI list
  3. Select the oc binary for Windows platform, and then click Download oc for Windows for x86_64.
  4. Save the file.
  5. Unzip the archive with a ZIP program.

  6. 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 OpenShift CLI, it is available using the oc command: 

C:\> oc <command>
2.1.2.2.3. Installing the OpenShift CLI on macOS using the web console
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You can install the OpenShift CLI (oc) binary on macOS by using the following procedure.

Procedure

  1. From the web console, click ?.

    click question mark

  2. Click Command Line Tools.

    CLI list

  3. Select the oc binary for macOS platform, and then click Download oc for Mac for x86_64.

    Note

    For macOS arm64, click Download oc for Mac for ARM 64.

  4. Save the file.
  5. Unpack and unzip the archive.

  6. 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 OpenShift CLI, it is available using the oc command: 

$ oc <command>

2.1.2.3. Installing the OpenShift CLI by using an RPM
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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.

Important

You must install oc for RHEL 9 by downloading the binary. Installing oc by using an RPM package is not supported on Red Hat Enterprise Linux (RHEL) 9.

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 4.15. 

    # subscription-manager repos --enable="rhocp-4.15-for-rhel-8-x86_64-rpms"

  6. Install the openshift-clients package: 

    # yum install openshift-clients

Verification

  • Verify your installation by using an oc command: 
$ oc <command>

2.1.2.4. Installing the OpenShift CLI by using Homebrew
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For macOS, you can install the OpenShift CLI (oc) by using the Homebrew package manager.

Prerequisites

  • You must have Homebrew (brew) installed.

Procedure

  • Install the openshift-cli package by running the following command: 

    $ brew install openshift-cli

Verification

  • Verify your installation by using an oc command: 
$ oc <command>

2.1.3. Logging in to the OpenShift CLI
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You can log in to the OpenShift CLI (oc) to access and manage your cluster.

Prerequisites

  • You must have access to an OpenShift Container Platform cluster.
  • The OpenShift CLI (oc) is installed.
Note

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.

Authentication headers are sent only when using HTTPS transport.

Procedure

  1. Enter the oc login command and pass in a user name: 

    $ oc login -u user1

  2. When prompted, enter the required information:

    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
Password:
    3 
    
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’s password.
Note

If you are logged in to the web console, you can generate an oc login command that includes your token and server information. You can use the command to log in to the OpenShift Container Platform CLI without the interactive prompts. To generate the command, select Copy login command from the username drop-down menu at the top right of the web console.

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

2.1.4. Logging in to the OpenShift CLI using a web browser
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You can log in to the OpenShift CLI (oc) with the help of a web browser to access and manage your cluster. This allows users to avoid inserting their access token into the command line.

Warning

Logging in to the CLI through the web browser runs a server on localhost with HTTP, not HTTPS; use with caution on multi-user workstations.

Prerequisites

  • You must have access to an OpenShift Container Platform cluster.
  • You must have installed the OpenShift CLI (oc).
  • You must have a browser installed.

Procedure

  1. Enter the oc login command with the --web flag: 

    $ oc login <cluster_url> --web
    1
    1
    Optionally, you can specify the server URL and callback port. For example, oc login <cluster_url> --web --callback-port 8280 localhost:8443.

  2. The web browser opens automatically. If it does not, click the link in the command output. If you do not specify the OpenShift Container Platform server oc tries to open the web console of the cluster specified in the current oc configuration file. If no oc configuration exists, oc prompts interactively for the server URL.

    Example output

    Opening login URL in the default browser: https://openshift.example.com
Opening in existing browser session.

  3. If more than one identity provider is available, select your choice from the options provided.
  4. Enter your username and password into the corresponding browser fields. After you are logged in, the browser displays the text access token received successfully; please return to your terminal.

  5. Check the CLI for a login confirmation.

    Example output

    Login successful.

You don't have any projects. You can try to create a new project, by running

    oc new-project <projectname>

Note

The web console defaults to the profile used in the previous session. To switch between Administrator and Developer profiles, log out of the OpenShift Container Platform web console and clear the cache.

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

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

2.1.5.1. Creating a project
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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".

2.1.5.2. Creating a new app
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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.

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

Note

When you run oc inside a pod and do not specify a namespace, the namespace of the pod is used by default. 

$ 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>

2.1.5.4. Viewing pod logs
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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

2.1.5.5. Viewing the current project
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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".

2.1.5.6. Viewing the status for the current project
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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.

2.1.5.7. Listing supported API resources
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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
...

2.1.6. Getting help
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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

...

2.1.7. Logging out of the OpenShift CLI
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You can log out the OpenShift 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.

2.2. Configuring the OpenShift CLI
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2.2.1. Enabling tab completion
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You can enable tab completion for the Bash or Zsh shells.

2.2.1.1. Enabling tab completion for Bash
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After you install the OpenShift CLI (oc), you can enable tab completion to automatically complete oc commands or suggest options when you press Tab. The following procedure enables tab completion for the Bash shell.

Prerequisites

  • You must have the OpenShift CLI (oc) installed.
  • You must have the package bash-completion installed.

Procedure

  1. Save the Bash completion code to a file: 

    $ oc completion bash > oc_bash_completion

  2. Copy the file to /etc/bash_completion.d/: 

    $ sudo cp oc_bash_completion /etc/bash_completion.d/

    You can also save the file to a local directory and source it from your .bashrc file instead.

Tab completion is enabled when you open a new terminal.

2.2.1.2. Enabling tab completion for Zsh
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After you install the OpenShift CLI (oc), you can enable tab completion to automatically complete oc commands or suggest options when you press Tab. The following procedure enables tab completion for the Zsh shell.

Prerequisites

  • You must have the OpenShift CLI (oc) installed.

Procedure

  • To add tab completion for oc to your .zshrc file, run the following command: 

    $ cat >>~/.zshrc<<EOF
autoload -Uz compinit
compinit
if [ $commands[oc] ]; then
  source <(oc completion zsh)
  compdef _oc oc
fi
EOF

Tab completion is enabled when you open a new terminal.

2.3. Usage of oc and kubectl commands
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The Kubernetes command-line interface (CLI), kubectl, can be used to run commands against a Kubernetes cluster. Because OpenShift Container Platform is a certified Kubernetes distribution, you can use the supported kubectl binaries that ship with OpenShift Container Platform , or you can gain extended functionality by using the oc binary.

2.3.1. The oc binary
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The oc binary offers the same capabilities as the kubectl binary, but it extends to natively support additional OpenShift Container Platform features, including:

  • Full support for OpenShift Container Platform resources

    Resources such as DeploymentConfig, BuildConfig, Route, ImageStream, and ImageStreamTag objects are specific to OpenShift Container Platform distributions, and build upon standard Kubernetes primitives.

  • Authentication

    The oc binary offers a built-in login command for authentication and lets you work with projects, which map Kubernetes namespaces to authenticated users. Read Understanding authentication for more information.

  • Additional commands

    The additional command oc new-app, for example, makes it easier to get new applications started using existing source code or pre-built images. Similarly, the additional command oc new-project makes it easier to start a project that you can switch to as your default.

Important

If you installed an earlier version of the oc binary, you cannot use it to complete all of the commands in OpenShift Container Platform 4.15 . If you want the latest features, you must download and install the latest version of the oc binary corresponding to your OpenShift Container Platform server version.

Non-security API changes will involve, at minimum, two minor releases (4.1 to 4.2 to 4.3, for example) to allow older oc binaries to update. Using new capabilities might require newer oc binaries. A 4.3 server might have additional capabilities that a 4.2 oc binary cannot use and a 4.3 oc binary might have additional capabilities that are unsupported by a 4.2 server.

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Table 2.1. Compatibility Matrix
 

X.Y (oc Client)

X.Y+N [a] (oc Client)

X.Y (Server)

redcircle 1

redcircle 3

X.Y+N [a] (Server)

redcircle 2

redcircle 1

[a] Where N is a number greater than or equal to 1.

redcircle 1 Fully compatible.

redcircle 2 oc client might not be able to access server features.

redcircle 3 oc client might provide options and features that might not be compatible with the accessed server.

2.3.2. The kubectl binary
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The kubectl binary is provided as a means to support existing workflows and scripts for new OpenShift Container Platform users coming from a standard Kubernetes environment, or for those who prefer to use the kubectl CLI. Existing users of kubectl can continue to use the binary to interact with Kubernetes primitives, with no changes required to the OpenShift Container Platform cluster.

You can install the supported kubectl binary by following the steps to Install the OpenShift CLI. The kubectl binary is included in the archive if you download the binary, or is installed when you install the CLI by using an RPM.

For more information, see the kubectl documentation.

2.4. Managing CLI profiles
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A CLI configuration file allows you to configure different profiles, or contexts, for use with the CLI tools overview. A context consists of user authentication an OpenShift Container Platform server information associated with a nickname.

2.4.1. About switches between CLI profiles
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Contexts allow you to easily switch between multiple users across multiple OpenShift Container Platform servers, or clusters, when using CLI operations. Nicknames make managing CLI configurations easier by providing short-hand references to contexts, user credentials, and cluster details. After a user logs in with the oc CLI for the first time, OpenShift Container Platform creates a ~/.kube/config file if one does not already exist. As more authentication and connection details are provided to the CLI, either automatically during an oc login operation or by manually configuring CLI profiles, the updated information is stored in the configuration file:

CLI config file

apiVersion: v1
clusters:
1 

- cluster:
    insecure-skip-tls-verify: true
    server: https://openshift1.example.com:8443
  name: openshift1.example.com:8443
- cluster:
    insecure-skip-tls-verify: true
    server: https://openshift2.example.com:8443
  name: openshift2.example.com:8443
contexts:
2 

- context:
    cluster: openshift1.example.com:8443
    namespace: alice-project
    user: alice/openshift1.example.com:8443
  name: alice-project/openshift1.example.com:8443/alice
- context:
    cluster: openshift1.example.com:8443
    namespace: joe-project
    user: alice/openshift1.example.com:8443
  name: joe-project/openshift1/alice
current-context: joe-project/openshift1.example.com:8443/alice
3 

kind: Config
preferences: {}
users:
4 

- name: alice/openshift1.example.com:8443
  user:
    token: xZHd2piv5_9vQrg-SKXRJ2Dsl9SceNJdhNTljEKTb8k

1
The clusters section defines connection details for OpenShift Container Platform clusters, including the address for their master server. In this example, one cluster is nicknamed openshift1.example.com:8443 and another is nicknamed openshift2.example.com:8443.
2
This contexts section defines two contexts: one nicknamed alice-project/openshift1.example.com:8443/alice, using the alice-project project, openshift1.example.com:8443 cluster, and alice user, and another nicknamed joe-project/openshift1.example.com:8443/alice, using the joe-project project, openshift1.example.com:8443 cluster and alice user.
3
The current-context parameter shows that the joe-project/openshift1.example.com:8443/alice context is currently in use, allowing the alice user to work in the joe-project project on the openshift1.example.com:8443 cluster.
4
The users section defines user credentials. In this example, the user nickname alice/openshift1.example.com:8443 uses an access token.

The CLI can support multiple configuration files which are loaded at runtime and merged together along with any override options specified from the command line. After you are logged in, you can use the oc status or oc project command to verify your current working environment:

Verify the current working environment

$ oc status

Example output

oc status
In project Joe's Project (joe-project)

service database (172.30.43.12:5434 -> 3306)
  database deploys docker.io/openshift/mysql-55-centos7:latest
    #1 deployed 25 minutes ago - 1 pod

service frontend (172.30.159.137:5432 -> 8080)
  frontend deploys origin-ruby-sample:latest <-
    builds https://github.com/openshift/ruby-hello-world with joe-project/ruby-20-centos7:latest
    #1 deployed 22 minutes ago - 2 pods

To see more information about a service or deployment, use 'oc describe service <name>' or 'oc describe dc <name>'.
You can use 'oc get all' to see lists of each of the types described in this example.

List the current project

$ oc project

Example output

Using project "joe-project" from context named "joe-project/openshift1.example.com:8443/alice" on server "https://openshift1.example.com:8443".

You can run the oc login command again and supply the required information during the interactive process, to log in using any other combination of user credentials and cluster details. A context is constructed based on the supplied information if one does not already exist. If you are already logged in and want to switch to another project the current user already has access to, use the oc project command and enter the name of the project: 

$ oc project alice-project

Example output

Now using project "alice-project" on server "https://openshift1.example.com:8443".

At any time, you can use the oc config view command to view your current CLI configuration, as seen in the output. Additional CLI configuration commands are also available for more advanced usage.

Note

If you have access to administrator credentials but are no longer logged in as the default system user system:admin, you can log back in as this user at any time as long as the credentials are still present in your CLI config file. The following command logs in and switches to the default project: 

$ oc login -u system:admin -n default

2.4.2. Manual configuration of CLI profiles
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Note

This section covers more advanced usage of CLI configurations. In most situations, you can use the oc login and oc project commands to log in and switch between contexts and projects.

If you want to manually configure your CLI config files, you can use the oc config command instead of directly modifying the files. The oc config command includes a number of helpful sub-commands for this purpose:

Expand
Table 2.2. CLI configuration subcommands
SubcommandUsage

set-cluster

Sets a cluster entry in the CLI config file. If the referenced cluster nickname already exists, the specified information is merged in. 

$ oc config set-cluster <cluster_nickname> [--server=<master_ip_or_fqdn>]
[--certificate-authority=<path/to/certificate/authority>]
[--api-version=<apiversion>] [--insecure-skip-tls-verify=true]

set-context

Sets a context entry in the CLI config file. If the referenced context nickname already exists, the specified information is merged in. 

$ oc config set-context <context_nickname> [--cluster=<cluster_nickname>]
[--user=<user_nickname>] [--namespace=<namespace>]

use-context

Sets the current context using the specified context nickname. 

$ oc config use-context <context_nickname>

set

Sets an individual value in the CLI config file. 

$ oc config set <property_name> <property_value>

The <property_name> is a dot-delimited name where each token represents either an attribute name or a map key. The <property_value> is the new value being set.

unset

Unsets individual values in the CLI config file. 

$ oc config unset <property_name>

The <property_name> is a dot-delimited name where each token represents either an attribute name or a map key.

view

Displays the merged CLI configuration currently in use. 

$ oc config view

Displays the result of the specified CLI config file. 

$ oc config view --config=<specific_filename>

Example usage

  • Log in as a user that uses an access token. This token is used by the alice user: 
$ oc login https://openshift1.example.com --token=ns7yVhuRNpDM9cgzfhhxQ7bM5s7N2ZVrkZepSRf4LC0
  • View the cluster entry automatically created: 
$ oc config view

Example output

apiVersion: v1
clusters:
- cluster:
    insecure-skip-tls-verify: true
    server: https://openshift1.example.com
  name: openshift1-example-com
contexts:
- context:
    cluster: openshift1-example-com
    namespace: default
    user: alice/openshift1-example-com
  name: default/openshift1-example-com/alice
current-context: default/openshift1-example-com/alice
kind: Config
preferences: {}
users:
- name: alice/openshift1.example.com
  user:
    token: ns7yVhuRNpDM9cgzfhhxQ7bM5s7N2ZVrkZepSRf4LC0

  • Update the current context to have users log in to the desired namespace: 
$ oc config set-context `oc config current-context` --namespace=<project_name>
  • Examine the current context, to confirm that the changes are implemented: 
$ oc whoami -c

All subsequent CLI operations uses the new context, unless otherwise specified by overriding CLI options or until the context is switched.

2.4.3. Load and merge rules
링크 복사

You can follow these rules, when issuing CLI operations for the loading and merging order for the CLI configuration:

  • CLI config files are retrieved from your workstation, using the following hierarchy and merge rules:

    • If the --config option is set, then only that file is loaded. The flag is set once and no merging takes place.
    • If the $KUBECONFIG environment variable is set, then it is used. The variable can be a list of paths, and if so the paths are merged together. When a value is modified, it is modified in the file that defines the stanza. When a value is created, it is created in the first file that exists. If no files in the chain exist, then it creates the last file in the list.
    • Otherwise, the ~/.kube/config file is used and no merging takes place.

  • The context to use is determined based on the first match in the following flow:

    • The value of the --context option.
    • The current-context value from the CLI config file.
    • An empty value is allowed at this stage.

  • The user and cluster to use is determined. At this point, you may or may not have a context; they are built based on the first match in the following flow, which is run once for the user and once for the cluster:

    • The value of the --user for user name and --cluster option for cluster name.
    • If the --context option is present, then use the context’s value.
    • An empty value is allowed at this stage.

  • The actual cluster information to use is determined. At this point, you may or may not have cluster information. Each piece of the cluster information is built based on the first match in the following flow:

    • The values of any of the following command-line options:

      • --server,
      • --api-version
      • --certificate-authority
      • --insecure-skip-tls-verify
    • If cluster information and a value for the attribute is present, then use it.
    • If you do not have a server location, then there is an error.

  • The actual user information to use is determined. Users are built using the same rules as clusters, except that you can only have one authentication technique per user; conflicting techniques cause the operation to fail. Command-line options take precedence over config file values. Valid command-line options are:

    • --auth-path
    • --client-certificate
    • --client-key
    • --token
  • For any information that is still missing, default values are used and prompts are given for additional information.

2.5. Extending the OpenShift CLI with plugins
링크 복사

You can write and install plugins to build on the default oc commands, allowing you to perform new and more complex tasks with the OpenShift Container Platform CLI.

2.5.1. Writing CLI plugins
링크 복사

You can write a plugin for the OpenShift Container Platform CLI in any programming language or script that allows you to write command-line commands. Note that you can not use a plugin to overwrite an existing oc command.

Procedure

This procedure creates a simple Bash plugin that prints a message to the terminal when the oc foo command is issued.

  1. Create a file called oc-foo.

    When naming your plugin file, keep the following in mind:

    • The file must begin with oc- or kubectl- to be recognized as a plugin.
    • The file name determines the command that invokes the plugin. For example, a plugin with the file name oc-foo-bar can be invoked by a command of oc foo bar. You can also use underscores if you want the command to contain dashes. For example, a plugin with the file name oc-foo_bar can be invoked by a command of oc foo-bar.

  2. Add the following contents to the file. 

    #!/bin/bash

# optional argument handling
if [[ "$1" == "version" ]]
then
    echo "1.0.0"
    exit 0
fi

# optional argument handling
if [[ "$1" == "config" ]]
then
    echo $KUBECONFIG
    exit 0
fi

echo "I am a plugin named kubectl-foo"

After you install this plugin for the OpenShift Container Platform CLI, it can be invoked using the oc foo command.

2.5.2. Installing and using CLI plugins
링크 복사

After you write a custom plugin for the OpenShift Container Platform CLI, you must install the plugin before use.

Prerequisites

  • You must have the oc CLI tool installed.
  • You must have a CLI plugin file that begins with oc- or kubectl-.

Procedure

  1. If necessary, update the plugin file to be executable. 

    $ chmod +x <plugin_file>

  2. Place the file anywhere in your PATH, such as /usr/local/bin/. 

    $ sudo mv <plugin_file> /usr/local/bin/.

  3. Run oc plugin list to make sure that the plugin is listed. 

    $ oc plugin list

    Example output

    The following compatible plugins are available:

/usr/local/bin/<plugin_file>

    If your plugin is not listed here, verify that the file begins with oc- or kubectl-, is executable, and is on your PATH.

  4. Invoke the new command or option introduced by the plugin.

    For example, if you built and installed the kubectl-ns plugin from the Sample plugin repository, you can use the following command to view the current namespace. 

    $ oc ns

    Note that the command to invoke the plugin depends on the plugin file name. For example, a plugin with the file name of oc-foo-bar is invoked by the oc foo bar command.

2.6. Managing CLI plugins with Krew
링크 복사

You can use Krew to install and manage plugins for the OpenShift CLI (oc).

Important

Using Krew to install and manage plugins for the OpenShift CLI is a Technology Preview feature only. Technology Preview features are not supported with Red Hat production service level agreements (SLAs) and might not be functionally complete. Red Hat does not recommend using them in production. These features provide early access to upcoming product features, enabling customers to test functionality and provide feedback during the development process.

For more information about the support scope of Red Hat Technology Preview features, see Technology Preview Features Support Scope.

2.6.1. Installing a CLI plugin with Krew
링크 복사

You can install a plugin for the OpenShift CLI (oc) with Krew.

Prerequisites

Procedure

  1. To list all available plugins, run the following command: 

    $ oc krew search

  2. To get information about a plugin, run the following command: 

    $ oc krew info <plugin_name>

  3. To install a plugin, run the following command: 

    $ oc krew install <plugin_name>

  4. To list all plugins that were installed by Krew, run the following command: 

    $ oc krew list