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Command line tool usage

Rahti can be used via the command line either with OpenShift's oc tool or with the kubectl tool from Kubernetes. Certain features specific to OpenShift are only available when using the oc tool.

How to install the oc tool

The oc tool is a single binary that only needs to be included in your path. You may download it from the latest release page in GitHub. The detailed instructions are:

  • Go to the aforementioned release page (https://github.com/openshift/origin/releases/latest). In the bottom you will see the list of clients. Download the "Openshift origin client" corresponding to your OS (Windows, Mac or Linux).
  • Once downloaded, extract the oc binary file.
  • Copy the file to a folder in your $PATH and make it executable. For Mac and Linux the steps are similar to the following:
$ echo $PATH
/usr/local/bin:/usr/local/sbin:/usr/bin:/usr/sbin:/bin:/sbin:~/bin
$ mkdir -p ~/bin
$ cp oc ~/bin/
$ chmod +x ~/bin/oc

In the example above, we are displaying the contents of the $PATH variable, choosing the bin folder in the home (~) folder, using mkdir just to be sure that the folder exist, copy the oc command (of course, we have to be in the folder oc was downloaded), and finally adding executable (+x) permissions to the oc binary. That is all.

In order to test that it was properly installed, open a new terminal, go to any folder, and run:

$ oc --help

It should show the list of all available commands.

The "Command Line Tools" page in the OpenShift web UI

Instructions for downloading the oc tool and logging in via the command line can be found in the "Command Line Tools" page in the web interface:

Command line tools

How to login with oc?

The oc login command to login can be found in one of the fields on the page. There is a button next to it for copying the command to the clipboard:

OpenShift Command Line Tools page

Copy the command and paste it in a terminal to start using OpenShift via the command line.

Note

If you open multiple terminals, the login session for oc will be active in all of them.

How to login in the registry?

In order to use Rahti internal container registry, it is necessary to login separately. Once you login, it is possible to use the client docker to pull and push from Rahti's registry.

Using personal account

After login with oc, it is possible to use the command to generate a token (oc whoami -t):

docker login -p $(oc whoami -t ) -u unused docker-registry.rahti.csc.fi

Using a service account token

Rahti also offers the opportunity of using an internal service account to interact with the registry. This is recommended for automated procedures like a CI pipeline. Even though by default 3 internal service accounts are created in every Rahti namespace: builder, default and deployer, it is recommended to create a dedicated internal service account and assign to it the system:image-pusher role.

oc create serviceaccount pusher
oc policy add-role-to-user system:image-pusher pusher
docker login -p $(oc sa get-token pusher) -u unused docker-registry.rahti.csc.fi

This service account token, the one you get with oc sa get-token pusher does not expire.

Checkout this documentation to know how to upload images: How to manually cache images in Rahti's registry

CLI cheat sheet

Basic usage:

oc <command> <--flags>
oc help <command>

Examples:

Authorize the CLI tool to the cluster:

oc login https://rahti.csc.fi:8443 --token=<secret access token>

This command can be obtained by clicking your usename and "Copy Login Command" in the web console:

copy login

Show projects:

oc projects

Switch to project my-project:

oc project my-project

Show all pods in the current namespace:

oc get pods

Show all pods in the namespace <my-other-name-space>:

oc get pods -n <my-other-namespace>

Show all pods that have the key-value pair app: myapp in metadata.labels:

oc get pods --selector app=myapp

Print the specifications of the pod mypod

oc get pod mypod -o yaml

Other useful commands

  • oc create creates an object. Example: oc create -f file.yaml
  • oc replace replaces an object. Example: oc replace -f file.yaml
  • oc delete deletes an object in OpenShift. Example: oc delete rc myreplicationcontroller
  • oc apply modifies an object according to the input. Example oc apply -f file.yaml
  • oc explain prints out the API documentation. Example: oc explain dc.spec
  • oc edit loads an object from the API to the local editor chosen by the $EDITOR environment variable. Example: oc edit DeploymentConfig mydc

Abbreviations

Object types have abbreviations that are recognized in the CLI:

Abbreviation Meaning
is ImageStream
dc DeploymentConfig
svc Service
bc BuildConfig
rc ReplicationController
pvc PersistentVolumeClaim

Further documentation

See the official documentation for more information about using the command line interface:

Last update: July 31, 2023