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Chapter 4. Using the oc tool
The optional OpenShift CLI (oc) tool provides a subset of oc commands for MicroShift deployments. Using oc is convenient if you are familiar with OpenShift Container Platform and Kubernetes.
4.1. About the OpenShift CLI
With the OpenShift command-line interface (CLI), the oc command, you can deploy and manage MicroShift projects from a terminal. The CLI oc tool is ideal in the following situations:
- Working directly with project source code
- Scripting Red Hat build of MicroShift operations
- Managing projects while restricted by bandwidth resources
A kubeconfig file must exist for the cluster to be accessible. The values are applied from built-in default values or a config.yaml, if one was created.
4.2. Using oc with a MicroShift cluster
Review the following sections to learn how to complete common tasks in MicroShift using the oc CLI.
4.2.1. Viewing pods
Use the oc get pods command to view the pods for the current project.
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 wideExample 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>4.2.2. Viewing pod logs
Use the oc logs command to view logs for a particular pod.
$ oc logs cakephp-ex-1-deployExample output
--> Scaling cakephp-ex-1 to 1
--> Success4.2.3. Listing supported API resources
Use the oc api-resources command to view the list of supported API resources on the server.
$ oc api-resourcesExample output
NAME SHORTNAMES APIGROUP NAMESPACED KIND
bindings true Binding
componentstatuses cs false ComponentStatus
configmaps cm true ConfigMap
...4.3. Getting help
You can get help with CLI commands and MicroShift resources in the following ways.
Use
oc help --flagto get information about a specific CLI command:Example: Get help for the
oc createcommand$ oc create --helpExample output
Create a resource by filename or stdin JSON and YAML formats are accepted. Usage: oc create -f FILENAME [flags] ...Use the
oc explaincommand to view the description and fields for a particular resource:Example: View documentation for the
Podresource$ oc explain podsExample 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 ...
4.4. oc command errors in Red Hat build of MicroShift
Not all OpenShift CLI (oc) commands are relevant for MicroShift deployments. When you use oc to make a request call against an unsupported API, the oc binary usually generates an error message about a resource that cannot be found.
Example output
For example, when the following new-project command is run:
$ oc new-project testThe following error message can be generated:
Error from server (NotFound): the server could not find the requested resource (get projectrequests.project.openshift.io)
And when the get projects command is run, another error can be generated as follows:
$ oc get projects
error: the server doesn't have a resource type "projects"
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