Openshift cheat rhce_r3v1 rhce

1
OpenShift Cheat Sheet
1. What is OpenShift?. . . . . . . . . . . . . . . . . . . 1
2. Cheat sheet guide. . . . . . . . . . . . . . . . . . . . 1
3. Command overview. . . . . . . . . . . . . . . . . . 2
4. Simple build and deploy overview. . . . . 4
5. Simple routing overview. . . . . . . . . . . . . 4
6. Examples. . . . . . . . . . . . . . . . . . . . . . . . . . . 5
7. Additional operations. . . . . . . . . . . . . . . 10
8. About the author. . . . . . . . . . . . . . . . . . . . 11
Table of Contents
What is Openshift?
From OpenShift.com:
OpenShift is Red Hat's Platform-as-a-Service (PaaS) that allows developers to quickly
develop, host, and scale applications in a cloud environment.
Openshift makes use of the Kubernetes upstream project to provide a secure, robust, and
extendable manner for orchestrating applications. Openshift works to further the access
management and build/deploy services that are provided in the upstream Kubernetes
project. Development teams are empowered to own and maintain their applications
through production environments, while operations teams can provide the guide rails for
developers to have that application ownership in a multi-tenant environment.
Cheatsheet Guide
This guide is mostly focused on the developer experience, however several administrator
tasks are detailed below. A high-level listing of operations from command line interface
is provided, followed by a walkthrough of an example application build, deploy, and
management. The command list is not exhaustive, but does cover the majority of
operations a developer will need to understand to manage an application's lifecycle.

2
Command Overview
Login/User management
oc login authenticate to an openshift cluster
oc logout end the current session
oc whoami show the current user context
Project management
oc project show the current project context
oc get projects show all project current login has access to
oc status show overview of current project resources
oc new-project create a new project in Openshift and change to that context
Resource management
oc new-app create a new application from from source code, container
image, or OpenShift template
oc new-build create a new build configuration from source code
oc label add/update/remove labels from an Openshift resource
oc annotate add/update/remove annotations from an Openshift resource
oc create create a new resource from filename or stdin
oc get retrieve a resource (use -o for additional output options)
oc replace replace an existing resource from filename or stdin
oc delete delete a resource
oc edit modify a resource from text editor
oc describe retrieve a resource with details
Cluster management
oc adm administrative functions for an openshift cluster
oc adm router|registry install a router or registry
oc adm policy manage role/scc to user/group bindings, as well as additional
policy administration
oc adm diagnostics run tests/validation against a cluster
oc adm cordon/uncordon/drain unschedule/schedule/drain a node
oc adm groups manage groups
oc adm top show usage statistics of resources

3
Additional resource management
oc patch Update fields for a resource with JSON or YAML segments
oc extract get configmaps or secrets and save to disk
oc set Modify miscellaneous application resources
oc set probe Add a readiness/liveness probe on pod template/deployment
configuration
oc set volumes Manage volume types on a pod template/deployment
configuration
oc set build-hook Set a script/command to execute as part of the build process
oc set build-secret set a secret to be included as part of the build process
oc set env set environment variables on a pod template/deployment
configuration/build configuration
oc set image update the image for deployment configurations/
daemonsets
oc set triggers set triggers for deployment configurations/build
configurations
Operational commands
oc logs retrieve the logs for a resource (build configurations,
deployment configurations, and pods)
oc rsh remote shell into a container
oc rsync copy files to or from a container
oc exec execute a command in a container
oc run create a deployment configuration from image
oc idle scale resources to zero replicas
Build / Deploy
oc rollout manage deployments from deployment configuration
oc rollout latest start a new deployment with the latest state
oc rollout undo perform a rollback operation
oc rollout history oc rollout history - View historical information for a
deployment configuration
oc rollout status watch the status of a rollout until complete
oc tag tag existing images into image streams
oc start-build start a new build from a build configuration
oc cancel-build cancel a build in progress
oc import-image pull in images and tags from an external Docker registry
oc scale change the number of pod replicas for a deployment

4
Simple Build/Deploy Overview
Simple Routing Overview
Im
ageStream
change
Inputs: image
Deploy config
Output:
containers
with
configuration
Inputs: SCM
Build config
Output:
image
SCM
trigger
User traffic
Route
Service
Port mapping defined in Deploy Config
Volume configuration defined in Deploy Config
Volume
Image and number of replicas
defined in Deploy Config
App Container

5
Examples
Login
First, we can login to the cluster to interact with Openshift via CLI
$ oc login -u myuser https://openshift.example.com
Authentication required for https://openshift.example.com
Username: myuser
Password:
Note that leaving the -p option off of login prompts for password. Additionally we can
verify our user context:
$ oc whoami
myuser
Create Project
Let's list out our current available projects (those that we have at least view access for):
$ oc get projects
If this is our first login and no one has added us to any existing projects, there shouldn't
be any projects listed. Let's create a project (allowed by self-provisioner role to all
authenticated users, in the default Openshift policy installation).
$ oc new-project myproject --display-name='My Project' --description='cool project owned by myuser'
Now using project "myproject" on server "https://openshift.example.com:443".
To build a new example applicatin on Ruby you can add applications to this project with
the 'new-app' command. For example, try:
oc new-app centos/ruby-22-centos7~https://github.com/openshift/ruby-ex.git

6
If you want to view the specifics of the project definition, output the full spec to YA
$ oc get project myproject1 -o yaml
apiVersion: v1
kind: Project
metadata:
annotations:
openshift.io/description: A really cool project owned by myuser
openshift.io/display-name: My Project
openshift.io/requester: myuser
openshift.io/sa.scc.mcs: s0:c51,c20
openshift.io/sa.scc.supplemental-groups: 1000000000/10000
openshift.io/sa.scc.uid-range: 1000000000/10000
creationTimestamp: 2017-02-10T15:36:18Z
labels:
name: myproject
resourceVersion: "32381158"
selfLink: /oapi/v1/projects/myproject
uid: aa94c906-efa6-11e6-af71-02a55ffb157d
spec:
finalizers:
- openshift.io/origin
- kubernetes
status:
phase: Active
Add users to project
We can add additional users to our project by default, since self-provisioners get the
"admin" role for any project they create:
$ oc adm policy add-role-to-user edit anotheruser
This allows anotheruser to edit resources within the project, but not manage policy
Create app from code and image
$ oc new-app centos/ruby-22-centos7~https://github.com/openshift/ruby-ex.git
--> Found Docker image 06f0cdc (2 days old) from Docker Hub for "centos/ruby-22-
centos7"
Ruby 2.2
--------
Platform for building and running Ruby 2.2 applicationsTags: builder, ruby, ruby22
* An image stream will be created as "ruby-22-centos7:latest" that will track the
source image
* A source build using source code from https://github.com/openshift/ruby-ex.git
will be created
* The resulting image will be pushed to image stream "ruby-ex:latest"
* Every time "ruby-22-centos7:latest" changes a new build will be triggered
* This image will be deployed in deployment config "ruby-ex"
* Port 8080/tcp will be load balanced by service "ruby-ex"
* Other containers can access this service through the hostname "ruby-ex"
--> Creating resources with label app=ruby-ex ...
imagestream "ruby-22-centos7" created
imagestream "ruby-ex" created
buildconfig "ruby-ex" created
deploymentconfig "ruby-ex" created
service "ruby-ex" created
--> Success
Build scheduled, use 'oc logs -f bc/ruby-ex' to track its progress.
Run 'oc status' to view your app.
The new-app command handles the majority of resource creation via template. Notice
that deploymentconfig/buildconfig/service/imagestream were all set up.

7
Get resources
We can view the resources that were created as part of the new-app command, as well
as the build/deploy resources that were created automatically. Notice that the new-app
automatically started a new build of our code, and the deployment config watches
successful builds to know when to next rollout/deploy. A good place to start with viewing
application status is checking the pods in your project:
$ oc get pods
NAME READY STATUS RESTARTS AGE
ruby-ex-1-a7y56 1/1 Running 0 24m
ruby-ex-1-build 0/1 Completed 0 26m
This shows us the build pod completed successfully. Additionally we can see that there is
one ready and running pod deployed with our application.
The status command shows us similar results:
$ oc status -v
In project My Project (myproject1) on server https://openshift.example.com:443
svc/ruby-ex - 172.30.36.21:8080
dc/ruby-ex deploys istag/ruby-ex:latest <-
bc/ruby-ex source builds https://github.com/openshift/ruby-ex.git on istag/ruby-
22-centos7:latest
deployment #1 deployed 26 minutes ago - 1 pod
Warnings:
* dc/ruby-ex has no readiness probe to verify pods are ready to accept traffic or
ensure deployment is successful.
try: oc set probe dc/ruby-ex --readiness ...
View details with 'oc describe <resource>/<name>' or list everything with 'oc get
all'.
Add a volume
If we want to attach a volume to our pods, the oc set volume command can be used:
$ oc set volume dc/ruby-ex --add --mount-path=/mnt/emptydir
info: Generated volume name: volume-7d1e8
deploymentconfigs/ruby-ex
$ oc get pods
NAME READY STATUS RESTARTS AGE
ruby-ex-1-a7y56 1/1 Running 0 2h
ruby-ex-1-build 0/1 Completed 0 2h
ruby-ex-2-deploy 0/1 ContainerCreating 0 5s
In this example, a simple emptyDir volume was attached, though the same command
can be used for Persistent Volumes. Also notice that the deployment configuration has a
ConfigChange trigger, so adding this volume automatically started a new deployment.

8
Edit resource
Making a change to any Openshift resource is simple. Let's change the /mnt/emptydir
mountpath above to /mnt/appdata:
$ oc edit dc ruby-ex
# Please edit the object below. Lines beginning with a '#' will be ignored,
# and an empty file will abort the edit. If an error occurs while saving this file
# will be reopened with the relevant failures.
#
...
volumeMounts:
- mountPath:/mnt/emptydir /mnt/appdata
name: volume-7d1e8
...
Saving the file in your text editor will update the resource, or report errors if validation
did not succeed. Note that this change on the deployment config kicks off another
deployment for our app.
Start build
If a new build from source is desired:
$ oc start-build ruby-ex
build "ruby-ex-2" started
Watch build
The build logs can be watched with the oc logs command (including -f option for follow):
$ oc logs -f bc/ruby-ex
Cloning "https://github.com/openshift/ruby-ex.git" ...
Commit: 855ab2de53ff897a19e1055f7554c64d19e02c50 (Merge pull request #6 from aj07/
typo)
Author: Ionut Palade <PI-Victor@users.noreply.github.com>
Date: Mon Dec 12 14:37:32 2016 +0100
---> Installing application source ...
---> Building your Ruby application from source ...
---> Running 'bundle install --deployment --without development:test' ...
Fetching gem metadata from https://rubygems.org/...............
Installing puma 3.4.0
Installing rack 1.6.4
Using bundler 1.7.8
Your bundle is complete!
Gems in the groups development and test were not installed.
It was installed into ./bundle
---> Cleaning up unused ruby gems ...
Pushing image 172.30.114.236:5000/myproject/ruby-ex:latest ...
Pushed 7/9 layers, 78% complete
Push successful

9
Start Deploy
Most configuration or image changes will automatically start a new deploy by default, but
new deployments can be started manually as well:
$ oc rollout latest ruby-ex
deploymentconfig "ruby-ex" rolled out
Watch Deploy
The overall deployment status can be watched via oc logs command:
$ oc logs -f dc/ruby-ex
--> Scaling up ruby-ex-5 from 0 to 1, scaling down ruby-ex-4 from 1 to 0 (keep 1
pods available, don't exceed 2 pods)
Scaling ruby-ex-5 up to 1
Scaling ruby-ex-4 down to 0
--> Success
Additionally container logs can be viewed with oc logs:
$ oc logs ruby-ex-5-kgzvd
[1] Puma starting in cluster mode...
[1] * Version 3.4.0 (ruby 2.2.2-p95), codename: Owl Bowl Brawl
[1] * Min threads: 0, max threads: 16
[1] * Environment: production
[1] * Process workers: 8
[1] * Phased restart available
[1] * Listening on tcp://0.0.0.0:8080
[1] Use Ctrl-C to stop
[1] - Worker 2 (pid: 29) booted, phase: 0
Remote shell
Interacting directly with the container is simple with oc rsh:
$ oc rsh ruby-ex-5-kgzvd
sh-4.2$ ls
Gemfile Gemfile.lock README.md bundle config.ru
Create route
$ oc expose service ruby-ex
route "ruby-ex" exposed
With no other options defined this will create a route for your application using the default
route naming (ex: $appname-$projectname.openshift.example.com)

10
Idle app
We're done testing our application, so we can idle the service in order to save resources.
This interacts with a Kubernetes service to set the pod replicas to 0, and when the service
is next accessed will automatically boot up the pods again:
$ oc idle ruby-ex
Marked service myproject1/ruby-ex to unidle resource DeploymentConfig myproject1/
ruby-ex (unidle to 1 replicas)
Idled DeploymentConfig myproject1/ruby-ex
Delete app
If we're completely done with our application, we can delete resources within the project
(or the project itself) to clean up:
$ oc delete services -l app=ruby-ex
service "ruby-ex" deleted
$ oc delete all -l app=ruby-ex
buildconfig "ruby-ex" deleted
imagestream "ruby-22-centos7" deleted
imagestream "ruby-ex" deleted
deploymentconfig "ruby-ex" deleted
$ oc delete project myproject
project "myproject" deleted
About the author
BEN PRITCHETT is a Systems Engineer within Red Hat's
IT department, deploying Red Hat's internal offerings of
Platform-as-a-Service technologies. His focus is to bridge
the gap between development and operations teams using
automation and training.
 http://github.com/bjpritch

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