oc allows you to manage your Openshift projects and applications through a terminal. Similar to how Openshift is built on top of Kubernetes with additional features, oc is built on top of kubectl but supports management of resources unique to Openshift. In order to allow for backwards compatibility with resources from a Kubernetes environment, kubectl is included in oc.
Enabling oc when minishift is running:
eval $(minishift oc-env)
The basic recipe for forming oc commands is:
oc <action> <object_type> <object_name_or_id>
Examples:
oc status -> overview of project resources
oc get project -> get current project
oc get pods -> list pods (to watch, add -w)
oc describe pod <pod_id> -> get detailed information about a pod
oc get pod <podname> -o yaml -> get a pod's YAML
Red Hat's documentation containing the different command options is here.
To use oc, you must log in first.
oc login
The default username/password is
developer/developer
First, we want to make sure we are in the correct project.
λ oc get project
NAME DISPLAY NAME STATUS
cascon-oc-config ActiveTo switch to a project, use
oc project <project_name>
Let's check the project status to get some basic information about our project and any applications within it.
λ oc status
In project cascon-oc-config on server https://192.168.64.2:8443
svc/mongodb - 172.30.8.66:27017
dc/mongodb deploys openshift/mongodb:3.2
deployment #1 deployed 13 days ago - 1 pod
http://nodejs-ex-cascon-oc-config.192.168.64.2.nip.io to pod port 8080-tcp (svc/nodejs-ex)
dc/nodejs-ex deploys istag/nodejs-ex:latest <-
bc/nodejs-ex source builds https://github.com/cloud-coder/cascon-2019-openshift on openshift/nodejs:10
deployment #5 deployed 13 days ago - 1 pod
deployment #4 deployed 13 days ago
deployment #3 deployed 13 days ago
Here we can see that we have a mongodb service, and that it has 1 deployment config (dc) and 1 deployment. We can also see a nodejs service with its route, deployment config (dc), build config (bc), and deployment history (3 deployments)
Let's check on our pods.
λ oc get pods -w
NAME READY STATUS RESTARTS AGE
mongodb-1-7xgzg 1/1 Running 1 13d
nodejs-ex-1-build 0/1 Completed 0 13d
nodejs-ex-5-kj5pc 1/1 Running 1 13dScale up the application in the web console to see real-time updates.
oc scale --replicas=2 dc/nodejs-ex
Let's check the logs for our nodejs pod.
λ oc logs -f nodejs-ex-5-kj5pc
git version 1.8.3.1
Environment:
DEV_MODE=false
NODE_ENV=production
DEBUG_PORT=5858
Running as user uid=1001(default) gid=0(root) groups=0(root)
Launching via npm...
npm info it worked if it ends with ok
npm info using npm@6.9.0
npm info using node@v10.16.3
npm info lifecycle nodejs-ex@0.0.1~prestart: nodejs-ex@0.0.1
npm info lifecycle nodejs-ex@0.0.1~start: nodejs-ex@0.0.1
> nodejs-ex@0.0.1 start /opt/app-root/src
> node server.js
Server running on http://0.0.0.0:8080
Connected to MongoDB at: mongodb://userUAY:GiDdfPOX7B1UTGnX@172.30.8.66:27017/sampledb
172.17.0.1 - - [24/Oct/2019:16:00:49 +0000] "GET / HTTP/1.1" 200 36928 "-" "Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:70.0) Gecko/20100101 Firefox/70.0"If we refresh the page, we should see a new HTTP GET request.
- Deployment Config
Similar to a Deployment in Kubernetes in that it describes the desired state of a component of the application, but with some extra features like automatic rollbacks and lifecycle hooks
oc get dc
oc get dc -o yaml
oc describe dc <dc_id>
λ oc describe dc nodejs-ex
Name: nodejs-ex
Namespace: cascon-oc-config
Created: 2 weeks ago
Labels: app=nodejs-ex
Annotations: openshift.io/generated-by=OpenShiftNewApp
Latest Version: 7
Selector: app=nodejs-ex,deploymentconfig=nodejs-ex
Replicas: 1
Triggers: Config, Image(nodejs-ex@latest, auto=true)
Strategy: Rolling
Template:
Pod Template:
Labels: app=nodejs-ex
deploymentconfig=nodejs-ex
Annotations: openshift.io/generated-by=OpenShiftNewApp
Containers:
nodejs-ex:
Image: 172.30.1.1:5000/cascon-oc-config/nodejs-ex@sha256:5b48b528252a0b9ae4be130eb5f5db830764096fae61f5ed0ffb6307b015e643
Port: 8080/TCP
Host Port: 0/TCP
Environment:
DATABASE_SERVICE_NAME: mongodb
MONGODB_USER: Optional: false
MONGODB_DATABASE: Optional: false
MONGODB_PASSWORD: badpassword
MONGODB_ADMIN_PASSWORD: Optional: false
Mounts:
Volumes:
Deployment #7 (latest):
Name: nodejs-ex-7
Created: about an hour ago
Status: Complete
Replicas: 1 current / 1 desired
Selector: app=nodejs-ex,deployment=nodejs-ex-7,deploymentconfig=nodejs-ex
Labels: app=nodejs-ex,openshift.io/deployment-config.name=nodejs-ex
Pods Status: 1 Running / 0 Waiting / 0 Succeeded / 0 Failed
Deployment #6:
Created: about an hour ago
Status: Failed
Replicas: 0 current / 0 desired
Deployment #5:
Created: 13 days ago
Status: Complete
Replicas: 0 current / 0 desired
Events:
Type Reason Age From Message
---- ------ ---- ---- -------
Normal DeploymentCreated 59m deploymentconfig-controller Created new replication controller "nodejs-ex-7" for version 7
Normal RolloutCancelled 59m deployer-controller Rollout for "cascon-oc-config/nodejs-ex-6" cancelled
Normal DeploymentAwaitingCancellation 59m (x7 over 59m) deploymentconfig-controller Deployment of version 7 awaiting cancellation of older running deployments
Normal DeploymentCancelled 59m deploymentconfig-controller Cancelled deployment "nodejs-ex-6" superceded by version 7
- Build Config
A build config describes how to take input like source code or an image and create a build, and ties in build hooks and triggers
oc get bc
oc get bc -o yaml
oc describe bc <bc_id>
λ oc describe bc nodejs-ex Name: nodejs-ex Namespace: cascon-oc-config Created: 2 weeks ago Labels: app=nodejs-ex Annotations: openshift.io/generated-by=OpenShiftNewApp Latest Version: 1 Strategy: Source URL: https://github.com/cloud-coder/cascon-2019-openshift From Image: ImageStreamTag openshift/nodejs:10 Output to: ImageStreamTag nodejs-ex:latest Build Run Policy: Serial Triggered by: Config, ImageChange Webhook GitHub: URL: https://192.168.64.2:8443/apis/build.openshift.io/v1/namespaces/cascon-oc-config/buildconfigs/nodejs-ex/webhooks//github Webhook Generic: URL: https://192.168.64.2:8443/apis/build.openshift.io/v1/namespaces/cascon-oc-config/buildconfigs/nodejs-ex/webhooks//generic AllowEnv: false Builds History Limit: Successful: 5 Failed: 5 Build Status Duration Creation Time nodejs-ex-1 complete 18s 2019-10-10 14:06:17 -0400 EDT Events:
How Builds Work - Builds | Developer Guide | OpenShift Container Platform 3.4
- Image Streams
Image streams are a way of abstracting references to Docker images, using tags to point to specific container images
oc get is
oc describe is <is_id>
Example: Using ImageStreams
oc get is -> list image streams
oc tag nodejs-ex:latest nodejs-ex:test5 -> tag latest build as "test5"
λ oc describe is nodejs-ex
Name: nodejs-ex
Namespace: cascon-oc-config
Created: 2 weeks ago
Labels: app=nodejs-ex
Annotations: openshift.io/generated-by=OpenShiftNewApp
Docker Pull Spec: 172.30.1.1:5000/cascon-oc-config/nodejs-ex
Image Lookup: local=false
Unique Images: 1
Tags: 3
latest
no spec tag
* 172.30.1.1:5000/cascon-oc-config/nodejs-ex@sha256:5b48b528252a0b9ae4be130eb5f5db830764096fae61f5ed0ffb6307b015e643
2 weeks ago
test1
tagged from nodejs-ex@sha256:5b48b528252a0b9ae4be130eb5f5db830764096fae61f5ed0ffb6307b015e643
* 172.30.1.1:5000/cascon-oc-config/nodejs-ex@sha256:5b48b528252a0b9ae4be130eb5f5db830764096fae61f5ed0ffb6307b015e643
13 days ago
test5
tagged from nodejs-ex@sha256:5b48b528252a0b9ae4be130eb5f5db830764096fae61f5ed0ffb6307b015e643
* 172.30.1.1:5000/cascon-oc-config/nodejs-ex@sha256:5b48b528252a0b9ae4be130eb5f5db830764096fae61f5ed0ffb6307b015e643
11 seconds ago
- Routes
A route exposes a service by giving it a externally-reachable hostname.
oc get routes
oc describe route <route_id>
λ oc describe route/nodejs-ex Name: nodejs-ex Namespace: cascon-oc-config Created: 2 weeks ago Labels: app=nodejs-ex Annotations: openshift.io/host.generated=true Requested Host: nodejs-ex-cascon-oc-config.192.168.64.2.nip.io exposed on router router 2 weeks ago Path: TLS Termination: Insecure Policy: Endpoint Port: 8080-tcp Service: nodejs-ex Weight: 100 (100%) Endpoints: 172.17.0.8:8080
Let's break our app!
- Make sure everything is working
λ oc get pods
NAME READY STATUS RESTARTS AGE
mongodb-1-7xgzg 1/1 Running 1 13d
nodejs-ex-1-build 0/1 Completed 0 13d
nodejs-ex-7-kj5pc 1/1 Running 0 35s- Mess up a deployment config
λ oc edit dc nodejs-exLook for this part of the deployment config:
spec:
containers:
- env:
- name: MONGODB_USER
valueFrom:
secretKeyRef:
key: database-user
name: mongodb
- name: MONGODB_PASSWORD
valueFrom:
secretKeyRef:
key: database-password
name: mongodb
- name: MONGODB_ADMIN_PASSWORD
valueFrom:
secretKeyRef:
key: database-admin-password
name: mongodb
- name: MONGODB_DATABASE
valueFrom:
secretKeyRef:
key: database-name
name: mongodbChange the password to a regular string:
- name: MONGODB_PASSWORD
value: wrongpasswordSave the file, and Openshift will use the new deployment config to create a new pod where the nodejs application can no longer connect to the database.
If you broke it correctly, the new pod should be up and running.
λ oc get pods
NAME READY STATUS RESTARTS AGE
mongodb-1-7xgzg 1/1 Running 1 13d
nodejs-ex-1-build 0/1 Completed 0 13d
nodejs-ex-7-tgjj2 1/1 Running 0 34mCheck the logs for the new pod
λ oc logs nodejs-ex-7-tgjj2
git version 1.8.3.1
Environment:
DEV_MODE=false
NODE_ENV=production
DEBUG_PORT=5858
Running as user uid=1001(default) gid=0(root) groups=0(root)
...
Server running on http://0.0.0.0:8080
Error connecting to Mongo. Message:
MongoError: Authentication failed.Check the application, if you're unsure of the url, check the routes:
λ oc get routes
NAME HOST/PORT PATH SERVICES PORT TERMINATION WILDCARD
nodejs-ex nodejs-ex-cascon-oc-config.192.168.64.2.nip.io nodejs-ex 8080-tcp NoneThe application now says that there is no database configured.
odo (or Openshift Do) is essentially a wrapper around the oc command-line tool to simplify everything for developers who might not know the details about Kubernetes or Openshift
In 3 commands you can build and deploy a new application with just the source code.
odo create nodejs
odo url create
odo push
Other odo commands:
odo project create myproject
odo catalog list components
odo log -f
odo create nodejs frontend
odo url create or odo url create frontend --port 8080
odo push
odo watch or odo watch &
odo url list