Deploying to Cloud Foundry and OpenShift

Scope

These are some notes/tutorial on what you’d do to deploy a simple app first to Cloud Foundry on the IBM Cloud, then the equivalent to OpenShift on the IBM Cloud. Hopefully this could be a “rosetta stone” if you’re coming from CF to OS.

Cloud Foundry

We’ll start with Cloud Foundry first, we’ll clone down a simple python app I’ve written then deploy it. Lets git clone this working repo down:

git clone git@github.com:jjasghar/cloud-native-python-example-app.git
cd cloud-native-python-example-app

As you can see it’s a very straight forward app, nothing too crazy pythonflask app. Go ahead and open up the main app.py.

vim app.py

Next we should verify that it works, this way we know our code works as we expect, and when we push it up to Cloud Foundry, everything should just fall into place.

Go ahead and create a virtualenv so you don’t “muddy up” your system python, and also verify you are running python3.

virtualenv venv
source ./venv/bin/active
python -v
Python 3.6.8 (default, Apr 2 2020, 13:34:55)
[GCC 4.8.5 20150623 (Red Hat 4.8.5-39)] on linux

Now install the dependancies, and verify it works as expected.

./venv/bin/pip install -r requirements.txt
./venv/bin/python app.py
# in another terminal
curl localhost:8080
curl localhost:8080/healthz
curl localhost:8080/healthzfoobar

Awesome, so we now see our output, lets take the next step to deploy it to Cloud Foundry. Open up the manifest.yaml to see the configuration.

---
applications:
  - name: hellonerds
    memory: 256M
    instances: 1

As you can see, it’s very straightforward, if you’re actually going to deploy this you’ll need to change the name. ;).

Next, open up the Procfile which is what tells Cloud Foundry how to run your application. Just like our local env, we just run the following:

web: python app.py

Next we need to log into the IBM Cloud via the CLI, and then push it up, luckily it’s pretty straight forward too.

ibmcloud login
ibmcloud cf install # if you haven't installed the cf plugin
ibmcloud target --cf
ibmcloud cf push # this will push the app into CF, and you should have your URL at the end

If you need to debug, use the following commands to check the logs, notice the --recent if you want to take the most recent logs.

ibmcloud cf logs hellonerds --recent

Awesome, and congrats, we have successfully ran our code locally and deployed our code to CF. Now lets look at the same code on OpenShift.

OpenShift

Now lets take the same code, and deploy it onto OpenShift. OpenShift under the covers is Kubernetes, so we’ll need to build a container and deploy it. If you notice, I already have a Dockerfile in the directory. If you want, you can build it locally, but as you can see it’s very sparse, and does what you’d expect such what a simple app would require.

The first step is you’ll need to login you OpenShift cluster, there’s a handful of ways to do this, I use the “Copy Login Command” from the main console, and get something like:

oc login --token=LARGETOKENHERE --server=https://c107-e.us-south.containers.cloud.ibm.com:31937

The next step is just good hygiene and practice with OpenShift, you need to create a new project.

oc new-project cfpython

You can name your project more or less anything, cfpython just seemed right at the time I’m writing this.

Now that you’ve created this, lets push the app into OpenShift, we’ll create a new app,

cd cloud-native-python-example-app # if you aren't there
oc new-app . # you can also do the following if you want to point it to a remote --> oc new-app https://github.com/jjasghar/cloud-native-python-example-app.git

You’ll notice that it’ll find the Dockerfile almost instantly, and even identify that it’s an python:3.7-alpine. Pretty neat eh?

It’ll kick off the build, and you can track it like it says:

oc logs -f bc/cloud-native-python-example-app
[-- snip --]
Successfully pushed image-registry.openshift-image-registry.svc:5000/cfpython/cloud-native-python-example-app@sha256:88209ad85f84a1094e1e2da1e1ed9fa05414022b64b7ee22000b2ac46f2bf544
Push successful

Next, we need to expose the app, that's with the following command:

oc expose svc/cloud-native-python-example-app
oc status # will give you the URL :)

Awesome! You’ve successfully deployed the same app into OpenShift now. The next step is to use Web-hooks with OpenShift and GitHub, so you can just commit to your repository, and kick off builds automatically. If you’d like to see that demo, I’ll have a YouTube link here walking through the beginning of this to the auto deploy.