Exercise 2: Logging and monitoring

In this exercise, we'll explore the out-of-the-box logging and monitoring capabilities that are offered in OpenShift.

Simulate Load on the Application

First, let's simulate some load on our application. Run the following script which will endlessly spam our app with requests:

With Linux/MacOS

while sleep 1; do curl -s <your_app_route>/info; done

With Windows

while($true){curl <your_app_route>/info}

Note: Retrieve the external URL from the OpenShift console, or from the URL of your Example Health application. Note that there may be an /index.html at the end that you need to replace with /info. We're hitting the /info endpoint which will trigger some logs from our app. For example:

http://patientui-health-example.myopenshift-xxx.us-east.containers.appdomain.cloud/info

OpenShift Logging

Since we only created one pod, seeing our logs will be straight forward. Navigate to Applications > Pods menu on the left on the console. You'll see two pods here, one for the build (that's already :heavy_check_mark: Completed), and one for the pod that is running your application.

Pods

Click into the Running pod and navigate to the Logs tab. You should see the Node.js application start-up logs, as well as periodic logs from your curl loop.

Logs

OpenShift Terminal

One of the great things about Kubernetes is the ability to quickly debug your application pods with SSH terminals. This is great for development, but generally is not recommended in production environments. OpenShift makes it even easier by allowing you to launch a terminal directly in the dashboard.

Switch to the Terminal tab, and run the following commands.

# This command shows you the the project files.
ls

# This command shows you the running processes.
ps aux

Terminal

OpenShift Monitoring

When deploying new apps, making configuration changes, or simply inspecting the state of your cluster, the OpenShift monitoring dashboard gives you an overview of your running assets. Access the Dashboard now by going to the Monitoring tab on the left side menu.

You can also dive in a bit deeper - the Events view is very useful for identifying the timeline of events and finding potential error messages. Hit the 'View Details' button on the top right.

View Details

You'll want to refer to this view throughout the lab. Almost all actions we take in in OpenShift will result in an event being fired in this view. As it is updated real-time, it's a great way to track changes to state.