Understanding & Optimising Your Application with APM

Here's a quick four step guide from us here at Divio to help you with APM.

Quick note: For help with using the Divio cloud PaaS for your applications, reach out to us for support using live chat or check our documentation.

But before we get stuck into the guide, let's take a closer look at APM and what it actually is.

What is APM?

APM is a general term that can comprise different metrics - such as application performance, code level profiling and network-based performance. In general, the goal of APM is to turn a black box product or service into something more transparent by providing insights into performance - something that different testing strategies might otherwise miss.

What APM Tool Should You Use?

Depending on your application type, different APM solutions can provide more granular and specialised tools to help you make sense of your application.

There are many different APM providers, but for this example, we will use Elastic APM as a popular, open-source choice and where the Elastic stack can be combined to add features such as logging and proactive monitoring. If you already have a preferred APM provider, the same general process should apply to integrating with a Divio project.

Step 1: Getting Started

To get started, head over to Elastic and create an account for the Elasticsearch service. For this post, the free trial account that Elastic provide will be sufficient.

Once you have created and activated your account, start an initial deployment to the cloud provider of your choice which is ideally in the same region as your Divio project to minimise the time differential.

While the deployment is in progress, be sure to note the one-time credentials (username, password, APM secret token etc.). Existing credentials cannot be revealed once deployed and will require resetting.

Step 2: Install Addon

Once your Elastic deployment is complete, from the Divio Control Panel, install the free "Divio Telemetry" addon into the application you wish to observe.

In order to complete the setup of the telemetry addon, the DEFAULT"_APM"_DSN environmental variable needs to be set. This can be done through the Control Panel, setting the variable for your test and live environments respectively and through the .env-local file on your local development environment.

Add the following to your .env-local file:

DEFAULT_APM_DSN = https://DIVIO_APP_NAME:APM_SECRET_TOKEN@ELASTIC_HOSTNAME.co:443

Note that the APM_SECRET_TOKEN and ELASTIC_HOSTNAME should reflect your settings in the Elastic Cloud. Your ELASTIC_HOSTNAME can be found through the Elastic deployment dashboard by copying the link the "APM Server URL".

Step 3: Begin Testing Connection

We can begin locally testing the connection with Elastic APM Server by running "divio app update" followed by "divio app up" to launch your local project.

Once your project is launched, login to the APM service through the Elastic Cloud control panel using your noted credentials. You may have to wait a few minutes for your local data to become available in the APM application.

If you don't see any results within a few minutes, you may have to add an index pattern. Click on the APM configuration link on the Kibana/APM dashboard and hit the "Load Kibana objects" button. This essentially prompts a refresh of your project data to allow it to be visualised. You should also double check the DEFAULT"_APM"_DSN is correctly set.

In this post, we wont explore Kibana rather it is best explained through the extensive Elastic documentation.

Step 4: Repeat

Once your data is available, we can proceed to repeat the steps for your test and live environments which each environment having its own view within Elastic APM.

As your application is being used and data gathered, you can explore the telemetry data to find bottlenecks or areas ripe for optimisation using Elastic APM.

If you're interested in further configuration options and the Elastic stack, refer to the Elastic documentation here.

You can find the source code for the Divio telemetry addon here.