Our goal is to deploy an application that will be automatically scaled (or de-scaled) depending on its use of resources. We’ll start by deploying an app first, and discuss how to accomplish auto-scaling later.

I already warned you that I assume that you are familiar with Kubernetes and that in this course we’ll explore a particular topic of monitoring, alerting, scaling, and a few other things. We will not discuss Pods, StatefulSets, Deployments, Services, Ingress, and other “basic” Kubernetes resources.

Deploy an application #

Let’s take a look at a definition of the application we’ll use in our examples.

cat scaling/go-demo-5-no-sidecar-mem.yml

If you are familiar with Kubernetes, the YAML definition should be self-explanatory. We’ll comment on only the parts that are relevant for auto-scaling.

The output, limited to the relevant parts, is as follows.

...
apiVersion: apps/v1
kind: StatefulSet
metadata:
  name: db
  namespace: go-demo-5
spec:
  ...
  template:
    ...
    spec:
      ...
      containers:
      - name: db
        ...
        resources:
          limits:
            memory: "150Mi"
            cpu: 0.2
          requests:
            memory: "100Mi"
            cpu: 0.1
        ...
      - name: db-sidecar
        ...

apiVersion: apps/v1
kind: Deployment
metadata:
  name: api
  namespace: go-demo-5
spec:
  ...
  template:
    ...
    spec:
      containers:
      - name: api
        ...
        resources:
          limits:
            memory: 15Mi
            cpu: 0.1
          requests:
            memory: 10Mi
            cpu: 0.01
...

We have two Pods that form an application. The api Deployment is a backend API that uses db StatefulSet for its state.

The essential parts of the definition are resources. Both the api and the db have requests ...