Conventions used

There are a number of text conventions used throughout this book.

Code in text: Indicates code words in text, database table names, folder names, filenames, file extensions, pathnames, dummy URLs, user input, and Twitter handles. Here is an example: “You should receive an error message indicating that the namespace must have the environment label. Update the test-namespace.yaml file to include the required label, and the namespace creation should be allowed.”

A block of code is set as follows:

kind: NetworkPolicy
apiVersion: networking.k8s.io/v1
metadata:
  name: frontend-to-backend
spec:
  podSelector:
    matchLabels:
      app: backend
  policyTypes:
  - Ingress
  ingress:
  - from:
    - podSelector:
        matchLabels:
          app: frontend
    ports:
    - protocol: TCP
      port: 80
---
kind: NetworkPolicy
apiVersion: networking.k8s.io/v1
metadata:
  name: backend-to-database
spec:
  podSelector:
    matchLabels:
      app: database
  policyTypes:
  - Ingress
  ingress:
  - from:
    - podSelector:
        matchLabels:
          app: backend
    ports:
    - protocol: TCP
      port: 3306

Any command-line input or output is written as follows:

$ kubectl apply -f networkPolicy.yaml

Bold: Indicates a new term, an important word, or words that you see onscreen. For instance, words in menus or dialog boxes appear in bold. Here is an example: “To create a new visualization, click on the Visualize tab in the left-hand menu. Click Create visualization to start creating a new visualization.”

Tips or important notes

Appear like this.