Summary - Deployment

Combine YAML, replicas and rollout to manage a Deployment.

Summary: Deployment

In this group:

The Deployment → ReplicaSet → Pod chain; a new ReplicaSet opens when the template changes.
YAML: apps/v1, replicas, selector.matchLabels (must match the template label), template; resources requests/limits.
Scaling: declarative (replicas + apply) or kubectl scale; rollout status waits.
Rolling update: maxSurge/maxUnavailable; set image and the change-cause annotation.
rollout history/undo/pause/resume/restart handle version management.

kubectl apply -f web.yaml
kubectl rollout status deploy/web
kubectl rollout undo deploy/web

Exercise A deployment with a safe strategy

Write a Deployment YAML: name web, replicas: 4; under strategy, type: RollingUpdate, maxSurge: 1, maxUnavailable: 0; selector and template label app: web; container named nginx, image nginx:1.27.

Show example solution

apiVersion: apps/v1
kind: Deployment
metadata:
  name: web
spec:
  replicas: 4
  strategy:
    type: RollingUpdate
    rollingUpdate:
      maxSurge: 1
      maxUnavailable: 0
  selector:
    matchLabels:
      app: web
  template:
    metadata:
      labels:
        app: web
    spec:
      containers:
        - name: nginx
          image: nginx:1.27

Test yourself

With replicas: 4, maxSurge: 1, maxUnavailable: 0, at most how many pods can run at once during an update?
- 8
- 3
- 5
- 4
Show answer

5 — 4 + maxSurge 1 = 5; it never drops below 4.

Specify the update strategy.

spec:
  strategy:
    type: ____

Show answer

spec:
  strategy:
    type: RollingUpdate

Match.

RollingUpdate

Gradual
Recreate

Close all first
revisionHistoryLimit

Kept ReplicaSet count
OOMKilled

Memory limit exceeded

Next lesson: What is a ReplicaSet?

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