Kaniko with S3 build context builds containers on EKS without Docker

Needed to build container images on EKS but couldn't run a Docker daemon. Kaniko's S3 build context feature solved it cleanly.

Upload source as tar.gz to S3, then point the Kaniko Job at it with --context=s3://.

apiVersion: batch/v1
kind: Job
metadata:
  name: kaniko-build
  namespace: build
spec:
  template:
    spec:
      serviceAccountName: kaniko
      containers:
      - name: kaniko
        image: gcr.io/kaniko-project/executor:latest
        args:
        - "--context=s3://my-bucket/build/context.tar.gz"
        - "--destination=123456789.dkr.ecr.ap-northeast-1.amazonaws.com/my-app:latest"
      restartPolicy: Never

The key is granting ECR push permissions (ecr:PutImage, ecr:CompleteLayerUpload, etc.) and S3 read permissions to the kaniko service account via Pod Identity. No credential mounts needed — Pod Identity handles it automatically. Build times were 70-130 seconds for a Python app.