Helm template for Antifragile patterns¶
Estimated time to read: 4 minutes
Creating a single Helm chart to demonstrate antifragile patterns in a single application may not be feasible, as some patterns are more relevant to specific use cases or system architectures. However, I can provide you with a sample Helm chart that includes some of these patterns and comments on how to implement other patterns.
Find below a Helm chart demonstrating a simple application with some antifragile patterns. Please note that you must replace your-docker-image with your actual Docker image name.
Chart.yaml:
apiVersion: v2
name: antifragile-demo
description: A Helm chart demonstrating antifragile patterns
version: 0.1.0
values.yaml:
replicaCount: 2 # Redundancy
image:
repository: your-docker-image
pullPolicy: IfNotPresent
service:
type: ClusterIP
port: 80
ingress:
enabled: false
annotations: {}
hosts:
- host: chart-example.local
paths:
- /
tls: []
resources: {}
autoscaling:
enabled: false
minReplicas: 2
maxReplicas: 4
targetCPUUtilizationPercentage: 50
istio:
enabled: true
retries: 3
timeout: 5s
rateLimit:
enabled: true
requestsPerSecond: 5
burst: 10
loadShedding:
enabled: true
httpRequestTimeout: 5s
maxRetries: 3
retryOn: "5xx,connect-failure,refused-stream"
circuitBreaker:
consecutiveErrors: 5
interval: 5s
baseEjectionTime: 30s
maxEjectionPercent: 10
connectionPool:
http:
http1MaxPendingRequests: 1024
maxRequestsPerConnection: 10
tcp:
maxConnections: 1024
connectTimeout: 5s
templates/deployment.yaml:
apiVersion: apps/v1
kind: Deployment
metadata:
name: {{ include "antifragile-demo.fullname" . }}
labels:
{{- include "antifragile-demo.labels" . | nindent 4 }}
spec:
replicas: {{ .Values.replicaCount }} # Redundancy
selector:
matchLabels:
{{- include "antifragile-demo.selectorLabels" . | nindent 6 }}
template:
metadata:
labels:
{{- include "antifragile-demo.selectorLabels" . | nindent 8 }}
annotations:
sidecar.istio.io/rewriteAppHTTPProbers: "true"
spec:
containers:
- name: {{ .Chart.Name }}
image: "{{ .Values.image.repository }}:{{ .Chart.AppVersion }}"
imagePullPolicy: {{ .Values.image.pullPolicy }}
ports:
- name: http
containerPort: 80
protocol: TCP
resources:
{{- toYaml .Values.resources | nindent 12 }}
templates/service.yaml:
apiVersion: v1
kind: Service
metadata:
name: {{ include "antifragile-demo.fullname" . }}
labels:
{{- include "antifragile-demo.labels" . | nindent 4 }}
spec:
type: {{ .Values.service.type }}
ports:
- port: {{ .Values.service.port }}
targetPort: http
protocol: TCP
name: http
selector:
{{- include "antifragile-demo.selectorLabels" . | nindent 4 }}
templates/hpa.yaml:
{{- if .Values.autoscaling.enabled }}
apiVersion: autoscaling/v1
kind: HorizontalPodAutoscaler
metadata:
name: {{ include "antifragile-demo.fullname" . }}
labels:
{{- include "antifragile-demo.labels" . | nindent 4 }}
spec:
scaleTargetRef:
apiVersion: apps/v1
kind: Deployment
name: {{ include "antifragile-demo.fullname" . }}
minReplicas: {{ .Values.autoscaling.minReplicas }}
maxReplicas: {{ .Values.autoscaling.maxReplicas }}
targetCPUUtilizationPercentage: {{ .Values.autoscaling.targetCPUUtilizationPercentage }}
{{- end }}
templates/istio-virtual-service.yaml:
{{- if .Values.istio.enabled }}
apiVersion: networking.istio.io/v1beta1
kind: VirtualService
metadata:
name: {{ include "antifragile-demo.fullname" . }}
spec:
hosts:
- "*"
gateways:
- istio-system/istio-autogenerated-k8s-ingress
http:
- match:
- uri:
prefix: /
route:
- destination:
host: {{ include "antifragile-demo.fullname" . }}.{{ .Release.Namespace }}.svc.cluster.local
port:
number: 80
retries:
attempts: {{ .Values.istio.loadShedding.maxRetries }}
perTryTimeout: {{ .Values.istio.loadShedding.httpRequestTimeout }}
retryOn: {{ .Values.istio.loadShedding.retryOn }}
timeout: {{ .Values.istio.loadShedding.httpRequestTimeout }}
{{- end }}
templates/istio-destination-rule.yaml:
{{- if .Values.istio.enabled }}
apiVersion: networking.istio.io/v1beta1
kind: DestinationRule
metadata:
name: {{ include "antifragile-demo.fullname" . }}
spec:
host: {{ include "antifragile-demo.fullname" . }}.{{ .Release.Namespace }}.svc.cluster.local
trafficPolicy:
connectionPool:
http:
http1MaxPendingRequests: {{ .Values.istio.connectionPool.http.http1MaxPendingRequests }}
maxRequestsPerConnection: {{ .Values.istio.connectionPool.http.maxRequestsPerConnection }}
tcp:
maxConnections: {{ .Values.istio.connectionPool.tcp.maxConnections }}
connectTimeout: {{ .Values.istio.connectionPool.tcp.connectTimeout }}
outlierDetection:
consecutiveErrors: {{ .Values.istio.circuitBreaker.consecutiveErrors }}
interval: {{ .Values.istio.circuitBreaker.interval }}
baseEjectionTime: {{ .Values.istio.circuitBreaker.baseEjectionTime }}
maxEjectionPercent: {{ .Values.istio.circuitBreaker.maxEjectionPercent }}
{{- if .Values.istio.rateLimit.enabled }}
loadBalancer:
simple: LEAST_CONN
rateLimit:
http1MaxPendingRequests: {{ .Values.istio.rateLimit.requestsPerSecond }}
{{- end }}
{{- end }}
These templates demonstrate several antifragile patterns, including Redundancy, Self-healing, Rate limiting, Monitoring and observability (when combined with Prometheus and Grafana), and Adaptive capacity Circuit breakers, Bulkheads, Isolation, and Timeouts: Use Istio to apply these patterns on the network level between microservices. Graceful degradation: Design your application to handle partial failures and continue functioning at reduced capacity. Load shedding: Use rate limiting and adaptive capacity to prevent system overload.
To cover other antifragile patterns, consider the following:
- Diversity: Deploy multiple versions of your application or use different technology stacks for different components.
- Modularity: Break your application into smaller, independent components (microservices).
- Loose coupling: Minimize dependencies between components and design them to communicate through well-defined interfaces.
- Feedback loops: Continuously monitor the health and performance of your system and use the collected data to adjust and improve.
To deploy the Helm chart:
Remember that this example template. You need to provide the details required to run in your environment.