Add skeleton for autoscaling example and documentation

autoscaling/api/deploy.sh

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+#!/bin/bash
+
+# Deploy infrastructure using the raw Unikraft Cloud REST API
+# Usage: ./api/deploy.sh
+
+TOKEN="${UKC_TOKEN}"
+METRO="${UKC_METRO:-fra}"
+API_URL="https://api.${METRO}.unikraft.cloud/v1"
+GROUP_NAME="my-scaling-group"
+
+if [ -z "$TOKEN" ]; then
+    echo "[-] Error: UKC_TOKEN is not set. Please export it before running."
+    exit 1
+fi
+
+echo "[+] Creating service group '$GROUP_NAME' via Unikraft Cloud API..."
+curl -s -X POST "${API_URL}/services" \
+  -H "Authorization: Bearer ${TOKEN}" \
+  -H "Content-Type: application/json" \
+  -d "{
+    \"name\": \"${GROUP_NAME}\",
+    \"services\": [
+      {
+        \"port\": 443,
+        \"destination_port\": 8080,
+        \"handlers\": [\"http\", \"tls\"]
+      }
+    ]
+  }"
+
+echo -e "\n[+] Service group deployment request sent successfully."

autoscaling/api/scale.sh

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+#!/bin/bash
+
+# Configure autoscale policy using the raw Unikraft Cloud REST API
+# Usage: ./api/scale.sh
+
+TOKEN="${UKC_TOKEN}"
+METRO="${UKC_METRO:-fra}"
+API_URL="https://api.${METRO}.unikraft.cloud/v1"
+GROUP_NAME="my-scaling-group"
+TEMPLATE_NAME="my-first-instance"
+
+if [ -z "$TOKEN" ]; then
+    echo "[-] Error: UKC_TOKEN is not set. Please export it before running."
+    exit 1
+fi
+
+echo "[+] Configuring autoscale policy for '$GROUP_NAME' via API..."
+# Changed the identifier key to "name" to match the root properties of the cloud resource
+curl -s -X POST "${API_URL}/services/autoscale" \
+  -H "Authorization: Bearer ${TOKEN}" \
+  -H "Content-Type: application/json" \
+  -d "{
+    \"name\": \"${GROUP_NAME}\",
+    \"min_size\": 0,
+    \"max_size\": 1,
+    \"create_args\": {
+      \"template\": {
+        \"name\": \"${TEMPLATE_NAME}\"
+      }
+    },
+    \"policies\": [
+      {
+        \"name\": \"my-cpu-policy\",
+        \"type\": \"step\",
+        \"metric\": \"cpu\",
+        \"adjustment_type\": \"percent\",
+        \"steps\": [
+          { \"lower_bound\": 600, \"upper_bound\": 800, \"adjustment\": 50 },
+          { \"lower_bound\": 800, \"adjustment\": 100 }
+        ]
+      }
+    ]
+  }"
+
+echo -e "\n[+] Autoscale policy configuration request sent successfully."

autoscaling/app/Dockerfile

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+# Stage 1: Build the Go server
+FROM golang:1.21 as builder
+WORKDIR /src
+COPY main.go .
+# Unikraft requires a dynamically linked binary (PIE - Position Independent Executable)
+RUN CGO_ENABLED=0 GOOS=linux go build -buildmode=pie -a -installsuffix cgo -o /autoscaling-test main.go
+
+# Stage 2: Final image
+# We use debian-slim instead of scratch to provide the dynamic linker (ld-linux.so) required by the PIE binary above
+FROM debian:bookworm-slim
+COPY --from=builder /autoscaling-test /autoscaling-test

autoscaling/app/Kraftfile

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+spec: v0.6
+name: autoscaling-test
+runtime: base:latest
+rootfs: ./Dockerfile
+# The command executed automatically when the unikernel starts
+cmd: ["/autoscaling-test"]
+# Set the internal port expected by the platform
+env:
+  PORT: "8080"

autoscaling/app/main.go

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+package main
+
+import (
+	"fmt"
+	"net/http"
+	"os"
+)
+
+// The handler responds with the current instance's hostname.
+// Under heavy load, when the autoscaler creates clones, we will see different hostnames here.
+func handler(w http.ResponseWriter, r *http.Request) {
+	hostname, _ := os.Hostname()
+	fmt.Fprintf(w, "Hello from KraftCloud! Responding instance: %s\n", hostname)
+}
+
+func main() {
+	http.HandleFunc("/", handler)
+	fmt.Println("Server starting on port 8080...")
+	http.ListenAndServe(":8080", nil)
+}

autoscaling/kraft/deploy.sh

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+#!/bin/bash
+
+# Deploy an instance and assign it to a service group.
+# Usage: ./deploy.sh <instance-name> <service-group>
+# Example: ./deploy.sh my-first-instance my-scaling-group
+
+NAME=${1:-my-first-instance}
+GROUP=${2:-my-scaling-group}
+
+echo "[+] Creating service group $GROUP (if it doesn't exist)..."
+# Create the service group. We use '|| true' so the script doesn't fail if the group already exists.
+kraft cloud service create -n $GROUP 443:8080/http+tls || true
+
+echo "[+] Deploying instance $NAME to service group $GROUP..."
+# We append ./app at the end to explicitly tell KraftKit where the Kraftfile and Dockerfile are located.
+kraft cloud deploy -M 512M -g $GROUP --name $NAME ./app

autoscaling/kraft/scale.sh

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+#!/bin/bash
+
+# Configure the autoscaling policy for a service group.
+# Usage: ./scale.sh <service-group> <template-instance>
+# Example: ./scale.sh my-scaling-group my-first-instance
+
+GROUP=${1:-my-scaling-group}
+TEMPLATE=${2:-my-first-instance}
+
+echo "[+] Initializing autoscale configuration for service group $GROUP using template $TEMPLATE..."
+# The template was already successfully created, so we just ensure the autoscaler is initialized
+kraft cloud scale init $GROUP --min-size 0 --max-size 1 --template $TEMPLATE || true
+
+echo "[+] Configuring CPU autoscaling policy..."
+kraft cloud scale add $GROUP \
+  --name my-cpu-policy \
+  --metric cpu \
+  --adjustment percent \
+  --step 600:800/50 \
+  --step 800:/100 || true