Integrate Jaeger with Istio service mesh for distributed tracing

#!/usr/bin/env bash
set -euo pipefail

# ---------------------------------------------------------------------------
# Istio + Jaeger distributed tracing installer
# Supports: Ubuntu, Debian, AlmaLinux, Rocky Linux
# ---------------------------------------------------------------------------

ISTIO_VERSION="${1:-1.23.2}"
WORKDIR="$(pwd)/istio-jaeger-install"
LOG_FILE="/tmp/istio-jaeger-install.log"

# --- Colors ---
RED='\033[0;31m'
GREEN='\033[0;32m'
YELLOW='\033[1;33m'
NC='\033[0m'

log_info()  { echo -e "${GREEN}[INFO]${NC} $*"; }
log_warn()  { echo -e "${YELLOW}[WARN]${NC} $*"; }
log_error() { echo -e "${RED}[ERROR]${NC} $*"; }

usage() {
    echo "Usage: $0 [ISTIO_VERSION]"
    echo "  ISTIO_VERSION   Optional. Default: 1.23.2"
    echo "Example: $0 1.23.2"
    exit 1
}

if [[ "${1:-}" == "-h" || "${1:-}" == "--help" ]]; then
    usage
fi

# --- Rollback on failure ---
cleanup_on_error() {
    log_error "Installation failed. See $LOG_FILE for details."
    log_warn "Attempting rollback of partially created resources..."
    if command -v istioctl >/dev/null 2>&1; then
        istioctl uninstall --purge -y >>"$LOG_FILE" 2>&1 || true
    fi
    if command -v helm >/dev/null 2>&1; then
        helm uninstall jaeger -n istio-system >>"$LOG_FILE" 2>&1 || true
    fi
    if command -v kubectl >/dev/null 2>&1; then
        kubectl delete namespace istio-system --ignore-not-found >>"$LOG_FILE" 2>&1 || true
    fi
    exit 1
}
trap cleanup_on_error ERR

# --- Root/sudo check ---
if [[ "$EUID" -ne 0 ]]; then
    if ! command -v sudo >/dev/null 2>&1; then
        log_error "This script must be run as root or with sudo available."
        exit 1
    fi
    SUDO="sudo"
else
    SUDO=""
fi

# --- Distro detection ---
echo "[1/10] Detecting operating system..."
if [ -f /etc/os-release ]; then
    . /etc/os-release
    case "$ID" in
        ubuntu|debian) PKG_MGR="apt"; PKG_INSTALL="apt install -y" ;;
        almalinux|rocky|centos|rhel|ol|fedora) PKG_MGR="dnf"; PKG_INSTALL="dnf install -y" ;;
        amzn) PKG_MGR="yum"; PKG_INSTALL="yum install -y" ;;
        *) log_error "Unsupported distro: $ID"; exit 1 ;;
    esac
else
    log_error "/etc/os-release not found. Cannot detect distro."
    exit 1
fi
log_info "Detected distro: $ID ($PKG_MGR)"

# --- Prerequisite checks ---
echo "[2/10] Checking prerequisite tools..."
if ! command -v kubectl >/dev/null 2>&1; then
    log_error "kubectl not found. Please install kubectl and configure cluster access first."
    exit 1
fi

log_info "Verifying cluster access..."
if ! kubectl cluster-info >>"$LOG_FILE" 2>&1; then
    log_error "Cannot reach Kubernetes cluster. Check your kubeconfig."
    exit 1
fi

NODE_COUNT=$(kubectl get nodes --no-headers 2>>"$LOG_FILE" | wc -l)
if [ "$NODE_COUNT" -lt 1 ]; then
    log_error "No worker nodes found in cluster."
    exit 1
fi
log_info "Cluster reachable with $NODE_COUNT node(s)."

# --- Install OS packages ---
echo "[3/10] Installing required packages (curl, tar, unzip)..."
if [ "$PKG_MGR" = "apt" ]; then
    $SUDO apt update >>"$LOG_FILE" 2>&1
    $SUDO $PKG_INSTALL curl tar unzip >>"$LOG_FILE" 2>&1
else
    $SUDO $PKG_INSTALL curl tar unzip >>"$LOG_FILE" 2>&1
fi
log_info "Base packages installed."

# --- Prepare working directory ---
echo "[4/10] Preparing working directory..."
mkdir -p "$WORKDIR"
chmod 755 "$WORKDIR"
cd "$WORKDIR"

# --- Install istioctl ---
echo "[5/10] Downloading and installing istioctl ${ISTIO_VERSION}..."
if [ ! -d "istio-${ISTIO_VERSION}" ]; then
    curl -sL "https://istio.io/downloadIstio" | ISTIO_VERSION="${ISTIO_VERSION}" sh - >>"$LOG_FILE" 2>&1
fi
export PATH="${WORKDIR}/istio-${ISTIO_VERSION}/bin:$PATH"

if ! command -v istioctl >/dev/null 2>&1; then
    log_error "istioctl installation failed."
    exit 1
fi
log_info "istioctl installed: $(istioctl version --remote=false 2>>"$LOG_FILE")"

# --- Install Helm ---
echo "[6/10] Installing Helm (if not already present)..."
if ! command -v helm >/dev/null 2>&1; then
    curl -sL https://raw.githubusercontent.com/helm/helm/main/scripts/get-helm-3 -o get-helm-3.sh
    chmod 755 get-helm-3.sh
    $SUDO ./get-helm-3.sh >>"$LOG_FILE" 2>&1
fi
log_info "Helm version: $(helm version --short 2>>"$LOG_FILE")"

# --- Create istio-system namespace ---
echo "[7/10] Creating istio-system namespace..."
kubectl get namespace istio-system >/dev/null 2>&1 || kubectl create namespace istio-system

# --- Install Istio with tracing enabled ---
echo "[8/10] Installing Istio control plane with tracing enabled..."
cat > "${WORKDIR}/istio-config.yaml" <<'EOF'
apiVersion: install.istio.io/v1alpha1
kind: IstioOperator
spec:
  profile: default
  meshConfig:
    enableTracing: true
    defaultConfig:
      tracing:
        sampling: 10.0
    extensionProviders:
    - name: jaeger
      opentelemetry:
        service: jaeger-collector.istio-system.svc.cluster.local
        port: 4317
  values:
    global:
      proxy:
        tracer: "opentelemetry"
EOF
chmod 644 "${WORKDIR}/istio-config.yaml"

istioctl install -f "${WORKDIR}/istio-config.yaml" -y >>"$LOG_FILE" 2>&1
log_info "Istio installed with tracing enabled."

# --- Enable sidecar injection on demo namespace ---
echo "[9/10] Creating demo-app namespace with sidecar injection enabled..."
kubectl get namespace demo-app >/dev/null 2>&1 || kubectl create namespace demo-app
kubectl label namespace demo-app istio-injection=enabled --overwrite >>"$LOG_FILE" 2>&1

# --- Deploy Jaeger via Helm ---
echo "[10/10] Deploying Jaeger via Helm..."
helm repo add jaegertracing https://jaegertracing.github.io/helm-charts >>"$LOG_FILE" 2>&1
helm repo update >>"$LOG_FILE" 2>&1

cat > "${WORKDIR}/jaeger-values.yaml" <<'EOF'
provisionDataStore:
  cassandra: false
  elasticsearch: false

storage:
  type: memory

collector:
  service:
    otlp:
      grpc:
        name: otlp-grpc
        port: 4317
      http:
        name: otlp-http
        port: 4318

query:
  service:
    type: ClusterIP
EOF
chmod 644 "${WORKDIR}/jaeger-values.yaml"

if helm status jaeger -n istio-system >/dev/null 2>&1; then
    log_warn "Jaeger release already exists, upgrading..."
    helm upgrade jaeger jaegertracing/jaeger -n istio-system -f "${WORKDIR}/jaeger-values.yaml" >>"$LOG_FILE" 2>&1
else
    helm install jaeger jaegertracing/jaeger -n istio-system -f "${WORKDIR}/jaeger-values.yaml" >>"$LOG_FILE" 2>&1
fi

# --- Verification ---
echo "Waiting for Jaeger pods to become ready..."
if ! kubectl wait --for=condition=Ready pod -l app.kubernetes.io/name=jaeger -n istio-system --timeout=180s >>"$LOG_FILE" 2>&1; then
    log_error "Jaeger pods did not become ready in time."
    exit 1
fi

echo "Verifying Istio control plane pods..."
if ! kubectl get pods -n istio-system -l app=istiod --no-headers | grep -q Running; then
    log_error "Istiod pod is not running."
    exit 1
fi

log_info "Istio control plane pods:"
kubectl get pods -n istio-system

log_info "Jaeger components:"
kubectl get pods -n istio-system -l app.kubernetes.io/name=jaeger

log_info "Installation complete."
log_info "Deploy your microservices into the 'demo-app' namespace to get automatic sidecar injection and tracing."
log_info "Full log available at: $LOG_FILE"

trap - ERR
exit 0