client-daemonset.yaml

# TCP client that connects to the demo server every 5 seconds.
# Runs on nodes labeled role=client (multiple nodes in the demo cluster).
#
# Reads the server address from the server-config ConfigMap, which is
# created by setup.sh with the server node's internal IP.
#
# Usage:
#   kubectl apply -f client-daemonset.yaml
#   kubectl logs -l app=demo-client --all-containers --prefix -f
apiVersion: apps/v1
kind: DaemonSet
metadata:
  name: demo-client
  labels:
    app: demo-client
spec:
  selector:
    matchLabels:
      app: demo-client
  template:
    metadata:
      labels:
        app: demo-client
    spec:
      runtimeClassName: reaper-v2
      nodeSelector:
        role: client
      containers:
        - name: client
          image: busybox
          env:
            - name: SERVER_IP
              valueFrom:
                configMapKeyRef:
                  name: server-config
                  key: SERVER_IP
          command: ["/bin/sh", "-c"]
          args:
            - |
              echo "Client starting on $(hostname), server at $SERVER_IP:9090"
              while true; do
                response=$(echo "" | socat -T2 - TCP:$SERVER_IP:9090 2>&1)
                if [ $? -eq 0 ]; then
                  echo "[$(hostname)] $(date -u +%H:%M:%S) <- $response"
                else
                  echo "[$(hostname)] $(date -u +%H:%M:%S) ERROR: $response"
                fi
                sleep 5
              done