Test env NATS cluster cut-over

scripts/create-cluster.sh

@@ -0,0 +1,69 @@
+#!/usr/bin/env bash
+# Create three distinct Proxmox LXC guests and start a JetStream cluster on vmbr1.
+# Does not touch host loopback NATS (127.0.0.1:4222) or vmbr0.
+set -euo pipefail
+ROOT="$(cd "$(dirname "$0")/.." && pwd)"
+# shellcheck disable=SC1091
+. "$ROOT/cluster.env"
+# shellcheck disable=SC1091
+. "$ROOT/scripts/lib-ct.sh"
+ct_require_proxmox
+
+mapfile -t rows < <(printf '%s\n' "$NODES" | awk 'NF==3 {print}')
+[[ ${#rows[@]} -eq 3 ]] || { echo "need exactly 3 nodes in cluster.env" >&2; exit 1; }
+
+declare -a VMIDS NAMES IPS
+for row in "${rows[@]}"; do
+  # shellcheck disable=SC2086
+  set -- $row
+  VMIDS+=("$1"); NAMES+=("$2"); IPS+=("$3")
+done
+
+i=0
+for i in 0 1 2; do
+  ct_ensure "${VMIDS[$i]}" "${NAMES[$i]}" "${IPS[$i]}"
+  ct_bootstrap_user "${VMIDS[$i]}"
+done
+
+# Install nats-server + conf + systemd on each guest
+for i in 0 1 2; do
+  routes=""
+  for j in 0 1 2; do
+    [[ $i -eq $j ]] && continue
+    routes="${routes}    nats-route://${IPS[$j]}:6222"$'\n'
+  done
+  tmpconf="$(mktemp)"
+  NAME="${NAMES[$i]}" IP="${IPS[$i]}" CLUSTER="$CLUSTER_NAME" ROUTES="$routes" \
+    python3 - "$ROOT/conf/nats.conf.tmpl" "$tmpconf" <<'PY'
+import os, pathlib, sys
+t = pathlib.Path(sys.argv[1]).read_text()
+out = t.replace("{{NAME}}", os.environ["NAME"]).replace("{{IP}}", os.environ["IP"]).replace("{{CLUSTER}}", os.environ["CLUSTER"]).replace("{{ROUTES}}", os.environ["ROUTES"])
+pathlib.Path(sys.argv[2]).write_text(out)
+PY
+  sudo pct exec "${VMIDS[$i]}" -- bash -c 'cat > /tmp/nats.conf' < "$tmpconf"
+  sudo pct exec "${VMIDS[$i]}" -- bash -c 'cat > /tmp/nats-server.service' < "$ROOT/systemd/nats-server.service"
+  rm -f "$tmpconf"
+  sudo pct exec "${VMIDS[$i]}" -- bash -lc "
+set -e
+export DEBIAN_FRONTEND=noninteractive
+id nats >/dev/null 2>&1 || useradd -r -s /usr/sbin/nologin nats
+install -d -m 755 -o nats -g nats /var/lib/nats/jetstream /etc/nats
+mv /tmp/nats.conf /etc/nats/nats.conf
+chown root:root /etc/nats/nats.conf
+chmod 644 /etc/nats/nats.conf
+if [[ ! -x /usr/local/bin/nats-server ]]; then
+  curl -fsSL https://github.com/nats-io/nats-server/releases/download/v${NATS_VER}/nats-server-v${NATS_VER}-linux-amd64.tar.gz -o /tmp/nats.tgz
+  tar -xzf /tmp/nats.tgz -C /tmp
+  install -m 0755 /tmp/nats-server-v${NATS_VER}-linux-amd64/nats-server /usr/local/bin/nats-server
+  rm -rf /tmp/nats.tgz /tmp/nats-server-v${NATS_VER}-linux-amd64
+fi
+install -m 644 /tmp/nats-server.service /etc/systemd/system/nats-server.service
+systemctl daemon-reload
+systemctl enable --now nats-server
+"
+  echo "nats-server ${NAMES[$i]} ${IPS[$i]}:4222 cluster ${IPS[$i]}:6222"
+done
+
+echo "cluster client URL: nats://${IPS[0]}:4222,nats://${IPS[1]}:4222,nats://${IPS[2]}:4222"
+echo "lab loopback NATS on the host is unchanged (127.0.0.1:4222)"
+echo "next: bash $ROOT/scripts/test.sh"