diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..a0708b2
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1,2 @@
+outputs
+*.log
\ No newline at end of file
diff --git a/experiments/k-node.sh b/experiments/k-node.sh
index 9e9ef39..08e852a 100755
--- a/experiments/k-node.sh
+++ b/experiments/k-node.sh
@@ -40,17 +40,18 @@ echoerr "* Timing log: ${output_log}"
 trap pm_stop EXIT INT TERM
 pm_start
 
+#cdx_set_log_level "INFO;trace:blockexcnetwork,blockexcengine,discoveryengine"
 cdx_launch_network "${node_count}"
 
-for i in $(seq 1 "${repetitions}"); do
-  for file_size in "${file_sizes[@]}"; do
+for file_size in "${file_sizes[@]}"; do
+  for i in $(seq 1 "${repetitions}"); do
     file_name=$(cdx_generate_file "${file_size}")
     cid=$(cdx_upload_file "0" "${file_name}")
 
     cdx_log_timings_start "${output_log}" "${file_size},${i},${cid}"
 
     handles=()
-    for j in $(seq 1 "${node_count}"); do
+    for j in $(seq 1 "$((node_count - 1))"); do
       cdx_download_file_async "$j" "$cid"
       # shellcheck disable=SC2128
       handles+=("$result")
diff --git a/src/codex.bash b/src/codex.bash
index 2140d7a..bb924b4 100644
--- a/src/codex.bash
+++ b/src/codex.bash
@@ -40,6 +40,8 @@ _cdx_log_level="INFO"
 echoerr "[codex] Node log level is ${_cdx_log_level}"
 
 # PID array for known Codex node processes
+# FIXME: right now only processes destroyed with cdx_destroy_node are removed from
+#   this array.
 declare -A _cdx_pids
 
 cdx_set_outputs() {
@@ -128,7 +130,7 @@ cdx_cmdline() {
   # shellcheck disable=SC2140
   echo "${cdx_cmd}"\
  "--data-dir=${_cdx_data}/codex-${node_index} --api-port=$(_cdx_api_port "$node_index")"\
- "--disc-port=$(_cdx_disc_port "$node_index") --log-level=${_cdx_log_level}"
+ "--disc-port=$(_cdx_disc_port "$node_index") '--log-level=${_cdx_log_level}'"
 }
 
 cdx_get_spr() {
@@ -163,9 +165,14 @@ cdx_launch_node() {
 
 cdx_launch_network() {
   local node_count="$1" bootstrap_spr
+  if [[ "$node_count" -lt 2 ]]; then
+    echoerr "Error: a Codex network needs at least 2 nodes"
+    return 1
+  fi
+
   cdx_launch_node 0 || return 1
   bootstrap_spr=$(cdx_get_spr 0) || return 1
-  for i in $(seq 1 "$node_count"); do
+  for i in $(seq 1 "$((node_count - 1))"); do
     cdx_launch_node "$i" "--bootstrap-node" "$bootstrap_spr" || return 1
   done
   return 0
diff --git a/test/test_codex.bats b/test/test_codex.bats
index d6e6c04..8c77303 100755
--- a/test/test_codex.bats
+++ b/test/test_codex.bats
@@ -149,6 +149,10 @@ setup() {
   pm_stop
 }
 
+@test "should refuse to launch a Codex network with less than 2 nodes" {
+  refute cdx_launch_network 1
+}
+
 @test "should launch a Codex network and allow uploading and downloading" {
   pm_start