Serialize ILM policy-load output with flock to stop interleaving

A single printf per block was not actually one write() call, so
concurrent jobs still occasionally interleaved their label and response
lines. Hold an flock around just the printf (curl still runs in
parallel) so each policy's block prints intact, keeping live
completion-order streaming.

salt/elasticsearch/tools/sbin_jinja/so-elasticsearch-ilm-policy-load

@@ -8,9 +8,13 @@
 
 MAX_JOBS=10
 
+# Lock used to serialize block writes so concurrent jobs never interleave their output.
+ILM_OUTPUT_LOCK=$(mktemp)
+trap 'rm -f "$ILM_OUTPUT_LOCK"' EXIT
+
 # Policies are loaded concurrently (up to MAX_JOBS at a time) for speed. Each policy's block is
-# printed atomically the moment its curl returns, so output appears in COMPLETION ORDER, not the
-# order policies are defined in configuration.
+# printed the moment its curl returns, so output appears in COMPLETION ORDER, not the order
+# policies are defined in configuration.
 echo "Loading ILM policies concurrently; output below appears in completion order, not configuration order."
 echo
 
@@ -19,8 +23,11 @@ put_policy() {
   result=$(curl -K /opt/so/conf/elasticsearch/curl.config -s -k -L \
     -X PUT "https://localhost:9200/_ilm/policy/${policyname}" \
     -H 'Content-Type: application/json' -d"${data}")
-  # Single atomic write so concurrent jobs don't interleave; prints live as each curl finishes.
-  printf 'Setting up %s policy...\n%s\n\n' "${desc}" "${result}"
+  # curl above ran in parallel; serialize just this block write so concurrent jobs never interleave.
+  {
+    flock 200
+    printf 'Setting up %s policy...\n%s\n\n' "${desc}" "${result}"
+  } 200>>"${ILM_OUTPUT_LOCK}"
 }
 
 # Block until fewer than MAX_JOBS background curls are running.