Use flock to prevent multiple instances running.

cronjob-dehydrated

@@ -1,4 +1,4 @@
 #!/bin/bash
 # Start the dehydrated-wrapper as a daemon, so that it doesn't prevent other cron jobs from running.
 
-daemon /opt/sbin/dehydrated-wrapper
+daemon -N -a 60 -l daemon.err -b daemon.debug -o daemon.info -n dehydrated-wrapper /opt/gitrepos/random-commands.git/dehydrated-wrapper

cronjob-update-mirrors-search-db

@@ -6,6 +6,21 @@ SCANDIR="/data/depository"
 DBFILE="/data/sites/slackware.uk/files/repository-search/search.db"
 RUNAS_GROUP="depository"
 
+# Only allow one copy of the script to run at any time.
+# shellcheck disable=SC2154
+if [[ "$FLOCK" != "$0" ]]; then
+  # shellcheck disable=SC2093
+  exec env FLOCK="$0" flock -E 10 -e -n "$0" "$0" "$@"
+  ERR="$?"
+  if (( ERR == 10 )); then
+    # File is locked, exit now.
+    exit 0
+  elif (( ERR > 0 )); then
+    printf "%s: %s\\n" "${0##*/}" "flock execution error" >&2
+    exit 1
+  fi
+fi
+
 RAND="$$$RANDOM"
 
 if ionice -c3 nice -n 19 sg "$RUNAS_GROUP" -c "/opt/bin/updatedb -l no -o \"$DBFILE.$RAND\" -U \"$SCANDIR\" >/dev/null 2>&1"; then

dehydrated-wrapper

@@ -2,4 +2,4 @@
 
 #Delay the run for 15 hours (from midnight) and then run at a random time within 3 hours after that.
 sleep $(( 54000 + (RANDOM % 10800) ))
-/opt/sbin/dehydrated -c >/dev/null
+/opt/gitrepos/dehydrated.git/dehydrated -c >/dev/null