small, complete setups built from kern's own knobs. each one is just config + a task or two.

the safe restart: snapshot, warn players, restart, and only then prune.

1. 1.instance → monitor → backups: intervalSecs: 0, onStop: true, keep: 14.
2. 2.instance → tasks → new task:

• ·action backup, dailyAt "03:55"
• ·action restart, dailyAt "04:00", announceMinutes [5, 1]

the 03:55 backup runs while the server is still up; the restart's onStop snapshot catches anything written in those five minutes.

1. 1.settings → notifications → webhook url: paste your discord webhook.
2. 2.enable send webhook events.
3. 3.instance → monitor → watchdog: enable auto-restart (max 5 attempts).

crash, restart attempts, and give-up events all hit the webhook. every payload carries both content (discord) and text (slack).

1. 1.instance → monitor → alerts: cpu threshold 0.9, sustained 60s.
2. 2.settings → notifications → add a log alert rule: pattern OutOfMemoryError|java\.lang\.OutOfMemory, enabled.

log alerts fire from the streamed console the moment the line appears — usually minutes before the process actually dies.

bash
#!/usr/bin/env bash
set -euo pipefail

kern-cli stop "Prod API" --wait --timeout 60s
rsync -a --delete ./build/ deploy@host:/srv/api/
kern-cli start "Prod API" --wait --timeout 120s
kern-cli wait "Prod API" --for healthy --timeout 60s
echo "deployed $(date -u +%FT%TZ)"

exit codes make failures loud: 3 if the instance was renamed, 4 if kern isn't running, 5 if it never came healthy.

bash
kern-cli list --format plain | awk -F'\t' '$4 != "true" { print "down:", $2 }'
kern-cli list --format plain | awk -F'\t' '$4 == "true" { n++ } END { print n " up" }'

one task per instance — or a single fleet command from a shortcut / phone automation:

bash
kern-cli stop --tag minecraft --wait --timeout 2m

watchdog with a low attempt count turns a broken plugin into five attempts and a notification instead of an all-night restart loop:

• ·monitor → watchdog: attempts 3.
• ·monitor → alerts: ram threshold 0.85, sustained 120s — memory creep usually precedes the crash.

kern-cli crash "Minecraft" then shows the exit code and the last lines, no log spelunking.

bash
kern-cli inspect ./paper-1.21            # jars, world, eula, suggested runtime
kern-cli add ./paper-1.21 --import --name "Paper" --group minecraft
kern-cli start "Paper" --wait

--import adopts the folder as-is — kern never moves or rewrites files it didn't create.

bash
kern-cli logs "Minecraft" --follow --grep "ERROR|FATAL" --format json \
  | jq -r '.line' \
  | while read -r line; do curl -s -X POST "$ALERT_URL" -d "$line"; done

offset-based following means no duplicate lines, even across rotations.