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Add kubernetes-deployment: probes, shutdown, JVM ergonomics, HPA

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Companion code for "Deploying Spring Boot 4 on Kubernetes: Probes, Graceful
Shutdown, Limits and JVM Ergonomics". A dependency outage under three
probe-group setups, a rolling restart under load four ways (three runs
each), the JVM's ergonomic choices for nine pod shapes, one GC-heavy load
under five CPU limits with throttling counters, and an HPA driven by a
Micrometer gauge through prometheus-adapter. Measured on k3s v1.36.4.

Co-Authored-By: Claude Opus 5 <[email protected]>
Claude-Session: https://claude.ai/code/session_01C3TETMrqVUWeFkNtz3Jbo3
This commit is contained in:
asmhatre
2026-09-11 17:12:10 +00:00
co-authored by Claude Opus 5
parent 644da9e65e
commit a065696478
72 changed files with 28415 additions and 2 deletions
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kubernetes-deployment/scripts/demo-probes.sh
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#!/usr/bin/env bash
# A downstream outage, with the downstream health indicator in the LIVENESS group and then in the
# READINESS group, and in neither (the default). Outage from t=0 to t=60, then 50 s of recovery.
# -> docs/output/probes-*.txt
set -uo pipefail
source "$(dirname "$0")/env.sh"
watch_outage() { # label, file
local label="$1" file="$2"
kubectl -n "$NS" rollout status deploy/orders --timeout=180s > /dev/null
sleep 5
{
echo "# $label"
echo "# health groups: liveness=$(kubectl -n "$NS" get deploy orders -o jsonpath='{.spec.template.spec.containers[0].env[?(@.name=="MANAGEMENT_ENDPOINT_HEALTH_GROUP_LIVENESS_INCLUDE")].value}') readiness=$(kubectl -n "$NS" get deploy orders -o jsonpath='{.spec.template.spec.containers[0].env[?(@.name=="MANAGEMENT_ENDPOINT_HEALTH_GROUP_READINESS_INCLUDE")].value}')"
echo "# t=0: kubectl scale deploy/downstream --replicas=0 t=60: back to 1"
echo
kubectl -n "$NS" scale deploy/downstream --replicas=0 > /dev/null
local start; start=$(date +%s)
local restored=no
for _ in $(seq 1 22); do
local t=$(( $(date +%s) - start ))
if [ "$t" -ge 60 ] && [ "$restored" = no ]; then
kubectl -n "$NS" scale deploy/downstream --replicas=1 > /dev/null; restored=yes
echo "-------- downstream restored --------"
fi
local pods; pods=$(kubectl -n "$NS" get pods -l app=orders --no-headers \
-o custom-columns=N:.metadata.name,R:.status.containerStatuses[0].ready,C:.status.containerStatuses[0].restartCount,S:.status.containerStatuses[0].state \
| awk '{st=$4; sub(/map\[/,"",st); sub(/:.*/,"",st); printf "%s ready=%s restarts=%s %s | ", substr($1,length($1)-4), $2, $3, st}')
local eps; eps=$(kubectl -n "$NS" get endpointslices -l kubernetes.io/service-name=orders -o jsonpath='{range .items[*].endpoints[*]}{.conditions.ready}{" "}{end}' | tr ' ' '\n' | grep -c true)
local work; work=$(kubectl -n "$NS" exec client -- wget -q -T 2 -O - http://orders:8080/work?ms=1 2>/dev/null | grep -c pod || true)
printf 't=%3ds %s serving endpoints=%s GET /work via Service: %s\n' "$t" "$pods" "$eps" "$([ "$work" = 1 ] && echo ok || echo FAIL)"
sleep 5
done
echo
echo "# Events (probe failures and kills) for orders pods:"
kubectl -n "$NS" get events --field-selector involvedObject.kind=Pod --sort-by=.lastTimestamp \
| grep -E '(Unhealthy|Killing|BackOff).*orders-' | awk '{ $1=""; $4=""; print }' | sed 's/^ //' | sort | uniq -c | sort -rn | head -8
} | tee "$OUT/$file"
}
kubectl apply -f "$MODULE_DIR/k8s/client.yaml" > /dev/null
kubectl -n "$NS" wait --for=condition=Ready pod/client --timeout=60s > /dev/null
kubectl -n "$NS" scale deploy/downstream --replicas=1 > /dev/null
kubectl -n "$NS" delete events --all > /dev/null 2>&1
kubectl -n "$NS" set env deploy/orders MANAGEMENT_ENDPOINT_HEALTH_GROUP_LIVENESS_INCLUDE=livenessState,downstream MANAGEMENT_ENDPOINT_HEALTH_GROUP_READINESS_INCLUDE- > /dev/null
watch_outage "downstream health indicator in the LIVENESS group" probes-liveness-includes-downstream.txt
kubectl -n "$NS" rollout status deploy/downstream --timeout=60s > /dev/null
kubectl -n "$NS" delete events --all > /dev/null 2>&1
kubectl -n "$NS" set env deploy/orders MANAGEMENT_ENDPOINT_HEALTH_GROUP_LIVENESS_INCLUDE- MANAGEMENT_ENDPOINT_HEALTH_GROUP_READINESS_INCLUDE=readinessState,downstream > /dev/null
watch_outage "downstream health indicator in the READINESS group" probes-readiness-includes-downstream.txt
kubectl -n "$NS" rollout status deploy/downstream --timeout=60s > /dev/null
kubectl -n "$NS" delete events --all > /dev/null 2>&1
kubectl -n "$NS" set env deploy/orders MANAGEMENT_ENDPOINT_HEALTH_GROUP_READINESS_INCLUDE- > /dev/null
watch_outage "downstream health indicator in NEITHER group (Spring Boot's default probe groups)" probes-default-groups.txt