HARUMI
01IDENTITY

PLATFORM-MINDED SOFTWARE ENGINEER · JAPAN

Harumi Morikawa

Platform / Backend Engineer

Enterprise Java applications, Camunda workflow systems and a self-managed Kubernetes platform — built, deployed and operated end to end.

I turn fragmented applications, infrastructure and operational knowledge into systems that are easier to run, debug and change.

Explore selected workRead how I work

BUILD
Product systems
OPERATE
Self-hosted Kubernetes
INVESTIGATE
Incidents and evidence

harumi.uk · self-hosted · 3 public apps · 6 systems running privately

02System status

03bare-metal nodes03public applications04selected systems01GitOps delivery path

03What I bring

  1. 01

    Operate real systems

    I work beyond feature delivery — deployment, observability, incident investigation and recovery are part of the system.

  2. 02

    Connect application and infrastructure

    I trace problems across Java, Camunda, Kafka, Kubernetes, Envoy, GitOps and identity boundaries.

  3. 03

    Turn incidents into knowledge

    I document assumptions, evidence, rejected fixes and decisions so that failures become reusable engineering knowledge.

04Selected systems

01

MakeUp

Solo developer & operator
One Kafka topic, one consumer, three delivery pathsMoodCalendarReminderAnniversarymakeup-eventsKAFKA TOPICEventConsumerPersistSSEWeb Push01 TOPIC01 CONSUMER03 DELIVERY PATHS
MakeUp card-appearance editor, drawn abstractlyCARD APPEARANCEPREVIEW · NO FILL SELECTEDUPLOAD IMAGELOCAL PREVIEW06 / 08

A relationship app for any close pair where each feature publishes to the same Kafka topic, and persistence, SSE and Web Push all happen in one flow.

Spring Boot · Next.js · Kafka · PostgreSQL

Read the write-up →

02

Camunda 8.8 operations

Operator
778REQUESTS
697CONNECTIONS

Tasklist182 requests / 88 connections

commonHttpProtocolOptions.maxRequestsPerConnection: 1

問題は、追加した「修正」だった。

The fix was the problem.

Evidence over guesswork.

The full Camunda 8 stack behind a single OIDC domain. Envoy measurements identified — and retired — a connection setting that was making latency worse.

Camunda 8.8 · Zeebe · Keycloak · Envoy

Read the write-up →

03

Home Kubernetes platform

Platform owner
Request path and two-stage GitOps deploy pathInternetCloudflare TunnelkgatewayApplicationKUBERNETES CLUSTERGitLabArgoCDCamundaMakeUpNOEMADocsSitenode-1 / bare metalnode-2 / bare metalGit pushGitLab CIImage buildTag bumpArgoCDClusterBUILD COMMITSEPARATE TAG-BUMP COMMIT / SOURCE OF TRUTH

Synced は、必ずしもデプロイ完了ではない。Synced is not always deployed.

Seven services on two bare-metal nodes behind one gateway, now fronted by a single console for health, resources and docs. Every deploy goes through the same two-stage GitOps pipeline.

Kubernetes · ArgoCD · GitLab CI · Cloudflare

Read the write-up →

04

Harumi Platform

Solo developer & operator
infra docs, camunda-infra and harumi-docs consolidating into harumi-platforminfra docscamunda-infraharumi-docsharumi-platformRBACRole: get,list on pods · namespace-scoped, no secrets

退役は、削除ではない。

Retire the surface, not the data.

3 ops surfaces → 1 console, zero downtime.

Three admin tools retired into one console. The rule for retiring any of them: port what it does first, then re-home whatever infrastructure was quietly living in its namespace, then delete.

Next.js · Kubernetes RBAC · ArgoCD · Go

Read the write-up →

05NOTES

Incident Method

Problems that took time to isolate, and the evidence behind each decision.

  1. An opacity animation was trapping the fixed elements
    Modal hiddenraise z-indexinspect paint orderremove opacity stacking context
  2. chroot /host was not the live node
    Node mount missingtrust chroot /hostinspect namespacesdelegate through host systemd
  3. 697 connections for 778 requests
    External access slowforce new connectionsinspect Envoy statsremove speculative fix
  4. A hand-signed token was correctly rejected
    No live ArgoCD datahand-sign a token, skip the passwordinspect the "revoked" checkreset password, use the real endpoint
  5. The PVC was never actually the blocker
    Workload rebalance stalledassume storage pins the nodeinspect a workload already running cross-nodemove three services onto the other node

06CURRENT / 2026

Platform reliability

AI-assisted document processing

Operational writing

07ABOUT

Based in Japan

中文 · 日本語 · English

Platform / Backend Engineer

Verify the source of truth.

Remove, don’t layer.

Ship, listen, revert honestly.

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