OSM — OpenStreetMap Platform

iNeed Asset Name

Open Street Map Server (ImpOSM)

What it is

OpenStreetMap data platform. ImpOSM is the import/processing component.
Managed by Zeeshan's team (GIS PM). Carlos handles DB/infra support.

Servers (PROD, dpko.un.org, RHEL 7)

• dfs-imposm-01 — ImpOSM import server
• dfs-osmpgsql-01, 02, 03 — PostgreSQL DB servers
• GIS servers: dfs-gisosm-01 (PROD), dfs-gisosm-11 (PRE)
• GIS DB: dfs-gispgsql-02 (PROD), dfs-gispgsql-12 (PRE)

Active Tasks

• OSM data migration - pending tasks (overdue Mar 19)
• Migration to Proxmox - Prepare OSM data server migration (overdue Mar 20)
• OSM Monthly patches - Consolidate procedure (due Mar 31)
• OSM Maps Batch 5A (due Mar 31)

Projects

• New OSM updates procedure - Consolidate and execute (no deadline)
• Migration to Proxmox - Phase 2 (overdue Mar 6)

FW Rules Issue (Current)

FW rules requested for OSM server access got stuck in security approval with Antonio Candelaria.
Zeeshan spoke to Antonio. Carlos to debrief with Zeeshan (call due this week).

Knowledge Gaps

• What does the monthly patch procedure involve step by step?
• What does OSM Batch 5A mean?
• What is the OSM data migration pending — what data?

Infrastructure Detail — unosm-r-app-01

Compiled 2026-03-31

Server Overview

Filesystem Layout

Note: Application data (imposm diffs, service account home dirs) lives under /home on root, NOT on /data.

Service Accounts

Application Stack

Imposm

• Location: /home/_osmprod/imposm/
• Versions: 0.11.1, 0.14.0, 0.14.2
• Function: keeps PostGIS DB in sync with OSM planet via daily replication diffs
• Replication source: https://planet.openstreetmap.org/replication/day/
• Diff storage: /home/_osmprod/imposm/diffs/osm_planet/ and osm_planet_buildings/
• State file: /home/_osmprod/imposm/diffs/osm_planet/last.state.txt

Imposm downloader behaviour:

• Uses parallel workers; temp files named SEQ.osc.gz~ID during download
• On success: renamed to final filename, temp files deleted automatically
• On interruption: orphaned temp files left behind — must be cleaned up manually
• Also contains LevelDB caches: nodes/, ways/, relations/, coords_rel_index/, ways_index/

osm2pgsql

• Service account: _osm2pgsql
• Handles bulk imports into PostGIS

osmosis 0.49.2 — present under imposm bin dir

Installed Agents

Security & Identity

• Domain-joined to global.un.org via SSSD
• auditd running (audit logging active)
• filebeat + Elastic Agent for log shipping

UNOSM Architecture (detailed reference)

Mental Model

• Write brain: unosm-r-db-01
• Read helpers: unosm-r-db-02, unosm-r-db-03
• Importer: unosm-r-app-01
• User entry points: unosm-r-app-02 (Brindisi), unosm-p-app-02 (Valencia)
• Traffic cop: NetScaler → osmpgsql.dfs.un.org
• Exporter: unosm-r-data-01

Database Layer (PostgreSQL)

Master

• unosm-r-db-01 (Brindisi)
• Handles all writes: INSERT, UPDATE, DELETE
• Manages transactions locally
• Generates WAL logs

Slaves

• unosm-r-db-02 (Brindisi)
• unosm-r-db-03 (Valencia)
• Read-only replicas
• Receive WAL logs asynchronously
• Can be slightly behind the master

Replication Model

• Asynchronous replication
• Master commits without waiting for slaves
• Faster writes, possible replication lag

Failure Behavior

• No automatic failover
• If unosm-r-db-01 fails:
  • Manual promotion of unosm-r-db-02 or unosm-r-db-03 required

Application Layer

Data Ingestion

• unosm-r-app-01
• Imports OpenStreetMap data using Imposm
• Feeds data into unosm-r-db-01

Client Access

• unosm-r-app-02 (Brindisi)
• unosm-p-app-02 (Valencia)
• Receive user requests
• Distribute read queries to database slaves

Load Balancing & Traffic Flow

Global Load Balancer

• NetScaler
• Public endpoint: osmpgsql.dfs.un.org
• Routes traffic based on:
  • Client location
  • Site load
  • Performance metrics

Current Behavior

• Active load balancing mainly within Brindisi
• Valencia is available but less actively used

Export & Supporting Services

Data Export

• unosm-r-data-01
• Dedicated to export jobs
• Prevents heavy exports from impacting core services

TL;DR Flow

Users → NetScaler → App Servers → Read SlavesImports → unosm-r-app-01 → unosm-r-db-01Writes → unosm-r-db-01 → WAL → Slaves