Back to course: Pos

POS | Reading Module

Pos User Journey and Failure Transitions

Status: Not Started | Pass threshold: 100% | Points: 65

L2 30 min

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Learning Guidance

Objectives

  • Trace user journey transitions from ingress to confirmation.
  • Spot where one failing service creates downstream false symptoms.
  • Frame escalation in business-impact language.

Source Artifacts

Internal source references are available for maintainers but are not exposed in deployed environments.

Field Evidence

Real incidents related to what you're learning.

Module Content

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Key Takeaways

  • Store terminal sends status and transaction events
  • PARM transforms and validates payloads
  • MQTT and SyncGateway replicate state
  • Poseidon and downstream consumers process updates
  • Store state converges across operations views

Overview

POS training builds instincts for edge connectivity, replication failures, and infra-heavy incident correlation.

Traversal Stages

  1. Store terminal sends status and transaction events
  2. PARM transforms and validates payloads
  3. MQTT and SyncGateway replicate state
  4. Poseidon and downstream consumers process updates
  5. Store state converges across operations views

Service Map Source

This map is derived from:

  • observability-audit/architecture/service-catalog.md
  • observability-audit/runbooks/by-scenario/store-offline.md
  • observability-audit/services/poseidon-pos.yaml

Critical POS Services

ServiceTeamTierIncident Role
poseidon-pospos2register and order handling in store
parm-next-genolympus2order transformation and store status routing
olympus-mqttolympus2message transport to/from POS
olympus-dgsolympus2POS management services
couchbasesreinfradata synchronization dependency

Key Dependencies

DependencyUsed ByRisk Type
MQTT brokersposeidon/olympusconnection and event loss
Couchbaseposeidon ecosystemreplication and storage failures
SyncGatewayPOS replicationdelayed or missing store sync
Brand middlewareparm and brand-specific connectorsorder transmission failure

Fast Impact Heuristics

  • Single-store issue is often local/store IT.
  • Multi-store regional issues often indicate network/middleware dependency.
  • Cross-brand POS degradation usually requires SRE and olympus engagement.

Monitor Index Source

Source: observability-audit/monitors/common-monitors.md.

P0/P1 Learning Monitors

Monitor IDNameServiceTeamNotes
115019671PARM Store Status Change Rateparm-next-genolympusstore offline and flapping analysis
132480908PARM Order Transformation Failuresparm-next-genolympustransmission failure to store systems
115808371PARM Unable to Send Updatesparm-next-genolympusstatus propagation degradation
180553148MQTT Connection Failure Rateposeidon-pospos/olympustransport layer instability
109686411Widespread SyncGateway Replication Errorsposeidon-possredistributed sync failure
65955587Can't Connect to Couchbasecouchbasesredata layer outage
66043382Couchbase Bucket Connectionscouchbasesreconnection stress indicator
213501682Container Restartsk8ssreinfra instability impacting POS services

Alert-to-Runbook Mapping

Monitor IDPrimary Runbook
115019671runbooks/store-offline-parm.md
132480908runbooks/parm-order-transformation.md
109686411runbooks/parm-order-transformation.md
180553148runbooks/store-offline-parm.md

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