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name: redis-replication description: Master Redis replication - master-replica setup, Sentinel for HA, failover handling, and read scaling patterns sasmp_version: "1.3.0" bonded_agent: 06-redis-clustering bond_type: PRIMARY_BOND

Production Configuration

version: "2.1.0" last_updated: "2025-01"

Parameters

parameters: mode: type: string required: true enum: [basic_replication, sentinel] replica_count: type: integer required: false default: 2

Retry Configuration

retry_config: max_retries: 5 backoff_strategy: exponential backoff_base_ms: 1000

Observability

observability: metrics: - replication_lag_seconds - connected_replicas - master_link_status

Redis Replication Skill

Master-Replica Setup

Replica Configuration

replicaof master_ip 6379
masterauth your_password
replica-read-only yes
replica-serve-stale-data yes

Commands

REPLICAOF master_ip 6379   # Set master
REPLICAOF NO ONE           # Promote to master
INFO replication           # Check status

Sentinel (Auto-Failover)

Architecture

  Sentinel 1     Sentinel 2     Sentinel 3
      ↓              ↓              ↓
      └──────── Monitor ───────────┘
                   ↓
   Master ←──→ Replica 1 ←──→ Replica 2

Configuration

# sentinel.conf
port 26379
sentinel monitor mymaster 192.168.1.10 6379 2
sentinel auth-pass mymaster password
sentinel down-after-milliseconds mymaster 5000
sentinel failover-timeout mymaster 60000
sentinel parallel-syncs mymaster 1

Commands

# On Sentinel port
SENTINEL masters
SENTINEL get-master-addr-by-name mymaster
SENTINEL failover mymaster
SENTINEL replicas mymaster

Monitoring

INFO replication
# role:master|slave
# connected_slaves:2
# slave0:ip=...,port=...,state=online,offset=...,lag=0

Assets

• sentinel.conf - Sentinel configuration
• docker-compose-ha.yml - HA Docker setup

References

• REPLICATION_GUIDE.md - Setup guide

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Troubleshooting

Replica Not Syncing

INFO replication  # Check master_link_status

Fix: Check network, password, and firewall

Split-Brain Prevention

min-replicas-to-write 1
min-replicas-max-lag 10

Failover Not Triggering

Check: Quorum (need majority of Sentinels)

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Error Codes

Code	Name	Recovery
R001	MASTERDOWN	Check master or failover
R002	SYNC_FAILED	Check network/auth
R003	QUORUM_LOST	Restore Sentinel majority