Redis Cluster for Horizontal Scaling

Advanced20 min

Deploy a Redis Cluster with automatic data sharding and high availability across multiple nodes for production workloads.

Prerequisites

-Redis 7+ installed
-At least 6 Redis instances (3 masters, 3 replicas)
-Network connectivity between all nodes

Steps

Prepare cluster configuration

Enable cluster mode in each Redis instance configuration.

$ redis-cli -p 7001 CONFIG SET cluster-enabled yes && redis-cli -p 7001 CONFIG SET cluster-config-file nodes-7001.conf && redis-cli -p 7001 CONFIG SET cluster-node-timeout 5000

Repeat for ports 7002-7006. Each node needs a unique cluster-config-file.

Create the cluster

Initialize the cluster with 3 masters and 3 replicas using redis-cli.

$ redis-cli --cluster create 127.0.0.1:7001 127.0.0.1:7002 127.0.0.1:7003 127.0.0.1:7004 127.0.0.1:7005 127.0.0.1:7006 --cluster-replicas 1

This redistributes all hash slots. Run on a fresh cluster or expect data to be reshuffled.

Verify cluster status

Check that all nodes joined the cluster and slots are assigned.

$ redis-cli -p 7001 CLUSTER INFO

Check cluster node roles

List all nodes with their roles, slot ranges, and replication status.

$ redis-cli -p 7001 CLUSTER NODES

Test cluster operations

Write and read data using cluster-aware mode in redis-cli.

$ redis-cli -c -p 7001 SET mykey 'hello' && redis-cli -c -p 7001 GET mykey

The -c flag enables cluster mode in redis-cli, automatically following MOVED redirections.

Full Script

full-script.sh

#!/bin/bash
# Redis Cluster Setup (local development)
set -euo pipefail

PORTS=(7001 7002 7003 7004 7005 7006)
BASE_DIR="/tmp/redis-cluster"

echo "=== Preparing node directories ==="
for PORT in "${PORTS[@]}"; do
  mkdir -p "$BASE_DIR/$PORT"
  cat > "$BASE_DIR/$PORT/redis.conf" <<CONF
port $PORT
cluster-enabled yes
cluster-config-file nodes-$PORT.conf
cluster-node-timeout 5000
appendonly yes
dir $BASE_DIR/$PORT
CONF
done

echo ""
echo "=== Starting Redis nodes ==="
for PORT in "${PORTS[@]}"; do
  redis-server "$BASE_DIR/$PORT/redis.conf" --daemonize yes
  echo "Started node on port $PORT"
done

sleep 2

echo ""
echo "=== Creating cluster ==="
redis-cli --cluster create \
  127.0.0.1:7001 127.0.0.1:7002 127.0.0.1:7003 \
  127.0.0.1:7004 127.0.0.1:7005 127.0.0.1:7006 \
  --cluster-replicas 1 --cluster-yes

echo ""
echo "=== Cluster info ==="
redis-cli -p 7001 CLUSTER INFO

echo ""
echo "=== Cluster nodes ==="
redis-cli -p 7001 CLUSTER NODES

echo ""
echo "=== Testing read/write ==="
redis-cli -c -p 7001 SET test:key "cluster-works"
redis-cli -c -p 7001 GET test:key

FAQ

Discussion

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#!/bin/bash # Redis Cluster Setup (local development) set -euo pipefail PORTS=(7001 7002 7003 7004 7005 7006) BASE_DIR="/tmp/redis-cluster" echo "=== Preparing node directories ===" for PORT in "${PORTS[@]}"; do mkdir -p "$BASE_DIR/$PORT" cat > "$BASE_DIR/$PORT/redis.conf" <<CONF port $PORT cluster-enabled yes cluster-config-file nodes-$PORT.conf cluster-node-timeout 5000 appendonly yes dir $BASE_DIR/$PORT CONF done echo "" echo "=== Starting Redis nodes ===" for PORT in "${PORTS[@]}"; do redis-server "$BASE_DIR/$PORT/redis.conf" --daemonize yes echo "Started node on port $PORT" done sleep 2 echo "" echo "=== Creating cluster ===" redis-cli --cluster create \ 127.0.0.1:7001 127.0.0.1:7002 127.0.0.1:7003 \ 127.0.0.1:7004 127.0.0.1:7005 127.0.0.1:7006 \ --cluster-replicas 1 --cluster-yes echo "" echo "=== Cluster info ===" redis-cli -p 7001 CLUSTER INFO echo "" echo "=== Cluster nodes ===" redis-cli -p 7001 CLUSTER NODES echo "" echo "=== Testing read/write ===" redis-cli -c -p 7001 SET test:key "cluster-works" redis-cli -c -p 7001 GET test:key