Senior LevelREST APIs & Web Services
How does the Redlock algorithm implement Distributed Locking across independent Redis nodes?
❓ Interview Prompt: Explain Distributed Locking, split-brain concurrency bugs, Redlock algorithm across N independent Redis master nodes, and TTL lock renewal.
When multiple distributed API server instances attempt to process the exact same job concurrently, standard single-node Redis locks fail if the Redis master crashes before replicating to slaves:
Redlock Algorithm Mechanics:
1
Client acquires lock across $N$ independent Redis master nodes (e.g. 5 nodes) using identical key and random value.
2
Client considers lock acquired ONLY if it obtains locks from a majority of nodes (at least $\lfloor N/2 \rfloor + 1 = 3$ nodes) within a small timeout.
3
Prevents split-brain execution and guarantees distributed mutual exclusion!
Code Implementation Example
typescript
import Redlock from 'redlock';
import { redisClient1, redisClient2, redisClient3 } from './redis-nodes';
const redlock = new Redlock([redisClient1, redisClient2, redisClient3], {
retryCount: 3,
retryDelay: 200
});
export async function processDistributedJob(jobId: string) {
// Acquire time-bound distributed lock across 3 independent Redis nodes!
const lock = await redlock.acquire(['locks:job:\${jobId}'], 5000);
try {
await executeJobLogic(jobId);
} finally {
await lock.release();
}
}💡Acquiring distributed locks across Redis nodes using Redlock in TypeScript.
🎯 Interview Key Takeaway
Use the Redlock algorithm across independent Redis nodes to prevent split-brain concurrency race conditions in distributed tasks.
#Redlock#Distributed Locking#Redis#Senior
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