Redlock with redis-ha cluster

Question

I have been trying to configure a distributed RedLock against a redis cluster installed in kubernetes from the helm chart stable/redis-ha. Ideally I would want the cluster to have multiple replicas (primary/secondary replication).

I am following the standard examples for setting this up using StackExchangeRedis and Redlock.Net

ConnectionMultiplexer redis = ConnectionMultiplexer.Connect("localhost:6379");

var multiplexers = new List<RedLockMultiplexer>
{
    redis
};

var redlockFactory = RedLockFactory.Create(multiplexers);

var resource = "the-thing-we-are-locking-on";
var expiry = TimeSpan.FromSeconds(30);

using (var redLock = await redlockFactory.CreateLockAsync(resource, expiry))
{
    //This is almost always false and the lock status is NoQuorum
    if (redLock.IsAcquired)
    {
        
    }
    
}

The behavior I am seeing is that the lock is generally never acquired, even in a single user environment. The status is NoQuorum which indicates that RedLock .Net was unable to get a majority, but with my current test cluster I only have one replica. I have been able to get it to work a few times, but it is generally flaky and stops working at random.

I already found this section about locking in clusters https://github.com/samcook/RedLock.net

Basically my understanding is that there is basic support, but you have to connect directly to all replicas in the cluster.

Has anyone successfully configured distributed locking against a cluster before?

Were you able to make it working? – Ranvir Apr 29 '21 at 03:27 — Ranvir, Apr 29 '21 at 03:27

score 0 · Answer 1 · answered Jul 04 '20 at 16:57

I've worked with the Polly folks on their duplicate request collapser (https://github.com/Polly-Contrib/Polly.Contrib.DuplicateRequestCollapser). I also made a distributed lock version of this using redis (https://github.com/Polly-Contrib/Polly.Contrib.DuplicateRequestCollapser.RedisDistributedLock).

I am not as familiar with redis clustering, however if their is some sort of sharding involved, you would need to acquire the distributed lock on each shard of the cluster before proceeding with the operation.

Both of these should have nuget packages. Let me know if this helps at all.

Redlock with redis-ha cluster

1 Answers1