Real Redis sandbox
Every scenario runs an actual Redis instance in a container — not a multiple-choice quiz or a video.
Labs · Redis
Practice real Redis scenarios before they happen
Keep a cache and data store alive under load. Practice the Redis failures that page on-call — eviction storms, big keys, blocking commands, failover and stale reads — against a real Redis sandbox.
Run rillence redis · real Redis in Docker · deterministic scoring.
What it is
A flight simulator for Redis operations
Boot a real Redis in a container, inject a realistic failure, and investigate with redis-cli or your own tooling. Deterministic scoring, zero production risk.
Real scenarios
Eviction storms, big keys, blocking commands, TTL leaks, failover and stale reads — injected into a live instance.
AI hints + deterministic scoring
Get progressive hints while you investigate, a scorecard for your fix and a postmortem explaining the root cause.
Built for individuals and teams
Practice alone, onboard new engineers, or run repeatable internal Redis team drills.
Scenarios
Redis scenarios, grouped into tracks
The Redis failure modes engineers actually meet in production — from keyspace hygiene to cluster and failover.
Keyspace, TTL & Basic Operations
CoreWrong DB, missing or short TTLs, namespace collisions, wrong key types and dangerous KEYS scans.
Memory, Eviction & Big Keys
CoreEviction storms, OOM, wrong maxmemory policy, big strings/hashes/lists and fragmentation spikes.
Latency, Slow Commands & Event Loop
CoreSlow HGETALL, large LRANGE, SMEMBERS on huge sets, Lua and KEYS blocking the event loop.
Clients, Connections & Backpressure
OperationsConnection storms, pool exhaustion, pipelining gone wrong and client-side backpressure.
Persistence, AOF/RDB & Recovery
OperationsFork latency on BGSAVE, AOF rewrite spikes, broken dumps and recovery from disk.
Cache Correctness & App Patterns
OperationsStale caches, thundering herds, cache stampede and incorrect invalidation.
Replication & Stale Reads
OperationsReplica lag, reading stale data from replicas and replication link failures.
Sentinel & Failover
AdvancedSentinel quorum, split-brain, failover that drops writes and misrouted clients.
Cluster & Sharding
AdvancedSlot migration, MOVED/ASK storms, hot slots and resharding under load.
Streams, Pub/Sub & Queues
AdvancedConsumer-group backlog, pending entries, lost messages and runaway queue growth.
Security, ACL & Operational Safety
AdvancedACL misconfig, unsafe commands, exposed instances and the FLUSHALL reflex.
Compound Redis Incident Control
CapstoneMulti-cause GameDays that combine memory, latency and failover under pressure.
How practice works
From paged to postmortem in four steps
Launch the lab
Run rillence redis to open the interactive REPL.
Start a scenario
Pick a scenario from any track and boot an isolated Redis sandbox.
Investigate
Connect with redis-cli — or any client you already use — and dig in.
Submit and score
Get deterministic Detect / Fix / Trap scoring and a postmortem.
Practice Redis scenarios before they become outages
One subscription covers every lab. Train your judgment in a safe sandbox, not in production.