Deadlock in obtaining Redis connection

[yarodinD]

Hello.
I'm using the following combination:
Spring Boot 2.1.1, spring-cloud-dependencies Greenwich.RC2, spring-boot-starter-data-redis 2.1.1, spring-session-data-redis 2.1.2, spring-cloud-starter-sleuth. Java 11

The Redis is accessed by using sentinel in front of it.

This fails because the main thread blocks while trying to get a Redis connection from lettuce.

Any other combination works: Going to redis directly instead of going through sentinel makes it work, switching to Jedis instead works, using lettuce 5.0 instead of 5.1 works also.
When I either leave sleuth or spring-session-data-redis out, the service starts again.

Thread dump is attached.

thread_dump_greenwich_rc2.txt

[marcingrzejszczak]

Can you provide a complete, minimal, verifiable sample that reproduces the problem rather than pasted code? It should be available as a GitHub (or similar) project or attached to this issue as a zip file.

[yarodinD]

@marcingrzejszczak Here it is.
Created directly with spring boot initiliazr, just added the redis settings in application.properties.
I tested it against a redis/sentinel running on docker, Redis 3.2.5 (I could reproduce the same behavior with 5.0.3)

sleuth-bug-demo.tar.gz

[mp911de]

@marcingrzejszczak The easiest way (for me and without losing mind with a Kubernetes cluster) to spin up a Redis Sentinel setup is:

1. Clone https://github.com/lettuce-io/lettuce-core.
2. Run make prepare ssl-keys start in lettuce-core.

The makefile spins up a few Redis instances. Redis Sentinel instances run at localhost ports 26379, 26380, and 26381.

3. Run make stop to shut down the Redis instances.