[BUG] CLUSTER SHARDS command returns "empty array" in slots section #13414
Description
We are running a 6-node Redis cluster (version 7.2.0) in a Docker environment with 1 replica. When we stop one of the master nodes in the cluster, the CLUSTER SHARDS command returns empty slots for that specific shard. The node from the failed shard returns the correct output for the CLUSTER SHARRD command.
Output with an empty array from the container which is not a part of the failed shard.
1) 1) "slots"
2) (empty array)
3) "nodes"
4) 1) 1) "id"
2) "b1c9fe739d6e8d0c519f98ac5e8ebcd1e52cfbe3"
3) "port"
4) (integer) 6379
5) "ip"
6) "172.18.0.3"
7) "endpoint"
8) "172.18.0.3"
9) "role"
10) "master"
11) "replication-offset"
12) (integer) 224
13) "health"
14) "fail"
2) 1) "id"
2) "42baa4b4da6a0cc4ef9e18c43c2f86403822b72b"
3) "port"
4) (integer) 6379
5) "ip"
6) "172.18.0.5"
7) "endpoint"
8) "172.18.0.5"
9) "role"
10) "master"
11) "replication-offset"
12) (integer) 224
13) "health"
14) "online"
2) 1) "slots"
2) 1) (integer) 5461
2) (integer) 10922
3) "nodes"
4) 1) 1) "id"
2) "7baa9f314205d4047655830f45e4014187918e0c"
3) "port"
4) (integer) 6379
5) "ip"
6) "172.18.0.6"
7) "endpoint"
8) "172.18.0.6"
9) "role"
10) "master"
11) "replication-offset"
12) (integer) 322
13) "health"
14) "online"
2) 1) "id"
2) "0c51817bbfb0879bf4aaad66a1244b76d1a64d2b"
3) "port"
4) (integer) 6379
5) "ip"
6) "172.18.0.7"
7) "endpoint"
8) "172.18.0.7"
9) "role"
10) "replica"
11) "replication-offset"
12) (integer) 322
13) "health"
14) "online"
3) 1) "slots"
2) 1) (integer) 0
2) (integer) 5460
3) "nodes"
4) 1) 1) "id"
2) "5fa7cec07512060397bcfda7bbb1cec73052a905"
3) "port"
4) (integer) 6379
5) "ip"
6) "172.18.0.2"
7) "endpoint"
8) "172.18.0.2"
9) "role"
10) "master"
11) "replication-offset"
12) (integer) 308
13) "health"
14) "online"
2) 1) "id"
2) "98d6ec2bd84ae48527f6c67148464d5e8d55afb1"
3) "port"
4) (integer) 6379
5) "ip"
6) "172.18.0.4"
7) "endpoint"
8) "172.18.0.4"
9) "role"
10) "replica"
11) "replication-offset"
12) (integer) 308
13) "health"
14) "online"
Correct output from one of the replicas (part of the same failed shard):
1) 1) "slots"
2) 1) (integer) 5461
2) (integer) 10922
3) "nodes"
4) 1) 1) "id"
2) "7baa9f314205d4047655830f45e4014187918e0c"
3) "port"
4) (integer) 6379
5) "ip"
6) "172.18.0.6"
7) "endpoint"
8) "172.18.0.6"
9) "role"
10) "master"
11) "replication-offset"
12) (integer) 12222
13) "health"
14) "online"
2) 1) "id"
2) "0c51817bbfb0879bf4aaad66a1244b76d1a64d2b"
3) "port"
4) (integer) 6379
5) "ip"
6) "172.18.0.7"
7) "endpoint"
8) "172.18.0.7"
9) "role"
10) "replica"
11) "replication-offset"
12) (integer) 12222
13) "health"
14) "online"
2) 1) "slots"
2) 1) (integer) 0
2) (integer) 5460
3) "nodes"
4) 1) 1) "id"
2) "98d6ec2bd84ae48527f6c67148464d5e8d55afb1"
3) "port"
4) (integer) 6379
5) "ip"
6) "172.18.0.4"
7) "endpoint"
8) "172.18.0.4"
9) "role"
10) "replica"
11) "replication-offset"
12) (integer) 12208
13) "health"
14) "online"
2) 1) "id"
2) "5fa7cec07512060397bcfda7bbb1cec73052a905"
3) "port"
4) (integer) 6379
5) "ip"
6) "172.18.0.2"
7) "endpoint"
8) "172.18.0.2"
9) "role"
10) "master"
11) "replication-offset"
12) (integer) 12208
13) "health"
14) "online"
3) 1) "slots"
2) 1) (integer) 10923
2) (integer) 16383
3) "nodes"
4) 1) 1) "id"
2) "42baa4b4da6a0cc4ef9e18c43c2f86403822b72b"
3) "port"
4) (integer) 6379
5) "ip"
6) "172.18.0.5"
7) "endpoint"
8) "172.18.0.5"
9) "role"
10) "master"
11) "replication-offset"
12) (integer) 224
13) "health"
14) "online"
2) 1) "id"
2) "b1c9fe739d6e8d0c519f98ac5e8ebcd1e52cfbe3"
3) "port"
4) (integer) 6379
5) "ip"
6) "172.18.0.3"
7) "endpoint"
8) "172.18.0.3"
9) "role"
10) "master"
11) "replication-offset"
12) (integer) 210
13) "health"
14) "fail"
Steps to reproduce the behavior and/or a minimal code sample.
- start cluster using attached docker-compose.yml.txt
- create a cluster using below command
docker exec -it redis-node-0 redis-cli --cluster create redis-node-0:6379 redis-node-1:6379 redis-node-2:6379 redis-node-3:6379 redis-node-4:6379 redis-node-5:6379 --cluster-replicas 1 - stop one of the container and check output of
CLUSTER SHARDScommand from different container.
docker stop redis-node-2
docker exec -it redis-node-0 redis-cli -h redis-node-5 CLUSTER SHARDS
docker exec -it redis-node-0 redis-cli -h redis-node-0 CLUSTER SHARDS
It should return slots correctly from all of the nodes in the cluster. Please let us know if we are doing something wrong or if this is expected behavior.