Shard allocation fails when splitting index on multi-node cluster

Elastic Stack Elasticsearch
1

I have a 3 node Elasticsearch cluster and an index of size 40GB on it which only has a single shard. The single shard of the index reside on one of the nodes. I am trying to split that index into 6 shards.

The problem is out of the 6 shards that are created, only 2 of the shards gets allocated to the node and rest 4 shards remain unassigned, because of which the index remains in red state. The 2 shards that are allocated are allocated on the same node on which the shard of the source node resides.

The _cluster/allocation/explain API gives the following output:

"node_allocation_decisions": [
        {
            "node_id": "",
            "node_name": "2-0",
            "transport_address": "",
            "node_attributes": {
                "availability_set": "2",
                "shard_indexing_pressure_enabled": "true"
            },
            "node_decision": "no",
            "weight_ranking": 1,
            "deciders": [
                {
                    "decider": "resize",
                    "decision": "NO",
                    "explanation": "source primary is allocated on another node"
                }
            ]
        },
        {
            "node_id": "",
            "node_name": "1-0",
            "transport_address": "",
            "node_attributes": {
                "availability_set": "1",
                "shard_indexing_pressure_enabled": "true"
            },
            "node_decision": "no",
            "weight_ranking": 2,
            "deciders": [
                {
                    "decider": "resize",
                    "decision": "NO",
                    "explanation": "source primary is allocated on another node"
                }
            ]
        },
        {
            "node_id": "",
            "node_name": "0-0",
            "transport_address": "",
            "node_attributes": {
                "availability_set": "0",
                "shard_indexing_pressure_enabled": "true"
            },
            "node_decision": "no",
            "weight_ranking": 3,
            "deciders": [
                {
                    "decider": "affinity",
                    "decision": "NO",
                    "explanation": "Number of shards [3] allocated for affinity attribute [availability_set] with value [0] would exceed maximum limit [2]"
                }
            ]
        }
    ]

How to split an index when I have a multi-node cluster and ensure that all shards are equally distributed across all the nodes?

2

This is not a message that Elasticsearch would emit. I think you must be using some other product. This forum is only about Elasticsearch. For help with other products, please ask for help on those products' own forums.