FessでElasticsearchを使用していると、プライマリシャードが未割り当てになってしまうことがありました。
_cluster/allocation/explain?pretty で確認をすると、以下が表示されます。
{
"note": "No shard was specified in the explain API request, so this response explains a randomly chosen unassigned shard. There may be other unassigned shards in this cluster which cannot be assigned for different reasons. It may not be possible to assign this shard until one of the other shards is assigned correctly. To explain the allocation of other shards (whether assigned or unassigned) you must specify the target shard in the request to this API.",
"index": "fess.20211019",
"shard": 3,
"primary": true,
"current_state": "unassigned",
"unassigned_info": {
"reason": "CLUSTER_RECOVERED",
"at": "2021-10-20T06:34:09.505Z",
"last_allocation_status": "no_valid_shard_copy"
},
"can_allocate": "no_valid_shard_copy",
"allocate_explanation": "cannot allocate because all found copies of the shard are either stale or corrupt",
"node_allocation_decisions": [
{
"node_id": "53PB99k_QfO5LEjpR01Wyw",
"node_name": "localhost.localdomain",
"transport_address": "127.0.0.1:9300",
"node_attributes": {
"ml.machine_memory": "16518074368",
"xpack.installed": "true",
"transform.node": "true",
"ml.max_open_jobs": "512",
"ml.max_jvm_size": "8258584576"
},
"node_decision": "no",
"store": {
"in_sync": true,
"allocation_id": "EZhFrp5pSsW6nerHgL67nw",
"store_exception": {
"type": "corrupt_index_exception",
"reason": "failed engine (reason: [merge failed]) (resource=preexisting_corruption)",
"caused_by": {
"type": "i_o_exception",
"reason": "failed engine (reason: [merge failed])",
"caused_by": {
"type": "corrupt_index_exception",
"reason": "checksum failed (hardware problem?) : expected=504f4028 actual=5cba0fa5 (resource=BufferedChecksumIndexInput(NIOFSIndexInput(path="/var/lib/elasticsearch/nodes/0/indices/8DOT_y2IRkOY_hXSN6CzWA/3/index/_ud_Lucene84_0.pos")))"
}
}
}
}
}
]
}
色々調べた結果、プライマリシャードをもう一度割り当てる方法は見つかりましたが、
未割り当てが発生しないようにしたいと考えております。
何か原因がわかるようでしたら、お教えいただけますでしょうか。
Elasticsearchのバージョンは、7.15.1です。