ES學習筆記之health api的實現
阿新 • • 發佈:2019-04-25
sting don ber true ava == fail nfa ide 使用health api可以查看es集群的健康度。 health api的用法如下:
, 判斷索引的各個分片狀態
curl ‘http://localhost:9200/_cluster/health‘
health api的返回值中有一個核心的字段status
, status
有3種取值: green, yellow, red。分別代表集群的3種狀態: 主分片和副本都已經分配,主分片已經分配副本分片沒有,制定分片沒有分配。
也就是說, health api關註的核心在於數據的高可用。
看health api的實現:
請求會路由到master節點,然後讀取clusterState中的routing_table
.
基於routing_table
public ClusterShardHealth(int shardId, final IndexShardRoutingTable shardRoutingTable) { this.shardId = shardId; for (ShardRouting shardRouting : shardRoutingTable) { if (shardRouting.active()) { activeShards++; if (shardRouting.relocating()) { // the shard is relocating, the one it is relocating to will be in initializing state, so we don‘t count it relocatingShards++; } if (shardRouting.primary()) { primaryActive = true; } } else if (shardRouting.initializing()) { initializingShards++; } else if (shardRouting.unassigned()) { unassignedShards++; } } if (primaryActive) { if (activeShards == shardRoutingTable.size()) { status = ClusterHealthStatus.GREEN; } else { status = ClusterHealthStatus.YELLOW; } } else { status = ClusterHealthStatus.RED; } }
基於分片,決定索引的狀態
public ClusterIndexHealth(IndexMetaData indexMetaData, IndexRoutingTable indexRoutingTable) { this.index = indexMetaData.getIndex(); this.numberOfShards = indexMetaData.getNumberOfShards(); this.numberOfReplicas = indexMetaData.getNumberOfReplicas(); this.validationFailures = indexRoutingTable.validate(indexMetaData); for (IndexShardRoutingTable shardRoutingTable : indexRoutingTable) { int shardId = shardRoutingTable.shardId().id(); shards.put(shardId, new ClusterShardHealth(shardId, shardRoutingTable)); } // update the index status status = ClusterHealthStatus.GREEN; for (ClusterShardHealth shardHealth : shards.values()) { if (shardHealth.isPrimaryActive()) { activePrimaryShards++; } activeShards += shardHealth.getActiveShards(); relocatingShards += shardHealth.getRelocatingShards(); initializingShards += shardHealth.getInitializingShards(); unassignedShards += shardHealth.getUnassignedShards(); if (shardHealth.getStatus() == ClusterHealthStatus.RED) { status = ClusterHealthStatus.RED; } else if (shardHealth.getStatus() == ClusterHealthStatus.YELLOW && status != ClusterHealthStatus.RED) { // do not override an existing red status = ClusterHealthStatus.YELLOW; } } if (!validationFailures.isEmpty()) { status = ClusterHealthStatus.RED; } else if (shards.isEmpty()) { // might be since none has been created yet (two phase index creation) status = ClusterHealthStatus.RED; } }
基於索引,決定集群的狀態。
public ClusterStateHealth(ClusterState clusterState, String[] concreteIndices) {
RoutingTableValidation validation = clusterState.routingTable().validate(clusterState.metaData());
validationFailures = validation.failures();
numberOfNodes = clusterState.nodes().size();
numberOfDataNodes = clusterState.nodes().dataNodes().size();
for (String index : concreteIndices) {
IndexRoutingTable indexRoutingTable = clusterState.routingTable().index(index);
IndexMetaData indexMetaData = clusterState.metaData().index(index);
if (indexRoutingTable == null) {
continue;
}
ClusterIndexHealth indexHealth = new ClusterIndexHealth(indexMetaData, indexRoutingTable);
indices.put(indexHealth.getIndex(), indexHealth);
}
status = ClusterHealthStatus.GREEN;
for (ClusterIndexHealth indexHealth : indices.values()) {
activePrimaryShards += indexHealth.getActivePrimaryShards();
activeShards += indexHealth.getActiveShards();
relocatingShards += indexHealth.getRelocatingShards();
initializingShards += indexHealth.getInitializingShards();
unassignedShards += indexHealth.getUnassignedShards();
if (indexHealth.getStatus() == ClusterHealthStatus.RED) {
status = ClusterHealthStatus.RED;
} else if (indexHealth.getStatus() == ClusterHealthStatus.YELLOW && status != ClusterHealthStatus.RED) {
status = ClusterHealthStatus.YELLOW;
}
}
if (!validationFailures.isEmpty()) {
status = ClusterHealthStatus.RED;
} else if (clusterState.blocks().hasGlobalBlock(RestStatus.SERVICE_UNAVAILABLE)) {
status = ClusterHealthStatus.RED;
}
// shortcut on green
if (status.equals(ClusterHealthStatus.GREEN)) {
this.activeShardsPercent = 100;
} else {
List<ShardRouting> shardRoutings = clusterState.getRoutingTable().allShards();
int activeShardCount = 0;
int totalShardCount = 0;
for (ShardRouting shardRouting : shardRoutings) {
if (shardRouting.active()) activeShardCount++;
totalShardCount++;
}
this.activeShardsPercent = (((double) activeShardCount) / totalShardCount) * 100;
}
}
理解health api, 需要理解clusterState。 好在這些都是只讀的信息,不難理解。
ES學習筆記之health api的實現