J-HowHuang commented on code in PR #16455: URL: https://github.com/apache/pinot/pull/16455#discussion_r2294440897
########## pinot-controller/src/main/java/org/apache/pinot/controller/helix/core/rebalance/tenant/TenantRebalanceChecker.java: ########## @@ -0,0 +1,307 @@ +/** + * Licensed to the Apache Software Foundation (ASF) under one + * or more contributor license agreements. See the NOTICE file + * distributed with this work for additional information + * regarding copyright ownership. The ASF licenses this file + * to you under the Apache License, Version 2.0 (the + * "License"); you may not use this file except in compliance + * with the License. You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, + * software distributed under the License is distributed on an + * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY + * KIND, either express or implied. See the License for the + * specific language governing permissions and limitations + * under the License. + */ +package org.apache.pinot.controller.helix.core.rebalance.tenant; + +import com.fasterxml.jackson.core.JsonProcessingException; +import java.util.ArrayList; +import java.util.Map; +import java.util.Objects; +import java.util.Properties; +import java.util.Set; +import java.util.UUID; +import javax.ws.rs.core.Response; +import org.apache.commons.lang3.StringUtils; +import org.apache.pinot.common.metrics.ControllerMetrics; +import org.apache.pinot.controller.ControllerConf; +import org.apache.pinot.controller.api.exception.ControllerApplicationException; +import org.apache.pinot.controller.helix.core.PinotHelixResourceManager; +import org.apache.pinot.controller.helix.core.controllerjob.ControllerJobTypes; +import org.apache.pinot.controller.helix.core.rebalance.RebalanceJobConstants; +import org.apache.pinot.controller.helix.core.rebalance.RebalanceResult; +import org.apache.pinot.controller.helix.core.rebalance.TableRebalanceProgressStats; +import org.apache.pinot.core.periodictask.BasePeriodicTask; +import org.apache.pinot.spi.utils.CommonConstants; +import org.apache.pinot.spi.utils.JsonUtils; +import org.slf4j.Logger; +import org.slf4j.LoggerFactory; + + +/** + * Periodic task to check if tenant rebalance jobs are stuck and retry them. Controller crashes or restarts could + * make a tenant rebalance job stuck. + * The task checks for each tenant rebalance job's metadata in ZK, look at the TenantTableRebalanceJobContext in + * ongoingJobsQueue, which is a list with table rebalance job ids that the controller is currently processing, to see + * if any of these table rebalance jobs has not updated their progress stats longer than the configured heartbeat + * timeout. If so, the tenant rebalance job is considered stuck, and the task will resume the tenant rebalance job by + * aborting all the ongoing table rebalance jobs, move the ongoing TenantTableRebalanceJobContext back to the head of + * the parallel queue, and then trigger the tenant rebalance job again with the updated context, with an attempt job ID + * <p> + * Notice that fundamentally this is not a retry but a resume, since we will not re-do the table rebalance for those + * tables that have already been processed. + */ +public class TenantRebalanceChecker extends BasePeriodicTask { + private final static String TASK_NAME = TenantRebalanceChecker.class.getSimpleName(); + private static final Logger LOGGER = LoggerFactory.getLogger(TenantRebalanceChecker.class); + private static final double RETRY_DELAY_SCALE_FACTOR = 2.0; + private final TenantRebalancer _tenantRebalancer; + private final PinotHelixResourceManager _pinotHelixResourceManager; + + public TenantRebalanceChecker(ControllerConf config, + ControllerMetrics controllerMetrics, + PinotHelixResourceManager pinotHelixResourceManager, TenantRebalancer tenantRebalancer) { + super(TASK_NAME, config.getTenantRebalanceCheckerFrequencyInSeconds(), + config.getTenantRebalanceCheckerInitialDelayInSeconds()); + _pinotHelixResourceManager = pinotHelixResourceManager; + _tenantRebalancer = tenantRebalancer; + } + + @Override + protected void runTask(Properties periodicTaskProperties) { + checkAndRetryTenantRebalance(); + } + + private void checkAndRetryTenantRebalance() { + Map<String, Map<String, String>> allJobMetadataByJobId = + _pinotHelixResourceManager.getAllJobs(Set.of(ControllerJobTypes.TENANT_REBALANCE), x -> true); + for (Map.Entry<String, Map<String, String>> entry : allJobMetadataByJobId.entrySet()) { + String jobId = entry.getKey(); + Map<String, String> jobZKMetadata = entry.getValue(); + + try { + // Check if the tenant rebalance job is stuck + String tenantRebalanceContextStr = + jobZKMetadata.get(RebalanceJobConstants.JOB_METADATA_KEY_REBALANCE_CONTEXT); + String tenantRebalanceProgressStatsStr = + jobZKMetadata.get(RebalanceJobConstants.JOB_METADATA_KEY_REBALANCE_PROGRESS_STATS); + if (StringUtils.isEmpty(tenantRebalanceContextStr) || StringUtils.isEmpty(tenantRebalanceProgressStatsStr)) { + // Skip rebalance job: {} as it has no job context or progress stats + LOGGER.info("Skip checking tenant rebalance job: {} as it has no job context or progress stats", jobId); + continue; + } + DefaultTenantRebalanceContext tenantRebalanceContext = + JsonUtils.stringToObject(tenantRebalanceContextStr, DefaultTenantRebalanceContext.class); + TenantRebalanceProgressStats progressStats = + JsonUtils.stringToObject(tenantRebalanceProgressStatsStr, TenantRebalanceProgressStats.class); + long statsUpdatedAt = Long.parseLong(jobZKMetadata.get(CommonConstants.ControllerJob.SUBMISSION_TIME_MS)); + + DefaultTenantRebalanceContext retryTenantRebalanceContext = + prepareRetryIfTenantRebalanceJobStuck(jobZKMetadata, tenantRebalanceContext, statsUpdatedAt); + if (retryTenantRebalanceContext != null) { + for (TenantRebalancer.TenantTableRebalanceJobContext ctx; + (ctx = retryTenantRebalanceContext.getOngoingJobsQueue().poll()) != null; ) { + abortTableRebalanceJob(ctx.getTableName()); + // the existing table rebalance job is aborted, we need to run the rebalance job with a new job ID. + TenantRebalancer.TenantTableRebalanceJobContext newCtx = + new TenantRebalancer.TenantTableRebalanceJobContext( + ctx.getTableName(), UUID.randomUUID().toString(), ctx.shouldRebalanceWithDowntime()); + retryTenantRebalanceContext.getParallelQueue().addFirst(newCtx); + } + // the retry tenant rebalance job id has been created in ZK, we can safely mark the original job as + // aborted, so that this original job will not be picked up again in the future. + markTenantRebalanceJobAsAborted(jobId, jobZKMetadata, tenantRebalanceContext, progressStats); + retryTenantRebalanceJob(retryTenantRebalanceContext, progressStats); + } else { + LOGGER.info("Tenant rebalance job: {} is not stuck", jobId); + } + } catch (JsonProcessingException e) { + // If we cannot parse the job metadata, we skip this job + LOGGER.warn("Failed to parse tenant rebalance context for job: {}, skipping", jobId); + } + } + } + + private void retryTenantRebalanceJob(DefaultTenantRebalanceContext tenantRebalanceContextForRetry, + TenantRebalanceProgressStats progressStats) { + ZkBasedTenantRebalanceObserver observer = + new ZkBasedTenantRebalanceObserver(tenantRebalanceContextForRetry.getJobId(), + tenantRebalanceContextForRetry.getConfig().getTenantName(), + progressStats, tenantRebalanceContextForRetry, _pinotHelixResourceManager); + ((DefaultTenantRebalancer) _tenantRebalancer).rebalanceWithContext(tenantRebalanceContextForRetry, observer); + } + + /** + * Check if the tenant rebalance job is stuck, and prepare to retry it if necessary. + * A tenant rebalance job is considered stuck if: + * 1. There are no ongoing jobs, but there are jobs in the parallel or sequential queue, and the stats have not been + * updated for longer than the heartbeat timeout. + * 2. There are ongoing table rebalance jobs, and at least one of them has not updated its status for longer than the + * heartbeat timeout. + * The retry is prepared by creating a new tenant rebalance job with an incremented attempt ID, and persisting it to + * ZK. + * + * @param jobZKMetadata The ZK metadata of the tenant rebalance job. + * @param tenantRebalanceContext The context of the tenant rebalance job. + * @param statsUpdatedAt The timestamp when the stats were last updated. + * @return The TenantRebalanceContext for retry if the tenant rebalance job is stuck and should be retried, null if + * other controller has prepared the retry first. Review Comment: good catch, thanks -- This is an automated message from the Apache Git Service. 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