yuzegao commented on code in PR #3295: URL: https://github.com/apache/kvrocks/pull/3295#discussion_r2637751747
########## src/cluster/cluster_failover.cc: ########## @@ -0,0 +1,293 @@ +/* + * 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. + * + */ + +#include "cluster_failover.h" + +#include <unistd.h> + +#include "cluster/cluster.h" +#include "common/io_util.h" +#include "common/time_util.h" +#include "logging.h" +#include "server/redis_reply.h" +#include "server/server.h" + +ClusterFailover::ClusterFailover(Server *srv) : srv_(srv) { + t_ = std::thread([this]() { loop(); }); +} + +ClusterFailover::~ClusterFailover() { + { + std::lock_guard<std::mutex> lock(mutex_); + stop_thread_ = true; + cv_.notify_all(); + } + if (t_.joinable()) t_.join(); +} + +Status ClusterFailover::Run(std::string slave_node_id, int timeout_ms) { + std::lock_guard<std::mutex> lock(mutex_); + if (state_ != FailoverState::kNone && state_ != FailoverState::kFailed) { + return {Status::NotOK, "Failover is already in progress"}; + } + + if (srv_->IsSlave()) { + return {Status::NotOK, "Current node is a slave, can't failover"}; + } + + slave_node_id_ = std::move(slave_node_id); + timeout_ms_ = timeout_ms; + state_ = FailoverState::kStarted; + failover_job_triggered_ = true; + cv_.notify_all(); + return Status::OK(); +} + +void ClusterFailover::loop() { + while (true) { + std::unique_lock<std::mutex> lock(mutex_); + cv_.wait(lock, [this]() { return stop_thread_ || failover_job_triggered_; }); + + if (stop_thread_) return; + + if (failover_job_triggered_) { + failover_job_triggered_ = false; + lock.unlock(); + runFailoverProcess(); + } + } +} + +void ClusterFailover::runFailoverProcess() { + auto ip_port = srv_->cluster->GetNodeIPPort(slave_node_id_); + if (!ip_port.IsOK()) { + error("[Failover] slave node not found in cluster {}", slave_node_id_); + abortFailover("Slave node not found in cluster"); + return; + } + node_ip_port_ = ip_port.GetValue().first + ":" + std::to_string(ip_port.GetValue().second); + node_ip_ = ip_port.GetValue().first; + node_port_ = ip_port.GetValue().second; + info("[Failover] slave node {} {} failover state: {}", slave_node_id_, node_ip_port_, static_cast<int>(state_.load())); + state_ = FailoverState::kCheck; + + auto s = checkSlaveStatus(); + if (!s.IsOK()) { + abortFailover(s.Msg()); + return; + } + + s = checkSlaveLag(); + if (!s.IsOK()) { + abortFailover("Slave lag check failed: " + s.Msg()); + return; + } + + info("[Failover] slave node {} {} check slave status success, enter pause state", slave_node_id_, node_ip_port_); + start_time_ms_ = util::GetTimeStampMS(); + // Enter Pause state (Stop writing) + state_ = FailoverState::kPause; + // Get current sequence + target_seq_ = srv_->storage->LatestSeqNumber(); + info("[Failover] slave node {} {} target sequence {}", slave_node_id_, node_ip_port_, target_seq_); + + state_ = FailoverState::kSyncWait; + s = waitReplicationSync(); + if (!s.IsOK()) { + abortFailover(s.Msg()); + return; + } + info("[Failover] slave node {} {} wait replication sync success, enter switch state, cost {} ms", slave_node_id_, + node_ip_port_, util::GetTimeStampMS() - start_time_ms_); + + state_ = FailoverState::kSwitch; + s = sendTakeoverCmd(); + if (!s.IsOK()) { + abortFailover(s.Msg()); + return; + } + + // Redirect slots + srv_->cluster->SetMySlotsMigrated(node_ip_port_); + + state_ = FailoverState::kSuccess; + info("[Failover] success {} {}", slave_node_id_, node_ip_port_); +} + +Status ClusterFailover::checkSlaveLag() { + auto start_offset_status = srv_->GetSlaveReplicationOffset(node_ip_port_); + if (!start_offset_status.IsOK()) { + return {Status::NotOK, "Failed to get slave offset: " + start_offset_status.Msg()}; + } + uint64_t start_offset = *start_offset_status; + int64_t start_sampling_ms = util::GetTimeStampMS(); + + // Wait 3s or half of timeout, but at least a bit to measure speed + int64_t wait_time = std::max(100, std::min(3000, timeout_ms_ / 2)); + std::this_thread::sleep_for(std::chrono::milliseconds(wait_time)); + + auto end_offset_status = srv_->GetSlaveReplicationOffset(node_ip_port_); + if (!end_offset_status.IsOK()) { + return {Status::NotOK, "Failed to get slave offset: " + end_offset_status.Msg()}; + } + uint64_t end_offset = *end_offset_status; + int64_t end_sampling_ms = util::GetTimeStampMS(); + + double elapsed_sec = (end_sampling_ms - start_sampling_ms) / 1000.0; + if (elapsed_sec <= 0) elapsed_sec = 0.001; + + uint64_t bytes = 0; + if (end_offset > start_offset) bytes = end_offset - start_offset; + double speed = bytes / elapsed_sec; + + uint64_t master_seq = srv_->storage->LatestSeqNumber(); + uint64_t lag = 0; + if (master_seq > end_offset) lag = master_seq - end_offset; + + if (lag == 0) return Status::OK(); + + if (speed <= 0.1) { // Basically 0 + return {Status::NotOK, fmt::format("Slave is not replicating (lag: {})", lag)}; + } + + double required_sec = lag / speed; + int64_t required_ms = static_cast<int64_t>(required_sec * 1000); + + int64_t elapsed_total = end_sampling_ms - start_sampling_ms; + int64_t remaining = timeout_ms_ - elapsed_total; + + if (required_ms > remaining) { + return {Status::NotOK, fmt::format("Estimated catchup time {}ms > remaining time {}ms (lag: {}, speed: {:.2f}/s)", + required_ms, remaining, lag, speed)}; + } + + info("[Failover] check: lag={}, speed={:.2f}/s, estimated_time={}ms, remaining={}ms", lag, speed, required_ms, + remaining); + return Status::OK(); +} + +Status ClusterFailover::checkSlaveStatus() { + // We could try to connect, but GetSlaveReplicationOffset checks connection. + auto offset = srv_->GetSlaveReplicationOffset(node_ip_port_); + if (!offset.IsOK()) { + error("[Failover] slave node {} {} not connected or not syncing", slave_node_id_, node_ip_port_); + return {Status::NotOK, "Slave not connected or not syncing"}; + } + info("[Failover] slave node {} {} is connected and syncing offset {}", slave_node_id_, node_ip_port_, offset.Msg()); + return Status::OK(); +} + +Status ClusterFailover::waitReplicationSync() { + while (true) { + if (util::GetTimeStampMS() - start_time_ms_ > static_cast<uint64_t>(timeout_ms_)) { + return {Status::NotOK, "Timeout waiting for replication sync"}; + } + + auto offset_status = srv_->GetSlaveReplicationOffset(node_ip_port_); + if (!offset_status.IsOK()) { + return {Status::NotOK, "Failed to get slave offset: " + offset_status.Msg()}; + } + + if (*offset_status >= target_seq_) { + return Status::OK(); + } + + std::this_thread::sleep_for(std::chrono::milliseconds(10)); + } +} + +Status ClusterFailover::sendTakeoverCmd() { + auto s = util::SockConnect(node_ip_, node_port_); + if (!s.IsOK()) { + return {Status::NotOK, "Failed to connect to slave: " + s.Msg()}; + } + int fd = *s; + + std::string pass = srv_->GetConfig()->requirepass; + if (!pass.empty()) { + std::string auth_cmd = redis::ArrayOfBulkStrings({"AUTH", pass}); + auto s_auth = util::SockSend(fd, auth_cmd); + if (!s_auth.IsOK()) { + close(fd); + return {Status::NotOK, "Failed to send AUTH: " + s_auth.Msg()}; + } + auto s_line = util::SockReadLine(fd); + if (!s_line.IsOK() || s_line.GetValue().substr(0, 3) != "+OK") { + close(fd); + return {Status::NotOK, "AUTH failed"}; + } Review Comment: Without resource leak risk, beacuse all path have close(fd). if (!pass.empty()) { std::string auth_cmd = redis::ArrayOfBulkStrings({"AUTH", pass}); auto s_auth = util::SockSend(fd, auth_cmd); if (!s_auth.IsOK()) { close(fd); return {Status::NotOK, "Failed to send AUTH: " + s_auth.Msg()}; } auto s_line = util::SockReadLine(fd); if (!s_line.IsOK() || s_line.GetValue().substr(0, 3) != "+OK") { close(fd); return {Status::NotOK, "AUTH failed"}; } } std::string cmd = redis::ArrayOfBulkStrings({"CLUSTERX", "TAKEOVER"}); auto s_send = util::SockSend(fd, cmd); if (!s_send.IsOK()) { close(fd); return {Status::NotOK, "Failed to send TAKEOVER: " + s_send.Msg()}; } auto s_resp = util::SockReadLine(fd); close(fd); -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: [email protected] For queries about this service, please contact Infrastructure at: [email protected]
