mirror of https://gitee.com/bigwinds/arangodb
598 lines
18 KiB
C++
598 lines
18 KiB
C++
////////////////////////////////////////////////////////////////////////////////
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/// DISCLAIMER
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///
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/// Copyright 2014-2016 ArangoDB GmbH, Cologne, Germany
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/// Copyright 2004-2014 triAGENS GmbH, Cologne, Germany
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///
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/// Licensed under the Apache License, Version 2.0 (the "License");
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/// you may not use this file except in compliance with the License.
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/// You may obtain a copy of the License at
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///
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/// http://www.apache.org/licenses/LICENSE-2.0
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///
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/// Unless required by applicable law or agreed to in writing, software
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/// distributed under the License is distributed on an "AS IS" BASIS,
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/// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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/// See the License for the specific language governing permissions and
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/// limitations under the License.
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///
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/// Copyright holder is ArangoDB GmbH, Cologne, Germany
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///
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/// @author Kaveh Vahedipour
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////////////////////////////////////////////////////////////////////////////////
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#include "Supervision.h"
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#include "Agent.h"
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#include "CleanOutServer.h"
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#include "FailedLeader.h"
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#include "FailedServer.h"
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#include "MoveShard.h"
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#include "Job.h"
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#include "Store.h"
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#include "Basics/ConditionLocker.h"
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#include "VocBase/server.h"
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#include <thread>
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using namespace arangodb;
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using namespace arangodb::consensus;
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std::string Supervision::_agencyPrefix = "/arango";
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Supervision::Supervision()
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: arangodb::Thread("Supervision"),
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_agent(nullptr),
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_snapshot("Supervision"),
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_frequency(5),
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_gracePeriod(15),
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_jobId(0),
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_jobIdMax(0) {}
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Supervision::~Supervision() { shutdown(); };
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void Supervision::wakeUp() {
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TRI_ASSERT(_agent != nullptr);
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if (!this->isStopping()) {
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_snapshot = _agent->readDB().get(_agencyPrefix);
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}
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_cv.signal();
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}
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static std::string const syncPrefix = "/Sync/ServerStates/";
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static std::string const healthPrefix = "/Supervision/Health/";
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static std::string const planDBServersPrefix = "/Plan/DBServers";
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static std::string const planCoordinatorsPrefix = "/Plan/Coordinators";
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static std::string const currentServersRegisteredPrefix
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= "/Current/ServersRegistered";
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std::vector<check_t> Supervision::checkDBServers() {
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std::vector<check_t> ret;
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Node::Children const& machinesPlanned =
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_snapshot(planDBServersPrefix).children();
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Node::Children const serversRegistered =
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_snapshot(currentServersRegisteredPrefix).children();
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std::vector<std::string> todelete;
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for (auto const& machine : _snapshot(healthPrefix).children()) {
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if (machine.first.substr(0,2) == "DB") {
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todelete.push_back(machine.first);
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}
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}
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for (auto const& machine : machinesPlanned) {
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bool good = false;
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std::string lastHeartbeatTime, lastHeartbeatAcked, lastStatus, heartbeatTime,
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heartbeatStatus, serverID;
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serverID = machine.first;
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heartbeatTime = _snapshot(syncPrefix + serverID + "/time").toJson();
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heartbeatStatus = _snapshot(syncPrefix + serverID + "/status").toJson();
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todelete.erase(
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std::remove(todelete.begin(), todelete.end(), serverID), todelete.end());
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try { // Existing
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lastHeartbeatTime =
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_snapshot(healthPrefix + serverID + "/LastHeartbeatSent").toJson();
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lastHeartbeatAcked =
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_snapshot(healthPrefix + serverID + "/LastHeartbeatAcked").toJson();
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lastStatus = _snapshot(healthPrefix + serverID + "/Status").toJson();
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if (lastHeartbeatTime != heartbeatTime) { // Update
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good = true;
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}
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} catch (...) { // New server
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good = true;
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}
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query_t report = std::make_shared<Builder>();
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report->openArray();
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report->openArray();
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report->openObject();
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report->add(_agencyPrefix + healthPrefix + serverID,
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VPackValue(VPackValueType::Object));
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report->add("LastHeartbeatSent", VPackValue(heartbeatTime));
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report->add("LastHeartbeatStatus", VPackValue(heartbeatStatus));
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report->add("Role", VPackValue("DBServer"));
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auto endpoint = serversRegistered.find(serverID);
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if (endpoint != serversRegistered.end()) {
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endpoint = endpoint->second->children().find("endpoint");
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if (endpoint != endpoint->second->children().end()) {
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if (endpoint->second->children().size() == 0) {
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VPackSlice epString = endpoint->second->slice();
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if (epString.isString()) {
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report->add("Endpoint", epString);
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}
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}
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}
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}
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if (good) {
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report->add("LastHeartbeatAcked",
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VPackValue(
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timepointToString(std::chrono::system_clock::now())));
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report->add("Status", VPackValue("GOOD"));
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} else {
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std::chrono::seconds t{0};
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t = std::chrono::duration_cast<std::chrono::seconds>(
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std::chrono::system_clock::now()-stringToTimepoint(lastHeartbeatAcked));
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if (t.count() > _gracePeriod) { // Failure
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if (lastStatus == "BAD") {
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report->add("Status", VPackValue("FAILED"));
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FailedServer fsj(_snapshot, _agent, std::to_string(_jobId++),
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"supervision", _agencyPrefix, serverID);
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}
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} else {
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report->add("Status", VPackValue("BAD"));
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}
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}
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report->close();
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report->close();
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report->close();
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report->close();
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if (!this->isStopping()) {
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_agent->write(report);
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}
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}
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if (!todelete.empty()) {
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query_t del = std::make_shared<Builder>();
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del->openArray();
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del->openArray();
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del->openObject();
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for (auto const& srv : todelete) {
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del->add(_agencyPrefix + healthPrefix + srv,
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VPackValue(VPackValueType::Object));
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del->add("op", VPackValue("delete"));
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del->close();
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}
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del->close(); del->close(); del->close();
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_agent->write(del);
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}
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return ret;
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}
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std::vector<check_t> Supervision::checkCoordinators() {
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std::vector<check_t> ret;
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Node::Children const& machinesPlanned =
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_snapshot(planCoordinatorsPrefix).children();
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Node::Children const serversRegistered =
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_snapshot(currentServersRegisteredPrefix).children();
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std::vector<std::string> todelete;
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for (auto const& machine : _snapshot(healthPrefix).children()) {
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if (machine.first.substr(0,2) == "Co") {
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todelete.push_back(machine.first);
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}
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}
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for (auto const& machine : machinesPlanned) {
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bool good = false;
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std::string lastHeartbeatTime, lastHeartbeatAcked, lastStatus, heartbeatTime,
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heartbeatStatus, serverID;
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serverID = machine.first;
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heartbeatTime = _snapshot(syncPrefix + serverID + "/time").toJson();
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heartbeatStatus = _snapshot(syncPrefix + serverID + "/status").toJson();
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todelete.erase(
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std::remove(todelete.begin(), todelete.end(), serverID), todelete.end());
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try { // Existing
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lastHeartbeatTime =
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_snapshot(healthPrefix + serverID + "/LastHeartbeatSent").toJson();
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lastStatus = _snapshot(healthPrefix + serverID + "/Status").toJson();
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if (lastHeartbeatTime != heartbeatTime) { // Update
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good = true;
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}
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} catch (...) { // New server
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good = true;
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}
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query_t report = std::make_shared<Builder>();
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report->openArray();
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report->openArray();
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report->openObject();
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report->add(_agencyPrefix + healthPrefix + serverID,
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VPackValue(VPackValueType::Object));
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report->add("LastHeartbeatSent", VPackValue(heartbeatTime));
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report->add("LastHeartbeatStatus", VPackValue(heartbeatStatus));
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report->add("Role", VPackValue("Coordinator"));
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auto endpoint = serversRegistered.find(serverID);
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if (endpoint != serversRegistered.end()) {
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endpoint = endpoint->second->children().find("endpoint");
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if (endpoint != endpoint->second->children().end()) {
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if (endpoint->second->children().size() == 0) {
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VPackSlice epString = endpoint->second->slice();
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if (epString.isString()) {
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report->add("Endpoint", epString);
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}
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}
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}
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}
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if (good) {
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report->add("LastHeartbeatAcked",
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VPackValue(
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timepointToString(std::chrono::system_clock::now())));
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report->add("Status", VPackValue("GOOD"));
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} else {
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std::chrono::seconds t{0};
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t = std::chrono::duration_cast<std::chrono::seconds>(
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std::chrono::system_clock::now()-stringToTimepoint(lastHeartbeatAcked));
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if (t.count() > _gracePeriod) { // Failure
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if (lastStatus == "BAD") {
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report->add("Status", VPackValue("FAILED"));
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}
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} else {
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report->add("Status", VPackValue("BAD"));
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}
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}
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report->close();
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report->close();
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report->close();
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report->close();
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if (!this->isStopping()) {
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_agent->write(report);
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}
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}
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if (!todelete.empty()) {
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query_t del = std::make_shared<Builder>();
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del->openArray();
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del->openArray();
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del->openObject();
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for (auto const& srv : todelete) {
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del->add(_agencyPrefix + healthPrefix + srv,
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VPackValue(VPackValueType::Object));
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del->add("op", VPackValue("delete"));
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del->close();
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}
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del->close(); del->close(); del->close();
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_agent->write(del);
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}
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return ret;
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}
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bool Supervision::updateSnapshot() {
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if (_agent == nullptr || this->isStopping()) {
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return false;
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}
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_snapshot = _agent->readDB().get(_agencyPrefix);
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return true;
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}
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bool Supervision::doChecks(bool timedout) {
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checkDBServers();
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checkCoordinators();
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return true;
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}
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void Supervision::run() {
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CONDITION_LOCKER(guard, _cv);
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TRI_ASSERT(_agent != nullptr);
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bool timedout = false;
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while (!this->isStopping()) {
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// Get agency prefix after cluster init
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if (_jobId == 0) {
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// We need the agency prefix to work, but it is only initialized by
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// some other server in the cluster. Since the supervision does not
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// make sense at all without other ArangoDB servers, we wait pretty
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// long here before giving up:
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if (!updateAgencyPrefix(1000, 1)) {
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LOG_TOPIC(DEBUG, Logger::AGENCY)
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<< "Cannot get prefix from Agency. Stopping supervision for good.";
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break;
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}
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}
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// Get bunch of job IDs from agency for future jobs
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if (_jobId == 0 || _jobId == _jobIdMax) {
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getUniqueIds(); // cannot fail but only hang
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}
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// Do nothing unless leader
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if (_agent->leading()) {
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timedout = _cv.wait(_frequency * 1000000); // quarter second
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} else {
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_cv.wait();
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}
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// Do supervision
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updateSnapshot();
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doChecks(timedout);
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shrinkCluster();
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workJobs();
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}
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}
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void Supervision::workJobs() {
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Node::Children const& todos = _snapshot(toDoPrefix).children();
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Node::Children const& pends = _snapshot(pendingPrefix).children();
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for (auto const& todoEnt : todos) {
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Node const& job = *todoEnt.second;
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std::string jobType = job("type").getString(),
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jobId = job("jobId").getString(),
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creator = job("creator").getString();
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if (jobType == "failedServer") {
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FailedServer fs(_snapshot, _agent, jobId, creator, _agencyPrefix);
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} else if (jobType == "cleanOutServer") {
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CleanOutServer cos(_snapshot, _agent, jobId, creator, _agencyPrefix);
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} else if (jobType == "moveShard") {
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MoveShard mv(_snapshot, _agent, jobId, creator, _agencyPrefix);
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} else if (jobType == "failedLeader") {
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FailedLeader fl(_snapshot, _agent, jobId, creator, _agencyPrefix);
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}
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}
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for (auto const& pendEnt : pends) {
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Node const& job = *pendEnt.second;
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std::string jobType = job("type").getString(),
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jobId = job("jobId").getString(),
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creator = job("creator").getString();
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if (jobType == "failedServer") {
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FailedServer fs(_snapshot, _agent, jobId, creator, _agencyPrefix);
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} else if (jobType == "cleanOutServer") {
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CleanOutServer cos(_snapshot, _agent, jobId, creator, _agencyPrefix);
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} else if (jobType == "moveShard") {
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MoveShard mv(_snapshot, _agent, jobId, creator, _agencyPrefix);
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} else if (jobType == "failedLeader") {
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FailedLeader fl(_snapshot, _agent, jobId, creator, _agencyPrefix);
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}
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}
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}
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// Shrink cluster if applicable
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void Supervision::shrinkCluster () {
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// Get servers from plan
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std::vector<std::string> availServers;
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Node::Children const& dbservers = _snapshot("/Plan/DBServers").children();
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for (auto const& srv : dbservers) {
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availServers.push_back(srv.first);
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}
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size_t targetNumDBServers;
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try {
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targetNumDBServers = _snapshot("/Target/NumberOfDBServers").getUInt();
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} catch (std::exception const& e) {
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LOG_TOPIC(DEBUG, Logger::AGENCY)
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<< "Cannot retrieve targeted number of db servers from agency" << e.what();
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return;
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}
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// If there are any cleanOutServer jobs todo or pending do nothing
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Node::Children const& todos = _snapshot(toDoPrefix).children();
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Node::Children const& pends = _snapshot(pendingPrefix).children();
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for (auto const& job : todos) {
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try {
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if ((*job.second)("type").getString() == "cleanOutServer") {
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return;
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}
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} catch (std::exception const& e) {
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LOG_TOPIC(WARN, Logger::AGENCY)
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<< "Failed to get job type of job " << job.first << ": " << e.what();
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return;
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}
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}
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for (auto const& job : pends) {
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try {
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if ((*job.second)("type").getString() == "cleanOutServer") {
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return;
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}
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} catch (std::exception const& e) {
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LOG_TOPIC(WARN, Logger::AGENCY)
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<< "Failed to get job type of job " << job.first << ": " << e.what();
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return;
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}
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}
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// Remove cleaned from ist
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if (_snapshot.exists("/Target/CleanedServers").size()==2) {
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for (auto const& srv :
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VPackArrayIterator(_snapshot("/Target/CleanedServers").slice())) {
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availServers.erase(
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std::remove(availServers.begin(), availServers.end(), srv.copyString()),
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availServers.end());
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}
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}
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// Only if number of servers in target is smaller than the available
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if (targetNumDBServers < availServers.size()) {
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// Minimum 1 DB server must remain
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if (availServers.size() == 1) {
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LOG_TOPIC(DEBUG, Logger::AGENCY) <<
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"Only one db server left for operation";
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return;
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}
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// Find greatest replication factor among all collections
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uint64_t maxReplFact = 1;
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Node::Children const& databases = _snapshot("/Plan/Collections").children();
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for (auto const& database : databases) {
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for (auto const& collptr : database.second->children()) {
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try {
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uint64_t replFact = (*collptr.second)("replicationFactor").getUInt();
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if (replFact > maxReplFact) {
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maxReplFact = replFact;
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}
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} catch (std::exception const&) {
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LOG_TOPIC(DEBUG, Logger::AGENCY) << "Cannot retrieve replication " <<
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"factor for collection " << collptr.first;
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return;
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}
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}
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}
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// If max number of replications is small than that of available
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if (maxReplFact < availServers.size()) {
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// Sort servers by name
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std::sort(availServers.begin(), availServers.end());
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// Clean out as long as number of available servers is bigger
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// than maxReplFactor and bigger than targeted number of db servers
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if (availServers.size() > maxReplFact &&
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availServers.size() > targetNumDBServers) {
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// Schedule last server for cleanout
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CleanOutServer(_snapshot, _agent, std::to_string(_jobId++),
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"supervision", _agencyPrefix, availServers.back());
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}
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}
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}
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}
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// Start thread
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bool Supervision::start() {
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Thread::start();
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return true;
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}
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// Start thread with agent
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bool Supervision::start(Agent* agent) {
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_agent = agent;
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_frequency = static_cast<long>(_agent->config().supervisionFrequency);
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return start();
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}
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// Get agency prefix fron agency
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bool Supervision::updateAgencyPrefix (size_t nTries, int intervalSec) {
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// Try nTries to get agency's prefix in intervals
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while (!this->isStopping()) {
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_snapshot = _agent->readDB().get("/");
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if (_snapshot.children().size() > 0) {
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_agencyPrefix = std::string("/") + _snapshot.children().begin()->first;
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LOG_TOPIC(DEBUG, Logger::AGENCY) << "Agency prefix is " << _agencyPrefix;
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return true;
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}
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std::this_thread::sleep_for (std::chrono::seconds(intervalSec));
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}
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// Stand-alone agency
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return false;
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}
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static std::string const syncLatest = "/Sync/LatestID";
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// Get bunch of cluster's unique ids from agency
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void Supervision::getUniqueIds() {
|
|
uint64_t latestId;
|
|
// Run forever, supervision does not make sense before the agency data
|
|
// is initialized by some other server...
|
|
while (!this->isStopping()) {
|
|
try {
|
|
latestId = std::stoul(
|
|
_agent->readDB().get(_agencyPrefix + "/Sync/LatestID").slice().toJson());
|
|
} catch (...) {
|
|
std::this_thread::sleep_for (std::chrono::seconds(1));
|
|
continue;
|
|
}
|
|
|
|
Builder uniq;
|
|
uniq.openArray();
|
|
uniq.openObject();
|
|
uniq.add(_agencyPrefix + syncLatest, VPackValue(latestId + 100000)); // new
|
|
uniq.close();
|
|
uniq.openObject();
|
|
uniq.add(_agencyPrefix + syncLatest, VPackValue(latestId)); // precond
|
|
uniq.close();
|
|
uniq.close();
|
|
|
|
auto result = transact(_agent, uniq);
|
|
|
|
if (!result.accepted || result.indices.empty()) {
|
|
LOG_TOPIC(DEBUG, Logger::AGENCY)
|
|
<< "We have lost agency leadership. Stopping any supervision processing "
|
|
<< __FILE__ << __LINE__;
|
|
return;
|
|
}
|
|
|
|
if (result.indices[0]) {
|
|
_agent->waitFor(result.indices[0]);
|
|
_jobId = latestId;
|
|
_jobIdMax = latestId + 100000;
|
|
return;
|
|
}
|
|
}
|
|
}
|
|
|
|
void Supervision::updateFromAgency() {
|
|
auto const& jobsPending =
|
|
_snapshot("/Supervision/Jobs/Pending").children();
|
|
|
|
for (auto const& jobent : jobsPending) {
|
|
auto const& job = *(jobent.second);
|
|
|
|
LOG_TOPIC(WARN, Logger::AGENCY)
|
|
<< job.name() << " " << job("failed").toJson() << job("");
|
|
}
|
|
}
|
|
|
|
void Supervision::beginShutdown() {
|
|
// Personal hygiene
|
|
Thread::beginShutdown();
|
|
|
|
CONDITION_LOCKER(guard, _cv);
|
|
guard.broadcast();
|
|
|
|
}
|
|
|
|
Store const& Supervision::store() const {
|
|
return _agent->readDB();
|
|
}
|