StatusWith<std::vector<std::string>> ShardingCatalogManager::_getDBNamesListFromShard( OperationContext* opCtx, std::shared_ptr<RemoteCommandTargeter> targeter) { auto swCommandResponse = _runCommandForAddShard(opCtx, targeter.get(), NamespaceString::kAdminDb, BSON("listDatabases" << 1 << "nameOnly" << true)); if (!swCommandResponse.isOK()) { return swCommandResponse.getStatus(); } auto cmdStatus = std::move(swCommandResponse.getValue().commandStatus); if (!cmdStatus.isOK()) { return cmdStatus; } auto cmdResult = std::move(swCommandResponse.getValue().response); std::vector<std::string> dbNames; for (const auto& dbEntry : cmdResult["databases"].Obj()) { const auto& dbName = dbEntry["name"].String(); if (!(dbName == NamespaceString::kAdminDb || dbName == NamespaceString::kLocalDb || dbName == NamespaceString::kConfigDb)) { dbNames.push_back(dbName); } } return dbNames; }
StatusWith<std::vector<std::string>> ShardingCatalogManagerImpl::_getDBNamesListFromShard( OperationContext* txn, std::shared_ptr<RemoteCommandTargeter> targeter) { auto swCommandResponse = _runCommandForAddShard(txn, targeter.get(), "admin", BSON("listDatabases" << 1)); if (!swCommandResponse.isOK()) { return swCommandResponse.getStatus(); } auto cmdStatus = std::move(swCommandResponse.getValue().commandStatus); if (!cmdStatus.isOK()) { return cmdStatus; } auto cmdResult = std::move(swCommandResponse.getValue().response); vector<string> dbNames; for (const auto& dbEntry : cmdResult["databases"].Obj()) { const string& dbName = dbEntry["name"].String(); if (!(dbName == "local" || dbName == "admin")) { dbNames.push_back(dbName); } } return dbNames; }
Status ShardingCatalogManager::_dropSessionsCollection( OperationContext* opCtx, std::shared_ptr<RemoteCommandTargeter> targeter) { BSONObjBuilder builder; builder.append("drop", NamespaceString::kLogicalSessionsNamespace.coll()); { BSONObjBuilder wcBuilder(builder.subobjStart("writeConcern")); wcBuilder.append("w", "majority"); } auto swCommandResponse = _runCommandForAddShard( opCtx, targeter.get(), NamespaceString::kLogicalSessionsNamespace.db(), builder.done()); if (!swCommandResponse.isOK()) { return swCommandResponse.getStatus(); } auto cmdStatus = std::move(swCommandResponse.getValue().commandStatus); if (!cmdStatus.isOK() && cmdStatus.code() != ErrorCodes::NamespaceNotFound) { return cmdStatus; } return Status::OK(); }
StatusWith<std::string> ShardingCatalogManager::addShard( OperationContext* opCtx, const std::string* shardProposedName, const ConnectionString& shardConnectionString, const long long maxSize) { if (shardConnectionString.type() == ConnectionString::INVALID) { return {ErrorCodes::BadValue, "Invalid connection string"}; } if (shardProposedName && shardProposedName->empty()) { return {ErrorCodes::BadValue, "shard name cannot be empty"}; } // Only one addShard operation can be in progress at a time. Lock::ExclusiveLock lk(opCtx->lockState(), _kShardMembershipLock); // Check if this shard has already been added (can happen in the case of a retry after a network // error, for example) and thus this addShard request should be considered a no-op. auto existingShard = _checkIfShardExists(opCtx, shardConnectionString, shardProposedName, maxSize); if (!existingShard.isOK()) { return existingShard.getStatus(); } if (existingShard.getValue()) { // These hosts already belong to an existing shard, so report success and terminate the // addShard request. Make sure to set the last optime for the client to the system last // optime so that we'll still wait for replication so that this state is visible in the // committed snapshot. repl::ReplClientInfo::forClient(opCtx->getClient()).setLastOpToSystemLastOpTime(opCtx); return existingShard.getValue()->getName(); } // Force a reload of the ShardRegistry to ensure that, in case this addShard is to re-add a // replica set that has recently been removed, we have detached the ReplicaSetMonitor for the // set with that setName from the ReplicaSetMonitorManager and will create a new // ReplicaSetMonitor when targeting the set below. // Note: This is necessary because as of 3.4, removeShard is performed by mongos (unlike // addShard), so the ShardRegistry is not synchronously reloaded on the config server when a // shard is removed. if (!Grid::get(opCtx)->shardRegistry()->reload(opCtx)) { // If the first reload joined an existing one, call reload again to ensure the reload is // fresh. Grid::get(opCtx)->shardRegistry()->reload(opCtx); } // TODO: Don't create a detached Shard object, create a detached RemoteCommandTargeter instead. const std::shared_ptr<Shard> shard{ Grid::get(opCtx)->shardRegistry()->createConnection(shardConnectionString)}; invariant(shard); auto targeter = shard->getTargeter(); auto stopMonitoringGuard = MakeGuard([&] { if (shardConnectionString.type() == ConnectionString::SET) { // This is a workaround for the case were we could have some bad shard being // requested to be added and we put that bad connection string on the global replica set // monitor registry. It needs to be cleaned up so that when a correct replica set is // added, it will be recreated. ReplicaSetMonitor::remove(shardConnectionString.getSetName()); } }); // Validate the specified connection string may serve as shard at all auto shardStatus = _validateHostAsShard(opCtx, targeter, shardProposedName, shardConnectionString); if (!shardStatus.isOK()) { return shardStatus.getStatus(); } ShardType& shardType = shardStatus.getValue(); // Check that none of the existing shard candidate's dbs exist already auto dbNamesStatus = _getDBNamesListFromShard(opCtx, targeter); if (!dbNamesStatus.isOK()) { return dbNamesStatus.getStatus(); } for (const auto& dbName : dbNamesStatus.getValue()) { auto dbt = Grid::get(opCtx)->catalogClient()->getDatabase( opCtx, dbName, repl::ReadConcernLevel::kLocalReadConcern); if (dbt.isOK()) { const auto& dbDoc = dbt.getValue().value; return Status(ErrorCodes::OperationFailed, str::stream() << "can't add shard " << "'" << shardConnectionString.toString() << "'" << " because a local database '" << dbName << "' exists in another " << dbDoc.getPrimary()); } else if (dbt != ErrorCodes::NamespaceNotFound) { return dbt.getStatus(); } } // Check that the shard candidate does not have a local config.system.sessions collection auto res = _dropSessionsCollection(opCtx, targeter); if (!res.isOK()) { return res.withContext( "can't add shard with a local copy of config.system.sessions, please drop this " "collection from the shard manually and try again."); } // If a name for a shard wasn't provided, generate one if (shardType.getName().empty()) { auto result = generateNewShardName(opCtx); if (!result.isOK()) { return result.getStatus(); } shardType.setName(result.getValue()); } if (maxSize > 0) { shardType.setMaxSizeMB(maxSize); } // Helper function that runs a command on the to-be shard and returns the status auto runCmdOnNewShard = [this, &opCtx, &targeter](const BSONObj& cmd) -> Status { auto swCommandResponse = _runCommandForAddShard(opCtx, targeter.get(), NamespaceString::kAdminDb, cmd); if (!swCommandResponse.isOK()) { return swCommandResponse.getStatus(); } // Grabs the underlying status from a StatusWith object by taking the first // non-OK status, if there is one. This is needed due to the semantics of // _runCommandForAddShard. auto commandResponse = std::move(swCommandResponse.getValue()); BatchedCommandResponse batchResponse; return Shard::CommandResponse::processBatchWriteResponse(commandResponse, &batchResponse); }; AddShard addShardCmd = add_shard_util::createAddShardCmd(opCtx, shardType.getName()); auto addShardCmdBSON = [&]() { // In 4.2, use the _addShard command to add the shard, which in turn inserts a // shardIdentity document into the shard and triggers sharding state initialization. // In the unlikely scenario that there's a downgrade to 4.0 between the // construction of this command object and the issuing of the command // on the receiving shard, the user will receive a rather harmless // CommandNotFound error for _addShard, and can simply retry. if (serverGlobalParams.featureCompatibility.getVersion() == ServerGlobalParams::FeatureCompatibility::Version::kFullyUpgradedTo42) { // Needed for IDL toBSON method BSONObj passthroughFields; return addShardCmd.toBSON(passthroughFields); } else { // To support backwards compatibility with v4.0 shards, insert a shardIdentity document // directly. return add_shard_util::createShardIdentityUpsertForAddShard(addShardCmd); } }(); auto addShardStatus = runCmdOnNewShard(addShardCmdBSON); if (!addShardStatus.isOK()) { return addShardStatus; } { // Hold the fcvLock across checking the FCV, sending setFCV to the new shard, and // writing the entry for the new shard to config.shards. This ensures the FCV doesn't change // after we send setFCV to the new shard, but before we write its entry to config.shards. // (Note, we don't use a Global IX lock here, because we don't want to hold the global lock // while blocking on the network). invariant(!opCtx->lockState()->isLocked()); Lock::SharedLock lk(opCtx->lockState(), FeatureCompatibilityVersion::fcvLock); BSONObj setFCVCmd; switch (serverGlobalParams.featureCompatibility.getVersion()) { case ServerGlobalParams::FeatureCompatibility::Version::kFullyUpgradedTo42: case ServerGlobalParams::FeatureCompatibility::Version::kUpgradingTo42: setFCVCmd = BSON(FeatureCompatibilityVersionCommandParser::kCommandName << FeatureCompatibilityVersionParser::kVersion42 << WriteConcernOptions::kWriteConcernField << opCtx->getWriteConcern().toBSON()); break; default: setFCVCmd = BSON(FeatureCompatibilityVersionCommandParser::kCommandName << FeatureCompatibilityVersionParser::kVersion40 << WriteConcernOptions::kWriteConcernField << opCtx->getWriteConcern().toBSON()); break; } auto versionResponse = _runCommandForAddShard(opCtx, targeter.get(), NamespaceString::kAdminDb, setFCVCmd); if (!versionResponse.isOK()) { return versionResponse.getStatus(); } if (!versionResponse.getValue().commandStatus.isOK()) { return versionResponse.getValue().commandStatus; } log() << "going to insert new entry for shard into config.shards: " << shardType.toString(); Status result = Grid::get(opCtx)->catalogClient()->insertConfigDocument( opCtx, ShardType::ConfigNS, shardType.toBSON(), ShardingCatalogClient::kLocalWriteConcern); if (!result.isOK()) { log() << "error adding shard: " << shardType.toBSON() << " err: " << result.reason(); return result; } } // Add all databases which were discovered on the new shard for (const auto& dbName : dbNamesStatus.getValue()) { DatabaseType dbt(dbName, shardType.getName(), false, databaseVersion::makeNew()); { const auto status = Grid::get(opCtx)->catalogClient()->updateConfigDocument( opCtx, DatabaseType::ConfigNS, BSON(DatabaseType::name(dbName)), dbt.toBSON(), true, ShardingCatalogClient::kLocalWriteConcern); if (!status.isOK()) { log() << "adding shard " << shardConnectionString.toString() << " even though could not add database " << dbName; } } } // Record in changelog BSONObjBuilder shardDetails; shardDetails.append("name", shardType.getName()); shardDetails.append("host", shardConnectionString.toString()); Grid::get(opCtx)->catalogClient()->logChange( opCtx, "addShard", "", shardDetails.obj(), ShardingCatalogClient::kMajorityWriteConcern); // Ensure the added shard is visible to this process. auto shardRegistry = Grid::get(opCtx)->shardRegistry(); if (!shardRegistry->getShard(opCtx, shardType.getName()).isOK()) { return {ErrorCodes::OperationFailed, "Could not find shard metadata for shard after adding it. This most likely " "indicates that the shard was removed immediately after it was added."}; } stopMonitoringGuard.Dismiss(); return shardType.getName(); }
StatusWith<ShardType> ShardingCatalogManager::_validateHostAsShard( OperationContext* opCtx, std::shared_ptr<RemoteCommandTargeter> targeter, const std::string* shardProposedName, const ConnectionString& connectionString) { auto swCommandResponse = _runCommandForAddShard( opCtx, targeter.get(), NamespaceString::kAdminDb, BSON("isMaster" << 1)); if (swCommandResponse.getStatus() == ErrorCodes::IncompatibleServerVersion) { return swCommandResponse.getStatus().withReason( str::stream() << "Cannot add " << connectionString.toString() << " as a shard because its binary version is not compatible with " "the cluster's featureCompatibilityVersion."); } else if (!swCommandResponse.isOK()) { return swCommandResponse.getStatus(); } // Check for a command response error auto resIsMasterStatus = std::move(swCommandResponse.getValue().commandStatus); if (!resIsMasterStatus.isOK()) { return resIsMasterStatus.withContext(str::stream() << "Error running isMaster against " << targeter->connectionString().toString()); } auto resIsMaster = std::move(swCommandResponse.getValue().response); // Fail if the node being added is a mongos. const std::string msg = resIsMaster.getStringField("msg"); if (msg == "isdbgrid") { return {ErrorCodes::IllegalOperation, "cannot add a mongos as a shard"}; } // Extract the maxWireVersion so we can verify that the node being added has a binary version // greater than or equal to the cluster's featureCompatibilityVersion. We expect an incompatible // binary node to be unable to communicate, returning an IncompatibleServerVersion error, // because of our internal wire version protocol. So we can safely invariant here that the node // is compatible. long long maxWireVersion; Status status = bsonExtractIntegerField(resIsMaster, "maxWireVersion", &maxWireVersion); if (!status.isOK()) { return status.withContext(str::stream() << "isMaster returned invalid 'maxWireVersion' " << "field when attempting to add " << connectionString.toString() << " as a shard"); } if (serverGlobalParams.featureCompatibility.getVersion() > ServerGlobalParams::FeatureCompatibility::Version::kFullyDowngradedTo40) { // If the cluster's FCV is 4.2, or upgrading to / downgrading from, the node being added // must be a v4.2 binary. invariant(maxWireVersion == WireVersion::LATEST_WIRE_VERSION); } else { // If the cluster's FCV is 4.0, the node being added must be a v4.0 or v4.2 binary. invariant(serverGlobalParams.featureCompatibility.getVersion() == ServerGlobalParams::FeatureCompatibility::Version::kFullyDowngradedTo40); invariant(maxWireVersion >= WireVersion::LATEST_WIRE_VERSION - 1); } // Check whether there is a master. If there isn't, the replica set may not have been // initiated. If the connection is a standalone, it will return true for isMaster. bool isMaster; status = bsonExtractBooleanField(resIsMaster, "ismaster", &isMaster); if (!status.isOK()) { return status.withContext(str::stream() << "isMaster returned invalid 'ismaster' " << "field when attempting to add " << connectionString.toString() << " as a shard"); } if (!isMaster) { return {ErrorCodes::NotMaster, str::stream() << connectionString.toString() << " does not have a master. If this is a replica set, ensure that it has a" << " healthy primary and that the set has been properly initiated."}; } const std::string providedSetName = connectionString.getSetName(); const std::string foundSetName = resIsMaster["setName"].str(); // Make sure the specified replica set name (if any) matches the actual shard's replica set if (providedSetName.empty() && !foundSetName.empty()) { return {ErrorCodes::OperationFailed, str::stream() << "host is part of set " << foundSetName << "; " << "use replica set url format " << "<setname>/<server1>,<server2>, ..."}; } if (!providedSetName.empty() && foundSetName.empty()) { return {ErrorCodes::OperationFailed, str::stream() << "host did not return a set name; " << "is the replica set still initializing? " << resIsMaster}; } // Make sure the set name specified in the connection string matches the one where its hosts // belong into if (!providedSetName.empty() && (providedSetName != foundSetName)) { return {ErrorCodes::OperationFailed, str::stream() << "the provided connection string (" << connectionString.toString() << ") does not match the actual set name " << foundSetName}; } // Is it a config server? if (resIsMaster.hasField("configsvr")) { return {ErrorCodes::OperationFailed, str::stream() << "Cannot add " << connectionString.toString() << " as a shard since it is a config server"}; } // If the shard is part of a replica set, make sure all the hosts mentioned in the connection // string are part of the set. It is fine if not all members of the set are mentioned in the // connection string, though. if (!providedSetName.empty()) { std::set<std::string> hostSet; BSONObjIterator iter(resIsMaster["hosts"].Obj()); while (iter.more()) { hostSet.insert(iter.next().String()); // host:port } if (resIsMaster["passives"].isABSONObj()) { BSONObjIterator piter(resIsMaster["passives"].Obj()); while (piter.more()) { hostSet.insert(piter.next().String()); // host:port } } if (resIsMaster["arbiters"].isABSONObj()) { BSONObjIterator piter(resIsMaster["arbiters"].Obj()); while (piter.more()) { hostSet.insert(piter.next().String()); // host:port } } for (const auto& hostEntry : connectionString.getServers()) { const auto& host = hostEntry.toString(); // host:port if (hostSet.find(host) == hostSet.end()) { return {ErrorCodes::OperationFailed, str::stream() << "in seed list " << connectionString.toString() << ", host " << host << " does not belong to replica set " << foundSetName << "; found " << resIsMaster.toString()}; } } } std::string actualShardName; if (shardProposedName) { actualShardName = *shardProposedName; } else if (!foundSetName.empty()) { // Default it to the name of the replica set actualShardName = foundSetName; } // Disallow adding shard replica set with name 'config' if (actualShardName == NamespaceString::kConfigDb) { return {ErrorCodes::BadValue, "use of shard replica set with name 'config' is not allowed"}; } // Retrieve the most up to date connection string that we know from the replica set monitor (if // this is a replica set shard, otherwise it will be the same value as connectionString). ConnectionString actualShardConnStr = targeter->connectionString(); ShardType shard; shard.setName(actualShardName); shard.setHost(actualShardConnStr.toString()); shard.setState(ShardType::ShardState::kShardAware); return shard; }
StatusWith<string> ShardingCatalogManagerImpl::addShard( OperationContext* txn, const std::string* shardProposedName, const ConnectionString& shardConnectionString, const long long maxSize) { if (shardConnectionString.type() == ConnectionString::INVALID) { return {ErrorCodes::BadValue, "Invalid connection string"}; } if (shardProposedName && shardProposedName->empty()) { return {ErrorCodes::BadValue, "shard name cannot be empty"}; } // TODO: Don't create a detached Shard object, create a detached RemoteCommandTargeter instead. const std::shared_ptr<Shard> shard{ Grid::get(txn)->shardRegistry()->createConnection(shardConnectionString)}; invariant(shard); auto targeter = shard->getTargeter(); // Validate the specified connection string may serve as shard at all auto shardStatus = _validateHostAsShard(txn, targeter, shardProposedName, shardConnectionString); if (!shardStatus.isOK()) { // TODO: This is a workaround for the case were we could have some bad shard being // requested to be added and we put that bad connection string on the global replica set // monitor registry. It needs to be cleaned up so that when a correct replica set is added, // it will be recreated. ReplicaSetMonitor::remove(shardConnectionString.getSetName()); return shardStatus.getStatus(); } ShardType& shardType = shardStatus.getValue(); auto dbNamesStatus = _getDBNamesListFromShard(txn, targeter); if (!dbNamesStatus.isOK()) { return dbNamesStatus.getStatus(); } // Check that none of the existing shard candidate's dbs exist already for (const string& dbName : dbNamesStatus.getValue()) { auto dbt = _catalogClient->getDatabase(txn, dbName); if (dbt.isOK()) { const auto& dbDoc = dbt.getValue().value; return Status(ErrorCodes::OperationFailed, str::stream() << "can't add shard " << "'" << shardConnectionString.toString() << "'" << " because a local database '" << dbName << "' exists in another " << dbDoc.getPrimary()); } else if (dbt != ErrorCodes::NamespaceNotFound) { return dbt.getStatus(); } } // If a name for a shard wasn't provided, generate one if (shardType.getName().empty()) { StatusWith<string> result = _generateNewShardName(txn); if (!result.isOK()) { return result.getStatus(); } shardType.setName(result.getValue()); } if (maxSize > 0) { shardType.setMaxSizeMB(maxSize); } ShardIdentityType shardIdentity; shardIdentity.setConfigsvrConnString( Grid::get(txn)->shardRegistry()->getConfigServerConnectionString()); shardIdentity.setShardName(shardType.getName()); shardIdentity.setClusterId(Grid::get(txn)->shardRegistry()->getClusterId()); auto validateStatus = shardIdentity.validate(); if (!validateStatus.isOK()) { return validateStatus; } log() << "going to insert shardIdentity document into shard: " << shardIdentity.toString(); auto updateRequest = shardIdentity.createUpsertForAddShard(); BatchedCommandRequest commandRequest(updateRequest.release()); commandRequest.setNS(NamespaceString::kConfigCollectionNamespace); commandRequest.setWriteConcern(kMajorityWriteConcern.toBSON()); auto swCommandResponse = _runCommandForAddShard(txn, targeter.get(), "admin", commandRequest.toBSON()); if (!swCommandResponse.isOK()) { return swCommandResponse.getStatus(); } auto commandResponse = std::move(swCommandResponse.getValue()); BatchedCommandResponse batchResponse; auto batchResponseStatus = Shard::CommandResponse::processBatchWriteResponse(commandResponse, &batchResponse); if (!batchResponseStatus.isOK()) { return batchResponseStatus; } log() << "going to insert new entry for shard into config.shards: " << shardType.toString(); Status result = _catalogClient->insertConfigDocument(txn, ShardType::ConfigNS, shardType.toBSON()); if (!result.isOK()) { log() << "error adding shard: " << shardType.toBSON() << " err: " << result.reason(); if (result == ErrorCodes::DuplicateKey) { // TODO(SERVER-24213): adding a shard that already exists should be considered success, // however this approach does no validation that we are adding the shard with the same // options. It also does not protect against adding the same shard with a different // shard name and slightly different connection string. This is a temporary hack to // get the continuous stepdown suite passing. warning() << "Received duplicate key error when inserting new shard with name " << shardType.getName() << " and connection string " << shardConnectionString.toString() << " to config.shards collection. This most likely means that there was an " "attempt to add a shard that already exists in the cluster"; return shardType.getName(); } return result; } // Add all databases which were discovered on the new shard for (const string& dbName : dbNamesStatus.getValue()) { DatabaseType dbt; dbt.setName(dbName); dbt.setPrimary(shardType.getName()); dbt.setSharded(false); Status status = _catalogClient->updateDatabase(txn, dbName, dbt); if (!status.isOK()) { log() << "adding shard " << shardConnectionString.toString() << " even though could not add database " << dbName; } } // Record in changelog BSONObjBuilder shardDetails; shardDetails.append("name", shardType.getName()); shardDetails.append("host", shardConnectionString.toString()); _catalogClient->logChange(txn, "addShard", "", shardDetails.obj()); // Ensure the added shard is visible to this process. auto shardRegistry = Grid::get(txn)->shardRegistry(); if (!shardRegistry->getShard(txn, shardType.getName())) { return {ErrorCodes::OperationFailed, "Could not find shard metadata for shard after adding it. This most likely " "indicates that the shard was removed immediately after it was added."}; } return shardType.getName(); }
StatusWith<ShardType> ShardingCatalogManagerImpl::_validateHostAsShard( OperationContext* txn, std::shared_ptr<RemoteCommandTargeter> targeter, const std::string* shardProposedName, const ConnectionString& connectionString) { // Check whether any host in the connection is already part of the cluster. Grid::get(txn)->shardRegistry()->reload(txn); for (const auto& hostAndPort : connectionString.getServers()) { std::shared_ptr<Shard> shard; shard = Grid::get(txn)->shardRegistry()->getShardNoReload(hostAndPort.toString()); if (shard) { return {ErrorCodes::OperationFailed, str::stream() << "'" << hostAndPort.toString() << "' " << "is already a member of the existing shard '" << shard->getConnString().toString() << "' (" << shard->getId() << ")."}; } } // Check for mongos and older version mongod connections, and whether the hosts // can be found for the user specified replset. auto swCommandResponse = _runCommandForAddShard(txn, targeter.get(), "admin", BSON("isMaster" << 1)); if (!swCommandResponse.isOK()) { if (swCommandResponse.getStatus() == ErrorCodes::RPCProtocolNegotiationFailed) { // Mongos to mongos commands are no longer supported in the wire protocol // (because mongos does not support OP_COMMAND), similarly for a new mongos // and an old mongod. So the call will fail in such cases. // TODO: If/When mongos ever supports opCommands, this logic will break because // cmdStatus will be OK. return {ErrorCodes::RPCProtocolNegotiationFailed, str::stream() << targeter->connectionString().toString() << " does not recognize the RPC protocol being used. This is" << " likely because it contains a node that is a mongos or an old" << " version of mongod."}; } else { return swCommandResponse.getStatus(); } } // Check for a command response error auto resIsMasterStatus = std::move(swCommandResponse.getValue().commandStatus); if (!resIsMasterStatus.isOK()) { return {resIsMasterStatus.code(), str::stream() << "Error running isMaster against " << targeter->connectionString().toString() << ": " << causedBy(resIsMasterStatus)}; } auto resIsMaster = std::move(swCommandResponse.getValue().response); // Check whether there is a master. If there isn't, the replica set may not have been // initiated. If the connection is a standalone, it will return true for isMaster. bool isMaster; Status status = bsonExtractBooleanField(resIsMaster, "ismaster", &isMaster); if (!status.isOK()) { return Status(status.code(), str::stream() << "isMaster returned invalid 'ismaster' " << "field when attempting to add " << connectionString.toString() << " as a shard: " << status.reason()); } if (!isMaster) { return {ErrorCodes::NotMaster, str::stream() << connectionString.toString() << " does not have a master. If this is a replica set, ensure that it has a" << " healthy primary and that the set has been properly initiated."}; } const string providedSetName = connectionString.getSetName(); const string foundSetName = resIsMaster["setName"].str(); // Make sure the specified replica set name (if any) matches the actual shard's replica set if (providedSetName.empty() && !foundSetName.empty()) { return {ErrorCodes::OperationFailed, str::stream() << "host is part of set " << foundSetName << "; " << "use replica set url format " << "<setname>/<server1>,<server2>, ..."}; } if (!providedSetName.empty() && foundSetName.empty()) { return {ErrorCodes::OperationFailed, str::stream() << "host did not return a set name; " << "is the replica set still initializing? " << resIsMaster}; } // Make sure the set name specified in the connection string matches the one where its hosts // belong into if (!providedSetName.empty() && (providedSetName != foundSetName)) { return {ErrorCodes::OperationFailed, str::stream() << "the provided connection string (" << connectionString.toString() << ") does not match the actual set name " << foundSetName}; } // Is it a config server? if (resIsMaster.hasField("configsvr")) { return {ErrorCodes::OperationFailed, str::stream() << "Cannot add " << connectionString.toString() << " as a shard since it is a config server"}; } // If the shard is part of a replica set, make sure all the hosts mentioned in the connection // string are part of the set. It is fine if not all members of the set are mentioned in the // connection string, though. if (!providedSetName.empty()) { std::set<string> hostSet; BSONObjIterator iter(resIsMaster["hosts"].Obj()); while (iter.more()) { hostSet.insert(iter.next().String()); // host:port } if (resIsMaster["passives"].isABSONObj()) { BSONObjIterator piter(resIsMaster["passives"].Obj()); while (piter.more()) { hostSet.insert(piter.next().String()); // host:port } } if (resIsMaster["arbiters"].isABSONObj()) { BSONObjIterator piter(resIsMaster["arbiters"].Obj()); while (piter.more()) { hostSet.insert(piter.next().String()); // host:port } } vector<HostAndPort> hosts = connectionString.getServers(); for (size_t i = 0; i < hosts.size(); i++) { const string host = hosts[i].toString(); // host:port if (hostSet.find(host) == hostSet.end()) { return {ErrorCodes::OperationFailed, str::stream() << "in seed list " << connectionString.toString() << ", host " << host << " does not belong to replica set " << foundSetName << "; found " << resIsMaster.toString()}; } } } string actualShardName; if (shardProposedName) { actualShardName = *shardProposedName; } else if (!foundSetName.empty()) { // Default it to the name of the replica set actualShardName = foundSetName; } // Disallow adding shard replica set with name 'config' if (actualShardName == "config") { return {ErrorCodes::BadValue, "use of shard replica set with name 'config' is not allowed"}; } // Retrieve the most up to date connection string that we know from the replica set monitor (if // this is a replica set shard, otherwise it will be the same value as connectionString). ConnectionString actualShardConnStr = targeter->connectionString(); ShardType shard; shard.setName(actualShardName); shard.setHost(actualShardConnStr.toString()); return shard; }
StatusWith<std::string> ShardingCatalogManagerImpl::addShard( OperationContext* opCtx, const std::string* shardProposedName, const ConnectionString& shardConnectionString, const long long maxSize) { if (shardConnectionString.type() == ConnectionString::INVALID) { return {ErrorCodes::BadValue, "Invalid connection string"}; } if (shardProposedName && shardProposedName->empty()) { return {ErrorCodes::BadValue, "shard name cannot be empty"}; } // Only one addShard operation can be in progress at a time. Lock::ExclusiveLock lk(opCtx->lockState(), _kShardMembershipLock); // Check if this shard has already been added (can happen in the case of a retry after a network // error, for example) and thus this addShard request should be considered a no-op. auto existingShard = _checkIfShardExists(opCtx, shardConnectionString, shardProposedName, maxSize); if (!existingShard.isOK()) { return existingShard.getStatus(); } if (existingShard.getValue()) { // These hosts already belong to an existing shard, so report success and terminate the // addShard request. Make sure to set the last optime for the client to the system last // optime so that we'll still wait for replication so that this state is visible in the // committed snapshot. repl::ReplClientInfo::forClient(opCtx->getClient()).setLastOpToSystemLastOpTime(opCtx); return existingShard.getValue()->getName(); } // Force a reload of the ShardRegistry to ensure that, in case this addShard is to re-add a // replica set that has recently been removed, we have detached the ReplicaSetMonitor for the // set with that setName from the ReplicaSetMonitorManager and will create a new // ReplicaSetMonitor when targeting the set below. // Note: This is necessary because as of 3.4, removeShard is performed by mongos (unlike // addShard), so the ShardRegistry is not synchronously reloaded on the config server when a // shard is removed. if (!Grid::get(opCtx)->shardRegistry()->reload(opCtx)) { // If the first reload joined an existing one, call reload again to ensure the reload is // fresh. Grid::get(opCtx)->shardRegistry()->reload(opCtx); } // TODO: Don't create a detached Shard object, create a detached RemoteCommandTargeter instead. const std::shared_ptr<Shard> shard{ Grid::get(opCtx)->shardRegistry()->createConnection(shardConnectionString)}; invariant(shard); auto targeter = shard->getTargeter(); auto stopMonitoringGuard = MakeGuard([&] { if (shardConnectionString.type() == ConnectionString::SET) { // This is a workaround for the case were we could have some bad shard being // requested to be added and we put that bad connection string on the global replica set // monitor registry. It needs to be cleaned up so that when a correct replica set is // added, it will be recreated. ReplicaSetMonitor::remove(shardConnectionString.getSetName()); } }); // Validate the specified connection string may serve as shard at all auto shardStatus = _validateHostAsShard(opCtx, targeter, shardProposedName, shardConnectionString); if (!shardStatus.isOK()) { return shardStatus.getStatus(); } ShardType& shardType = shardStatus.getValue(); // Check that none of the existing shard candidate's dbs exist already auto dbNamesStatus = _getDBNamesListFromShard(opCtx, targeter); if (!dbNamesStatus.isOK()) { return dbNamesStatus.getStatus(); } for (const auto& dbName : dbNamesStatus.getValue()) { auto dbt = Grid::get(opCtx)->catalogClient(opCtx)->getDatabase(opCtx, dbName); if (dbt.isOK()) { const auto& dbDoc = dbt.getValue().value; return Status(ErrorCodes::OperationFailed, str::stream() << "can't add shard " << "'" << shardConnectionString.toString() << "'" << " because a local database '" << dbName << "' exists in another " << dbDoc.getPrimary()); } else if (dbt != ErrorCodes::NamespaceNotFound) { return dbt.getStatus(); } } // If a name for a shard wasn't provided, generate one if (shardType.getName().empty()) { auto result = generateNewShardName(opCtx); if (!result.isOK()) { return result.getStatus(); } shardType.setName(result.getValue()); } if (maxSize > 0) { shardType.setMaxSizeMB(maxSize); } // If the minimum allowed version for the cluster is 3.4, set the featureCompatibilityVersion to // 3.4 on the shard. if (serverGlobalParams.featureCompatibility.version.load() == ServerGlobalParams::FeatureCompatibility::Version::k34) { auto versionResponse = _runCommandForAddShard(opCtx, targeter.get(), "admin", BSON(FeatureCompatibilityVersion::kCommandName << FeatureCompatibilityVersionCommandParser::kVersion34)); if (!versionResponse.isOK()) { return versionResponse.getStatus(); } if (!versionResponse.getValue().commandStatus.isOK()) { if (versionResponse.getStatus().code() == ErrorCodes::CommandNotFound) { return {ErrorCodes::OperationFailed, "featureCompatibilityVersion for cluster is 3.4, cannot add a shard with " "version below 3.4. See " "http://dochub.mongodb.org/core/3.4-feature-compatibility."}; } return versionResponse.getValue().commandStatus; } } if (!MONGO_FAIL_POINT(dontUpsertShardIdentityOnNewShards)) { auto commandRequest = createShardIdentityUpsertForAddShard(opCtx, shardType.getName()); LOG(2) << "going to insert shardIdentity document into shard: " << shardType; auto swCommandResponse = _runCommandForAddShard(opCtx, targeter.get(), "admin", commandRequest); if (!swCommandResponse.isOK()) { return swCommandResponse.getStatus(); } auto commandResponse = std::move(swCommandResponse.getValue()); BatchedCommandResponse batchResponse; auto batchResponseStatus = Shard::CommandResponse::processBatchWriteResponse(commandResponse, &batchResponse); if (!batchResponseStatus.isOK()) { return batchResponseStatus; } } log() << "going to insert new entry for shard into config.shards: " << shardType.toString(); Status result = Grid::get(opCtx)->catalogClient(opCtx)->insertConfigDocument( opCtx, ShardType::ConfigNS, shardType.toBSON(), ShardingCatalogClient::kMajorityWriteConcern); if (!result.isOK()) { log() << "error adding shard: " << shardType.toBSON() << " err: " << result.reason(); return result; } // Add all databases which were discovered on the new shard for (const auto& dbName : dbNamesStatus.getValue()) { DatabaseType dbt; dbt.setName(dbName); dbt.setPrimary(shardType.getName()); dbt.setSharded(false); Status status = Grid::get(opCtx)->catalogClient(opCtx)->updateDatabase(opCtx, dbName, dbt); if (!status.isOK()) { log() << "adding shard " << shardConnectionString.toString() << " even though could not add database " << dbName; } } // Record in changelog BSONObjBuilder shardDetails; shardDetails.append("name", shardType.getName()); shardDetails.append("host", shardConnectionString.toString()); Grid::get(opCtx)->catalogClient(opCtx)->logChange( opCtx, "addShard", "", shardDetails.obj(), ShardingCatalogClient::kMajorityWriteConcern); // Ensure the added shard is visible to this process. auto shardRegistry = Grid::get(opCtx)->shardRegistry(); if (!shardRegistry->getShard(opCtx, shardType.getName()).isOK()) { return {ErrorCodes::OperationFailed, "Could not find shard metadata for shard after adding it. This most likely " "indicates that the shard was removed immediately after it was added."}; } stopMonitoringGuard.Dismiss(); return shardType.getName(); }
StatusWith<ShardType> ShardingCatalogManagerImpl::_validateHostAsShard( OperationContext* opCtx, std::shared_ptr<RemoteCommandTargeter> targeter, const std::string* shardProposedName, const ConnectionString& connectionString) { // Check if the node being added is a mongos or a version of mongod too old to speak the current // communication protocol. auto swCommandResponse = _runCommandForAddShard(opCtx, targeter.get(), "admin", BSON("isMaster" << 1)); if (!swCommandResponse.isOK()) { if (swCommandResponse.getStatus() == ErrorCodes::RPCProtocolNegotiationFailed) { // Mongos to mongos commands are no longer supported in the wire protocol // (because mongos does not support OP_COMMAND), similarly for a new mongos // and an old mongod. So the call will fail in such cases. // TODO: If/When mongos ever supports opCommands, this logic will break because // cmdStatus will be OK. return {ErrorCodes::RPCProtocolNegotiationFailed, str::stream() << targeter->connectionString().toString() << " does not recognize the RPC protocol being used. This is" << " likely because it contains a node that is a mongos or an old" << " version of mongod."}; } else { return swCommandResponse.getStatus(); } } // Check for a command response error auto resIsMasterStatus = std::move(swCommandResponse.getValue().commandStatus); if (!resIsMasterStatus.isOK()) { return {resIsMasterStatus.code(), str::stream() << "Error running isMaster against " << targeter->connectionString().toString() << ": " << causedBy(resIsMasterStatus)}; } auto resIsMaster = std::move(swCommandResponse.getValue().response); // Check that the node being added is a new enough version. // If we're running this code, that means the mongos that the addShard request originated from // must be at least version 3.4 (since 3.2 mongoses don't know about the _configsvrAddShard // command). Since it is illegal to have v3.4 mongoses with v3.2 shards, we should reject // adding any shards that are not v3.4. We can determine this by checking that the // maxWireVersion reported in isMaster is at least COMMANDS_ACCEPT_WRITE_CONCERN. // TODO(SERVER-25623): This approach won't work to prevent v3.6 mongoses from adding v3.4 // shards, so we'll have to rethink this during the 3.5 development cycle. long long maxWireVersion; Status status = bsonExtractIntegerField(resIsMaster, "maxWireVersion", &maxWireVersion); if (!status.isOK()) { return Status(status.code(), str::stream() << "isMaster returned invalid 'maxWireVersion' " << "field when attempting to add " << connectionString.toString() << " as a shard: " << status.reason()); } if (maxWireVersion < WireVersion::COMMANDS_ACCEPT_WRITE_CONCERN) { return Status(ErrorCodes::IncompatibleServerVersion, str::stream() << "Cannot add " << connectionString.toString() << " as a shard because we detected a mongod with server " "version older than 3.4.0. It is invalid to add v3.2 and " "older shards through a v3.4 mongos."); } // Check whether there is a master. If there isn't, the replica set may not have been // initiated. If the connection is a standalone, it will return true for isMaster. bool isMaster; status = bsonExtractBooleanField(resIsMaster, "ismaster", &isMaster); if (!status.isOK()) { return Status(status.code(), str::stream() << "isMaster returned invalid 'ismaster' " << "field when attempting to add " << connectionString.toString() << " as a shard: " << status.reason()); } if (!isMaster) { return {ErrorCodes::NotMaster, str::stream() << connectionString.toString() << " does not have a master. If this is a replica set, ensure that it has a" << " healthy primary and that the set has been properly initiated."}; } const std::string providedSetName = connectionString.getSetName(); const std::string foundSetName = resIsMaster["setName"].str(); // Make sure the specified replica set name (if any) matches the actual shard's replica set if (providedSetName.empty() && !foundSetName.empty()) { return {ErrorCodes::OperationFailed, str::stream() << "host is part of set " << foundSetName << "; " << "use replica set url format " << "<setname>/<server1>,<server2>, ..."}; } if (!providedSetName.empty() && foundSetName.empty()) { return {ErrorCodes::OperationFailed, str::stream() << "host did not return a set name; " << "is the replica set still initializing? " << resIsMaster}; } // Make sure the set name specified in the connection string matches the one where its hosts // belong into if (!providedSetName.empty() && (providedSetName != foundSetName)) { return {ErrorCodes::OperationFailed, str::stream() << "the provided connection string (" << connectionString.toString() << ") does not match the actual set name " << foundSetName}; } // Is it a config server? if (resIsMaster.hasField("configsvr")) { return {ErrorCodes::OperationFailed, str::stream() << "Cannot add " << connectionString.toString() << " as a shard since it is a config server"}; } // If the shard is part of a replica set, make sure all the hosts mentioned in the connection // string are part of the set. It is fine if not all members of the set are mentioned in the // connection string, though. if (!providedSetName.empty()) { std::set<std::string> hostSet; BSONObjIterator iter(resIsMaster["hosts"].Obj()); while (iter.more()) { hostSet.insert(iter.next().String()); // host:port } if (resIsMaster["passives"].isABSONObj()) { BSONObjIterator piter(resIsMaster["passives"].Obj()); while (piter.more()) { hostSet.insert(piter.next().String()); // host:port } } if (resIsMaster["arbiters"].isABSONObj()) { BSONObjIterator piter(resIsMaster["arbiters"].Obj()); while (piter.more()) { hostSet.insert(piter.next().String()); // host:port } } for (const auto& hostEntry : connectionString.getServers()) { const auto& host = hostEntry.toString(); // host:port if (hostSet.find(host) == hostSet.end()) { return {ErrorCodes::OperationFailed, str::stream() << "in seed list " << connectionString.toString() << ", host " << host << " does not belong to replica set " << foundSetName << "; found " << resIsMaster.toString()}; } } } std::string actualShardName; if (shardProposedName) { actualShardName = *shardProposedName; } else if (!foundSetName.empty()) { // Default it to the name of the replica set actualShardName = foundSetName; } // Disallow adding shard replica set with name 'config' if (actualShardName == NamespaceString::kConfigDb) { return {ErrorCodes::BadValue, "use of shard replica set with name 'config' is not allowed"}; } // Retrieve the most up to date connection string that we know from the replica set monitor (if // this is a replica set shard, otherwise it will be the same value as connectionString). ConnectionString actualShardConnStr = targeter->connectionString(); ShardType shard; shard.setName(actualShardName); shard.setHost(actualShardConnStr.toString()); shard.setState(ShardType::ShardState::kShardAware); return shard; }