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<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;
}