Documentation
¶
Overview ¶
Package config contains functions and types used for managing dragonboat's configurations.
Index ¶
Examples ¶
Constants ¶
This section is empty.
Variables ¶
This section is empty.
Functions ¶
func IsValidAddress ¶
IsValidAddress returns whether the input address is valid.
Types ¶
type CompressionType ¶
type CompressionType = pb.CompressionType
CompressionType is the type of the compression.
const ( // NoCompression is the CompressionType value used to indicate not to use // any compression. NoCompression CompressionType = pb.NoCompression // Snappy is the CompressionType value used to indicate that google snappy // is used for data compression. Snappy CompressionType = pb.Snappy )
type Config ¶
type Config struct {
// NodeID is a non-zero value used to identify a node within a Raft cluster.
NodeID uint64
// ClusterID is the unique value used to identify a Raft cluster.
ClusterID uint64
// CheckQuorum specifies whether the leader node should periodically check
// non-leader node status and step down to become a follower node when it no
// longer has the quorum.
CheckQuorum bool
// ElectionRTT is the minimum number of message RTT between elections. Message
// RTT is defined by NodeHostConfig.RTTMillisecond. The Raft paper suggests it
// to be a magnitude greater than HeartbeatRTT, which is the interval between
// two heartbeats. In Raft, the actual interval between elections is
// randomized to be between ElectionRTT and 2 * ElectionRTT.
//
// As an example, assuming NodeHostConfig.RTTMillisecond is 100 millisecond,
// to set the election interval to be 1 second, then ElectionRTT should be set
// to 10.
//
// When CheckQuorum is enabled, ElectionRTT also defines the interval for
// checking leader quorum.
ElectionRTT uint64
// HeartbeatRTT is the number of message RTT between heartbeats. Message
// RTT is defined by NodeHostConfig.RTTMillisecond. The Raft paper suggest the
// heartbeat interval to be close to the average RTT between nodes.
//
// As an example, assuming NodeHostConfig.RTTMillisecond is 100 millisecond,
// to set the heartbeat interval to be every 200 milliseconds, then
// HeartbeatRTT should be set to 2.
HeartbeatRTT uint64
// SnapshotEntries defines how often the state machine should be snapshotted
// automcatically. It is defined in terms of the number of applied Raft log
// entries. SnapshotEntries can be set to 0 to disable such automatic
// snapshotting.
//
// When SnapshotEntries is set to N, it means a snapshot is created for
// roughly every N applied Raft log entries (proposals). This also implies
// that sending N log entries to a follower is more expensive than sending a
// snapshot.
//
// Once a snapshot is generated, Raft log entries covered by the new snapshot
// can be compacted. This involves two steps, redundant log entries are first
// marked as deleted, then they are physically removed from the underlying
// storage when a LogDB compaction is issued at a later stage. See the godoc
// on CompactionOverhead for details on what log entries are actually removed
// and compacted after generating a snapshot.
//
// Once automatic snapshotting is disabled by setting the SnapshotEntries
// field to 0, users can still use NodeHost's RequestSnapshot or
// SyncRequestSnapshot methods to manually request snapshots.
SnapshotEntries uint64
// CompactionOverhead defines the number of most recent entries to keep after
// each Raft log compaction. Raft log compaction is performance automatically
// every time when a snapshot is created.
//
// For example, when a snapshot is created at let's say index 10,000, then all
// Raft log entries with index <= 10,000 can be removed from that node as they
// have already been covered by the created snapshot image. This frees up the
// maximum storage space but comes at the cost that the full snapshot will
// have to be sent to the follower if the follower requires any Raft log entry
// at index <= 10,000. When CompactionOverhead is set to say 500, Dragonboat
// then compacts the Raft log up to index 9,500 and keeps Raft log entries
// between index (9,500, 1,0000]. As a result, the node can still replicate
// Raft log entries between index (9,500, 1,0000] to other peers and only fall
// back to stream the full snapshot if any Raft log entry with index <= 9,500
// is required to be replicated.
CompactionOverhead uint64
// OrderedConfigChange determines whether Raft membership change is enforced
// with ordered config change ID.
OrderedConfigChange bool
// MaxInMemLogSize is the target size in bytes allowed for storing in memory
// Raft logs on each Raft node. In memory Raft logs are the ones that have
// not been applied yet.
// MaxInMemLogSize is a target value implemented to prevent unbounded memory
// growth, it is not for precisely limiting the exact memory usage.
// When MaxInMemLogSize is 0, the target is set to math.MaxUint64. When
// MaxInMemLogSize is set and the target is reached, error will be returned
// when clients try to make new proposals.
// MaxInMemLogSize is recommended to be significantly larger than the biggest
// proposal you are going to use.
MaxInMemLogSize uint64
// SnapshotCompressionType is the compression type to use for compressing
// generated snapshot data. No compression is used by default.
SnapshotCompressionType CompressionType
// EntryCompressionType is the compression type to use for compressing the
// payload of user proposals. When Snappy is used, the maximum proposal
// payload allowed is roughly limited to 3.42GBytes.
EntryCompressionType CompressionType
// DisableAutoCompactions disables auto compaction used for reclaiming Raft
// entry storage spaces. By default, compaction is issued every time when
// a snapshot is captured, this helps to reclaim disk spaces as soon as
// possible at the cost of higher IO overhead. Users can disable such auto
// compactions and use NodeHost.RequestCompaction to manually request such
// compactions when necessary.
DisableAutoCompactions bool
// IsObserver indicates whether this is an observer Raft node without voting
// power. Described as non-voting members in the section 4.2.1 of Diego
// Ongaro's thesis, observer nodes are usually used to allow a new node to
// join the cluster and catch up with other existing ndoes without impacting
// the availability. Extra observer nodes can also be introduced to serve
// read-only requests without affecting system write throughput.
//
// Observer support is currently experimental.
IsObserver bool
// IsWitness indicates whether this is a witness Raft node without actual log
// replication and do not have state machine. It is mentioned in the section
// 11.7.2 of Diego Ongaro's thesis.
//
// Witness support is currently experimental.
IsWitness bool
// Quiesce specifies whether to let the Raft cluster enter quiesce mode when
// there is no cluster activity. Clusters in quiesce mode do not exchange
// heartbeat messages to minimize bandwidth consumption.
//
// Quiesce support is currently experimental.
Quiesce bool
}
Config is used to configure Raft nodes.
type LogDBFactoryFunc ¶
LogDBFactoryFunc is the factory function that creates NodeHost's persistent storage module known as Log DB.
type NodeHostConfig ¶
type NodeHostConfig struct {
// DeploymentID is used to determine whether two NodeHost instances belong to
// the same deployment and thus allowed to communicate with each other. This
// helps to prvent accidentially misconfigured NodeHost instances to cause
// data corruption errors by sending out of context messages to unrelated
// Raft nodes.
// For a particular dragonboat based application, you can set DeploymentID
// to the same uint64 value on all production NodeHost instances, then use
// different DeploymentID values on your staging and dev environment. It is
// also recommended to use different DeploymentID values for different
// dragonboat based applications.
// When not set, the default value 0 will be used as the deployment ID and
// thus allowing all NodeHost instances with deployment ID 0 to communicate
// with each other.
DeploymentID uint64
// WALDir is the directory used for storing the WAL of Raft entries. It is
// recommended to use low latency storage such as NVME SSD with power loss
// protection to store such WAL data. Leave WALDir to have zero value will
// have everything stored in NodeHostDir.
WALDir string
// NodeHostDir is where everything else is stored.
NodeHostDir string
// RTTMillisecond defines the average Rround Trip Time (RTT) in milliseconds
// between two NodeHost instances. Such a RTT interval is internally used as
// a logical clock tick, Raft heartbeat and election intervals are both
// defined in term of how many such RTT intervals.
// Note that RTTMillisecond is the combined delays between two NodeHost
// instances including all delays caused by network transmission, delays
// caused by NodeHost queuing and processing. As an example, when fully
// loaded, the average Rround Trip Time between two of our NodeHost instances
// used for benchmarking purposes is up to 500 microseconds when the ping time
// between them is 100 microseconds. Set RTTMillisecond to 1 when it is less
// than 1 million in your environment.
RTTMillisecond uint64
// RaftAddress is a hostname:port or IP:port address used by the Raft RPC
// module for exchanging Raft messages and snapshots. This is also the
// identifier for a NodeHost instance. RaftAddress should be set to the
// public address that can be accessed from remote NodeHost instances.
RaftAddress string
// ListenAddress is a hostname:port or IP:port address used by the Raft RPC
// module to listen on for Raft message and snapshots. When the ListenAddress
// field is not set, The Raft RPC module listens on RaftAddress. If 0.0.0.0
// is specified as the IP of the ListenAddress, Dragonboat listens to the
// specified port on all interfaces. When hostname or domain name is
// specified, it is locally resolved to IP addresses first and Dragonboat
// listens to all resolved IP addresses.
ListenAddress string
// MutualTLS defines whether to use mutual TLS for authenticating servers
// and clients. Insecure communication is used when MutualTLS is set to
// False.
// See https://github.com/lni/dragonboat/wiki/TLS-in-Dragonboat for more
// details on how to use Mutual TLS.
MutualTLS bool
// CAFile is the path of the CA certificate file. This field is ignored when
// MutualTLS is false.
CAFile string
// CertFile is the path of the node certificate file. This field is ignored
// when MutualTLS is false.
CertFile string
// KeyFile is the path of the node key file. This field is ignored when
// MutualTLS is false.
KeyFile string
// MaxSendQueueSize is the maximum size in bytes of each send queue.
// Once the maximum size is reached, further replication messages will be
// dropped to restrict memory usage. When set to 0, it means the send queue
// size is unlimited.
MaxSendQueueSize uint64
// MaxReceiveQueueSize is the maximum size in bytes of each receive queue.
// Once the maximum size is reached, further replication messages will be
// dropped to restrict memory usage. When set to 0, it means the queue size
// is unlimited.
MaxReceiveQueueSize uint64
// LogDBFactory is the factory function used for creating the Log DB instance
// used by NodeHost. The default zero value causes the default built-in RocksDB
// based Log DB implementation to be used.
LogDBFactory LogDBFactoryFunc
// RaftRPCFactory is the factory function used for creating the Raft RPC
// instance for exchanging Raft message between NodeHost instances. The default
// zero value causes the built-in TCP based RPC module to be used.
RaftRPCFactory RaftRPCFactoryFunc
// EnableMetrics determines whether health metrics in Prometheus format should
// be enabled.
EnableMetrics bool
// RaftEventListener is the listener for Raft events, such as Raft leadership
// change, exposed to user space. NodeHost uses a single dedicated goroutine
// to invoke all RaftEventListener methods one by one, CPU intensive or IO
// related procedures that can cause long delays should be offloaded to worker
// goroutines managed by users. See the raftio.IRaftEventListener definition
// for more details.
RaftEventListener raftio.IRaftEventListener
// MaxSnapshotSendBytesPerSecond defines how much snapshot data can be sent
// every second for all Raft clusters managed by the NodeHost instance.
// The default value 0 means there is no limit set for snapshot streaming.
MaxSnapshotSendBytesPerSecond uint64
// MaxSnapshotRecvBytesPerSecond defines how much snapshot data can be
// received each second for all Raft clusters managed by the NodeHost instance.
// The default value 0 means there is no limit for receiving snapshot data.
MaxSnapshotRecvBytesPerSecond uint64
// FS is the filesystem used by tests. Dragonboat applications are not
// required to explicitly set this field.
FS IFS
// SystemEventsListener allows users to be notified for system events such
// as snapshot creation, log compaction and snapshot streaming. It is usually
// used for testing purposes or for other advanced usages, Dragonboat
// applications are not required to explicitly set this field.
SystemEventListener raftio.ISystemEventListener
// SystemTickerPrecision is the precision of the system ticker. This value is
// usually set in tests. Dragonboat applications are not required to
// explicitly set this field.
SystemTickerPrecision time.Duration
}
NodeHostConfig is the configuration used to configure NodeHost instances.
Example ¶
nhc := NodeHostConfig{
WALDir: "/data/wal",
NodeHostDir: "/data/dragonboat-data",
RTTMillisecond: 200,
// RaftAddress is the public address that will be used by others to contact
// this NodeHost instance.
RaftAddress: "node01.raft.company.com:5012",
// ListenAddress is the local address to listen on. This field is typically
// set when there is port forwarding involved, e.g. your docker container
// might has a private address of 172.17.0.2 when the public address of the
// host is node01.raft.company.com and tcp port 5012 has been published.
ListenAddress: "172.17.0.2:5012",
// set this if you want to use gRPC based RPC module for exchanging raft data between raft nodes.
// RaftRPCFactory: rpc.NewRaftGRPC,
}
_ = nhc
Output:
func (*NodeHostConfig) GetClientTLSConfig ¶
func (c *NodeHostConfig) GetClientTLSConfig(target string) (*tls.Config, error)
GetClientTLSConfig returns the client tls.Config instance for the specified target based on the TLS settings in NodeHostConfig.
func (*NodeHostConfig) GetListenAddress ¶
func (c *NodeHostConfig) GetListenAddress() string
GetListenAddress returns the actual address the RPC module is going to listen on.
func (*NodeHostConfig) GetServerTLSConfig ¶
func (c *NodeHostConfig) GetServerTLSConfig() (*tls.Config, error)
GetServerTLSConfig returns the server tls.Config instance based on the TLS settings in NodeHostConfig.
func (*NodeHostConfig) Prepare ¶
func (c *NodeHostConfig) Prepare() error
Prepare sets the default value for NodeHostConfig.
func (*NodeHostConfig) Validate ¶
func (c *NodeHostConfig) Validate() error
Validate validates the NodeHostConfig instance and return an error when the configuration is considered as invalid.
type RaftRPCFactoryFunc ¶
type RaftRPCFactoryFunc func(NodeHostConfig, raftio.RequestHandler, raftio.IChunkHandler) raftio.IRaftRPC
RaftRPCFactoryFunc is the factory function that creates the Raft RPC module instance for exchanging Raft messages between NodeHosts.
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