open-consul/consul/config.go

383 lines
14 KiB
Go

package consul
import (
"fmt"
"io"
"net"
"os"
"time"
"github.com/hashicorp/consul/tlsutil"
"github.com/hashicorp/memberlist"
"github.com/hashicorp/raft"
"github.com/hashicorp/serf/serf"
)
const (
DefaultDC = "dc1"
DefaultLANSerfPort = 8301
DefaultWANSerfPort = 8302
// DefaultRaftMultiplier is used as a baseline Raft configuration that
// will be reliable on a very basic server. See docs/guides/performance.html
// for information on how this value was obtained.
DefaultRaftMultiplier uint = 5
// MaxRaftMultiplier is a fairly arbitrary upper bound that limits the
// amount of performance detuning that's possible.
MaxRaftMultiplier uint = 10
)
var (
DefaultRPCAddr = &net.TCPAddr{IP: net.ParseIP("0.0.0.0"), Port: 8300}
)
// ProtocolVersionMap is the mapping of Consul protocol versions
// to Serf protocol versions. We mask the Serf protocols using
// our own protocol version.
var protocolVersionMap map[uint8]uint8
func init() {
protocolVersionMap = map[uint8]uint8{
1: 4,
2: 4,
3: 4,
}
}
// Config is used to configure the server
type Config struct {
// Bootstrap mode is used to bring up the first Consul server.
// It is required so that it can elect a leader without any
// other nodes being present
Bootstrap bool
// BootstrapExpect mode is used to automatically bring up a collection of
// Consul servers. This can be used to automatically bring up a collection
// of nodes.
BootstrapExpect int
// Datacenter is the datacenter this Consul server represents
Datacenter string
// DataDir is the directory to store our state in
DataDir string
// DevMode is used to enable a development server mode.
DevMode bool
// Node name is the name we use to advertise. Defaults to hostname.
NodeName string
// Domain is the DNS domain for the records. Defaults to "consul."
Domain string
// RaftConfig is the configuration used for Raft in the local DC
RaftConfig *raft.Config
// RPCAddr is the RPC address used by Consul. This should be reachable
// by the WAN and LAN
RPCAddr *net.TCPAddr
// RPCAdvertise is the address that is advertised to other nodes for
// the RPC endpoint. This can differ from the RPC address, if for example
// the RPCAddr is unspecified "0.0.0.0:8300", but this address must be
// reachable
RPCAdvertise *net.TCPAddr
// SerfLANConfig is the configuration for the intra-dc serf
SerfLANConfig *serf.Config
// SerfWANConfig is the configuration for the cross-dc serf
SerfWANConfig *serf.Config
// ReconcileInterval controls how often we reconcile the strongly
// consistent store with the Serf info. This is used to handle nodes
// that are force removed, as well as intermittent unavailability during
// leader election.
ReconcileInterval time.Duration
// LogOutput is the location to write logs to. If this is not set,
// logs will go to stderr.
LogOutput io.Writer
// ProtocolVersion is the protocol version to speak. This must be between
// ProtocolVersionMin and ProtocolVersionMax.
ProtocolVersion uint8
// VerifyIncoming is used to verify the authenticity of incoming connections.
// This means that TCP requests are forbidden, only allowing for TLS. TLS connections
// must match a provided certificate authority. This can be used to force client auth.
VerifyIncoming bool
// VerifyOutgoing is used to verify the authenticity of outgoing connections.
// This means that TLS requests are used, and TCP requests are not made. TLS connections
// must match a provided certificate authority. This is used to verify authenticity of
// server nodes.
VerifyOutgoing bool
// VerifyServerHostname is used to enable hostname verification of servers. This
// ensures that the certificate presented is valid for server.<datacenter>.<domain>.
// This prevents a compromised client from being restarted as a server, and then
// intercepting request traffic as well as being added as a raft peer. This should be
// enabled by default with VerifyOutgoing, but for legacy reasons we cannot break
// existing clients.
VerifyServerHostname bool
// CAFile is a path to a certificate authority file. This is used with VerifyIncoming
// or VerifyOutgoing to verify the TLS connection.
CAFile string
// CertFile is used to provide a TLS certificate that is used for serving TLS connections.
// Must be provided to serve TLS connections.
CertFile string
// KeyFile is used to provide a TLS key that is used for serving TLS connections.
// Must be provided to serve TLS connections.
KeyFile string
// ServerName is used with the TLS certificate to ensure the name we
// provide matches the certificate
ServerName string
// RejoinAfterLeave controls our interaction with Serf.
// When set to false (default), a leave causes a Consul to not rejoin
// the cluster until an explicit join is received. If this is set to
// true, we ignore the leave, and rejoin the cluster on start.
RejoinAfterLeave bool
// Build is a string that is gossiped around, and can be used to help
// operators track which versions are actively deployed
Build string
// ACLToken is the default token to use when making a request.
// If not provided, the anonymous token is used. This enables
// backwards compatibility as well.
ACLToken string
// ACLMasterToken is used to bootstrap the ACL system. It should be specified
// on the servers in the ACLDatacenter. When the leader comes online, it ensures
// that the Master token is available. This provides the initial token.
ACLMasterToken string
// ACLDatacenter provides the authoritative datacenter for ACL
// tokens. If not provided, ACL verification is disabled.
ACLDatacenter string
// ACLTTL controls the time-to-live of cached ACL policies.
// It can be set to zero to disable caching, but this adds
// a substantial cost.
ACLTTL time.Duration
// ACLDefaultPolicy is used to control the ACL interaction when
// there is no defined policy. This can be "allow" which means
// ACLs are used to black-list, or "deny" which means ACLs are
// white-lists.
ACLDefaultPolicy string
// ACLDownPolicy controls the behavior of ACLs if the ACLDatacenter
// cannot be contacted. It can be either "deny" to deny all requests,
// or "extend-cache" which ignores the ACLCacheInterval and uses
// cached policies. If a policy is not in the cache, it acts like deny.
// "allow" can be used to allow all requests. This is not recommended.
ACLDownPolicy string
// ACLReplicationToken is used to fetch ACLs from the ACLDatacenter in
// order to replicate them locally. Setting this to a non-empty value
// also enables replication. Replication is only available in datacenters
// other than the ACLDatacenter.
ACLReplicationToken string
// ACLReplicationInterval is the interval at which replication passes
// will occur. Queries to the ACLDatacenter may block, so replication
// can happen less often than this, but the interval forms the upper
// limit to how fast we will go if there was constant ACL churn on the
// remote end.
ACLReplicationInterval time.Duration
// ACLReplicationApplyLimit is the max number of replication-related
// apply operations that we allow during a one second period. This is
// used to limit the amount of Raft bandwidth used for replication.
ACLReplicationApplyLimit int
// TombstoneTTL is used to control how long KV tombstones are retained.
// This provides a window of time where the X-Consul-Index is monotonic.
// Outside this window, the index may not be monotonic. This is a result
// of a few trade offs:
// 1) The index is defined by the data view and not globally. This is a
// performance optimization that prevents any write from incrementing the
// index for all data views.
// 2) Tombstones are not kept indefinitely, since otherwise storage required
// is also monotonic. This prevents deletes from reducing the disk space
// used.
// In theory, neither of these are intrinsic limitations, however for the
// purposes of building a practical system, they are reasonable trade offs.
//
// It is also possible to set this to an incredibly long time, thereby
// simulating infinite retention. This is not recommended however.
//
TombstoneTTL time.Duration
// TombstoneTTLGranularity is used to control how granular the timers are
// for the Tombstone GC. This is used to batch the GC of many keys together
// to reduce overhead. It is unlikely a user would ever need to tune this.
TombstoneTTLGranularity time.Duration
// Minimum Session TTL
SessionTTLMin time.Duration
// ServerUp callback can be used to trigger a notification that
// a Consul server is now up and known about.
ServerUp func()
// UserEventHandler callback can be used to handle incoming
// user events. This function should not block.
UserEventHandler func(serf.UserEvent)
// DisableCoordinates controls features related to network coordinates.
DisableCoordinates bool
// CoordinateUpdatePeriod controls how long a server batches coordinate
// updates before applying them in a Raft transaction. A larger period
// leads to fewer Raft transactions, but also the stored coordinates
// being more stale.
CoordinateUpdatePeriod time.Duration
// CoordinateUpdateBatchSize controls the maximum number of updates a
// server batches before applying them in a Raft transaction.
CoordinateUpdateBatchSize int
// CoordinateUpdateMaxBatches controls the maximum number of batches we
// are willing to apply in one period. After this limit we will issue a
// warning and discard the remaining updates.
CoordinateUpdateMaxBatches int
// RPCHoldTimeout is how long an RPC can be "held" before it is errored.
// This is used to paper over a loss of leadership by instead holding RPCs,
// so that the caller experiences a slow response rather than an error.
// This period is meant to be long enough for a leader election to take
// place, and a small jitter is applied to avoid a thundering herd.
RPCHoldTimeout time.Duration
}
// CheckVersion is used to check if the ProtocolVersion is valid
func (c *Config) CheckVersion() error {
if c.ProtocolVersion < ProtocolVersionMin {
return fmt.Errorf("Protocol version '%d' too low. Must be in range: [%d, %d]",
c.ProtocolVersion, ProtocolVersionMin, ProtocolVersionMax)
} else if c.ProtocolVersion > ProtocolVersionMax {
return fmt.Errorf("Protocol version '%d' too high. Must be in range: [%d, %d]",
c.ProtocolVersion, ProtocolVersionMin, ProtocolVersionMax)
}
return nil
}
// CheckACL is used to sanity check the ACL configuration
func (c *Config) CheckACL() error {
switch c.ACLDefaultPolicy {
case "allow":
case "deny":
default:
return fmt.Errorf("Unsupported default ACL policy: %s", c.ACLDefaultPolicy)
}
switch c.ACLDownPolicy {
case "allow":
case "deny":
case "extend-cache":
default:
return fmt.Errorf("Unsupported down ACL policy: %s", c.ACLDownPolicy)
}
return nil
}
// DefaultConfig is used to return a sane default configuration
func DefaultConfig() *Config {
hostname, err := os.Hostname()
if err != nil {
panic(err)
}
conf := &Config{
Datacenter: DefaultDC,
NodeName: hostname,
RPCAddr: DefaultRPCAddr,
RaftConfig: raft.DefaultConfig(),
SerfLANConfig: serf.DefaultConfig(),
SerfWANConfig: serf.DefaultConfig(),
ReconcileInterval: 60 * time.Second,
ProtocolVersion: ProtocolVersion2Compatible,
ACLTTL: 30 * time.Second,
ACLDefaultPolicy: "allow",
ACLDownPolicy: "extend-cache",
ACLReplicationInterval: 30 * time.Second,
ACLReplicationApplyLimit: 100, // ops / sec
TombstoneTTL: 15 * time.Minute,
TombstoneTTLGranularity: 30 * time.Second,
SessionTTLMin: 10 * time.Second,
DisableCoordinates: false,
// These are tuned to provide a total throughput of 128 updates
// per second. If you update these, you should update the client-
// side SyncCoordinateRateTarget parameter accordingly.
CoordinateUpdatePeriod: 5 * time.Second,
CoordinateUpdateBatchSize: 128,
CoordinateUpdateMaxBatches: 5,
// This holds RPCs during leader elections. For the default Raft
// config the election timeout is 5 seconds, so we set this a
// bit longer to try to cover that period. This should be more
// than enough when running in the high performance mode.
RPCHoldTimeout: 7 * time.Second,
}
// Increase our reap interval to 3 days instead of 24h.
conf.SerfLANConfig.ReconnectTimeout = 3 * 24 * time.Hour
conf.SerfWANConfig.ReconnectTimeout = 3 * 24 * time.Hour
// WAN Serf should use the WAN timing, since we are using it
// to communicate between DC's
conf.SerfWANConfig.MemberlistConfig = memberlist.DefaultWANConfig()
// Ensure we don't have port conflicts
conf.SerfLANConfig.MemberlistConfig.BindPort = DefaultLANSerfPort
conf.SerfWANConfig.MemberlistConfig.BindPort = DefaultWANSerfPort
// Enable interoperability with unversioned Raft library, and don't
// start using new ID-based features yet.
conf.RaftConfig.ProtocolVersion = 1
conf.ScaleRaft(DefaultRaftMultiplier)
// Disable shutdown on removal
conf.RaftConfig.ShutdownOnRemove = false
return conf
}
// ScaleRaft sets the config to have Raft timing parameters scaled by the given
// performance multiplier. This is done in an idempotent way so it's not tricky
// to call this when composing configurations and potentially calling this
// multiple times on the same structure.
func (c *Config) ScaleRaft(raftMultRaw uint) {
raftMult := time.Duration(raftMultRaw)
def := raft.DefaultConfig()
c.RaftConfig.HeartbeatTimeout = raftMult * def.HeartbeatTimeout
c.RaftConfig.ElectionTimeout = raftMult * def.ElectionTimeout
c.RaftConfig.LeaderLeaseTimeout = raftMult * def.LeaderLeaseTimeout
}
func (c *Config) tlsConfig() *tlsutil.Config {
tlsConf := &tlsutil.Config{
VerifyIncoming: c.VerifyIncoming,
VerifyOutgoing: c.VerifyOutgoing,
VerifyServerHostname: c.VerifyServerHostname,
CAFile: c.CAFile,
CertFile: c.CertFile,
KeyFile: c.KeyFile,
NodeName: c.NodeName,
ServerName: c.ServerName,
Domain: c.Domain,
}
return tlsConf
}