open-consul/agent/nodeid.go

134 lines
3.5 KiB
Go

package agent
import (
"crypto/sha512"
"fmt"
"io/ioutil"
"os"
"path/filepath"
"strings"
"github.com/hashicorp/consul/agent/config"
"github.com/hashicorp/consul/lib"
"github.com/hashicorp/consul/types"
"github.com/hashicorp/go-uuid"
"github.com/shirou/gopsutil/host"
)
// setupNodeID will pull the persisted node ID, if any, or create a random one
// and persist it.
// FIXME: move to a different file.
func (a *Agent) setupNodeID(config *config.RuntimeConfig) error {
// If they've configured a node ID manually then just use that, as
// long as it's valid.
if config.NodeID != "" {
config.NodeID = types.NodeID(strings.ToLower(string(config.NodeID)))
if _, err := uuid.ParseUUID(string(config.NodeID)); err != nil {
return err
}
return nil
}
// For dev mode we have no filesystem access so just make one.
if a.config.DataDir == "" {
id, err := a.makeNodeID()
if err != nil {
return err
}
config.NodeID = types.NodeID(id)
return nil
}
// Load saved state, if any. Since a user could edit this, we also
// validate it.
fileID := filepath.Join(config.DataDir, "node-id")
if _, err := os.Stat(fileID); err == nil {
rawID, err := ioutil.ReadFile(fileID)
if err != nil {
return err
}
nodeID := strings.TrimSpace(string(rawID))
nodeID = strings.ToLower(nodeID)
if _, err := uuid.ParseUUID(nodeID); err != nil {
return err
}
config.NodeID = types.NodeID(nodeID)
}
// If we still don't have a valid node ID, make one.
if config.NodeID == "" {
id, err := a.makeNodeID()
if err != nil {
return err
}
if err := lib.EnsurePath(fileID, false); err != nil {
return err
}
if err := ioutil.WriteFile(fileID, []byte(id), 0600); err != nil {
return err
}
config.NodeID = types.NodeID(id)
}
return nil
}
// makeNodeID will try to find a host-specific ID, or else will generate a
// random ID. The returned ID will always be formatted as a GUID. We don't tell
// the caller whether this ID is random or stable since the consequences are
// high for us if this changes, so we will persist it either way. This will let
// gopsutil change implementations without affecting in-place upgrades of nodes.
func (a *Agent) makeNodeID() (string, error) {
// If they've disabled host-based IDs then just make a random one.
if a.config.DisableHostNodeID {
return a.makeRandomID()
}
// Try to get a stable ID associated with the host itself.
info, err := host.Info()
if err != nil {
a.logger.Debug("Couldn't get a unique ID from the host", "error", err)
return a.makeRandomID()
}
// Make sure the host ID parses as a UUID, since we don't have complete
// control over this process.
id := strings.ToLower(info.HostID)
if _, err := uuid.ParseUUID(id); err != nil {
a.logger.Debug("Unique ID from host isn't formatted as a UUID",
"id", id,
"error", err,
)
return a.makeRandomID()
}
// Hash the input to make it well distributed. The reported Host UUID may be
// similar across nodes if they are on a cloud provider or on motherboards
// created from the same batch.
buf := sha512.Sum512([]byte(id))
id = fmt.Sprintf("%08x-%04x-%04x-%04x-%12x",
buf[0:4],
buf[4:6],
buf[6:8],
buf[8:10],
buf[10:16])
a.logger.Debug("Using unique ID from host as node ID", "id", id)
return id, nil
}
// makeRandomID will generate a random UUID for a node.
func (a *Agent) makeRandomID() (string, error) {
id, err := uuid.GenerateUUID()
if err != nil {
return "", err
}
a.logger.Debug("Using random ID as node ID", "id", id)
return id, nil
}