open-consul/agent/consul/merge.go

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package consul
import (
"fmt"
"sync"
"github.com/hashicorp/go-version"
"github.com/hashicorp/serf/serf"
"github.com/hashicorp/consul/agent/metadata"
"github.com/hashicorp/consul/types"
)
// lanMergeDelegate is used to handle a cluster merge on the LAN gossip
// ring. We check that the peers are in the same datacenter and abort the
// merge if there is a mis-match.
type lanMergeDelegate struct {
dc string
nodeID types.NodeID
nodeName string
segment string
server bool
partition string
}
// uniqueIDMinVersion is the lowest version where we insist that nodes
// have a unique ID.
var uniqueIDMinVersion = version.Must(version.NewVersion("0.8.5"))
func (md *lanMergeDelegate) NotifyMerge(members []*serf.Member) error {
nodeMap := make(map[types.NodeID]string)
for _, m := range members {
if rawID, ok := m.Tags["id"]; ok && rawID != "" {
if m.Status == serf.StatusLeft {
continue
}
nodeID := types.NodeID(rawID)
// See if there's another node that conflicts with us.
if (nodeID == md.nodeID) && (m.Name != md.nodeName) {
return fmt.Errorf("Member '%s' has conflicting node ID '%s' with this agent's ID",
m.Name, nodeID)
}
// See if there are any two nodes that conflict with each
// other. This lets us only do joins into a hygienic
// cluster now that node IDs are critical for operation.
if other, ok := nodeMap[nodeID]; ok {
return fmt.Errorf("Member '%s' has conflicting node ID '%s' with member '%s'",
m.Name, nodeID, other)
}
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// Only map nodes with a version that's >= than when
// we made host-based IDs opt-in, which helps prevent
// chaos when upgrading older clusters. See #3070 for
// more details.
if ver, err := metadata.Build(m); err == nil {
if ver.Compare(uniqueIDMinVersion) >= 0 {
nodeMap[nodeID] = m.Name
}
}
}
if ok, dc := isConsulNode(*m); ok {
if dc != md.dc {
return fmt.Errorf("Member '%s' part of wrong datacenter '%s'",
m.Name, dc)
}
}
if ok, parts := metadata.IsConsulServer(*m); ok {
if parts.Datacenter != md.dc {
return fmt.Errorf("Member '%s' part of wrong datacenter '%s'",
m.Name, parts.Datacenter)
}
}
if err := md.enterpriseNotifyMergeMember(m); err != nil {
return err
}
}
return nil
}
// wanMergeDelegate is used to handle a cluster merge on the WAN gossip
// ring. We check that the peers are server nodes and abort the merge
// otherwise.
type wanMergeDelegate struct {
localDatacenter string
federationDisabledLock sync.Mutex
federationDisabled bool
}
// SetWANFederationDisabled selectively disables the wan pool from accepting
// non-local members. If the toggle changed the current value it returns true.
func (md *wanMergeDelegate) SetWANFederationDisabled(disabled bool) bool {
md.federationDisabledLock.Lock()
prior := md.federationDisabled
md.federationDisabled = disabled
md.federationDisabledLock.Unlock()
return prior != disabled
}
func (md *wanMergeDelegate) NotifyMerge(members []*serf.Member) error {
// Deliberately hold this lock during the entire merge so calls to
// SetWANFederationDisabled returning immediately imply that the flag takes
// effect for all future merges.
md.federationDisabledLock.Lock()
defer md.federationDisabledLock.Unlock()
for _, m := range members {
ok, srv := metadata.IsConsulServer(*m)
if !ok {
return fmt.Errorf("Member '%s' is not a server", m.Name)
}
if md.federationDisabled {
if srv.Datacenter != md.localDatacenter {
return fmt.Errorf("Member '%s' part of wrong datacenter '%s'; WAN federation is disabled", m.Name, srv.Datacenter)
}
}
}
return nil
}