open-consul/agent/consul/merge.go

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package consul
import (
"fmt"
"github.com/hashicorp/consul/agent/metadata"
"github.com/hashicorp/consul/types"
"github.com/hashicorp/go-version"
"github.com/hashicorp/serf/serf"
)
// 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
}
// 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 != "" {
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 segment := m.Tags["segment"]; segment != md.segment {
return fmt.Errorf("Member '%s' part of wrong segment '%s' (expected '%s')",
m.Name, segment, md.segment)
}
}
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 {
}
func (md *wanMergeDelegate) NotifyMerge(members []*serf.Member) error {
for _, m := range members {
ok, _ := metadata.IsConsulServer(*m)
if !ok {
return fmt.Errorf("Member '%s' is not a server", m.Name)
}
}
return nil
}