diff --git a/.changelog/9650.txt b/.changelog/9650.txt new file mode 100644 index 000000000..f0d404a68 --- /dev/null +++ b/.changelog/9650.txt @@ -0,0 +1,3 @@ +```release-note:bug +xds: deduplicate mesh gateway listeners by address in a stable way to prevent some LDS churn +``` diff --git a/agent/xds/listeners.go b/agent/xds/listeners.go index 78df10a92..23f6613d8 100644 --- a/agent/xds/listeners.go +++ b/agent/xds/listeners.go @@ -7,6 +7,7 @@ import ( "net" "net/url" "regexp" + "sort" "strconv" "strings" "time" @@ -199,13 +200,11 @@ func (s *Server) listenersFromSnapshotGateway(cInfo connectionInfo, cfgSnap *pro s.Logger.Warn("failed to parse Connect.Proxy.Config", "error", err) } - // Prevent invalid configurations of binding to the same port/addr twice - // including with the any addresses + // We'll collect all of the desired listeners first, and deduplicate them later. type namedAddress struct { name string structs.ServiceAddress } - seen := make(map[structs.ServiceAddress]bool) addrs := make([]namedAddress, 0) var resources []proto.Message @@ -219,10 +218,7 @@ func (s *Server) listenersFromSnapshotGateway(cInfo connectionInfo, cfgSnap *pro Address: addr, Port: cfgSnap.Port, } - if !seen[a] { - addrs = append(addrs, namedAddress{name: "default", ServiceAddress: a}) - seen[a] = true - } + addrs = append(addrs, namedAddress{name: "default", ServiceAddress: a}) } if cfg.BindTaggedAddresses { @@ -231,10 +227,7 @@ func (s *Server) listenersFromSnapshotGateway(cInfo connectionInfo, cfgSnap *pro Address: addrCfg.Address, Port: addrCfg.Port, } - if !seen[a] { - addrs = append(addrs, namedAddress{name: name, ServiceAddress: a}) - seen[a] = true - } + addrs = append(addrs, namedAddress{name: name, ServiceAddress: a}) } } @@ -243,14 +236,27 @@ func (s *Server) listenersFromSnapshotGateway(cInfo connectionInfo, cfgSnap *pro Address: addrCfg.Address, Port: addrCfg.Port, } - if !seen[a] { - addrs = append(addrs, namedAddress{name: name, ServiceAddress: a}) - seen[a] = true - } + addrs = append(addrs, namedAddress{name: name, ServiceAddress: a}) } - // Make listeners once deduplicated + // Prevent invalid configurations of binding to the same port/addr twice + // including with the any addresses + // + // Sort the list and then if two items share a service address, take the + // first one to ensure we generate one listener per address and it's + // stable. + sort.Slice(addrs, func(i, j int) bool { + return addrs[i].name < addrs[j].name + }) + + // Make listeners and deduplicate on the fly. + seen := make(map[structs.ServiceAddress]bool) for _, a := range addrs { + if seen[a.ServiceAddress] { + continue + } + seen[a.ServiceAddress] = true + var l *envoy.Listener switch cfgSnap.Kind { diff --git a/agent/xds/listeners_test.go b/agent/xds/listeners_test.go index 9ac9a5e24..0e9c4b932 100644 --- a/agent/xds/listeners_test.go +++ b/agent/xds/listeners_test.go @@ -418,15 +418,15 @@ func TestListenersFromSnapshot(t *testing.T) { "envoy_gateway_no_default_bind": true, "envoy_gateway_bind_tagged_addresses": true, "envoy_gateway_bind_addresses": map[string]structs.ServiceAddress{ + // This bind address should not get a listener due to deduplication and it sorts to the end + "z-duplicate-of-tagged-wan-addr": { + Address: "198.18.0.1", + Port: 443, + }, "foo": { Address: "198.17.2.3", Port: 8080, }, - // This bind address should not get a listener due to deduplication - "duplicate-of-tagged-wan-addr": { - Address: "198.18.0.1", - Port: 443, - }, }, } },