core: merge reserved_ports into host_networks (#13651)

Fixes #13505 This fixes #13505 by treating reserved_ports like we treat a lot of jobspec settings: merging settings from more global stanzas (client.reserved.reserved_ports) "down" into more specific stanzas (client.host_networks[].reserved_ports). As discussed in #13505 there are other options, and since it's totally broken right now we have some flexibility: Treat overlapping reserved_ports on addresses as invalid and refuse to start agents. However, I'm not sure there's a cohesive model we want to publish right now since so much 0.9-0.12 compat code still exists! We would have to explain to folks that if their -network-interface and host_network addresses overlapped, they could only specify reserved_ports in one place or the other?! It gets ugly. Use the global client.reserved.reserved_ports value as the default and treat host_network[].reserverd_ports as overrides. My first suggestion in the issue, but @groggemans made me realize the addresses on the agent's interface (as configured by -network-interface) may overlap with host_networks, so you'd need to remove the global reserved_ports from addresses shared with a shared network?! This seemed really confusing and subtle for users to me. So I think "merging down" creates the most expressive yet understandable approach. I've played around with it a bit, and it doesn't seem too surprising. The only frustrating part is how difficult it is to observe the available addresses and ports on a node! However that's a job for another PR.
2022-07-12 14:40:25 -07:00 · 2022-07-12 14:40:25 -07:00 · 3e50f72fad
parent b9ebf94131
commit 3e50f72fad
12 changed files with 499 additions and 208 deletions
--- a/.changelog/13651.txt
+++ b/.changelog/13651.txt
@ -0,0 +1,3 @@
+```release-note:bug
+core: Fixed a bug where reserved ports on multiple node networks would be treated as a collision. `client.reserved.reserved_ports` is now merged into each `host_network`'s reserved ports instead of being treated as a collision.
+```
--- a/command/agent/command.go
+++ b/command/agent/command.go
@ -399,6 +399,7 @@ func (c *Command) IsValidConfig(config, cmdConfig *Config) bool {
 	}

 	for _, hn := range config.Client.HostNetworks {
+		// Ensure port range is valid
 		if _, err := structs.ParsePortRanges(hn.ReservedPorts); err != nil {
 			c.Ui.Error(fmt.Sprintf("host_network[%q].reserved_ports %q invalid: %v",
 				hn.Name, hn.ReservedPorts, err))
--- a/nomad/structs/funcs.go
+++ b/nomad/structs/funcs.go
@ -207,8 +207,11 @@ func AllocsFit(node *Node, allocs []*Allocation, netIdx *NetworkIndex, checkDevi
 		netIdx = NewNetworkIndex()
 		defer netIdx.Release()

-		if collision, reason := netIdx.SetNode(node); collision {
-			return false, fmt.Sprintf("reserved node port collision: %v", reason), used, nil
+		if err := netIdx.SetNode(node); err != nil {
+			// To maintain backward compatibility with when SetNode
+			// returned collision+reason like AddAllocs, return
+			// this as a reason instead of an error.
+			return false, fmt.Sprintf("reserved node port collision: %v", err), used, nil
 		}
 		if collision, reason := netIdx.AddAllocs(allocs); collision {
 			return false, fmt.Sprintf("reserved alloc port collision: %v", reason), used, nil
@ -530,6 +533,10 @@ func ParsePortRanges(spec string) ([]uint64, error) {
 				if err != nil {
 					return nil, err
 				}
+
+				if port > MaxValidPort {
+					return nil, fmt.Errorf("port must be < %d but found %d", MaxValidPort, port)
+				}
 				ports[port] = struct{}{}
 			}
 		case 2:
--- a/nomad/structs/network.go
+++ b/nomad/structs/network.go
@ -36,12 +36,32 @@ var (

 // NetworkIndex is used to index the available network resources
 // and the used network resources on a machine given allocations
+//
+// Fields are exported so they may be JSON serialized for debugging.
+// Fields are *not* intended to be used directly.
 type NetworkIndex struct {
-	AvailNetworks  []*NetworkResource              // List of available networks
-	NodeNetworks   []*NodeNetworkResource          // List of available node networks
-	AvailAddresses map[string][]NodeNetworkAddress // Map of host network aliases to list of addresses
+	// TaskNetworks are the node networks available for
+	// task.resources.network asks.
+	TaskNetworks []*NetworkResource
+
+	// GroupNetworks are the node networks available for group.network
+	// asks.
+	GroupNetworks []*NodeNetworkResource
+
+	// HostNetworks indexes addresses by host network alias
+	HostNetworks map[string][]NodeNetworkAddress
+
+	// UsedPorts tracks which ports are used on a per-IP address basis. For
+	// example if a node has `network_interface=lo` and port 22 reserved,
+	// then on a dual stack loopback interface UsedPorts would contain:
+	// {
+	//  "127.0.0.1": Bitmap{22},
+	//  "::1":       Bitmap{22},
+	// }
+	UsedPorts map[string]Bitmap
+
+	// Deprecated bandwidth fields
 	AvailBandwidth map[string]int // Bandwidth by device
-	UsedPorts      map[string]Bitmap               // Ports by IP
 	UsedBandwidth  map[string]int // Bandwidth by device

 	MinDynamicPort int // The smallest dynamic port generated
@ -51,9 +71,9 @@ type NetworkIndex struct {
 // NewNetworkIndex is used to construct a new network index
 func NewNetworkIndex() *NetworkIndex {
 	return &NetworkIndex{
-		AvailAddresses: make(map[string][]NodeNetworkAddress),
-		AvailBandwidth: make(map[string]int),
+		HostNetworks:   make(map[string][]NodeNetworkAddress),
 		UsedPorts:      make(map[string]Bitmap),
+		AvailBandwidth: make(map[string]int),
 		UsedBandwidth:  make(map[string]int),
 		MinDynamicPort: DefaultMinDynamicPort,
 		MaxDynamicPort: DefaultMaxDynamicPort,
@ -84,9 +104,9 @@ func (idx *NetworkIndex) Copy() *NetworkIndex {
 	c := new(NetworkIndex)
 	*c = *idx

-	c.AvailNetworks = copyNetworkResources(idx.AvailNetworks)
-	c.NodeNetworks = copyNodeNetworks(idx.NodeNetworks)
-	c.AvailAddresses = copyAvailAddresses(idx.AvailAddresses)
+	c.TaskNetworks = copyNetworkResources(idx.TaskNetworks)
+	c.GroupNetworks = copyNodeNetworks(idx.GroupNetworks)
+	c.HostNetworks = copyAvailAddresses(idx.HostNetworks)
 	if idx.AvailBandwidth != nil && len(idx.AvailBandwidth) == 0 {
 		c.AvailBandwidth = make(map[string]int)
 	} else {
@ -171,61 +191,141 @@ func (idx *NetworkIndex) Overcommitted() bool {
 	return false
 }

-// SetNode is used to setup the available network resources. Returns
-// true if there is a collision
-func (idx *NetworkIndex) SetNode(node *Node) (collide bool, reason string) {
+// SetNode is used to initialize a node's network index with available IPs,
+// reserved ports, and other details from a node's configuration and
+// fingerprinting.
+//
+// SetNode must be idempotent as preemption causes SetNode to be called
+// multiple times on the same NetworkIndex, only clearing UsedPorts between
+// calls.
+//
+// An error is returned if the Node cannot produce a consistent NetworkIndex
+// such as if reserved_ports are unparseable.
+//
+// Any errors returned by SetNode indicate a bug! The bug may lie in client
+// code not properly validating its configuration or it may lie in improper
+// Node object handling by servers. Users should not be able to cause SetNode
+// to error. Data that cause SetNode to error should be caught upstream such as
+// a client agent refusing to start with an invalid configuration.
+func (idx *NetworkIndex) SetNode(node *Node) error {

-	// COMPAT(0.11): Remove in 0.11
-	// Grab the network resources, handling both new and old
-	var networks []*NetworkResource
+	// COMPAT(0.11): Deprecated. taskNetworks are only used for
+	// task.resources.network asks which have been deprecated since before
+	// 0.11.
+	// Grab the network resources, handling both new and old Node layouts
+	// from clients.
+	var taskNetworks []*NetworkResource
 	if node.NodeResources != nil && len(node.NodeResources.Networks) != 0 {
-		networks = node.NodeResources.Networks
+		taskNetworks = node.NodeResources.Networks
 	} else if node.Resources != nil {
-		networks = node.Resources.Networks
+		taskNetworks = node.Resources.Networks
 	}

+	// Reserved ports get merged downward. For example given an agent
+	// config:
+	//
+	// client.reserved.reserved_ports = "22"
+	// client.host_network["eth0"] = {reserved_ports = "80,443"}
+	// client.host_network["eth1"] = {reserved_ports = "1-1000"}
+	//
+	// Addresses on taskNetworks reserve port 22
+	// Addresses on eth0 reserve 22,80,443 (note 22 is also reserved!)
+	// Addresses on eth1 reserve 1-1000
+	globalResPorts := []uint{}
+
+	if node.ReservedResources != nil && node.ReservedResources.Networks.ReservedHostPorts != "" {
+		resPorts, err := ParsePortRanges(node.ReservedResources.Networks.ReservedHostPorts)
+		if err != nil {
+			// This is a fatal error that should have been
+			// prevented by client validation.
+			return fmt.Errorf("error parsing reserved_ports: %w", err)
+		}
+
+		globalResPorts = make([]uint, len(resPorts))
+		for i, p := range resPorts {
+			globalResPorts[i] = uint(p)
+		}
+	} else if node.Reserved != nil {
+		// COMPAT(0.11): Remove after 0.11. Nodes stopped reporting
+		// reserved ports under Node.Reserved.Resources in #4750 / v0.9
+		for _, n := range node.Reserved.Networks {
+			used := idx.getUsedPortsFor(n.IP)
+			for _, ports := range [][]Port{n.ReservedPorts, n.DynamicPorts} {
+				for _, p := range ports {
+					if p.Value > MaxValidPort || p.Value < 0 {
+						// This is a fatal error that
+						// should have been prevented
+						// by validation upstream.
+						return fmt.Errorf("invalid port %d for reserved_ports", p.Value)
+					}
+
+					globalResPorts = append(globalResPorts, uint(p.Value))
+					used.Set(uint(p.Value))
+				}
+			}
+
+			// Reserve mbits
+			if n.Device != "" {
+				idx.UsedBandwidth[n.Device] += n.MBits
+			}
+		}
+	}
+
+	// Filter task networks down to those with a device. For example
+	// taskNetworks may contain a "bridge" interface which has no device
+	// set and cannot be used to fulfill asks.
+	for _, n := range taskNetworks {
+		if n.Device != "" {
+			idx.TaskNetworks = append(idx.TaskNetworks, n)
+			idx.AvailBandwidth[n.Device] = n.MBits
+
+			// Reserve ports
+			used := idx.getUsedPortsFor(n.IP)
+			for _, p := range globalResPorts {
+				used.Set(p)
+			}
+		}
+	}
+
+	// nodeNetworks are used for group.network asks.
 	var nodeNetworks []*NodeNetworkResource
 	if node.NodeResources != nil && len(node.NodeResources.NodeNetworks) != 0 {
 		nodeNetworks = node.NodeResources.NodeNetworks
 	}

-	// Add the available CIDR blocks
-	for _, n := range networks {
-		if n.Device != "" {
-			idx.AvailNetworks = append(idx.AvailNetworks, n)
-			idx.AvailBandwidth[n.Device] = n.MBits
-		}
-	}
-
-	// TODO: upgrade path?
-	// is it possible to get duplicates here?
 	for _, n := range nodeNetworks {
 		for _, a := range n.Addresses {
-			idx.AvailAddresses[a.Alias] = append(idx.AvailAddresses[a.Alias], a)
-			if c, r := idx.AddReservedPortsForIP(a.ReservedPorts, a.Address); c {
-				collide = true
-				reason = fmt.Sprintf("collision when reserving ports for node network %s in node %s: %v", a.Alias, node.ID, r)
-			}
-		}
-	}
-
-	// COMPAT(0.11): Remove in 0.11
-	// Handle reserving ports, handling both new and old
-	if node.ReservedResources != nil && node.ReservedResources.Networks.ReservedHostPorts != "" {
-		c, r := idx.AddReservedPortRange(node.ReservedResources.Networks.ReservedHostPorts)
-		collide = c
-		if collide {
-			reason = fmt.Sprintf("collision when reserving port range for node %s: %v", node.ID, r)
-		}
-	} else if node.Reserved != nil {
-		for _, n := range node.Reserved.Networks {
-			if c, r := idx.AddReserved(n); c {
-				collide = true
-				reason = fmt.Sprintf("collision when reserving network %s for node %s: %v", n.IP, node.ID, r)
+			// Index host networks by their unique alias for asks
+			// with group.network.port.host_network set.
+			idx.HostNetworks[a.Alias] = append(idx.HostNetworks[a.Alias], a)
+
+			// Mark reserved ports as used without worrying about
+			// collisions. This effectively merges
+			// client.reserved.reserved_ports into each
+			// host_network.
+			used := idx.getUsedPortsFor(a.Address)
+			for _, p := range globalResPorts {
+				used.Set(p)
+			}
+
+			// If ReservedPorts is set on the NodeNetwork, use it
+			// and the global reserved ports.
+			if a.ReservedPorts != "" {
+				rp, err := ParsePortRanges(a.ReservedPorts)
+				if err != nil {
+					// This is a fatal error that should
+					// have been prevented by validation
+					// upstream.
+					return fmt.Errorf("error parsing reserved_ports for network %q: %w", a.Alias, err)
+				}
+				for _, p := range rp {
+					used.Set(uint(p))
+				}
 			}
 		}
 	}

+	// Set dynamic port range (applies to all addresses)
 	if node.NodeResources != nil && node.NodeResources.MinDynamicPort > 0 {
 		idx.MinDynamicPort = node.NodeResources.MinDynamicPort
 	}
@ -234,11 +334,16 @@ func (idx *NetworkIndex) SetNode(node *Node) (collide bool, reason string) {
 		idx.MaxDynamicPort = node.NodeResources.MaxDynamicPort
 	}

-	return
+	return nil
 }

 // AddAllocs is used to add the used network resources. Returns
 // true if there is a collision
+//
+// AddAllocs may be called multiple times for the same NetworkIndex with
+// UsedPorts cleared between calls (by Release). Therefore AddAllocs must be
+// determistic and must not manipulate state outside of UsedPorts as that state
+// would persist between Release calls.
 func (idx *NetworkIndex) AddAllocs(allocs []*Allocation) (collide bool, reason string) {
 	for _, alloc := range allocs {
 		// Do not consider the resource impact of terminal allocations
@ -338,51 +443,11 @@ func (idx *NetworkIndex) AddReservedPorts(ports AllocatedPorts) (collide bool, r
 	return
 }

-// AddReservedPortRange marks the ports given as reserved on all network
-// interfaces. The port format is comma delimited, with spans given as n1-n2
-// (80,100-200,205)
-func (idx *NetworkIndex) AddReservedPortRange(ports string) (collide bool, reasons []string) {
-	// Convert the ports into a slice of ints
-	resPorts, err := ParsePortRanges(ports)
-	if err != nil {
-		return
-	}
-
-	// Ensure we create a bitmap for each available network
-	for _, n := range idx.AvailNetworks {
-		idx.getUsedPortsFor(n.IP)
-	}
-
-	for _, used := range idx.UsedPorts {
-		for _, port := range resPorts {
-			// Guard against invalid port
-			if port >= MaxValidPort {
-				return true, []string{fmt.Sprintf("invalid port %d", port)}
-			}
-			if used.Check(uint(port)) {
-				collide = true
-				reason := fmt.Sprintf("port %d already in use", port)
-				reasons = append(reasons, reason)
-			} else {
-				used.Set(uint(port))
-			}
-		}
-	}
-
-	return
-}
-
 // AddReservedPortsForIP checks whether any reserved ports collide with those
 // in use for the IP address.
-func (idx *NetworkIndex) AddReservedPortsForIP(ports string, ip string) (collide bool, reasons []string) {
-	// Convert the ports into a slice of ints
-	resPorts, err := ParsePortRanges(ports)
-	if err != nil {
-		return
-	}
-
+func (idx *NetworkIndex) AddReservedPortsForIP(ports []uint64, ip string) (collide bool, reasons []string) {
 	used := idx.getUsedPortsFor(ip)
-	for _, port := range resPorts {
+	for _, port := range ports {
 		// Guard against invalid port
 		if port >= MaxValidPort {
 			return true, []string{fmt.Sprintf("invalid port %d", port)}
@ -401,22 +466,13 @@ func (idx *NetworkIndex) AddReservedPortsForIP(ports string, ip string) (collide

 // yieldIP is used to iteratively invoke the callback with
 // an available IP
-func (idx *NetworkIndex) yieldIP(cb func(net *NetworkResource, ip net.IP) bool) {
-	inc := func(ip net.IP) {
-		for j := len(ip) - 1; j >= 0; j-- {
-			ip[j]++
-			if ip[j] > 0 {
-				break
-			}
-		}
-	}
-
-	for _, n := range idx.AvailNetworks {
+func (idx *NetworkIndex) yieldIP(cb func(net *NetworkResource, offerIP net.IP) bool) {
+	for _, n := range idx.TaskNetworks {
 		ip, ipnet, err := net.ParseCIDR(n.CIDR)
 		if err != nil {
 			continue
 		}
-		for ip := ip.Mask(ipnet.Mask); ipnet.Contains(ip); inc(ip) {
+		for ip := ip.Mask(ipnet.Mask); ipnet.Contains(ip); incIP(ip) {
 			if cb(n, ip) {
 				return
 			}
@ -424,6 +480,26 @@ func (idx *NetworkIndex) yieldIP(cb func(net *NetworkResource, ip net.IP) bool)
 	}
 }

+func incIP(ip net.IP) {
+	// Iterate over IP octects from right to left
+	for j := len(ip) - 1; j >= 0; j-- {
+
+		// Increment octect
+		ip[j]++
+
+		// If this octect did not wrap around to 0, it's the next IP to
+		// try. If it did wrap (p[j]==0), then the next octect is
+		// incremented.
+		if ip[j] > 0 {
+			break
+		}
+	}
+}
+
+// AssignPorts based on an ask from the scheduler processing a group.network
+// stanza. Supports multi-interfaces through node configured host_networks.
+//
+// AssignTaskNetwork supports the deprecated task.resources.network stanza.
 func (idx *NetworkIndex) AssignPorts(ask *NetworkResource) (AllocatedPorts, error) {
 	var offer AllocatedPorts

@ -437,7 +513,7 @@ func (idx *NetworkIndex) AssignPorts(ask *NetworkResource) (AllocatedPorts, erro
 		// if allocPort is still nil after the loop, the port wasn't available for reservation
 		var allocPort *AllocatedPortMapping
 		var addrErr error
-		for _, addr := range idx.AvailAddresses[port.HostNetwork] {
+		for _, addr := range idx.HostNetworks[port.HostNetwork] {
 			used := idx.getUsedPortsFor(addr.Address)
 			// Guard against invalid port
 			if port.Value < 0 || port.Value >= MaxValidPort {
@ -472,7 +548,7 @@ func (idx *NetworkIndex) AssignPorts(ask *NetworkResource) (AllocatedPorts, erro
 	for _, port := range ask.DynamicPorts {
 		var allocPort *AllocatedPortMapping
 		var addrErr error
-		for _, addr := range idx.AvailAddresses[port.HostNetwork] {
+		for _, addr := range idx.HostNetworks[port.HostNetwork] {
 			used := idx.getUsedPortsFor(addr.Address)
 			// Try to stochastically pick the dynamic ports as it is faster and
 			// lower memory usage.
@ -512,13 +588,18 @@ func (idx *NetworkIndex) AssignPorts(ask *NetworkResource) (AllocatedPorts, erro
 	return offer, nil
 }

-// AssignNetwork is used to assign network resources given an ask.
-// If the ask cannot be satisfied, returns nil
-func (idx *NetworkIndex) AssignNetwork(ask *NetworkResource) (out *NetworkResource, err error) {
+// AssignTaskNetwork is used to offer network resources given a
+// task.resources.network ask.  If the ask cannot be satisfied, returns nil
+//
+// AssignTaskNetwork and task.resources.network are deprecated in favor of
+// AssignPorts and group.network. AssignTaskNetwork does not support multiple
+// interfaces and only uses the node's default interface. AssignPorts is the
+// method that is used for group.network asks.
+func (idx *NetworkIndex) AssignTaskNetwork(ask *NetworkResource) (out *NetworkResource, err error) {
 	err = fmt.Errorf("no networks available")
-	idx.yieldIP(func(n *NetworkResource, ip net.IP) (stop bool) {
+	idx.yieldIP(func(n *NetworkResource, offerIP net.IP) (stop bool) {
 		// Convert the IP to a string
-		ipStr := ip.String()
+		offerIPStr := offerIP.String()

 		// Check if we would exceed the bandwidth cap
 		availBandwidth := idx.AvailBandwidth[n.Device]
@ -528,7 +609,7 @@ func (idx *NetworkIndex) AssignNetwork(ask *NetworkResource) (out *NetworkResour
 			return
 		}

-		used := idx.UsedPorts[ipStr]
+		used := idx.UsedPorts[offerIPStr]

 		// Check if any of the reserved ports are in use
 		for _, port := range ask.ReservedPorts {
@ -549,7 +630,7 @@ func (idx *NetworkIndex) AssignNetwork(ask *NetworkResource) (out *NetworkResour
 		offer := &NetworkResource{
 			Mode:          ask.Mode,
 			Device:        n.Device,
-			IP:            ipStr,
+			IP:            offerIPStr,
 			MBits:         ask.MBits,
 			DNS:           ask.DNS,
 			ReservedPorts: ask.ReservedPorts,
--- a/nomad/structs/network_test.go
+++ b/nomad/structs/network_test.go
@ -189,20 +189,10 @@ func TestNetworkIndex_SetNode(t *testing.T) {
 			},
 		},
 	}
-	collide, reason := idx.SetNode(n)
-	if collide || reason != "" {
-		t.Fatalf("bad")
-	}
-
-	if len(idx.AvailNetworks) != 1 {
-		t.Fatalf("Bad")
-	}
-	if idx.AvailBandwidth["eth0"] != 1000 {
-		t.Fatalf("Bad")
-	}
-	if !idx.UsedPorts["192.168.0.100"].Check(22) {
-		t.Fatalf("Bad")
-	}
+	require.NoError(t, idx.SetNode(n))
+	require.Len(t, idx.TaskNetworks, 1)
+	require.Equal(t, 1000, idx.AvailBandwidth["eth0"])
+	require.True(t, idx.UsedPorts["192.168.0.100"].Check(22))
 }

 func TestNetworkIndex_AddAllocs(t *testing.T) {
@ -327,7 +317,7 @@ func TestNetworkIndex_yieldIP(t *testing.T) {
 	}
 }

-func TestNetworkIndex_AssignNetwork(t *testing.T) {
+func TestNetworkIndex_AssignTaskNetwork(t *testing.T) {
 	ci.Parallel(t)
 	idx := NewNetworkIndex()
 	n := &Node{
@ -379,7 +369,7 @@ func TestNetworkIndex_AssignNetwork(t *testing.T) {
 	ask := &NetworkResource{
 		ReservedPorts: []Port{{"main", 8000, 0, ""}},
 	}
-	offer, err := idx.AssignNetwork(ask)
+	offer, err := idx.AssignTaskNetwork(ask)
 	require.NoError(t, err)
 	require.NotNil(t, offer)
 	require.Equal(t, "192.168.0.101", offer.IP)
@ -391,7 +381,7 @@ func TestNetworkIndex_AssignNetwork(t *testing.T) {
 	ask = &NetworkResource{
 		DynamicPorts: []Port{{"http", 0, 80, ""}, {"https", 0, 443, ""}, {"admin", 0, -1, ""}},
 	}
-	offer, err = idx.AssignNetwork(ask)
+	offer, err = idx.AssignTaskNetwork(ask)
 	require.NoError(t, err)
 	require.NotNil(t, offer)
 	require.Equal(t, "192.168.0.100", offer.IP)
@ -410,7 +400,7 @@ func TestNetworkIndex_AssignNetwork(t *testing.T) {
 		ReservedPorts: []Port{{"main", 2345, 0, ""}},
 		DynamicPorts:  []Port{{"http", 0, 80, ""}, {"https", 0, 443, ""}, {"admin", 0, 8080, ""}},
 	}
-	offer, err = idx.AssignNetwork(ask)
+	offer, err = idx.AssignTaskNetwork(ask)
 	require.NoError(t, err)
 	require.NotNil(t, offer)
 	require.Equal(t, "192.168.0.100", offer.IP)
@ -423,7 +413,7 @@ func TestNetworkIndex_AssignNetwork(t *testing.T) {
 	ask = &NetworkResource{
 		MBits: 1000,
 	}
-	offer, err = idx.AssignNetwork(ask)
+	offer, err = idx.AssignTaskNetwork(ask)
 	require.Error(t, err)
 	require.Equal(t, "bandwidth exceeded", err.Error())
 	require.Nil(t, offer)
@ -431,7 +421,7 @@ func TestNetworkIndex_AssignNetwork(t *testing.T) {

 // This test ensures that even with a small domain of available ports we are
 // able to make a dynamic port allocation.
-func TestNetworkIndex_AssignNetwork_Dynamic_Contention(t *testing.T) {
+func TestNetworkIndex_AssignTaskNetwork_Dynamic_Contention(t *testing.T) {
 	ci.Parallel(t)

 	// Create a node that only has one free port
@ -459,7 +449,7 @@ func TestNetworkIndex_AssignNetwork_Dynamic_Contention(t *testing.T) {
 	ask := &NetworkResource{
 		DynamicPorts: []Port{{"http", 0, 80, ""}},
 	}
-	offer, err := idx.AssignNetwork(ask)
+	offer, err := idx.AssignTaskNetwork(ask)
 	if err != nil {
 		t.Fatalf("err: %v", err)
 	}
@ -503,23 +493,11 @@ func TestNetworkIndex_SetNode_Old(t *testing.T) {
 			},
 		},
 	}
-	collide, reason := idx.SetNode(n)
-	if collide || reason != "" {
-		t.Fatalf("bad")
-	}
-
-	if len(idx.AvailNetworks) != 1 {
-		t.Fatalf("Bad")
-	}
-	if idx.AvailBandwidth["eth0"] != 1000 {
-		t.Fatalf("Bad")
-	}
-	if idx.UsedBandwidth["eth0"] != 1 {
-		t.Fatalf("Bad")
-	}
-	if !idx.UsedPorts["192.168.0.100"].Check(22) {
-		t.Fatalf("Bad")
-	}
+	require.NoError(t, idx.SetNode(n))
+	require.Len(t, idx.TaskNetworks, 1)
+	require.Equal(t, 1000, idx.AvailBandwidth["eth0"])
+	require.Equal(t, 1, idx.UsedBandwidth["eth0"])
+	require.True(t, idx.UsedPorts["192.168.0.100"].Check(22))
 }

 // COMPAT(0.11): Remove in 0.11
@ -618,7 +596,7 @@ func TestNetworkIndex_yieldIP_Old(t *testing.T) {
 }

 // COMPAT(0.11): Remove in 0.11
-func TestNetworkIndex_AssignNetwork_Old(t *testing.T) {
+func TestNetworkIndex_AssignTaskNetwork_Old(t *testing.T) {
 	ci.Parallel(t)

 	idx := NewNetworkIndex()
@ -681,7 +659,7 @@ func TestNetworkIndex_AssignNetwork_Old(t *testing.T) {
 	ask := &NetworkResource{
 		ReservedPorts: []Port{{"main", 8000, 0, ""}},
 	}
-	offer, err := idx.AssignNetwork(ask)
+	offer, err := idx.AssignTaskNetwork(ask)
 	if err != nil {
 		t.Fatalf("err: %v", err)
 	}
@ -700,7 +678,7 @@ func TestNetworkIndex_AssignNetwork_Old(t *testing.T) {
 	ask = &NetworkResource{
 		DynamicPorts: []Port{{"http", 0, 80, ""}, {"https", 0, 443, ""}, {"admin", 0, 8080, ""}},
 	}
-	offer, err = idx.AssignNetwork(ask)
+	offer, err = idx.AssignTaskNetwork(ask)
 	if err != nil {
 		t.Fatalf("err: %v", err)
 	}
@ -724,7 +702,7 @@ func TestNetworkIndex_AssignNetwork_Old(t *testing.T) {
 		ReservedPorts: []Port{{"main", 2345, 0, ""}},
 		DynamicPorts:  []Port{{"http", 0, 80, ""}, {"https", 0, 443, ""}, {"admin", 0, 8080, ""}},
 	}
-	offer, err = idx.AssignNetwork(ask)
+	offer, err = idx.AssignTaskNetwork(ask)
 	if err != nil {
 		t.Fatalf("err: %v", err)
 	}
@ -744,7 +722,7 @@ func TestNetworkIndex_AssignNetwork_Old(t *testing.T) {
 	ask = &NetworkResource{
 		MBits: 1000,
 	}
-	offer, err = idx.AssignNetwork(ask)
+	offer, err = idx.AssignTaskNetwork(ask)
 	if err.Error() != "bandwidth exceeded" {
 		t.Fatalf("err: %v", err)
 	}
@ -756,7 +734,7 @@ func TestNetworkIndex_AssignNetwork_Old(t *testing.T) {
 // COMPAT(0.11): Remove in 0.11
 // This test ensures that even with a small domain of available ports we are
 // able to make a dynamic port allocation.
-func TestNetworkIndex_AssignNetwork_Dynamic_Contention_Old(t *testing.T) {
+func TestNetworkIndex_AssignTaskNetwork_Dynamic_Contention_Old(t *testing.T) {
 	ci.Parallel(t)

 	// Create a node that only has one free port
@ -791,7 +769,7 @@ func TestNetworkIndex_AssignNetwork_Dynamic_Contention_Old(t *testing.T) {
 	ask := &NetworkResource{
 		DynamicPorts: []Port{{"http", 0, 80, ""}},
 	}
-	offer, err := idx.AssignNetwork(ask)
+	offer, err := idx.AssignTaskNetwork(ask)
 	if err != nil {
 		t.Fatalf("err: %v", err)
 	}
@ -823,3 +801,116 @@ func TestIntContains(t *testing.T) {
 		t.Fatalf("bad")
 	}
 }
+
+func TestNetworkIndex_SetNode_HostNets(t *testing.T) {
+	ci.Parallel(t)
+
+	idx := NewNetworkIndex()
+	n := &Node{
+		NodeResources: &NodeResources{
+			Networks: []*NetworkResource{
+				// As of Nomad v1.3 bridge networks get
+				// registered with only their mode set.
+				{
+					Mode: "bridge",
+				},
+
+				// Localhost (agent interface)
+				{
+					CIDR:   "127.0.0.1/32",
+					Device: "lo",
+					IP:     "127.0.0.1",
+					MBits:  1000,
+					Mode:   "host",
+				},
+				{
+					CIDR:   "::1/128",
+					Device: "lo",
+					IP:     "::1",
+					MBits:  1000,
+					Mode:   "host",
+				},
+
+				// Node.NodeResources.Networks does *not*
+				// contain host_networks.
+			},
+			NodeNetworks: []*NodeNetworkResource{
+				// As of Nomad v1.3 bridge networks get
+				// registered with only their mode set.
+				{
+					Mode: "bridge",
+				},
+				{
+					Addresses: []NodeNetworkAddress{
+						{
+							Address: "127.0.0.1",
+							Alias:   "default",
+							Family:  "ipv4",
+						},
+						{
+							Address: "::1",
+							Alias:   "default",
+							Family:  "ipv6",
+						},
+					},
+					Device: "lo",
+					Mode:   "host",
+					Speed:  1000,
+				},
+				{
+					Addresses: []NodeNetworkAddress{
+						{
+							Address:       "192.168.0.1",
+							Alias:         "eth0",
+							Family:        "ipv4",
+							ReservedPorts: "22",
+						},
+					},
+					Device:     "enxaaaaaaaaaaaa",
+					MacAddress: "aa:aa:aa:aa:aa:aa",
+					Mode:       "host",
+					Speed:      1000,
+				},
+				{
+					Addresses: []NodeNetworkAddress{
+						{
+							Address:       "192.168.1.1",
+							Alias:         "eth1",
+							Family:        "ipv4",
+							ReservedPorts: "80",
+						},
+					},
+					Device:     "enxbbbbbbbbbbbb",
+					MacAddress: "bb:bb:bb:bb:bb:bb",
+					Mode:       "host",
+					Speed:      1000,
+				},
+			},
+		},
+		ReservedResources: &NodeReservedResources{
+			Networks: NodeReservedNetworkResources{
+				ReservedHostPorts: "22",
+			},
+		},
+	}
+
+	require.NoError(t, idx.SetNode(n))
+
+	// TaskNetworks should only contain the bridge and agent network
+	require.Len(t, idx.TaskNetworks, 2)
+
+	// Ports should be used across all 4 IPs
+	require.Equal(t, 4, len(idx.UsedPorts))
+
+	// 22 should be reserved on all IPs
+	require.True(t, idx.UsedPorts["127.0.0.1"].Check(22))
+	require.True(t, idx.UsedPorts["::1"].Check(22))
+	require.True(t, idx.UsedPorts["192.168.0.1"].Check(22))
+	require.True(t, idx.UsedPorts["192.168.1.1"].Check(22))
+
+	// 80 should only be reserved on eth1's address
+	require.False(t, idx.UsedPorts["127.0.0.1"].Check(80))
+	require.False(t, idx.UsedPorts["::1"].Check(80))
+	require.False(t, idx.UsedPorts["192.168.0.1"].Check(80))
+	require.True(t, idx.UsedPorts["192.168.1.1"].Check(80))
+}
--- a/nomad/structs/structs.go
+++ b/nomad/structs/structs.go
@ -2913,10 +2913,20 @@ type NodeResources struct {
 	Cpu     NodeCpuResources
 	Memory  NodeMemoryResources
 	Disk    NodeDiskResources
-	Networks     Networks
-	NodeNetworks []*NodeNetworkResource
 	Devices []*NodeDeviceResource

+	// NodeNetworks was added in Nomad 0.12 to support multiple interfaces.
+	// It is the superset of host_networks, fingerprinted networks, and the
+	// node's default interface.
+	NodeNetworks []*NodeNetworkResource
+
+	// Networks is the node's bridge network and default interface. It is
+	// only used when scheduling jobs with a deprecated
+	// task.resources.network stanza.
+	Networks Networks
+
+	// MinDynamicPort and MaxDynamicPort represent the inclusive port range
+	// to select dynamic ports from across all networks.
 	MinDynamicPort int
 	MaxDynamicPort int
 }
@ -2993,17 +3003,8 @@ func (n *NodeResources) Merge(o *NodeResources) {
 	}

 	if len(o.NodeNetworks) != 0 {
-		lookupNetwork := func(nets []*NodeNetworkResource, name string) (int, *NodeNetworkResource) {
-			for i, nw := range nets {
-				if nw.Device == name {
-					return i, nw
-				}
-			}
-			return 0, nil
-		}
-
 		for _, nw := range o.NodeNetworks {
-			if i, nnw := lookupNetwork(n.NodeNetworks, nw.Device); nnw != nil {
+			if i, nnw := lookupNetworkByDevice(n.NodeNetworks, nw.Device); nnw != nil {
 				n.NodeNetworks[i] = nw
 			} else {
 				n.NodeNetworks = append(n.NodeNetworks, nw)
@ -3012,6 +3013,15 @@ func (n *NodeResources) Merge(o *NodeResources) {
 	}
 }

+func lookupNetworkByDevice(nets []*NodeNetworkResource, name string) (int, *NodeNetworkResource) {
+	for i, nw := range nets {
+		if nw.Device == name {
+			return i, nw
+		}
+	}
+	return 0, nil
+}
+
 func (n *NodeResources) Equals(o *NodeResources) bool {
 	if o == nil && n == nil {
 		return true
--- a/scheduler/context_test.go
+++ b/scheduler/context_test.go
@ -435,7 +435,7 @@ func TestPortCollisionEvent_Copy(t *testing.T) {
 	evCopy.Allocations = append(evCopy.Allocations, mock.Alloc())
 	require.NotEqual(t, ev.Allocations, evCopy.Allocations)

-	evCopy.NetIndex.AddReservedPortRange("1000-2000")
+	evCopy.NetIndex.AddAllocs(evCopy.Allocations)
 	require.NotEqual(t, ev.NetIndex, evCopy.NetIndex)
 }

--- a/scheduler/feasible.go
+++ b/scheduler/feasible.go
@ -417,13 +417,13 @@ func (c *NetworkChecker) hasHostNetworks(option *structs.Node) bool {
 			}
 			found := false
 			for _, net := range option.NodeResources.NodeNetworks {
-				if net.HasAlias(hostNetworkValue.(string)) {
+				if net.HasAlias(hostNetworkValue) {
 					found = true
 					break
 				}
 			}
 			if !found {
-				c.ctx.Metrics().FilterNode(option, fmt.Sprintf("missing host network %q for port %q", hostNetworkValue.(string), port.Label))
+				c.ctx.Metrics().FilterNode(option, fmt.Sprintf("missing host network %q for port %q", hostNetworkValue, port.Label))
 				return false
 			}
 		}
@ -766,7 +766,7 @@ func (c *ConstraintChecker) meetsConstraint(constraint *structs.Constraint, opti
 }

 // resolveTarget is used to resolve the LTarget and RTarget of a Constraint.
-func resolveTarget(target string, node *structs.Node) (interface{}, bool) {
+func resolveTarget(target string, node *structs.Node) (string, bool) {
 	// If no prefix, this must be a literal value
 	if !strings.HasPrefix(target, "${") {
 		return target, true
@ -797,7 +797,7 @@ func resolveTarget(target string, node *structs.Node) (interface{}, bool) {
 		return val, ok

 	default:
-		return nil, false
+		return "", false
 	}
 }

--- a/scheduler/propertyset.go
+++ b/scheduler/propertyset.go
@ -342,14 +342,5 @@ func getProperty(n *structs.Node, property string) (string, bool) {
 		return "", false
 	}

-	val, ok := resolveTarget(property, n)
-	if !ok {
-		return "", false
-	}
-	nodeValue, ok := val.(string)
-	if !ok {
-		return "", false
-	}
-
-	return nodeValue, true
+	return resolveTarget(property, n)
 }
--- a/scheduler/rank.go
+++ b/scheduler/rank.go
@ -211,13 +211,13 @@ OUTER:
 		// the node. If it does collide though, it means we found a bug! So
 		// collect as much information as possible.
 		netIdx := structs.NewNetworkIndex()
-		if collide, reason := netIdx.SetNode(option.Node); collide {
+		if err := netIdx.SetNode(option.Node); err != nil {
 			iter.ctx.SendEvent(&PortCollisionEvent{
-				Reason:   reason,
+				Reason:   err.Error(),
 				NetIndex: netIdx.Copy(),
 				Node:     option.Node,
 			})
-			iter.ctx.Metrics().ExhaustedNode(option.Node, "network: port collision")
+			iter.ctx.Metrics().ExhaustedNode(option.Node, "network: invalid node")
 			continue
 		}
 		if collide, reason := netIdx.AddAllocs(proposed); collide {
@ -274,7 +274,7 @@ OUTER:
 			for i, port := range ask.DynamicPorts {
 				if port.HostNetwork != "" {
 					if hostNetworkValue, hostNetworkOk := resolveTarget(port.HostNetwork, option.Node); hostNetworkOk {
-						ask.DynamicPorts[i].HostNetwork = hostNetworkValue.(string)
+						ask.DynamicPorts[i].HostNetwork = hostNetworkValue
 					} else {
 						iter.ctx.Logger().Named("binpack").Error(fmt.Sprintf("Invalid template for %s host network in port %s", port.HostNetwork, port.Label))
 						netIdx.Release()
@ -285,7 +285,7 @@ OUTER:
 			for i, port := range ask.ReservedPorts {
 				if port.HostNetwork != "" {
 					if hostNetworkValue, hostNetworkOk := resolveTarget(port.HostNetwork, option.Node); hostNetworkOk {
-						ask.ReservedPorts[i].HostNetwork = hostNetworkValue.(string)
+						ask.ReservedPorts[i].HostNetwork = hostNetworkValue
 					} else {
 						iter.ctx.Logger().Named("binpack").Error(fmt.Sprintf("Invalid template for %s host network in port %s", port.HostNetwork, port.Label))
 						netIdx.Release()
@ -363,7 +363,7 @@ OUTER:
 			// Check if we need a network resource
 			if len(task.Resources.Networks) > 0 {
 				ask := task.Resources.Networks[0].Copy()
-				offer, err := netIdx.AssignNetwork(ask)
+				offer, err := netIdx.AssignTaskNetwork(ask)
 				if offer == nil {
 					// If eviction is not enabled, mark this node as exhausted and continue
 					if !iter.evict {
@ -393,7 +393,7 @@ OUTER:
 					netIdx.SetNode(option.Node)
 					netIdx.AddAllocs(proposed)

-					offer, err = netIdx.AssignNetwork(ask)
+					offer, err = netIdx.AssignTaskNetwork(ask)
 					if offer == nil {
 						iter.ctx.Logger().Named("binpack").Debug("unexpected error, unable to create network offer after considering preemption", "error", err)
 						netIdx.Release()
--- a/scheduler/rank_test.go
+++ b/scheduler/rank_test.go
@ -492,12 +492,13 @@ func TestBinPackIterator_Network_Failure(t *testing.T) {
 	require.Equal(1, ctx.metrics.DimensionExhausted["network: bandwidth exceeded"])
 }

-func TestBinPackIterator_Network_PortCollision_Node(t *testing.T) {
+func TestBinPackIterator_Network_NoCollision_Node(t *testing.T) {
 	_, ctx := testContext(t)
 	eventsCh := make(chan interface{})
 	ctx.eventsCh = eventsCh

-	// Collide on host with duplicate IPs.
+	// Host networks can have overlapping addresses in which case their
+	// reserved ports are merged.
 	nodes := []*RankedNode{
 		{
 			Node: &structs.Node{
@ -577,9 +578,110 @@ func TestBinPackIterator_Network_PortCollision_Node(t *testing.T) {
 	scoreNorm := NewScoreNormalizationIterator(ctx, binp)
 	out := collectRanked(scoreNorm)

-	// We expect a placement failure due to  port collision.
+	// Placement should succeed since reserved ports are merged instead of
+	// treating them as a collision
+	require.Len(t, out, 1)
+}
+
+// TestBinPackIterator_Network_NodeError asserts that NetworkIndex.SetNode can
+// return an error and cause a node to be infeasible.
+//
+// This should never happen as it indicates "bad" configuration was either not
+// caught by validation or caused by bugs in serverside Node handling.
+func TestBinPackIterator_Network_NodeError(t *testing.T) {
+	_, ctx := testContext(t)
+	eventsCh := make(chan interface{})
+	ctx.eventsCh = eventsCh
+
+	nodes := []*RankedNode{
+		{
+			Node: &structs.Node{
+				ID: uuid.Generate(),
+				Resources: &structs.Resources{
+					Networks: []*structs.NetworkResource{
+						{
+							Device: "eth0",
+							CIDR:   "192.168.0.100/32",
+							IP:     "192.158.0.100",
+						},
+					},
+				},
+				NodeResources: &structs.NodeResources{
+					Cpu: structs.NodeCpuResources{
+						CpuShares: 4096,
+					},
+					Memory: structs.NodeMemoryResources{
+						MemoryMB: 4096,
+					},
+					Networks: []*structs.NetworkResource{
+						{
+							Device: "eth0",
+							CIDR:   "192.168.0.100/32",
+							IP:     "192.158.0.100",
+						},
+					},
+					NodeNetworks: []*structs.NodeNetworkResource{
+						{
+							Mode:   "host",
+							Device: "eth0",
+							Addresses: []structs.NodeNetworkAddress{
+								{
+									Alias:         "default",
+									Address:       "192.168.0.100",
+									ReservedPorts: "22,80",
+								},
+								{
+									Alias:         "private",
+									Address:       "192.168.0.100",
+									ReservedPorts: "22",
+								},
+							},
+						},
+					},
+				},
+				ReservedResources: &structs.NodeReservedResources{
+					Networks: structs.NodeReservedNetworkResources{
+						ReservedHostPorts: "not-valid-ports",
+					},
+				},
+			},
+		},
+	}
+	static := NewStaticRankIterator(ctx, nodes)
+
+	taskGroup := &structs.TaskGroup{
+		EphemeralDisk: &structs.EphemeralDisk{},
+		Tasks: []*structs.Task{
+			{
+				Name: "web",
+				Resources: &structs.Resources{
+					CPU:      1024,
+					MemoryMB: 1024,
+					Networks: []*structs.NetworkResource{
+						{
+							Device: "eth0",
+						},
+					},
+				},
+			},
+		},
+		Networks: []*structs.NetworkResource{
+			{
+				Device: "eth0",
+			},
+		},
+	}
+	binp := NewBinPackIterator(ctx, static, false, 0, testSchedulerConfig)
+	binp.SetTaskGroup(taskGroup)
+
+	scoreNorm := NewScoreNormalizationIterator(ctx, binp)
+	out := collectRanked(scoreNorm)
+
+	// We expect a placement failure because the node has invalid reserved
+	// ports
 	require.Len(t, out, 0)
-	require.Equal(t, 1, ctx.metrics.DimensionExhausted["network: port collision"])
+	require.Equal(t, 1, ctx.metrics.DimensionExhausted["network: invalid node"],
+		ctx.metrics.DimensionExhausted)
 }

 func TestBinPackIterator_Network_PortCollision_Alloc(t *testing.T) {
--- a/website/content/docs/configuration/client.mdx
+++ b/website/content/docs/configuration/client.mdx
@ -206,9 +206,12 @@ chroot as doing so would cause infinite recursion.

 - `disk` `(int: 0)` - Specifies the amount of disk to reserve, in MB.

- `reserved_ports` `(string: "")` - Specifies a comma-separated list of ports to
-  reserve on all fingerprinted network devices. Ranges can be specified by using
-  a hyphen separated the two inclusive ends.
+- `reserved_ports` `(string: "")` - Specifies a comma-separated list of ports
+  to reserve on all fingerprinted network devices. Ranges can be specified by
+  using a hyphen separating the two inclusive ends. See also
+  [`host_network`](#host_network-stanza) for reserving ports on specific host
+  networks.
+

 ### `artifact` Parameters

@ -396,8 +399,10 @@ client {
 - `interface` `(string: "")` - Filters searching of addresses to a specific interface.

 - `reserved_ports` `(string: "")` - Specifies a comma-separated list of ports to
-  reserve on all fingerprinted network devices. Ranges can be specified by using
+  reserve on all addresses associated with this network. Ranges can be specified by using
  a hyphen separating the two inclusive ends.
+  [`reserved.reserved_ports`](#reserved_ports) are also reserved on each host
+  network.

 ## `client` Examples