drivers/docker: support mapping multiple host ports to the same container port

CHANGELOG.md

@@ -10,6 +10,7 @@ BUG FIXES:
  * consul: Fixed a bug where failing tasks with group services would only cause the allocation to restart once instead of respecting the `restart` field. [[GH-9869](https://github.com/hashicorp/nomad/issues/9869)]
  * consul/connect: Fixed a bug where gateway proxy connection default timeout not set [[GH-9851](https://github.com/hashicorp/nomad/pull/9851)]
  * consul/connect: Fixed a bug preventing more than one connect gateway per Nomad client [[GH-9849](https://github.com/hashicorp/nomad/pull/9849)]
+ * drivers/docker: Fixed a bug preventing multiple ports to be mapped to the same container port [[GH-9951](https://github.com/hashicorp/nomad/issues/9951)]
  * scheduler: Fixed a bug where shared ports were not persisted during inplace updates for service jobs. [[GH-9830](https://github.com/hashicorp/nomad/issues/9830)]
  * scheduler: Fixed a bug where job statuses and summaries where duplicated and miscalculated when registering a job. [[GH-9768](https://github.com/hashicorp/nomad/issues/9768)]
   * scheduler (Enterprise): Fixed a bug where the deprecated network `mbits` field was being considered as part of quota enforcement. [[GH-9920](https://github.com/hashicorp/nomad/issues/9920)]

drivers/docker/driver_default.go

@@ -7,8 +7,8 @@ import (
 	docker "github.com/fsouza/go-dockerclient"
 )
 
-func getPortBinding(ip string, port string) []docker.PortBinding {
-	return []docker.PortBinding{{HostIP: ip, HostPort: port}}
+func getPortBinding(ip string, port string) docker.PortBinding {
+	return docker.PortBinding{HostIP: ip, HostPort: port}
 }
 
 func tweakCapabilities(basics, adds, drops []string) ([]string, error) {

drivers/docker/driver_windows.go

@@ -3,8 +3,8 @@ package docker
 import docker "github.com/fsouza/go-dockerclient"
 
 //Currently Windows containers don't support host ip in port binding.
-func getPortBinding(ip string, port string) []docker.PortBinding {
-	return []docker.PortBinding{{HostIP: "", HostPort: port}}
+func getPortBinding(ip string, port string) docker.PortBinding {
+	return docker.PortBinding{HostIP: "", HostPort: port}
 }
 
 func tweakCapabilities(basics, adds, drops []string) ([]string, error) {

drivers/docker/ports.go

@@ -8,6 +8,9 @@ import (
 	"github.com/hashicorp/nomad/helper/pluginutils/hclutils"
 )
 
+// publishedPorts is a utility struct to keep track of the port bindings to publish.
+// After calling add for each port, the publishedPorts and exposedPorts fields can be
+// used in the docker container and host configs
 type publishedPorts struct {
 	logger         hclog.Logger
 	publishedPorts map[docker.Port][]docker.PortBinding
@@ -22,7 +25,7 @@ func newPublishedPorts(logger hclog.Logger) *publishedPorts {
 	}
 }
 
-// adds the port to the structures the Docker API expects for declaring mapped ports
+// addMapped adds the port to the structures the Docker API expects for declaring mapped ports
 func (p *publishedPorts) addMapped(label, ip string, port int, portMap hclutils.MapStrInt) {
 	// By default we will map the allocated port 1:1 to the container
 	containerPortInt := port
@@ -35,18 +38,29 @@ func (p *publishedPorts) addMapped(label, ip string, port int, portMap hclutils.
 	p.add(label, ip, port, containerPortInt)
 }
 
+// add adds a port binding for the given port mapping
 func (p *publishedPorts) add(label, ip string, port, to int) {
+	// if to is not set, use the port value per default docker functionality
 	if to == 0 {
 		to = port
 	}
-	hostPortStr := strconv.Itoa(port)
-	containerPort := docker.Port(strconv.Itoa(to))
 
-	p.publishedPorts[containerPort+"/tcp"] = getPortBinding(ip, hostPortStr)
-	p.publishedPorts[containerPort+"/udp"] = getPortBinding(ip, hostPortStr)
-	p.logger.Debug("allocated static port", "ip", ip, "port", port)
+	// two docker port bindings are created for each port for tcp and udp
+	cPortTCP := docker.Port(strconv.Itoa(to) + "/tcp")
+	cPortUDP := docker.Port(strconv.Itoa(to) + "/udp")
+	binding := getPortBinding(ip, strconv.Itoa(port))
 
-	p.exposedPorts[containerPort+"/tcp"] = struct{}{}
-	p.exposedPorts[containerPort+"/udp"] = struct{}{}
-	p.logger.Debug("exposed port", "port", port)
+	if _, ok := p.publishedPorts[cPortTCP]; !ok {
+		// initialize both tcp and udp binding slices since they are always created together
+		p.publishedPorts[cPortTCP] = []docker.PortBinding{}
+		p.publishedPorts[cPortUDP] = []docker.PortBinding{}
+	}
+
+	p.publishedPorts[cPortTCP] = append(p.publishedPorts[cPortTCP], binding)
+	p.publishedPorts[cPortUDP] = append(p.publishedPorts[cPortUDP], binding)
+	p.logger.Debug("allocated static port", "ip", ip, "port", port, "label", label)
+
+	p.exposedPorts[cPortTCP] = struct{}{}
+	p.exposedPorts[cPortUDP] = struct{}{}
+	p.logger.Debug("exposed port", "port", port, "label", label)
 }

drivers/docker/ports_test.go

@@ -0,0 +1,19 @@
+package docker
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/require"
+
+	"github.com/hashicorp/nomad/helper/testlog"
+)
+
+func TestPublishedPorts_add(t *testing.T) {
+	p := newPublishedPorts(testlog.HCLogger(t))
+	p.add("label", "10.0.0.1", 1234, 80)
+	p.add("label", "10.0.0.1", 5678, 80)
+	for _, bindings := range p.publishedPorts {
+		require.Len(t, bindings, 2)
+	}
+	require.Len(t, p.exposedPorts, 2)
+}