Skip to content
New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Jump to bottom

rkt: Don't require port_map with host networking #3615

Merged
merged 1 commit into from
Dec 4, 2017
Merged

rkt: Don't require port_map with host networking #3615

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Jump to
Jump to file
Failed to load files.
Diff view
Diff view
1 change: 1 addition & 0 deletions CHANGELOG.md
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -45,6 +45,7 @@ BUG FIXES:
* client: Fix allocation accounting in GC and trigger GCs on allocation
updates [GH-3445]
* driver/rkt: Remove pods on shutdown [GH-3562]
* driver/rkt: Don't require port maps when using host networking [GH-3615]
* template: Fix issue where multiple environment variable templates would be
parsed incorrectly when contents of one have changed after the initial
rendering [GH-3529]
Expand Down
25 changes: 16 additions & 9 deletions client/driver/rkt.go
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -529,6 +529,9 @@ func (d *RktDriver) Start(ctx *ExecContext, task *structs.Task) (*StartResponse,
if len(driverConfig.PortMap) > 0 {
return nil, fmt.Errorf("Trying to map ports but no network interface is available")
}
} else if network == "host" {
// Port mapping is skipped when host networking is used.
d.logger.Println("[DEBUG] driver.rkt: Ignoring port_map when using --net=host")
} else {
// TODO add support for more than one network
network := task.Resources.Networks[0]
Expand Down Expand Up @@ -657,15 +660,19 @@ func (d *RktDriver) Start(ctx *ExecContext, task *structs.Task) (*StartResponse,
}
go h.run()

d.logger.Printf("[DEBUG] driver.rkt: retrieving network information for pod %q (UUID %s) for task %q", img, uuid, d.taskName)
driverNetwork, err := rktGetDriverNetwork(uuid, driverConfig.PortMap)
if err != nil && !pluginClient.Exited() {
d.logger.Printf("[WARN] driver.rkt: network status retrieval for pod %q (UUID %s) for task %q failed. Last error: %v", img, uuid, d.taskName, err)

// If a portmap was given, this turns into a fatal error
if len(driverConfig.PortMap) != 0 {
pluginClient.Kill()
return nil, fmt.Errorf("Trying to map ports but driver could not determine network information")
// Only return a driver network if *not* using host networking
var driverNetwork *cstructs.DriverNetwork
if network != "host" {
d.logger.Printf("[DEBUG] driver.rkt: retrieving network information for pod %q (UUID %s) for task %q", img, uuid, d.taskName)
driverNetwork, err = rktGetDriverNetwork(uuid, driverConfig.PortMap)
if err != nil && !pluginClient.Exited() {
d.logger.Printf("[WARN] driver.rkt: network status retrieval for pod %q (UUID %s) for task %q failed. Last error: %v", img, uuid, d.taskName, err)

// If a portmap was given, this turns into a fatal error
if len(driverConfig.PortMap) != 0 {
pluginClient.Kill()
return nil, fmt.Errorf("Trying to map ports but driver could not determine network information")
}
}
}

Copy link
Contributor

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

I am concerned about nil pointer dereferencing in downstream code like

nomad/command/agent/consul/client.go

Line 575 in a52cb34

if net.Advertise() {
that use the DriverNetwork struct, isn't that going to panic when network == "host" ?

Copy link
Member Author

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

So I have regrets about how I implemented DriverNetwork, but it was designed to gracefully handle nils since the vast majority of drivers don't implement it (so they return nil).

nomad/client/driver/driver.go

Lines 199 to 201 in 730e2aa

// Network may be nil as not all drivers or configurations create
// networks.
Network *cstructs.DriverNetwork

And if you look at each of the methods on DriverNetwork they handle nil:

nomad/client/structs/structs.go

Lines 134 to 186 in 730e2aa

// DriverNetwork is the network created by driver's (eg Docker's bridge
// network) during Prestart.
type DriverNetwork struct {
// PortMap can be set by drivers to replace ports in environment
// variables with driver-specific mappings.
PortMap map[string]int
// IP is the IP address for the task created by the driver.
IP string
// AutoAdvertise indicates whether the driver thinks services that
// choose to auto-advertise-addresses should use this IP instead of the
// host's. eg If a Docker network plugin is used
AutoAdvertise bool
}
// Advertise returns true if the driver suggests using the IP set. May be
// called on a nil Network in which case it returns false.
func (d *DriverNetwork) Advertise() bool {
return d != nil && d.AutoAdvertise
}
// Copy a DriverNetwork struct. If it is nil, nil is returned.
func (d *DriverNetwork) Copy() *DriverNetwork {
if d == nil {
return nil
}
pm := make(map[string]int, len(d.PortMap))
for k, v := range d.PortMap {
pm[k] = v
}
return &DriverNetwork{
PortMap: pm,
IP: d.IP,
AutoAdvertise: d.AutoAdvertise,
}
}
// Hash the contents of a DriverNetwork struct to detect changes. If it is nil,
// an empty slice is returned.
func (d *DriverNetwork) Hash() []byte {
if d == nil {
return []byte{}
}
h := md5.New()
io.WriteString(h, d.IP)
io.WriteString(h, strconv.FormatBool(d.AutoAdvertise))
for k, v := range d.PortMap {
io.WriteString(h, k)
io.WriteString(h, strconv.Itoa(v))
}
return h.Sum(nil)
}

Definitely something worth changing/fixing in the future, but I think it's out of scope for this PR.

Copy link
Contributor

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Agreed, thanks for the explain.

Expand Down
66 changes: 66 additions & 0 deletions client/driver/rkt_test.go
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -519,6 +519,72 @@ func TestRktDriver_PortsMapping(t *testing.T) {
}
}

// TestRktDriver_PortsMapping_Host asserts that port_map isn't required when
// host networking is used.
func TestRktDriver_PortsMapping_Host(t *testing.T) {
if !testutil.IsTravis() {
t.Parallel()
}
if os.Getenv("NOMAD_TEST_RKT") == "" {
t.Skip("skipping rkt tests")
}

ctestutils.RktCompatible(t)
task := &structs.Task{
Name: "etcd",
Driver: "rkt",
Config: map[string]interface{}{
"image": "docker://redis:latest",
"net": []string{"host"},
},
LogConfig: &structs.LogConfig{
MaxFiles: 10,
MaxFileSizeMB: 10,
},
Resources: &structs.Resources{
MemoryMB: 256,
CPU: 512,
Networks: []*structs.NetworkResource{
{
IP: "127.0.0.1",
ReservedPorts: []structs.Port{{Label: "main", Value: 8080}},
},
},
},
}

ctx := testDriverContexts(t, task)
defer ctx.AllocDir.Destroy()
d := NewRktDriver(ctx.DriverCtx)

if _, err := d.Prestart(ctx.ExecCtx, task); err != nil {
t.Fatalf("error in prestart: %v", err)
}
resp, err := d.Start(ctx.ExecCtx, task)
if err != nil {
t.Fatalf("err: %v", err)
}
if resp.Network != nil {
t.Fatalf("No network should be returned with --net=host but found: %#v", resp.Network)
}

failCh := make(chan error, 1)
go func() {
time.Sleep(1 * time.Second)
if err := resp.Handle.Kill(); err != nil {
failCh <- err
}
}()

select {
case err := <-failCh:
t.Fatalf("failed to kill handle: %v", err)
case <-resp.Handle.WaitCh():
case <-time.After(time.Duration(testutil.TestMultiplier()*15) * time.Second):
t.Fatalf("timeout")
}
}

func TestRktDriver_HandlerExec(t *testing.T) {
if !testutil.IsTravis() {
t.Parallel()
Expand Down