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runsc do fallback to internal network on failure

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In case setting up network fails, log a warning and fallback to internal
network.

Closes #4498

PiperOrigin-RevId: 337442632
This commit is contained in:
Fabricio Voznika
2020-10-15 21:51:02 -07:00
committed by gVisor bot
parent 0a7e32bd17
commit fc40ead685
1 changed files with 29 additions and 16 deletions
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runsc/cmd/do.go
+29 -16
View File
@@ -17,6 +17,7 @@ package cmd
import (
"context"
"encoding/json"
"errors"
"fmt"
"io/ioutil"
"math/rand"
@@ -36,6 +37,8 @@ import (
"gvisor.dev/gvisor/runsc/specutils"
)
var errNoDefaultInterface = errors.New("no default interface found")
// Do implements subcommands.Command for the "do" command. It sets up a simple
// sandbox and executes the command inside it. See Usage() for more details.
type Do struct {
@@ -126,26 +129,28 @@ func (c *Do) Execute(_ context.Context, f *flag.FlagSet, args ...interface{}) su
cid := fmt.Sprintf("runsc-%06d", rand.Int31n(1000000))
if conf.Network == config.NetworkNone {
netns := specs.LinuxNamespace{
Type: specs.NetworkNamespace,
}
if spec.Linux != nil {
panic("spec.Linux is not nil")
}
spec.Linux = &specs.Linux{Namespaces: []specs.LinuxNamespace{netns}}
addNamespace(spec, specs.LinuxNamespace{Type: specs.NetworkNamespace})
} else if conf.Rootless {
if conf.Network == config.NetworkSandbox {
c.notifyUser("*** Warning: using host network due to --rootless ***")
c.notifyUser("*** Warning: sandbox network isn't supported with --rootless, switching to host ***")
conf.Network = config.NetworkHost
}
} else {
clean, err := c.setupNet(cid, spec)
if err != nil {
switch clean, err := c.setupNet(cid, spec); err {
case errNoDefaultInterface:
log.Warningf("Network interface not found, using internal network")
addNamespace(spec, specs.LinuxNamespace{Type: specs.NetworkNamespace})
conf.Network = config.NetworkHost
case nil:
// Setup successfull.
defer clean()
default:
return Errorf("Error setting up network: %v", err)
}
defer clean()
}
out, err := json.Marshal(spec)
@@ -199,6 +204,13 @@ func (c *Do) Execute(_ context.Context, f *flag.FlagSet, args ...interface{}) su
return subcommands.ExitSuccess
}
func addNamespace(spec *specs.Spec, ns specs.LinuxNamespace) {
if spec.Linux == nil {
spec.Linux = &specs.Linux{}
}
spec.Linux.Namespaces = append(spec.Linux.Namespaces, ns)
}
func (c *Do) notifyUser(format string, v ...interface{}) {
if !c.quiet {
fmt.Printf(format+"\n", v...)
@@ -219,10 +231,14 @@ func resolvePath(path string) (string, error) {
return path, nil
}
// setupNet setups up the sandbox network, including the creation of a network
// namespace, and iptable rules to redirect the traffic. Returns a cleanup
// function to tear down the network. Returns errNoDefaultInterface when there
// is no network interface available to setup the network.
func (c *Do) setupNet(cid string, spec *specs.Spec) (func(), error) {
dev, err := defaultDevice()
if err != nil {
return nil, err
return nil, errNoDefaultInterface
}
peerIP, err := calculatePeerIP(c.ip)
if err != nil {
@@ -279,14 +295,11 @@ func (c *Do) setupNet(cid string, spec *specs.Spec) (func(), error) {
return nil, err
}
if spec.Linux == nil {
spec.Linux = &specs.Linux{}
}
netns := specs.LinuxNamespace{
Type: specs.NetworkNamespace,
Path: filepath.Join("/var/run/netns", cid),
}
spec.Linux.Namespaces = append(spec.Linux.Namespaces, netns)
addNamespace(spec, netns)
return func() { c.cleanupNet(cid, dev, resolvPath, hostnamePath, hostsPath) }, nil
}