diff options
| -rw-r--r-- | runsc/cmd/checkpoint.go | 57 | ||||
| -rw-r--r-- | runsc/container/BUILD | 1 | ||||
| -rw-r--r-- | runsc/container/container.go | 57 |
3 files changed, 109 insertions, 6 deletions
diff --git a/runsc/cmd/checkpoint.go b/runsc/cmd/checkpoint.go index a28eb0f02..9348289ca 100644 --- a/runsc/cmd/checkpoint.go +++ b/runsc/cmd/checkpoint.go @@ -17,12 +17,15 @@ package cmd import ( "os" "path/filepath" + "syscall" "context" "flag" "github.com/google/subcommands" + "gvisor.googlesource.com/gvisor/pkg/log" "gvisor.googlesource.com/gvisor/runsc/boot" "gvisor.googlesource.com/gvisor/runsc/container" + "gvisor.googlesource.com/gvisor/runsc/specutils" ) // File containing the container's saved image/state within the given image-path's directory. @@ -30,7 +33,8 @@ const checkpointFileName = "checkpoint.img" // Checkpoint implements subcommands.Command for the "checkpoint" command. type Checkpoint struct { - imagePath string + imagePath string + leaveRunning bool } // Name implements subcommands.Command.Name. @@ -51,14 +55,12 @@ func (*Checkpoint) Usage() string { // SetFlags implements subcommands.Command.SetFlags. func (c *Checkpoint) SetFlags(f *flag.FlagSet) { - f.StringVar(&c.imagePath, "image-path", "", "path to saved container image") + f.StringVar(&c.imagePath, "image-path", "", "directory path to saved container image") + f.BoolVar(&c.leaveRunning, "leave-running", false, "restart the container after checkpointing") // Unimplemented flags necessary for compatibility with docker. var wp string f.StringVar(&wp, "work-path", "", "ignored") - - var lr bool - f.BoolVar(&lr, "leave-running", false, "ignored") } // Execute implements subcommands.Command.Execute. @@ -71,6 +73,7 @@ func (c *Checkpoint) Execute(_ context.Context, f *flag.FlagSet, args ...interfa id := f.Arg(0) conf := args[0].(*boot.Config) + waitStatus := args[1].(*syscall.WaitStatus) cont, err := container.Load(conf.RootDir, id) if err != nil { @@ -98,5 +101,49 @@ func (c *Checkpoint) Execute(_ context.Context, f *flag.FlagSet, args ...interfa Fatalf("checkpoint failed: %v", err) } + if !c.leaveRunning { + return subcommands.ExitSuccess + } + + // TODO: Make it possible to restore into same container. + // For now, we can fake it by destroying the container and making a + // new container with the same ID. This hack does not work with docker + // which uses the container pid to ensure that the restore-container is + // actually the same as the checkpoint-container. By restoring into + // the same container, we will solve the docker incompatibility. + + // Restore into new container with same ID. + bundleDir := cont.BundleDir + if bundleDir == "" { + Fatalf("error setting bundleDir") + } + + spec, err := specutils.ReadSpec(bundleDir) + if err != nil { + Fatalf("error reading spec: %v", err) + } + + specutils.LogSpec(spec) + + if cont.ConsoleSocket != "" { + log.Warningf("ignoring console socket since it cannot be restored") + } + + if err := cont.DestroyAndWait(); err != nil { + Fatalf("error destroying container: %v", err) + } + + cont, err = container.Create(id, spec, conf, bundleDir, "", "", fullImagePath) + if err != nil { + Fatalf("error restoring container: %v", err) + } + + if err := cont.Start(conf); err != nil { + Fatalf("error starting container: %v", err) + } + + ws, err := cont.Wait() + *waitStatus = ws + return subcommands.ExitSuccess } diff --git a/runsc/container/BUILD b/runsc/container/BUILD index 61e05e1c3..679d7e097 100644 --- a/runsc/container/BUILD +++ b/runsc/container/BUILD @@ -16,6 +16,7 @@ go_library( deps = [ "//pkg/log", "//pkg/sentry/control", + "//pkg/syserror", "//runsc/boot", "//runsc/sandbox", "//runsc/specutils", diff --git a/runsc/container/container.go b/runsc/container/container.go index 042c76577..8dca721f6 100644 --- a/runsc/container/container.go +++ b/runsc/container/container.go @@ -30,6 +30,7 @@ import ( specs "github.com/opencontainers/runtime-spec/specs-go" "gvisor.googlesource.com/gvisor/pkg/log" "gvisor.googlesource.com/gvisor/pkg/sentry/control" + "gvisor.googlesource.com/gvisor/pkg/syserror" "gvisor.googlesource.com/gvisor/runsc/boot" "gvisor.googlesource.com/gvisor/runsc/sandbox" "gvisor.googlesource.com/gvisor/runsc/specutils" @@ -100,11 +101,12 @@ type Container struct { func Load(rootDir, id string) (*Container, error) { log.Debugf("Load container %q %q", rootDir, id) if err := validateID(id); err != nil { - return nil, err + return nil, fmt.Errorf("error validating id: %v", err) } cRoot, err := findContainerRoot(rootDir, id) if err != nil { + // Preserve error so that callers can distinguish 'not found' errors. return nil, err } @@ -471,6 +473,32 @@ func (c *Container) Destroy() error { c.Sandbox = nil c.Status = Stopped + + return nil +} + +// DestroyAndWait frees all resources associated with the container +// and waits for destroy to finish before returning. +func (c *Container) DestroyAndWait() error { + sandboxPid := c.Sandbox.Pid + goferPid := c.Sandbox.GoferPid + + if err := c.Destroy(); err != nil { + return fmt.Errorf("error destroying container %v: %v", c, err) + } + + if sandboxPid != 0 { + if err := waitForDeath(sandboxPid, 5*time.Second); err != nil { + return fmt.Errorf("error waiting for sandbox death: %v", err) + } + } + + if goferPid != 0 { + if err := waitForDeath(goferPid, 5*time.Second); err != nil { + return fmt.Errorf("error waiting for gofer death: %v", err) + } + } + return nil } @@ -490,3 +518,30 @@ func (c *Container) save() error { } return nil } + +// waitForDeath ensures that process is dead before proceeding. +// +// This is racy because the kernel can potentially reuse the pid in the time +// between the process' death and the first check after the process has ended. +func waitForDeath(pid int, timeout time.Duration) error { + backoff := 1 * time.Millisecond + for start := time.Now(); time.Now().Sub(start) < timeout; { + + if err := syscall.Kill(pid, 0); err != nil { + if err == syserror.ESRCH { + // pid does not exist so process must have died + return nil + } + return fmt.Errorf("error killing pid (%d): %v", pid, err) + } + // pid is still alive. + + // Process continues to run, backoff and retry. + time.Sleep(backoff) + backoff *= 2 + if backoff > 1*time.Second { + backoff = 1 * time.Second + } + } + return fmt.Errorf("timed out waiting for process (%d)", pid) +} |