From 0028578b432d207e1e5b313c76e587eae275bdac Mon Sep 17 00:00:00 2001 From: Adrian Reber Date: Wed, 6 Feb 2019 19:22:46 +0000 Subject: Added support to migrate containers This commit adds an option to the checkpoint command to export a checkpoint into a tar.gz file as well as importing a checkpoint tar.gz file during restore. With all checkpoint artifacts in one file it is possible to easily transfer a checkpoint and thus enabling container migration in Podman. With the following steps it is possible to migrate a running container from one system (source) to another (destination). Source system: * podman container checkpoint -l -e /tmp/checkpoint.tar.gz * scp /tmp/checkpoint.tar.gz destination:/tmp Destination system: * podman pull 'container-image-as-on-source-system' * podman container restore -i /tmp/checkpoint.tar.gz The exported tar.gz file contains the checkpoint image as created by CRIU and a few additional JSON files describing the state of the checkpointed container. Now the container is running on the destination system with the same state just as during checkpointing. If the container is kept running on the source system with the checkpoint flag '-R', the result will be that the same container is running on two different hosts. Signed-off-by: Adrian Reber --- pkg/adapter/checkpoint_restore.go | 99 +++++++++++++++++++++++++++++++++++++++ pkg/adapter/containers.go | 6 ++- pkg/adapter/containers_remote.go | 10 +++- 3 files changed, 112 insertions(+), 3 deletions(-) create mode 100644 pkg/adapter/checkpoint_restore.go (limited to 'pkg') diff --git a/pkg/adapter/checkpoint_restore.go b/pkg/adapter/checkpoint_restore.go new file mode 100644 index 000000000..9df1704ea --- /dev/null +++ b/pkg/adapter/checkpoint_restore.go @@ -0,0 +1,99 @@ +// +build !remoteclient + +package adapter + +import ( + "context" + "github.com/containers/libpod/libpod" + "github.com/containers/storage/pkg/archive" + jsoniter "github.com/json-iterator/go" + spec "github.com/opencontainers/runtime-spec/specs-go" + "github.com/pkg/errors" + "io/ioutil" + "os" + "path/filepath" +) + +// Prefixing the checkpoint/restore related functions with 'cr' + +// crImportFromJSON imports the JSON files stored in the exported +// checkpoint tarball +func crImportFromJSON(filePath string, v interface{}) error { + jsonFile, err := os.Open(filePath) + if err != nil { + return errors.Wrapf(err, "Failed to open container definition %s for restore", filePath) + } + defer jsonFile.Close() + + content, err := ioutil.ReadAll(jsonFile) + if err != nil { + return errors.Wrapf(err, "Failed to read container definition %s for restore", filePath) + } + json := jsoniter.ConfigCompatibleWithStandardLibrary + if err = json.Unmarshal([]byte(content), v); err != nil { + return errors.Wrapf(err, "Failed to unmarshal container definition %s for restore", filePath) + } + + return nil +} + +// crImportCheckpoint it the function which imports the information +// from checkpoint tarball and re-creates the container from that information +func crImportCheckpoint(ctx context.Context, runtime *libpod.Runtime, input string) ([]*libpod.Container, error) { + // First get the container definition from the + // tarball to a temporary directory + archiveFile, err := os.Open(input) + if err != nil { + return nil, errors.Wrapf(err, "Failed to open checkpoint archive %s for import", input) + } + defer archiveFile.Close() + options := &archive.TarOptions{ + // Here we only need the files config.dump and spec.dump + ExcludePatterns: []string{ + "checkpoint", + "artifacts", + "ctr.log", + "network.status", + }, + } + dir, err := ioutil.TempDir("", "checkpoint") + if err != nil { + return nil, err + } + defer os.RemoveAll(dir) + err = archive.Untar(archiveFile, dir, options) + if err != nil { + return nil, errors.Wrapf(err, "Unpacking of checkpoint archive %s failed", input) + } + + // Load spec.dump from temporary directory + spec := new(spec.Spec) + if err := crImportFromJSON(filepath.Join(dir, "spec.dump"), spec); err != nil { + return nil, err + } + + // Load config.dump from temporary directory + config := new(libpod.ContainerConfig) + if err = crImportFromJSON(filepath.Join(dir, "config.dump"), config); err != nil { + return nil, err + } + + // This should not happen as checkpoints with these options are not exported. + if (len(config.Dependencies) > 0) || (len(config.NamedVolumes) > 0) { + return nil, errors.Errorf("Cannot import checkpoints of containers with named volumes or dependencies") + } + + // Now create a new container from the just loaded information + container, err := runtime.RestoreContainer(ctx, spec, config) + if err != nil { + return nil, err + } + + var containers []*libpod.Container + if container == nil { + return nil, nil + } + + containers = append(containers, container) + return containers, nil +} diff --git a/pkg/adapter/containers.go b/pkg/adapter/containers.go index 34ee70d3d..b7f4c272b 100644 --- a/pkg/adapter/containers.go +++ b/pkg/adapter/containers.go @@ -526,7 +526,7 @@ func (r *LocalRuntime) Checkpoint(c *cliconfig.CheckpointValues, options libpod. } // Restore one or more containers -func (r *LocalRuntime) Restore(c *cliconfig.RestoreValues, options libpod.ContainerCheckpointOptions) error { +func (r *LocalRuntime) Restore(ctx context.Context, c *cliconfig.RestoreValues, options libpod.ContainerCheckpointOptions) error { var ( containers []*libpod.Container err, lastError error @@ -538,7 +538,9 @@ func (r *LocalRuntime) Restore(c *cliconfig.RestoreValues, options libpod.Contai return state == libpod.ContainerStateExited }) - if c.All { + if c.Import != "" { + containers, err = crImportCheckpoint(ctx, r.Runtime, c.Import) + } else if c.All { containers, err = r.GetContainers(filterFuncs...) } else { containers, err = shortcuts.GetContainersByContext(false, c.Latest, c.InputArgs, r.Runtime) diff --git a/pkg/adapter/containers_remote.go b/pkg/adapter/containers_remote.go index bc6a9cfcd..776fcbb70 100644 --- a/pkg/adapter/containers_remote.go +++ b/pkg/adapter/containers_remote.go @@ -664,6 +664,10 @@ func (r *LocalRuntime) Attach(ctx context.Context, c *cliconfig.AttachValues) er // Checkpoint one or more containers func (r *LocalRuntime) Checkpoint(c *cliconfig.CheckpointValues, options libpod.ContainerCheckpointOptions) error { + if c.Export != "" { + return errors.New("the remote client does not support exporting checkpoints") + } + var lastError error ids, err := iopodman.GetContainersByContext().Call(r.Conn, c.All, c.Latest, c.InputArgs) if err != nil { @@ -699,7 +703,11 @@ func (r *LocalRuntime) Checkpoint(c *cliconfig.CheckpointValues, options libpod. } // Restore one or more containers -func (r *LocalRuntime) Restore(c *cliconfig.RestoreValues, options libpod.ContainerCheckpointOptions) error { +func (r *LocalRuntime) Restore(ctx context.Context, c *cliconfig.RestoreValues, options libpod.ContainerCheckpointOptions) error { + if c.Import != "" { + return errors.New("the remote client does not support importing checkpoints") + } + var lastError error ids, err := iopodman.GetContainersByContext().Call(r.Conn, c.All, c.Latest, c.InputArgs) if err != nil { -- cgit v1.2.3-54-g00ecf