diff options
Diffstat (limited to 'shim/v1')
| -rw-r--r-- | shim/v1/BUILD | 41 | ||||
| -rw-r--r-- | shim/v1/README.md | 50 | ||||
| -rw-r--r-- | shim/v1/api.go | 24 | ||||
| -rw-r--r-- | shim/v1/config.go | 40 | ||||
| -rw-r--r-- | shim/v1/main.go | 265 |
5 files changed, 420 insertions, 0 deletions
diff --git a/shim/v1/BUILD b/shim/v1/BUILD new file mode 100644 index 000000000..7b837630c --- /dev/null +++ b/shim/v1/BUILD @@ -0,0 +1,41 @@ +load("//tools:defs.bzl", "go_binary") +load("//website:defs.bzl", "doc") + +package(licenses = ["notice"]) + +go_binary( + name = "gvisor-containerd-shim", + srcs = [ + "api.go", + "config.go", + "main.go", + ], + static = True, + visibility = [ + "//visibility:public", + ], + deps = [ + "//pkg/shim/runsc", + "//pkg/shim/v1/shim", + "@com_github_burntsushi_toml//:go_default_library", + "@com_github_containerd_containerd//events:go_default_library", + "@com_github_containerd_containerd//namespaces:go_default_library", + "@com_github_containerd_containerd//runtime/v1/shim/v1:go_default_library", + "@com_github_containerd_containerd//sys:go_default_library", + "@com_github_containerd_containerd//sys/reaper:go_default_library", + "@com_github_containerd_ttrpc//:go_default_library", + "@com_github_containerd_typeurl//:go_default_library", + "@com_github_gogo_protobuf//types:go_default_library", + "@org_golang_x_sys//unix:go_default_library", + ], +) + +doc( + name = "doc", + src = "README.md", + category = "User Guide", + permalink = "/docs/user_guide/gvisor-containerd-shim/", + subcategory = "Advanced", + visibility = ["//website:__pkg__"], + weight = "93", +) diff --git a/shim/v1/README.md b/shim/v1/README.md new file mode 100644 index 000000000..7aa4513a1 --- /dev/null +++ b/shim/v1/README.md @@ -0,0 +1,50 @@ +# gvisor-containerd-shim + +> Note: This shim version is supported only for containerd versions less than +> 1.2. If you are using a containerd version greater than or equal to 1.2, then +> please use `containerd-shim-runsc-v1` (Shim API v1). +> +> This containerd shim is supported only in a best-effort capacity. + +This document describes how to configure and use `gvisor-containerd-shim`. + +## Containerd Configuration + +To use this shim, you must configure `/etc/containerd/config.toml` as follows: + +``` +[plugins.linux] + shim = "/usr/bin/gvisor-containerd-shim" +[plugins.cri.containerd.runtimes.gvisor] + runtime_type = "io.containerd.runtime.v1.linux" + runtime_engine = "/usr/bin/runsc" + runtime_root = "/run/containerd/runsc" +``` + +In order to pick-up the new configuration, you may need to restart containerd: + +```shell +sudo systemctl restart containerd +``` + +## Shim Confguration + +The shim configuration is stored in `/etc/containerd/runsc.toml`. The +configuration file supports two values. + +* `runc_shim`: The path to the runc shim. This is used by + `gvisor-containerd-shim` to run standard containers. + +* `runsc_config`: This is a set of key/value pairs that are converted into + `runsc` command line flags. You can learn more about which flags are + available by running `runsc flags`. + +For example, a configuration might look as follows: + +``` +runc_shim = "/usr/local/bin/containerd-shim" +[runsc_config] +platform = "kvm" +debug = true +debug-log = /var/log/%ID%/gvisor/ +``` diff --git a/shim/v1/api.go b/shim/v1/api.go new file mode 100644 index 000000000..2444d23f1 --- /dev/null +++ b/shim/v1/api.go @@ -0,0 +1,24 @@ +// Copyright 2018 The containerd Authors. +// Copyright 2019 The gVisor Authors. +// +// Licensed under the Apache License, Version 2.0 (the "License"); +// you may not use this file except in compliance with the License. +// You may obtain a copy of the License at +// +// https://www.apache.org/licenses/LICENSE-2.0 +// +// Unless required by applicable law or agreed to in writing, software +// distributed under the License is distributed on an "AS IS" BASIS, +// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. +// See the License for the specific language governing permissions and +// limitations under the License. + +package main + +import ( + shim "github.com/containerd/containerd/runtime/v1/shim/v1" +) + +type KillRequest = shim.KillRequest + +var registerShimService = shim.RegisterShimService diff --git a/shim/v1/config.go b/shim/v1/config.go new file mode 100644 index 000000000..a72cc7754 --- /dev/null +++ b/shim/v1/config.go @@ -0,0 +1,40 @@ +// Copyright 2018 The gVisor Authors. +// +// Licensed under the Apache License, Version 2.0 (the "License"); +// you may not use this file except in compliance with the License. +// You may obtain a copy of the License at +// +// https://www.apache.org/licenses/LICENSE-2.0 +// +// Unless required by applicable law or agreed to in writing, software +// distributed under the License is distributed on an "AS IS" BASIS, +// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. +// See the License for the specific language governing permissions and +// limitations under the License. + +package main + +import "github.com/BurntSushi/toml" + +// config is the configuration for gvisor containerd shim. +type config struct { + // RuncShim is the shim binary path for standard containerd-shim for runc. + // When the runtime is `runc`, gvisor containerd shim will exec current + // process to standard containerd-shim. This is a work around for containerd + // 1.1. In containerd 1.2, containerd will choose different containerd-shims + // based on runtime. + RuncShim string `toml:"runc_shim"` + // RunscConfig is configuration for runsc. The key value will be converted + // to runsc flags --key=value directly. + RunscConfig map[string]string `toml:"runsc_config"` +} + +// loadConfig load gvisor containerd shim config from config file. +func loadConfig(path string) (*config, error) { + var c config + _, err := toml.DecodeFile(path, &c) + if err != nil { + return &c, err + } + return &c, nil +} diff --git a/shim/v1/main.go b/shim/v1/main.go new file mode 100644 index 000000000..3159923af --- /dev/null +++ b/shim/v1/main.go @@ -0,0 +1,265 @@ +// Copyright 2018 The containerd Authors. +// Copyright 2019 The gVisor Authors. +// +// Licensed under the Apache License, Version 2.0 (the "License"); +// you may not use this file except in compliance with the License. +// You may obtain a copy of the License at +// +// https://www.apache.org/licenses/LICENSE-2.0 +// +// Unless required by applicable law or agreed to in writing, software +// distributed under the License is distributed on an "AS IS" BASIS, +// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. +// See the License for the specific language governing permissions and +// limitations under the License. + +package main + +import ( + "bytes" + "context" + "flag" + "fmt" + "log" + "net" + "os" + "os/exec" + "os/signal" + "path/filepath" + "strings" + "sync" + "syscall" + + "github.com/containerd/containerd/events" + "github.com/containerd/containerd/namespaces" + "github.com/containerd/containerd/sys" + "github.com/containerd/containerd/sys/reaper" + "github.com/containerd/ttrpc" + "github.com/containerd/typeurl" + "github.com/gogo/protobuf/types" + "golang.org/x/sys/unix" + + "gvisor.dev/gvisor/pkg/shim/runsc" + "gvisor.dev/gvisor/pkg/shim/v1/shim" +) + +var ( + debugFlag bool + namespaceFlag string + socketFlag string + addressFlag string + workdirFlag string + runtimeRootFlag string + containerdBinaryFlag string + shimConfigFlag string +) + +// Containerd defaults to runc, unless another runtime is explicitly specified. +// We keep the same default to make the default behavior consistent. +const defaultRoot = "/run/containerd/runc" + +func init() { + flag.BoolVar(&debugFlag, "debug", false, "enable debug output in logs") + flag.StringVar(&namespaceFlag, "namespace", "", "namespace that owns the shim") + flag.StringVar(&socketFlag, "socket", "", "abstract socket path to serve") + flag.StringVar(&addressFlag, "address", "", "grpc address back to main containerd") + flag.StringVar(&workdirFlag, "workdir", "", "path used to storge large temporary data") + flag.StringVar(&runtimeRootFlag, "runtime-root", defaultRoot, "root directory for the runtime") + + // Currently, the `containerd publish` utility is embedded in the + // daemon binary. The daemon invokes `containerd-shim + // -containerd-binary ...` with its own os.Executable() path. + flag.StringVar(&containerdBinaryFlag, "containerd-binary", "containerd", "path to containerd binary (used for `containerd publish`)") + flag.StringVar(&shimConfigFlag, "config", "/etc/containerd/runsc.toml", "path to the shim configuration file") +} + +func main() { + flag.Parse() + + // This is a hack. Exec current process to run standard containerd-shim + // if runtime root is not `runsc`. We don't need this for shim v2 api. + if filepath.Base(runtimeRootFlag) != "runsc" { + if err := executeRuncShim(); err != nil { + fmt.Fprintf(os.Stderr, "gvisor-containerd-shim: %s\n", err) + os.Exit(1) + } + } + + // Run regular shim if needed. + if err := executeShim(); err != nil { + fmt.Fprintf(os.Stderr, "gvisor-containerd-shim: %s\n", err) + os.Exit(1) + } +} + +// executeRuncShim execs current process to a containerd-shim process and +// retains all flags and envs. +func executeRuncShim() error { + c, err := loadConfig(shimConfigFlag) + if err != nil && !os.IsNotExist(err) { + return fmt.Errorf("failed to load shim config: %w", err) + } + shimPath := c.RuncShim + if shimPath == "" { + shimPath, err = exec.LookPath("containerd-shim") + if err != nil { + return fmt.Errorf("lookup containerd-shim failed: %w", err) + } + } + + args := append([]string{shimPath}, os.Args[1:]...) + if err := syscall.Exec(shimPath, args, os.Environ()); err != nil { + return fmt.Errorf("exec containerd-shim @ %q failed: %w", shimPath, err) + } + return nil +} + +func executeShim() error { + // start handling signals as soon as possible so that things are + // properly reaped or if runtime exits before we hit the handler. + signals, err := setupSignals() + if err != nil { + return err + } + path, err := os.Getwd() + if err != nil { + return err + } + server, err := ttrpc.NewServer(ttrpc.WithServerHandshaker(ttrpc.UnixSocketRequireSameUser())) + if err != nil { + return fmt.Errorf("failed creating server: %w", err) + } + c, err := loadConfig(shimConfigFlag) + if err != nil && !os.IsNotExist(err) { + return fmt.Errorf("failed to load shim config: %w", err) + } + sv, err := shim.NewService( + shim.Config{ + Path: path, + Namespace: namespaceFlag, + WorkDir: workdirFlag, + RuntimeRoot: runtimeRootFlag, + RunscConfig: c.RunscConfig, + }, + &remoteEventsPublisher{address: addressFlag}, + ) + if err != nil { + return err + } + registerShimService(server, sv) + if err := serve(server, socketFlag); err != nil { + return err + } + return handleSignals(signals, server, sv) +} + +// serve serves the ttrpc API over a unix socket at the provided path this +// function does not block. +func serve(server *ttrpc.Server, path string) error { + var ( + l net.Listener + err error + ) + if path == "" { + l, err = net.FileListener(os.NewFile(3, "socket")) + path = "[inherited from parent]" + } else { + if len(path) > 106 { + return fmt.Errorf("%q: unix socket path too long (> 106)", path) + } + l, err = net.Listen("unix", "\x00"+path) + } + if err != nil { + return err + } + go func() { + defer l.Close() + err := server.Serve(context.Background(), l) + if err != nil && !strings.Contains(err.Error(), "use of closed network connection") { + log.Fatalf("ttrpc server failure: %v", err) + } + }() + return nil +} + +// setupSignals creates a new signal handler for all signals and sets the shim +// as a sub-reaper so that the container processes are reparented. +func setupSignals() (chan os.Signal, error) { + signals := make(chan os.Signal, 32) + signal.Notify(signals, unix.SIGTERM, unix.SIGINT, unix.SIGCHLD, unix.SIGPIPE) + // make sure runc is setup to use the monitor for waiting on processes. + // TODO(random-liu): Move shim/reaper.go to a separate package. + runsc.Monitor = reaper.Default + // Set the shim as the subreaper for all orphaned processes created by + // the container. + if err := unix.Prctl(unix.PR_SET_CHILD_SUBREAPER, 1, 0, 0, 0); err != nil { + return nil, err + } + return signals, nil +} + +func handleSignals(signals chan os.Signal, server *ttrpc.Server, sv *shim.Service) error { + var ( + termOnce sync.Once + done = make(chan struct{}) + ) + + for { + select { + case <-done: + return nil + case s := <-signals: + switch s { + case unix.SIGCHLD: + if _, err := sys.Reap(false); err != nil { + log.Printf("reap error: %v", err) + } + case unix.SIGTERM, unix.SIGINT: + go termOnce.Do(func() { + ctx := context.TODO() + if err := server.Shutdown(ctx); err != nil { + log.Printf("failed to shutdown server: %v", err) + } + // Ensure our child is dead if any. + sv.Kill(ctx, &KillRequest{ + Signal: uint32(syscall.SIGKILL), + All: true, + }) + sv.Delete(context.Background(), &types.Empty{}) + close(done) + }) + case unix.SIGPIPE: + } + } + } +} + +type remoteEventsPublisher struct { + address string +} + +func (l *remoteEventsPublisher) Publish(ctx context.Context, topic string, event events.Event) error { + ns, _ := namespaces.Namespace(ctx) + encoded, err := typeurl.MarshalAny(event) + if err != nil { + return err + } + data, err := encoded.Marshal() + if err != nil { + return err + } + cmd := exec.CommandContext(ctx, containerdBinaryFlag, "--address", l.address, "publish", "--topic", topic, "--namespace", ns) + cmd.Stdin = bytes.NewReader(data) + c, err := reaper.Default.Start(cmd) + if err != nil { + return err + } + status, err := reaper.Default.Wait(cmd, c) + if err != nil { + return fmt.Errorf("failed to publish event: %w", err) + } + if status != 0 { + return fmt.Errorf("failed to publish event: status %d", status) + } + return nil +} |