README
¶
embedshim
The embedshim is the kind of task runtime implementation, which can be used as plugin in containerd.
With current shim design, it is used to manage the lifecycle of container process and allow to be reconnected after containerd restart. The one of the key design elements of a small shim is to be a container process monitoring, at least it is important to containerd created by runC-like runtime.
Without pidfd and ebpf trace point feature, it is unlikely to receive exit notification in time and receive exit code correctly as non-parents after shim dies. And in kubernetes infra, even if the containers in pod can share one shim, the VmRSS of shim(Go Runtime) is still about 8MB.
So, this plugin aims to provide task runtime implementation with pidfd and eBPF sched_process_exit tracepoint to manage deamonless container with low overhead.
Build/Install
The embedshim needs to compile bpf with clang/llvm. So install clang/llvm as first.
$ echo "deb http://apt.llvm.org/focal/ llvm-toolchain-focal main" | sudo tee -a /etc/apt/sources.lis
$ wget -O - https://apt.llvm.org/llvm-snapshot.gpg.key | sudo apt-key add -
$ sudo apt-get update -y
$ sudo apt-get install -y g++ libelf-dev clang lld llvm
And then pull the repo and build it.
$ git clone https://github.com/fuweid/embedshim.git
$ cd embedshim
$ git submodule update --init --recursive
$ make
$ sudo make install
The binary is named by embedshim-containerd which has full functionality in
linux. You can just replace your local containerd with it.
$ sudo install bin/embedshim-containerd $(command -v containerd)
$ sudo systemctl restart containerd
And check plugin with ctr
$ ctr plugin ls | grep embed
io.containerd.runtime.v1 embed linux/amd64 ok
Status
The embedshim supports to run container in headless or with input. But it still works in progress, do not use in production.
- Support Pause/Resume
- Task Event(Create/Start/Exit/Delete/OOM) support
Requirements
- raw tracepoint bpf >= kernel v4.18
- CO-RE BTF vmlinux support >= kernel v5.4
- pidfd polling >= kernel v5.3
License
- The user space components are licensed under the Apache License, Version 2.0.
- The BPF code are under the General Public License, Version 2.0.
Documentation
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Index ¶
- func New(ic *plugin.InitContext) (interface{}, error)
- func NewPlatform() (stdio.Platform, error)
- type CheckpointConfig
- type Config
- type Process
- type TaskManager
- func (manager *TaskManager) Add(ctx context.Context, task runtime.Task) error
- func (manager *TaskManager) Create(ctx context.Context, id string, opts runtime.CreateOpts) (_ runtime.Task, retErr error)
- func (manager *TaskManager) Delete(ctx context.Context, id string)
- func (manager *TaskManager) Get(ctx context.Context, id string) (runtime.Task, error)
- func (*TaskManager) ID() string
- func (manager *TaskManager) Tasks(ctx context.Context, all bool) ([]runtime.Task, error)
Constants ¶
This section is empty.
Variables ¶
This section is empty.
Functions ¶
func New ¶
func New(ic *plugin.InitContext) (interface{}, error)
func NewPlatform ¶
NewPlatform returns a linux platform for use with I/O operations
Types ¶
type CheckpointConfig ¶
type CheckpointConfig struct {
WorkDir string
Path string
Exit bool
AllowOpenTCP bool
AllowExternalUnixSockets bool
AllowTerminal bool
FileLocks bool
EmptyNamespaces []string
}
CheckpointConfig holds task checkpoint configuration
type Process ¶
type Process interface {
// ID returns the id for the process
ID() string
// Pid returns the pid for the process
Pid() int
// ExitStatus returns the exit status
ExitStatus() int
// ExitedAt is the time the process exited
ExitedAt() time.Time
// Stdin returns the process STDIN
Stdin() io.Closer
// Stdio returns io information for the container
Stdio() stdio.Stdio
// Status returns the process status
Status(context.Context) (string, error)
// Wait blocks until the process has exited
Wait()
// Resize resizes the process console
Resize(ws console.WinSize) error
// Start execution of the process
Start(context.Context) error
// Delete deletes the process and its resourcess
Delete(context.Context) error
// Kill kills the process
Kill(context.Context, uint32, bool) error
// SetExited sets the exit status for the process
SetExited(status int)
}
Process on a system
type TaskManager ¶
type TaskManager struct {
// contains filtered or unexported fields
}
func (*TaskManager) Create ¶
func (manager *TaskManager) Create(ctx context.Context, id string, opts runtime.CreateOpts) (_ runtime.Task, retErr error)
func (*TaskManager) ID ¶
func (*TaskManager) ID() string
Source Files
Directories