205 lines
5.0 KiB
Markdown
205 lines
5.0 KiB
Markdown
# cgroups
|
|
|
|
[](https://github.com/containerd/cgroups/actions?query=workflow%3ACI)
|
|
[](https://codecov.io/gh/containerd/cgroups)
|
|
[](https://godoc.org/github.com/containerd/cgroups)
|
|
[](https://goreportcard.com/report/github.com/containerd/cgroups)
|
|
|
|
Go package for creating, managing, inspecting, and destroying cgroups.
|
|
The resources format for settings on the cgroup uses the OCI runtime-spec found
|
|
[here](https://github.com/opencontainers/runtime-spec).
|
|
|
|
## Examples (v1)
|
|
|
|
### Create a new cgroup
|
|
|
|
This creates a new cgroup using a static path for all subsystems under `/test`.
|
|
|
|
* /sys/fs/cgroup/cpu/test
|
|
* /sys/fs/cgroup/memory/test
|
|
* etc....
|
|
|
|
It uses a single hierarchy and specifies cpu shares as a resource constraint and
|
|
uses the v1 implementation of cgroups.
|
|
|
|
|
|
```go
|
|
shares := uint64(100)
|
|
control, err := cgroups.New(cgroups.V1, cgroups.StaticPath("/test"), &specs.LinuxResources{
|
|
CPU: &specs.LinuxCPU{
|
|
Shares: &shares,
|
|
},
|
|
})
|
|
defer control.Delete()
|
|
```
|
|
|
|
### Create with systemd slice support
|
|
|
|
|
|
```go
|
|
control, err := cgroups.New(cgroups.Systemd, cgroups.Slice("system.slice", "runc-test"), &specs.LinuxResources{
|
|
CPU: &specs.CPU{
|
|
Shares: &shares,
|
|
},
|
|
})
|
|
|
|
```
|
|
|
|
### Load an existing cgroup
|
|
|
|
```go
|
|
control, err = cgroups.Load(cgroups.V1, cgroups.StaticPath("/test"))
|
|
```
|
|
|
|
### Add a process to the cgroup
|
|
|
|
```go
|
|
if err := control.Add(cgroups.Process{Pid:1234}); err != nil {
|
|
}
|
|
```
|
|
|
|
### Update the cgroup
|
|
|
|
To update the resources applied in the cgroup
|
|
|
|
```go
|
|
shares = uint64(200)
|
|
if err := control.Update(&specs.LinuxResources{
|
|
CPU: &specs.LinuxCPU{
|
|
Shares: &shares,
|
|
},
|
|
}); err != nil {
|
|
}
|
|
```
|
|
|
|
### Freeze and Thaw the cgroup
|
|
|
|
```go
|
|
if err := control.Freeze(); err != nil {
|
|
}
|
|
if err := control.Thaw(); err != nil {
|
|
}
|
|
```
|
|
|
|
### List all processes in the cgroup or recursively
|
|
|
|
```go
|
|
processes, err := control.Processes(cgroups.Devices, recursive)
|
|
```
|
|
|
|
### Get Stats on the cgroup
|
|
|
|
```go
|
|
stats, err := control.Stat()
|
|
```
|
|
|
|
By adding `cgroups.IgnoreNotExist` all non-existent files will be ignored, e.g. swap memory stats without swap enabled
|
|
```go
|
|
stats, err := control.Stat(cgroups.IgnoreNotExist)
|
|
```
|
|
|
|
### Move process across cgroups
|
|
|
|
This allows you to take processes from one cgroup and move them to another.
|
|
|
|
```go
|
|
err := control.MoveTo(destination)
|
|
```
|
|
|
|
### Create subcgroup
|
|
|
|
```go
|
|
subCgroup, err := control.New("child", resources)
|
|
```
|
|
|
|
### Registering for memory events
|
|
|
|
This allows you to get notified by an eventfd for v1 memory cgroups events.
|
|
|
|
```go
|
|
event := cgroups.MemoryThresholdEvent(50 * 1024 * 1024, false)
|
|
efd, err := control.RegisterMemoryEvent(event)
|
|
```
|
|
|
|
```go
|
|
event := cgroups.MemoryPressureEvent(cgroups.MediumPressure, cgroups.DefaultMode)
|
|
efd, err := control.RegisterMemoryEvent(event)
|
|
```
|
|
|
|
```go
|
|
efd, err := control.OOMEventFD()
|
|
// or by using RegisterMemoryEvent
|
|
event := cgroups.OOMEvent()
|
|
efd, err := control.RegisterMemoryEvent(event)
|
|
```
|
|
|
|
## Examples (v2/unified)
|
|
|
|
### Check that the current system is running cgroups v2
|
|
|
|
```go
|
|
var cgroupV2 bool
|
|
if cgroups.Mode() == cgroups.Unified {
|
|
cgroupV2 = true
|
|
}
|
|
```
|
|
|
|
### Create a new cgroup
|
|
|
|
This creates a new systemd v2 cgroup slice. Systemd slices consider ["-" a special character](https://www.freedesktop.org/software/systemd/man/systemd.slice.html),
|
|
so the resulting slice would be located here on disk:
|
|
|
|
* /sys/fs/cgroup/my.slice/my-cgroup.slice/my-cgroup-abc.slice
|
|
|
|
```go
|
|
import (
|
|
cgroupsv2 "github.com/containerd/cgroups/v2"
|
|
specs "github.com/opencontainers/runtime-spec/specs-go"
|
|
)
|
|
|
|
res := cgroupsv2.Resources{}
|
|
// dummy PID of -1 is used for creating a "general slice" to be used as a parent cgroup.
|
|
// see https://github.com/containerd/cgroups/blob/1df78138f1e1e6ee593db155c6b369466f577651/v2/manager.go#L732-L735
|
|
m, err := cgroupsv2.NewSystemd("/", "my-cgroup-abc.slice", -1, &res)
|
|
if err != nil {
|
|
return err
|
|
}
|
|
```
|
|
|
|
### Load an existing cgroup
|
|
|
|
```go
|
|
m, err := cgroupsv2.LoadSystemd("/", "my-cgroup-abc.slice")
|
|
if err != nil {
|
|
return err
|
|
}
|
|
```
|
|
|
|
### Delete a cgroup
|
|
|
|
```go
|
|
m, err := cgroupsv2.LoadSystemd("/", "my-cgroup-abc.slice")
|
|
if err != nil {
|
|
return err
|
|
}
|
|
err = m.DeleteSystemd()
|
|
if err != nil {
|
|
return err
|
|
}
|
|
```
|
|
|
|
### Attention
|
|
|
|
All static path should not include `/sys/fs/cgroup/` prefix, it should start with your own cgroups name
|
|
|
|
## Project details
|
|
|
|
Cgroups is a containerd sub-project, licensed under the [Apache 2.0 license](./LICENSE).
|
|
As a containerd sub-project, you will find the:
|
|
|
|
* [Project governance](https://github.com/containerd/project/blob/main/GOVERNANCE.md),
|
|
* [Maintainers](https://github.com/containerd/project/blob/main/MAINTAINERS),
|
|
* and [Contributing guidelines](https://github.com/containerd/project/blob/main/CONTRIBUTING.md)
|
|
|
|
information in our [`containerd/project`](https://github.com/containerd/project) repository.
|