mirror of https://github.com/k3s-io/k3s
150 lines
3.7 KiB
Markdown
150 lines
3.7 KiB
Markdown
# cgroups
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[](https://travis-ci.org/containerd/cgroups)
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[](https://codecov.io/gh/containerd/cgroups)
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[](https://godoc.org/github.com/containerd/cgroups)
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[](https://goreportcard.com/report/github.com/containerd/cgroups)
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Go package for creating, managing, inspecting, and destroying cgroups.
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The resources format for settings on the cgroup uses the OCI runtime-spec found
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[here](https://github.com/opencontainers/runtime-spec).
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## Examples
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### Create a new cgroup
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This creates a new cgroup using a static path for all subsystems under `/test`.
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* /sys/fs/cgroup/cpu/test
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* /sys/fs/cgroup/memory/test
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* etc....
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It uses a single hierarchy and specifies cpu shares as a resource constraint and
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uses the v1 implementation of cgroups.
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```go
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shares := uint64(100)
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control, err := cgroups.New(cgroups.V1, cgroups.StaticPath("/test"), &specs.LinuxResources{
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CPU: &specs.CPU{
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Shares: &shares,
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},
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})
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defer control.Delete()
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```
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### Create with systemd slice support
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```go
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control, err := cgroups.New(cgroups.Systemd, cgroups.Slice("system.slice", "runc-test"), &specs.LinuxResources{
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CPU: &specs.CPU{
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Shares: &shares,
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},
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})
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```
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### Load an existing cgroup
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```go
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control, err = cgroups.Load(cgroups.V1, cgroups.StaticPath("/test"))
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```
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### Add a process to the cgroup
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```go
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if err := control.Add(cgroups.Process{Pid:1234}); err != nil {
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}
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```
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### Update the cgroup
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To update the resources applied in the cgroup
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```go
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shares = uint64(200)
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if err := control.Update(&specs.LinuxResources{
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CPU: &specs.CPU{
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Shares: &shares,
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},
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}); err != nil {
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}
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```
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### Freeze and Thaw the cgroup
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```go
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if err := control.Freeze(); err != nil {
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}
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if err := control.Thaw(); err != nil {
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}
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```
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### List all processes in the cgroup or recursively
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```go
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processes, err := control.Processes(cgroups.Devices, recursive)
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```
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### Get Stats on the cgroup
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```go
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stats, err := control.Stat()
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```
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By adding `cgroups.IgnoreNotExist` all non-existent files will be ignored, e.g. swap memory stats without swap enabled
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```go
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stats, err := control.Stat(cgroups.IgnoreNotExist)
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```
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### Move process across cgroups
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This allows you to take processes from one cgroup and move them to another.
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```go
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err := control.MoveTo(destination)
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```
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### Create subcgroup
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```go
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subCgroup, err := control.New("child", resources)
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```
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### Registering for memory events
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This allows you to get notified by an eventfd for v1 memory cgroups events.
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```go
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event := cgroups.MemoryThresholdEvent(50 * 1024 * 1024, false)
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efd, err := control.RegisterMemoryEvent(event)
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```
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```go
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event := cgroups.MemoryPressureEvent(cgroups.MediumPressure, cgroups.DefaultMode)
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efd, err := control.RegisterMemoryEvent(event)
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```
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```go
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efd, err := control.OOMEventFD()
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// or by using RegisterMemoryEvent
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event := cgroups.OOMEvent()
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efd, err := control.RegisterMemoryEvent(event)
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```
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### Attention
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All static path should not include `/sys/fs/cgroup/` prefix, it should start with your own cgroups name
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## Project details
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Cgroups is a containerd sub-project, licensed under the [Apache 2.0 license](./LICENSE).
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As a containerd sub-project, you will find the:
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* [Project governance](https://github.com/containerd/project/blob/master/GOVERNANCE.md),
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* [Maintainers](https://github.com/containerd/project/blob/master/MAINTAINERS),
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* and [Contributing guidelines](https://github.com/containerd/project/blob/master/CONTRIBUTING.md)
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information in our [`containerd/project`](https://github.com/containerd/project) repository.
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