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moby--moby/daemon/pause.go
Cory Snider 4bafaa00aa Refactor libcontainerd to minimize c8d RPCs
The containerd client is very chatty at the best of times. Because the
libcontained API is stateless and references containers and processes by
string ID for every method call, the implementation is essentially
forced to use the containerd client in a way which amplifies the number
of redundant RPCs invoked to perform any operation. The libcontainerd
remote implementation has to reload the containerd container, task
and/or process metadata for nearly every operation. This in turn
amplifies the number of context switches between dockerd and containerd
to perform any container operation or handle a containerd event,
increasing the load on the system which could otherwise be allocated to
workloads.

Overhaul the libcontainerd interface to reduce the impedance mismatch
with the containerd client so that the containerd client can be used
more efficiently. Split the API out into container, task and process
interfaces which the consumer is expected to retain so that
libcontainerd can retain state---especially the analogous containerd
client objects---without having to manage any state-store inside the
libcontainerd client.

Signed-off-by: Cory Snider <csnider@mirantis.com>
2022-08-24 14:59:08 -04:00

56 lines
1.4 KiB
Go

package daemon // import "github.com/docker/docker/daemon"
import (
"context"
"fmt"
"github.com/docker/docker/container"
"github.com/sirupsen/logrus"
)
// ContainerPause pauses a container
func (daemon *Daemon) ContainerPause(name string) error {
ctr, err := daemon.GetContainer(name)
if err != nil {
return err
}
return daemon.containerPause(ctr)
}
// containerPause pauses the container execution without stopping the process.
// The execution can be resumed by calling containerUnpause.
func (daemon *Daemon) containerPause(container *container.Container) error {
container.Lock()
defer container.Unlock()
// We cannot Pause the container which is not running
tsk, err := container.GetRunningTask()
if err != nil {
return err
}
// We cannot Pause the container which is already paused
if container.Paused {
return errNotPaused(container.ID)
}
// We cannot Pause the container which is restarting
if container.Restarting {
return errContainerIsRestarting(container.ID)
}
if err := tsk.Pause(context.Background()); err != nil {
return fmt.Errorf("cannot pause container %s: %s", container.ID, err)
}
container.Paused = true
daemon.setStateCounter(container)
daemon.updateHealthMonitor(container)
daemon.LogContainerEvent(container, "pause")
if err := container.CheckpointTo(daemon.containersReplica); err != nil {
logrus.WithError(err).Warn("could not save container to disk")
}
return nil
}