moby/integration/container/daemon_linux_test.go

package container

import (
	"context"
	"fmt"
	"io/ioutil"
	"strconv"
	"strings"
	"testing"

	"github.com/docker/docker/api/types"
	"github.com/docker/docker/api/types/container"
	"github.com/docker/docker/integration-cli/daemon"
	"github.com/stretchr/testify/assert"
	"golang.org/x/sys/unix"
)

// This is a regression test for #36145
// It ensures that a container can be started when the daemon was improperly
// shutdown when the daemon is brought back up.
//
// The regression is due to improper error handling preventing a container from
// being restored and as such have the resources cleaned up.
//
// To test this, we need to kill dockerd, then kill both the containerd-shim and
// the container process, then start dockerd back up and attempt to start the
// container again.
func TestContainerStartOnDaemonRestart(t *testing.T) {
	t.Parallel()

	d := daemon.New(t, "", "dockerd", daemon.Config{})
	d.StartWithBusybox(t, "--iptables=false")
	defer d.Stop(t)

	client, err := d.NewClient()
	assert.NoError(t, err, "error creating client")

	ctx := context.Background()
	c, err := client.ContainerCreate(ctx,
		&container.Config{
			Image: "busybox",
			Cmd:   []string{"top"},
		},
		nil,
		nil,
		"",
	)
	assert.NoError(t, err, "error creating test container")
	defer client.ContainerRemove(ctx, c.ID, types.ContainerRemoveOptions{Force: true})

	err = client.ContainerStart(ctx, c.ID, types.ContainerStartOptions{})
	assert.NoError(t, err, "error starting test container")

	inspect, err := client.ContainerInspect(ctx, c.ID)
	assert.NoError(t, err, "error getting inspect data")

	ppid := getContainerdShimPid(t, inspect)

	err = d.Kill()
	assert.NoError(t, err, "failed to kill test daemon")

	err = unix.Kill(inspect.State.Pid, unix.SIGKILL)
	assert.NoError(t, err, "failed to kill container process")

	err = unix.Kill(ppid, unix.SIGKILL)
	assert.NoError(t, err, "failed to kill containerd-shim")

	d.Start(t, "--iptables=false")

	err = client.ContainerStart(ctx, c.ID, types.ContainerStartOptions{})
	assert.NoError(t, err, "failed to start test container")
}

func getContainerdShimPid(t *testing.T, c types.ContainerJSON) int {
	statB, err := ioutil.ReadFile(fmt.Sprintf("/proc/%d/stat", c.State.Pid))
	assert.NoError(t, err, "error looking up containerd-shim pid")

	// ppid is the 4th entry in `/proc/pid/stat`
	ppid, err := strconv.Atoi(strings.Fields(string(statB))[3])
	assert.NoError(t, err, "error converting ppid field to int")

	assert.NotEqual(t, ppid, 1, "got unexpected ppid")
	return ppid
}