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moby--moby/integration-cli/docker_cli_update_unix_test.go
Sebastiaan van Stijn d2e23405be
Set minimum memory limit to 6M, to account for higher startup memory use
For some time, we defined a minimum limit for `--memory` limits to account for
overhead during startup, and to supply a reasonable functional container.

Changes in the runtime (runc) introduced a higher memory footprint during container
startup, which now lead to obscure error-messages that are unfriendly for users:

    run --rm --memory=4m alpine echo success
    docker: Error response from daemon: OCI runtime create failed: container_linux.go:349: starting container process caused "process_linux.go:449: container init caused \"process_linux.go:415: setting cgroup config for procHooks process caused \\\"failed to write \\\\\\\"4194304\\\\\\\" to \\\\\\\"/sys/fs/cgroup/memory/docker/1254c8d63f85442e599b17dff895f4543c897755ee3bd9b56d5d3d17724b38d7/memory.limit_in_bytes\\\\\\\": write /sys/fs/cgroup/memory/docker/1254c8d63f85442e599b17dff895f4543c897755ee3bd9b56d5d3d17724b38d7/memory.limit_in_bytes: device or resource busy\\\"\"": unknown.
    ERRO[0000] error waiting for container: context canceled

Containers that fail to start because of this limit, will not be marked as OOMKilled,
which makes it harder for users to find the cause of the failure.

Note that _after_ this memory is only required during startup of the container. After
the container was started, the container may not consume this memory, and limits
could (manually) be lowered, for example, an alpine container running only a shell
can run with 512k of memory;

    echo 524288  > /sys/fs/cgroup/memory/docker/acdd326419f0898be63b0463cfc81cd17fb34d2dae6f8aa3768ee6a075ca5c86/memory.limit_in_bytes

However, restarting the container will reset that manual limit to the container's
configuration. While `docker container update` would allow for the updated limit to
be persisted, (re)starting the container after updating produces the same error message
again, so we cannot use different limits for `docker run` / `docker create` and `docker update`.

This patch raises the minimum memory limnit to 6M, so that a better error-message is
produced if a user tries to create a container with a memory-limit that is too low:

    docker create --memory=4m alpine echo success
    docker: Error response from daemon: Minimum memory limit allowed is 6MB.

Possibly, this constraint could be handled by runc, so that different runtimes
could set a best-matching limit (other runtimes may require less overhead).

Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
2020-07-01 13:29:07 +02:00

337 lines
11 KiB
Go

// +build !windows
package main
import (
"context"
"encoding/json"
"fmt"
"os/exec"
"strings"
"testing"
"time"
"github.com/creack/pty"
"github.com/docker/docker/api/types"
"github.com/docker/docker/client"
"github.com/docker/docker/pkg/parsers/kernel"
"github.com/docker/docker/testutil/request"
"gotest.tools/v3/assert"
)
func (s *DockerSuite) TestUpdateRunningContainer(c *testing.T) {
testRequires(c, DaemonIsLinux)
testRequires(c, memoryLimitSupport)
name := "test-update-container"
dockerCmd(c, "run", "-d", "--name", name, "-m", "300M", "busybox", "top")
dockerCmd(c, "update", "-m", "500M", name)
assert.Equal(c, inspectField(c, name, "HostConfig.Memory"), "524288000")
file := "/sys/fs/cgroup/memory/memory.limit_in_bytes"
out, _ := dockerCmd(c, "exec", name, "cat", file)
assert.Equal(c, strings.TrimSpace(out), "524288000")
}
func (s *DockerSuite) TestUpdateRunningContainerWithRestart(c *testing.T) {
testRequires(c, DaemonIsLinux)
testRequires(c, memoryLimitSupport)
name := "test-update-container"
dockerCmd(c, "run", "-d", "--name", name, "-m", "300M", "busybox", "top")
dockerCmd(c, "update", "-m", "500M", name)
dockerCmd(c, "restart", name)
assert.Equal(c, inspectField(c, name, "HostConfig.Memory"), "524288000")
file := "/sys/fs/cgroup/memory/memory.limit_in_bytes"
out, _ := dockerCmd(c, "exec", name, "cat", file)
assert.Equal(c, strings.TrimSpace(out), "524288000")
}
func (s *DockerSuite) TestUpdateStoppedContainer(c *testing.T) {
testRequires(c, DaemonIsLinux)
testRequires(c, memoryLimitSupport)
name := "test-update-container"
file := "/sys/fs/cgroup/memory/memory.limit_in_bytes"
dockerCmd(c, "run", "--name", name, "-m", "300M", "busybox", "cat", file)
dockerCmd(c, "update", "-m", "500M", name)
assert.Equal(c, inspectField(c, name, "HostConfig.Memory"), "524288000")
out, _ := dockerCmd(c, "start", "-a", name)
assert.Equal(c, strings.TrimSpace(out), "524288000")
}
func (s *DockerSuite) TestUpdatePausedContainer(c *testing.T) {
testRequires(c, DaemonIsLinux)
testRequires(c, cpuShare)
name := "test-update-container"
dockerCmd(c, "run", "-d", "--name", name, "--cpu-shares", "1000", "busybox", "top")
dockerCmd(c, "pause", name)
dockerCmd(c, "update", "--cpu-shares", "500", name)
assert.Equal(c, inspectField(c, name, "HostConfig.CPUShares"), "500")
dockerCmd(c, "unpause", name)
file := "/sys/fs/cgroup/cpu/cpu.shares"
out, _ := dockerCmd(c, "exec", name, "cat", file)
assert.Equal(c, strings.TrimSpace(out), "500")
}
func (s *DockerSuite) TestUpdateWithUntouchedFields(c *testing.T) {
testRequires(c, DaemonIsLinux)
testRequires(c, memoryLimitSupport)
testRequires(c, cpuShare)
name := "test-update-container"
dockerCmd(c, "run", "-d", "--name", name, "-m", "300M", "--cpu-shares", "800", "busybox", "top")
dockerCmd(c, "update", "-m", "500M", name)
// Update memory and not touch cpus, `cpuset.cpus` should still have the old value
out := inspectField(c, name, "HostConfig.CPUShares")
assert.Equal(c, out, "800")
file := "/sys/fs/cgroup/cpu/cpu.shares"
out, _ = dockerCmd(c, "exec", name, "cat", file)
assert.Equal(c, strings.TrimSpace(out), "800")
}
func (s *DockerSuite) TestUpdateContainerInvalidValue(c *testing.T) {
testRequires(c, DaemonIsLinux)
testRequires(c, memoryLimitSupport)
name := "test-update-container"
dockerCmd(c, "run", "-d", "--name", name, "-m", "300M", "busybox", "true")
out, _, err := dockerCmdWithError("update", "-m", "2M", name)
assert.ErrorContains(c, err, "")
expected := "Minimum memory limit allowed is 6MB"
assert.Assert(c, strings.Contains(out, expected))
}
func (s *DockerSuite) TestUpdateContainerWithoutFlags(c *testing.T) {
testRequires(c, DaemonIsLinux)
testRequires(c, memoryLimitSupport)
name := "test-update-container"
dockerCmd(c, "run", "-d", "--name", name, "-m", "300M", "busybox", "true")
_, _, err := dockerCmdWithError("update", name)
assert.ErrorContains(c, err, "")
}
func (s *DockerSuite) TestUpdateKernelMemory(c *testing.T) {
testRequires(c, DaemonIsLinux, kernelMemorySupport)
name := "test-update-container"
dockerCmd(c, "run", "-d", "--name", name, "--kernel-memory", "50M", "busybox", "top")
dockerCmd(c, "update", "--kernel-memory", "100M", name)
assert.Equal(c, inspectField(c, name, "HostConfig.KernelMemory"), "104857600")
file := "/sys/fs/cgroup/memory/memory.kmem.limit_in_bytes"
out, _ := dockerCmd(c, "exec", name, "cat", file)
assert.Equal(c, strings.TrimSpace(out), "104857600")
}
func (s *DockerSuite) TestUpdateKernelMemoryUninitialized(c *testing.T) {
testRequires(c, DaemonIsLinux, kernelMemorySupport)
isNewKernel := CheckKernelVersion(4, 6, 0)
name := "test-update-container"
dockerCmd(c, "run", "-d", "--name", name, "busybox", "top")
_, _, err := dockerCmdWithError("update", "--kernel-memory", "100M", name)
// Update kernel memory to a running container without kernel memory initialized
// is not allowed before kernel version 4.6.
if !isNewKernel {
assert.ErrorContains(c, err, "")
} else {
assert.NilError(c, err)
}
dockerCmd(c, "pause", name)
_, _, err = dockerCmdWithError("update", "--kernel-memory", "200M", name)
if !isNewKernel {
assert.ErrorContains(c, err, "")
} else {
assert.NilError(c, err)
}
dockerCmd(c, "unpause", name)
dockerCmd(c, "stop", name)
dockerCmd(c, "update", "--kernel-memory", "300M", name)
dockerCmd(c, "start", name)
assert.Equal(c, inspectField(c, name, "HostConfig.KernelMemory"), "314572800")
file := "/sys/fs/cgroup/memory/memory.kmem.limit_in_bytes"
out, _ := dockerCmd(c, "exec", name, "cat", file)
assert.Equal(c, strings.TrimSpace(out), "314572800")
}
// GetKernelVersion gets the current kernel version.
func GetKernelVersion() *kernel.VersionInfo {
v, _ := kernel.ParseRelease(testEnv.DaemonInfo.KernelVersion)
return v
}
// CheckKernelVersion checks if current kernel is newer than (or equal to)
// the given version.
func CheckKernelVersion(k, major, minor int) bool {
return kernel.CompareKernelVersion(*GetKernelVersion(), kernel.VersionInfo{Kernel: k, Major: major, Minor: minor}) >= 0
}
func (s *DockerSuite) TestUpdateSwapMemoryOnly(c *testing.T) {
testRequires(c, DaemonIsLinux)
testRequires(c, memoryLimitSupport)
testRequires(c, swapMemorySupport)
name := "test-update-container"
dockerCmd(c, "run", "-d", "--name", name, "--memory", "300M", "--memory-swap", "500M", "busybox", "top")
dockerCmd(c, "update", "--memory-swap", "600M", name)
assert.Equal(c, inspectField(c, name, "HostConfig.MemorySwap"), "629145600")
file := "/sys/fs/cgroup/memory/memory.memsw.limit_in_bytes"
out, _ := dockerCmd(c, "exec", name, "cat", file)
assert.Equal(c, strings.TrimSpace(out), "629145600")
}
func (s *DockerSuite) TestUpdateInvalidSwapMemory(c *testing.T) {
testRequires(c, DaemonIsLinux)
testRequires(c, memoryLimitSupport)
testRequires(c, swapMemorySupport)
name := "test-update-container"
dockerCmd(c, "run", "-d", "--name", name, "--memory", "300M", "--memory-swap", "500M", "busybox", "top")
_, _, err := dockerCmdWithError("update", "--memory-swap", "200M", name)
// Update invalid swap memory should fail.
// This will pass docker config validation, but failed at kernel validation
assert.ErrorContains(c, err, "")
// Update invalid swap memory with failure should not change HostConfig
assert.Equal(c, inspectField(c, name, "HostConfig.Memory"), "314572800")
assert.Equal(c, inspectField(c, name, "HostConfig.MemorySwap"), "524288000")
dockerCmd(c, "update", "--memory-swap", "600M", name)
assert.Equal(c, inspectField(c, name, "HostConfig.MemorySwap"), "629145600")
file := "/sys/fs/cgroup/memory/memory.memsw.limit_in_bytes"
out, _ := dockerCmd(c, "exec", name, "cat", file)
assert.Equal(c, strings.TrimSpace(out), "629145600")
}
func (s *DockerSuite) TestUpdateStats(c *testing.T) {
testRequires(c, DaemonIsLinux)
testRequires(c, memoryLimitSupport)
testRequires(c, cpuCfsQuota)
name := "foo"
dockerCmd(c, "run", "-d", "-ti", "--name", name, "-m", "500m", "busybox")
assert.NilError(c, waitRun(name))
getMemLimit := func(id string) uint64 {
resp, body, err := request.Get(fmt.Sprintf("/containers/%s/stats?stream=false", id))
assert.NilError(c, err)
assert.Equal(c, resp.Header.Get("Content-Type"), "application/json")
var v *types.Stats
err = json.NewDecoder(body).Decode(&v)
assert.NilError(c, err)
body.Close()
return v.MemoryStats.Limit
}
preMemLimit := getMemLimit(name)
dockerCmd(c, "update", "--cpu-quota", "2000", name)
curMemLimit := getMemLimit(name)
assert.Equal(c, preMemLimit, curMemLimit)
}
func (s *DockerSuite) TestUpdateMemoryWithSwapMemory(c *testing.T) {
testRequires(c, DaemonIsLinux)
testRequires(c, memoryLimitSupport)
testRequires(c, swapMemorySupport)
name := "test-update-container"
dockerCmd(c, "run", "-d", "--name", name, "--memory", "300M", "busybox", "top")
out, _, err := dockerCmdWithError("update", "--memory", "800M", name)
assert.ErrorContains(c, err, "")
assert.Assert(c, strings.Contains(out, "Memory limit should be smaller than already set memoryswap limit"))
dockerCmd(c, "update", "--memory", "800M", "--memory-swap", "1000M", name)
}
func (s *DockerSuite) TestUpdateNotAffectMonitorRestartPolicy(c *testing.T) {
testRequires(c, DaemonIsLinux, cpuShare)
out, _ := dockerCmd(c, "run", "-tid", "--restart=always", "busybox", "sh")
id := strings.TrimSpace(out)
dockerCmd(c, "update", "--cpu-shares", "512", id)
cpty, tty, err := pty.Open()
assert.NilError(c, err)
defer cpty.Close()
cmd := exec.Command(dockerBinary, "attach", id)
cmd.Stdin = tty
assert.NilError(c, cmd.Start())
defer cmd.Process.Kill()
_, err = cpty.Write([]byte("exit\n"))
assert.NilError(c, err)
assert.NilError(c, cmd.Wait())
// container should restart again and keep running
err = waitInspect(id, "{{.RestartCount}}", "1", 30*time.Second)
assert.NilError(c, err)
assert.NilError(c, waitRun(id))
}
func (s *DockerSuite) TestUpdateWithNanoCPUs(c *testing.T) {
testRequires(c, cpuCfsQuota, cpuCfsPeriod)
file1 := "/sys/fs/cgroup/cpu/cpu.cfs_quota_us"
file2 := "/sys/fs/cgroup/cpu/cpu.cfs_period_us"
out, _ := dockerCmd(c, "run", "-d", "--cpus", "0.5", "--name", "top", "busybox", "top")
assert.Assert(c, strings.TrimSpace(out) != "")
out, _ = dockerCmd(c, "exec", "top", "sh", "-c", fmt.Sprintf("cat %s && cat %s", file1, file2))
assert.Equal(c, strings.TrimSpace(out), "50000\n100000")
clt, err := client.NewClientWithOpts(client.FromEnv)
assert.NilError(c, err)
inspect, err := clt.ContainerInspect(context.Background(), "top")
assert.NilError(c, err)
assert.Equal(c, inspect.HostConfig.NanoCPUs, int64(500000000))
out = inspectField(c, "top", "HostConfig.CpuQuota")
assert.Equal(c, out, "0", "CPU CFS quota should be 0")
out = inspectField(c, "top", "HostConfig.CpuPeriod")
assert.Equal(c, out, "0", "CPU CFS period should be 0")
out, _, err = dockerCmdWithError("update", "--cpu-quota", "80000", "top")
assert.ErrorContains(c, err, "")
assert.Assert(c, strings.Contains(out, "Conflicting options: CPU Quota cannot be updated as NanoCPUs has already been set"))
dockerCmd(c, "update", "--cpus", "0.8", "top")
inspect, err = clt.ContainerInspect(context.Background(), "top")
assert.NilError(c, err)
assert.Equal(c, inspect.HostConfig.NanoCPUs, int64(800000000))
out = inspectField(c, "top", "HostConfig.CpuQuota")
assert.Equal(c, out, "0", "CPU CFS quota should be 0")
out = inspectField(c, "top", "HostConfig.CpuPeriod")
assert.Equal(c, out, "0", "CPU CFS period should be 0")
out, _ = dockerCmd(c, "exec", "top", "sh", "-c", fmt.Sprintf("cat %s && cat %s", file1, file2))
assert.Equal(c, strings.TrimSpace(out), "80000\n100000")
}