implement podman update

podman update allows users to change the cgroup configuration of an existing container using the already defined resource limits flags
from podman create/run. The supported flags in crun are:

–memory
–cpus
–cpuset-cpus
–cpuset-mems
–memory-swap
–memory-reservation
–cpu-shares
–cpu-quota
–cpu-period
–blkio-weight
–cpu-rt-period
–cpu-rt-runtime
-device-read-bps
-device-write-bps
-device-read-iops
-device-write-iops
-memory-swappiness
-blkio-weight-device

resolves containers#15067

Signed-off-by: Charlie Doern <cdoern@redhat.com>

cmd/podman/common/create.go

@@ -28,10 +28,10 @@ func ContainerToPodOptions(containerCreate *entities.ContainerCreateOptions, pod
 }
 
 // DefineCreateFlags declares and instantiates the container create flags
-func DefineCreateFlags(cmd *cobra.Command, cf *entities.ContainerCreateOptions, isInfra bool, clone bool) {
+func DefineCreateFlags(cmd *cobra.Command, cf *entities.ContainerCreateOptions, mode entities.ContainerMode) {
 	createFlags := cmd.Flags()
 
-	if !isInfra && !clone { // regular create flags
+	if mode == entities.CreateMode { // regular create flags
 		annotationFlagName := "annotation"
 		createFlags.StringSliceVar(
 			&cf.Annotation,
@@ -103,22 +103,6 @@ func DefineCreateFlags(cmd *cobra.Command, cf *entities.ContainerCreateOptions,
 		)
 		_ = cmd.RegisterFlagCompletionFunc(deviceCgroupRuleFlagName, completion.AutocompleteNone)
 
-		deviceReadIopsFlagName := "device-read-iops"
-		createFlags.StringSliceVar(
-			&cf.DeviceReadIOPs,
-			deviceReadIopsFlagName, []string{},
-			"Limit read rate (IO per second) from a device (e.g. --device-read-iops=/dev/sda:1000)",
-		)
-		_ = cmd.RegisterFlagCompletionFunc(deviceReadIopsFlagName, completion.AutocompleteDefault)
-
-		deviceWriteIopsFlagName := "device-write-iops"
-		createFlags.StringSliceVar(
-			&cf.DeviceWriteIOPs,
-			deviceWriteIopsFlagName, []string{},
-			"Limit write rate (IO per second) to a device (e.g. --device-write-iops=/dev/sda:1000)",
-		)
-		_ = cmd.RegisterFlagCompletionFunc(deviceWriteIopsFlagName, completion.AutocompleteDefault)
-
 		createFlags.Bool(
 			"disable-content-trust", false,
 			"This is a Docker specific option and is a NOOP",
@@ -589,7 +573,7 @@ func DefineCreateFlags(cmd *cobra.Command, cf *entities.ContainerCreateOptions,
 			`If a container with the same name exists, replace it`,
 		)
 	}
-	if isInfra || (!clone && !isInfra) { // infra container flags, create should also pick these up
+	if mode == entities.InfraMode || (mode == entities.CreateMode) { // infra container flags, create should also pick these up
 		shmSizeFlagName := "shm-size"
 		createFlags.String(
 			shmSizeFlagName, shmSize(),
@@ -669,7 +653,7 @@ func DefineCreateFlags(cmd *cobra.Command, cf *entities.ContainerCreateOptions,
 		)
 		_ = cmd.RegisterFlagCompletionFunc(cgroupParentFlagName, completion.AutocompleteDefault)
 		var conmonPidfileFlagName string
-		if !isInfra {
+		if mode == entities.CreateMode {
 			conmonPidfileFlagName = "conmon-pidfile"
 		} else {
 			conmonPidfileFlagName = "infra-conmon-pidfile"
@@ -682,7 +666,7 @@ func DefineCreateFlags(cmd *cobra.Command, cf *entities.ContainerCreateOptions,
 		_ = cmd.RegisterFlagCompletionFunc(conmonPidfileFlagName, completion.AutocompleteDefault)
 
 		var entrypointFlagName string
-		if !isInfra {
+		if mode == entities.CreateMode {
 			entrypointFlagName = "entrypoint"
 		} else {
 			entrypointFlagName = "infra-command"
@@ -717,7 +701,7 @@ func DefineCreateFlags(cmd *cobra.Command, cf *entities.ContainerCreateOptions,
 		)
 		_ = cmd.RegisterFlagCompletionFunc(labelFileFlagName, completion.AutocompleteDefault)
 
-		if isInfra {
+		if mode == entities.InfraMode {
 			nameFlagName := "infra-name"
 			createFlags.StringVar(
 				&cf.Name,
@@ -767,7 +751,8 @@ func DefineCreateFlags(cmd *cobra.Command, cf *entities.ContainerCreateOptions,
 		)
 		_ = cmd.RegisterFlagCompletionFunc(volumesFromFlagName, AutocompleteContainers)
 	}
-	if clone || !isInfra { // clone and create only flags, we need this level of separation so clone does not pick up all of the flags
+
+	if mode == entities.CloneMode || mode == entities.CreateMode {
 		nameFlagName := "name"
 		createFlags.StringVar(
 			&cf.Name,
@@ -783,7 +768,8 @@ func DefineCreateFlags(cmd *cobra.Command, cf *entities.ContainerCreateOptions,
 			"Run container in an existing pod",
 		)
 		_ = cmd.RegisterFlagCompletionFunc(podFlagName, AutocompletePods)
-
+	}
+	if mode != entities.InfraMode { // clone create and update only flags, we need this level of separation so clone does not pick up all of the flags
 		cpuPeriodFlagName := "cpu-period"
 		createFlags.Uint64Var(
 			&cf.CPUPeriod,
@@ -832,8 +818,24 @@ func DefineCreateFlags(cmd *cobra.Command, cf *entities.ContainerCreateOptions,
 		)
 		_ = cmd.RegisterFlagCompletionFunc(memorySwappinessFlagName, completion.AutocompleteNone)
 	}
-	// anyone can use these
+	if mode == entities.CreateMode || mode == entities.UpdateMode {
+		deviceReadIopsFlagName := "device-read-iops"
+		createFlags.StringSliceVar(
+			&cf.DeviceReadIOPs,
+			deviceReadIopsFlagName, []string{},
+			"Limit read rate (IO per second) from a device (e.g. --device-read-iops=/dev/sda:1000)",
+		)
+		_ = cmd.RegisterFlagCompletionFunc(deviceReadIopsFlagName, completion.AutocompleteDefault)
 
+		deviceWriteIopsFlagName := "device-write-iops"
+		createFlags.StringSliceVar(
+			&cf.DeviceWriteIOPs,
+			deviceWriteIopsFlagName, []string{},
+			"Limit write rate (IO per second) to a device (e.g. --device-write-iops=/dev/sda:1000)",
+		)
+		_ = cmd.RegisterFlagCompletionFunc(deviceWriteIopsFlagName, completion.AutocompleteDefault)
+	}
+	// anyone can use these
 	cpusFlagName := "cpus"
 	createFlags.Float64Var(
 		&cf.CPUS,

cmd/podman/containers/clone.go

@@ -41,7 +41,7 @@ func cloneFlags(cmd *cobra.Command) {
 	flags.BoolVarP(&ctrClone.Force, forceFlagName, "f", false, "force the existing container to be destroyed")
 
 	common.DefineCreateDefaults(&ctrClone.CreateOpts)
-	common.DefineCreateFlags(cmd, &ctrClone.CreateOpts, false, true)
+	common.DefineCreateFlags(cmd, &ctrClone.CreateOpts, entities.CloneMode)
 }
 func init() {
 	registry.Commands = append(registry.Commands, registry.CliCommand{

cmd/podman/containers/create.go

@@ -72,7 +72,7 @@ func createFlags(cmd *cobra.Command) {
 
 	flags.SetInterspersed(false)
 	common.DefineCreateDefaults(&cliVals)
-	common.DefineCreateFlags(cmd, &cliVals, false, false)
+	common.DefineCreateFlags(cmd, &cliVals, entities.CreateMode)
 	common.DefineNetFlags(cmd)
 
 	flags.SetNormalizeFunc(utils.AliasFlags)

cmd/podman/containers/run.go

@@ -61,7 +61,7 @@ func runFlags(cmd *cobra.Command) {
 
 	flags.SetInterspersed(false)
 	common.DefineCreateDefaults(&cliVals)
-	common.DefineCreateFlags(cmd, &cliVals, false, false)
+	common.DefineCreateFlags(cmd, &cliVals, entities.CreateMode)
 	common.DefineNetFlags(cmd)
 
 	flags.SetNormalizeFunc(utils.AliasFlags)

cmd/podman/containers/update.go

@@ -0,0 +1,83 @@
+package containers
+
+import (
+	"context"
+	"fmt"
+
+	"github.com/containers/podman/v4/cmd/podman/common"
+	"github.com/containers/podman/v4/cmd/podman/registry"
+	"github.com/containers/podman/v4/pkg/domain/entities"
+	"github.com/containers/podman/v4/pkg/specgen"
+	"github.com/containers/podman/v4/pkg/specgenutil"
+	"github.com/opencontainers/runtime-spec/specs-go"
+	"github.com/spf13/cobra"
+)
+
+var (
+	updateDescription = `Updates the cgroup configuration of a given container`
+
+	updateCommand = &cobra.Command{
+		Use:               "update [options] CONTAINER",
+		Short:             "update an existing container",
+		Long:              updateDescription,
+		RunE:              update,
+		Args:              cobra.ExactArgs(1),
+		ValidArgsFunction: common.AutocompleteContainers,
+		Example:           `podman update --cpus=5 foobar_container`,
+	}
+
+	containerUpdateCommand = &cobra.Command{
+		Args:              updateCommand.Args,
+		Use:               updateCommand.Use,
+		Short:             updateCommand.Short,
+		Long:              updateCommand.Long,
+		RunE:              updateCommand.RunE,
+		ValidArgsFunction: updateCommand.ValidArgsFunction,
+		Example:           `podman container update --cpus=5 foobar_container`,
+	}
+)
+var (
+	updateOpts entities.ContainerCreateOptions
+)
+
+func updateFlags(cmd *cobra.Command) {
+	common.DefineCreateDefaults(&updateOpts)
+	common.DefineCreateFlags(cmd, &updateOpts, entities.UpdateMode)
+}
+
+func init() {
+	registry.Commands = append(registry.Commands, registry.CliCommand{
+		Command: updateCommand,
+	})
+	updateFlags(updateCommand)
+
+	registry.Commands = append(registry.Commands, registry.CliCommand{
+		Command: containerUpdateCommand,
+		Parent:  containerCmd,
+	})
+	updateFlags(containerUpdateCommand)
+}
+
+func update(cmd *cobra.Command, args []string) error {
+	var err error
+	// use a specgen since this is the easiest way to hold resource info
+	s := &specgen.SpecGenerator{}
+	s.ResourceLimits = &specs.LinuxResources{}
+
+	// we need to pass the whole specgen since throttle devices are parsed later due to cross compat.
+	s.ResourceLimits, err = specgenutil.GetResources(s, &updateOpts)
+	if err != nil {
+		return err
+	}
+
+	opts := &entities.ContainerUpdateOptions{
+		NameOrID: args[0],
+		Specgen:  s,
+	}
+	rep, err := registry.ContainerEngine().ContainerUpdate(context.Background(), opts)
+	if err != nil {
+		return err
+	}
+	fmt.Println(rep)
+	return nil
+}

cmd/podman/pods/clone.go

@@ -44,7 +44,7 @@ func cloneFlags(cmd *cobra.Command) {
 	_ = podCloneCommand.RegisterFlagCompletionFunc(nameFlagName, completion.AutocompleteNone)
 
 	common.DefineCreateDefaults(&podClone.InfraOptions)
-	common.DefineCreateFlags(cmd, &podClone.InfraOptions, true, false)
+	common.DefineCreateFlags(cmd, &podClone.InfraOptions, entities.InfraMode)
 
 	podClone.InfraOptions.MemorySwappiness = -1 // this is not implemented for pods yet, need to set -1 default manually
 

cmd/podman/pods/create.go

@@ -65,7 +65,7 @@ func init() {
 	flags := createCommand.Flags()
 	flags.SetInterspersed(false)
 	common.DefineCreateDefaults(&infraOptions)
-	common.DefineCreateFlags(createCommand, &infraOptions, true, false)
+	common.DefineCreateFlags(createCommand, &infraOptions, entities.InfraMode)
 	common.DefineNetFlags(createCommand)
 
 	flags.BoolVar(&createOptions.Infra, "infra", true, "Create an infra container associated with the pod to share namespaces with")

docs/source/markdown/.gitignore

@@ -6,3 +6,4 @@ podman-pod-clone.1.md
 podman-pod-create.1.md
 podman-pull.1.md
 podman-run.1.md
+podman-update.1.md

docs/source/markdown/links/podman-container-update.1

@@ -0,0 +1 @@
+.so man1/podman-update.1

docs/source/markdown/options/cpus.md

@@ -0,0 +1,9 @@
+#### **--cpus**=*number*
+
+Number of CPUs. The default is *0.0* which means no limit. This is shorthand
+for **--cpu-period** and **--cpu-quota**, so you may only set either
+**--cpus** or **--cpu-period** and **--cpu-quota**.
+
+On some systems, changing the CPU limits may not be allowed for non-root
+users. For more details, see
+https://github.com/containers/podman/blob/main/troubleshooting.md#26-running-containers-with-cpu-limits-fails-with-a-permissions-error

docs/source/markdown/options/device-read-bps.md

@@ -0,0 +1,3 @@
+#### **--device-read-bps**=*path*
+
+Limit read rate (bytes per second) from a device (e.g. --device-read-bps=/dev/sda:1mb).

docs/source/markdown/options/device-read-iops.md

@@ -0,0 +1,3 @@
+#### **--device-read-iops**=*path:rate*
+
+Limit read rate (in IO operations per second) from a device (e.g. **--device-read-iops=/dev/sda:1000**).

docs/source/markdown/options/device-write-bps.md

@@ -0,0 +1,3 @@
+#### **--device-write-bps**=*path:rate*
+
+Limit write rate (in bytes per second) to a device (e.g. **--device-write-bps=/dev/sda:1mb**).

docs/source/markdown/options/device-write-iops.md

@@ -0,0 +1,3 @@
+#### **--device-write-iops**=*path*
+
+Limit write rate (IO per second) to a device (e.g. --device-write-iops=/dev/sda:1000)

docs/source/markdown/options/memory-reservation.md

@@ -0,0 +1,9 @@
+#### **--memory-reservation**=*limit*
+
+Memory soft limit (format: `<number>[<unit>]`, where unit = b (bytes), k (kibibytes), m (mebibytes), or g (gibibytes))
+
+After setting memory reservation, when the system detects memory contention
+or low memory, containers are forced to restrict their consumption to their
+reservation. So you should always set the value below **--memory**, otherwise the
+hard limit will take precedence. By default, memory reservation will be the same
+as memory limit.

docs/source/markdown/options/memory-swap.md

@@ -0,0 +1,10 @@
+#### **--memory-swap**=*limit*
+
+A limit value equal to memory plus swap. Must be used with the  **-m**
+(**--memory**) flag. The swap `LIMIT` should always be larger than **-m**
+(**--memory**) value. By default, the swap `LIMIT` will be set to double
+the value of --memory.
+
+The format of `LIMIT` is `<number>[<unit>]`. Unit can be `b` (bytes),
+`k` (kibibytes), `m` (mebibytes), or `g` (gibibytes). If you don't specify a
+unit, `b` is used. Set LIMIT to `-1` to enable unlimited swap.

docs/source/markdown/options/memory.md

@@ -0,0 +1,9 @@
+#### **--memory**, **-m**=*limit*
+
+Memory limit (format: `<number>[<unit>]`, where unit = b (bytes), k (kibibytes), m (mebibytes), or g (gibibytes))
+
+Allows you to constrain the memory available to a container. If the host
+supports swap memory, then the **-m** memory setting can be larger than physical
+RAM. If a limit of 0 is specified (not using **-m**), the container's memory is
+not limited. The actual limit may be rounded up to a multiple of the operating
+system's page size (the value would be very large, that's millions of trillions).

docs/source/markdown/podman-container-clone.1.md.in

@@ -50,13 +50,9 @@ If none are specified, the original container's CPU memory nodes are used.
 
 @@option destroy
 
-#### **--device-read-bps**=*path*
+@@option device-read-bps
 
-Limit read rate (bytes per second) from a device (e.g. --device-read-bps=/dev/sda:1mb).
-
-#### **--device-write-bps**=*path*
-
-Limit write rate (bytes per second) to a device (e.g. --device-write-bps=/dev/sda:1mb)
+@@option device-write-bps
 
 #### **--force**, **-f**
 

docs/source/markdown/podman-container.1.md

@@ -46,6 +46,7 @@ The container command allows you to manage containers
 | top        | [podman-top(1)](podman-top.1.md)                    | Display the running processes of a container.                                |
 | unmount    | [podman-unmount(1)](podman-unmount.1.md)            | Unmount a working container's root filesystem.(Alias unmount)                |
 | unpause    | [podman-unpause(1)](podman-unpause.1.md)            | Unpause one or more containers.                                              |
+| update     | [podman-update(1)](podman-update.1.md)              | Updates the cgroup configuration of a given container.                      |
 | wait       | [podman-wait(1)](podman-wait.1.md)                  | Wait on one or more containers to stop and print their exit codes.           |
 
 ## SEE ALSO