@@ -61,6 +61,10 @@ type TaskSpec struct {

 	// spec. If not present, the one on cluster default on swarm.Spec will be

 	// used, finally falling back to the engine default if not specified.

 	LogDriver *Driver `json:",omitempty"`

+

+	// ForceUpdate is a counter that triggers an update even if no relevant

+	// parameters have been changed.

+	ForceUpdate uint64

 }

 // Resources represents resources (CPU/Memory).

@@ -37,6 +37,7 @@ func newUpdateCommand(dockerCli *command.DockerCli) *cobra.Command {

 	flags.String("image", "", "Service image tag")

 	flags.String("args", "", "Service command args")

 	flags.Bool("rollback", false, "Rollback to previous specification")

+	flags.Bool("force", false, "Force update even if no changes require it")

 	addServiceFlags(cmd, opts)

 	flags.Var(newListOptsVar(), flagEnvRemove, "Remove an environment variable")

@@ -257,6 +258,15 @@ func updateService(flags *pflag.FlagSet, spec *swarm.ServiceSpec) error {

 		return err

 	}

+	force, err := flags.GetBool("force")

+	if err != nil {

+		return err

+	}

+

+	if force {

+		spec.TaskTemplate.ForceUpdate++

+	}

+

 	return nil

 }

@@ -2473,6 +2473,7 @@ _docker_service_update() {

 		--constraint

 		--endpoint-mode

 		--env -e

+		--force

 		--group-add

 		--label -l

 		--limit-cpu

@@ -1185,6 +1185,7 @@ __docker_service_subcommand() {

                 "($help)--arg=[Service command args]:arguments: _normal" \

                 "($help)*--container-label-add=[Add or update container labels]:label: " \

                 "($help)*--container-label-rm=[Remove a container label by its key]:label: " \

+                "($help)--force[Force update]" \

                 "($help)*--group-rm=[Remove previously added user groups from the container]:group:_groups" \

                 "($help)--image=[Service image tag]:image:__docker_repositories" \

                 "($help)--rollback[Rollback to previous specification]" \

@@ -74,6 +74,7 @@ func serviceSpecFromGRPC(spec *swarmapi.ServiceSpec) *types.ServiceSpec {

 			Placement:     placementFromGRPC(spec.Task.Placement),

 			LogDriver:     driverFromGRPC(spec.Task.LogDriver),

 			Networks:      taskNetworks,

+			ForceUpdate:   spec.Task.ForceUpdate,

 		},

 		Networks:     serviceNetworks,

@@ -136,9 +137,10 @@ func ServiceSpecToGRPC(s types.ServiceSpec) (swarmapi.ServiceSpec, error) {

 			Labels: s.Labels,

 		},

 		Task: swarmapi.TaskSpec{

-			Resources: resourcesToGRPC(s.TaskTemplate.Resources),

-			LogDriver: driverToGRPC(s.TaskTemplate.LogDriver),

-			Networks:  taskNetworks,

+			Resources:   resourcesToGRPC(s.TaskTemplate.Resources),

+			LogDriver:   driverToGRPC(s.TaskTemplate.LogDriver),

+			Networks:    taskNetworks,

+			ForceUpdate: s.TaskTemplate.ForceUpdate,

 		},

 		Networks: serviceNetworks,

 	}

@@ -149,6 +149,7 @@ This section lists each version from latest to oldest.  Each listing includes a

   containers that are tasks (part of a service in swarm mode).

 * `POST /containers/create` now takes `StopTimeout` field.

 * `POST /services/create` and `POST /services/(id or name)/update` now accept `Monitor` and `MaxFailureRatio` parameters, which control the response to failures during service updates.

+* `POST /services/(id or name)/update` now accepts a `ForceUpdate` parameter inside the `TaskTemplate`, which causes the service to be updated even if there are no changes which would ordinarily trigger an update.

 * `GET /networks/(name)` now returns field `Created` in response to show network created time.

 * `POST /containers/(id or name)/exec` now accepts an `Env` field, which holds a list of environment variables to be set in the context of the command execution.

 * `GET /volumes`, `GET /volumes/(name)`, and `POST /volumes/create` now return the `Options` field which holds the driver specific options to use for when creating the volume.

@@ -4915,7 +4915,8 @@ List services

               "Condition": "any",

               "MaxAttempts": 0

             },

-            "Placement": {}

+            "Placement": {},

+            "ForceUpdate": 0

           },

           "Mode": {

             "Replicated": {

@@ -5038,7 +5039,8 @@ image](#create-an-image) section for more details.

           "Condition": "on-failure",

           "Delay": 10000000000.0,

           "MaxAttempts": 10

-        }

+        },

+        "ForceUpdate": 0

       },

       "Mode": {

         "Replicated": {

@@ -5132,6 +5134,7 @@ image](#create-an-image) section for more details.

         - **Window** – Windows is the time window used to evaluate the restart policy (default value is

           0, which is unbounded).

     - **Placement** – An array of constraints.

+    - **ForceUpdate**: A counter that triggers an update even if no relevant parameters have been changed.

 - **Mode** – Scheduling mode for the service (`replicated` or `global`, defaults to `replicated`).

 - **UpdateConfig** – Specification for the update strategy of the service.

     - **Parallelism** – Maximum number of tasks to be updated in one iteration (0 means unlimited

@@ -5303,7 +5306,8 @@ image](#create-an-image) section for more details.

           "Condition": "any",

           "MaxAttempts": 0

         },

-        "Placement": {}

+        "Placement": {},

+        "ForceUpdate": 0

       },

       "Mode": {

         "Replicated": {

@@ -5374,6 +5378,7 @@ image](#create-an-image) section for more details.

         - **Window** – Windows is the time window used to evaluate the restart policy (default value is

           0, which is unbounded).

     - **Placement** – An array of constraints.

+    - **ForceUpdate**: A counter that triggers an update even if no relevant parameters have been changed.

 - **Mode** – Scheduling mode for the service (`replicated` or `global`, defaults to `replicated`).

 - **UpdateConfig** – Specification for the update strategy of the service.

     - **Parallelism** – Maximum number of tasks to be updated in one iteration (0 means unlimited

@@ -29,6 +29,7 @@ Options:

       --endpoint-mode string             Endpoint mode (vip or dnsrr)

       --env-add value                    Add or update environment variables (default [])

       --env-rm value                     Remove an environment variable (default [])

+      --force                            Force update even if no changes require it

       --group-add value                  Add additional user groups to the container (default [])

       --group-rm value                   Remove previously added user groups from the container (default [])

       --help                             Print usage

@@ -67,6 +68,12 @@ Updates a service as described by the specified parameters. This command has to

 The parameters are the same as [`docker service create`](service_create.md). Please look at the description there

 for further information.

+Normally, updating a service will only cause the service's tasks to be replaced with new ones if a change to the

+service requires recreating the tasks for it to take effect. For example, only changing the

+`--update-parallelism` setting will not recreate the tasks, because the individual tasks are not affected by this

+setting. However, the `--force` flag will cause the tasks to be recreated anyway. This can be used to perform a

+rolling restart without any changes to the service parameters.

+

 ## Examples

 ### Update a service

@@ -75,6 +82,19 @@ for further information.

 $ docker service update --limit-cpu 2 redis

 ```

+### Perform a rolling restart with no parameter changes

+

+```bash

+$ docker service update --force --update-parallelism 1 --update-delay 30s redis

+```

+

+In this example, the `--force` flag causes the service's tasks to be shut down

+and replaced with new ones even though none of the other parameters would

+normally cause that to happen. The `--update-parallelism 1` setting ensures

+that only one task is replaced at a time (this is the default behavior). The

+`--update-delay 30s` setting introduces a 30 second delay between tasks, so

+that the rolling restart happens gradually.

+

 ### Adding and removing mounts

 Use the `--mount-add` or `--mount-rm` options add or remove a service's bind-mounts