docker-cli/docs/reference/commandline/service_create.md

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description = "The service create command description and usage"
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# service create

```Markdown
Usage:  docker service create [OPTIONS] IMAGE [COMMAND] [ARG...]

Create a new service

Options:
      --constraint value               Placement constraints (default [])
      --container-label value          Service container labels (default [])
      --endpoint-mode string           Endpoint mode (vip or dnsrr)
  -e, --env value                      Set environment variables (default [])
      --group-add value                Add additional user groups to the container (default [])
      --help                           Print usage
  -l, --label value                    Service labels (default [])
      --limit-cpu value                Limit CPUs (default 0.000)
      --limit-memory value             Limit Memory (default 0 B)
      --log-driver string              Logging driver for service
      --log-opt value                  Logging driver options (default [])
      --mode string                    Service mode (replicated or global) (default "replicated")
      --mount value                    Attach a mount to the service
      --name string                    Service name
      --network value                  Network attachments (default [])
  -p, --publish value                  Publish a port as a node port (default [])
      --replicas value                 Number of tasks (default none)
      --reserve-cpu value              Reserve CPUs (default 0.000)
      --reserve-memory value           Reserve Memory (default 0 B)
      --restart-condition string       Restart when condition is met (none, on-failure, or any)
      --restart-delay value            Delay between restart attempts (default none)
      --restart-max-attempts value     Maximum number of restarts before giving up (default none)
      --restart-window value           Window used to evaluate the restart policy (default none)
      --stop-grace-period value        Time to wait before force killing a container (default none)
      --update-delay duration          Delay between updates
      --update-failure-action string   Action on update failure (pause|continue) (default "pause")
      --update-parallelism uint        Maximum number of tasks updated simultaneously (0 to update all at once) (default 1)
  -u, --user string                    Username or UID (format: <name|uid>[:<group|gid>])
      --with-registry-auth             Send registry authentication details to Swarm agents
  -w, --workdir string                 Working directory inside the container
```

Creates a service as described by the specified parameters. You must run this
command on a manager node.

## Examples

### Create a service

```bash
$ docker service create --name redis redis:3.0.6
dmu1ept4cxcfe8k8lhtux3ro3

$ docker service ls
ID            NAME   REPLICAS  IMAGE        COMMAND
dmu1ept4cxcf  redis  1/1       redis:3.0.6
```

### Create a service with 5 replica tasks (--replicas)

Use the `--replicas` flag to set the number of replica tasks for a replicated
service. The following command creates a `redis` service with `5` replica tasks:

```bash
$ docker service create --name redis --replicas=5 redis:3.0.6
4cdgfyky7ozwh3htjfw0d12qv
```

The above command sets the *desired* number of tasks for the service. Even
though the command returns immediately, actual scaling of the service may take
some time. The `REPLICAS` column shows both the *actual* and *desired* number
of replica tasks for the service.

In the following example the desired state is  `5` replicas, but the current
number of `RUNNING` tasks is `3`:

```bash
$ docker service ls
ID            NAME    REPLICAS  IMAGE        COMMAND
4cdgfyky7ozw  redis   3/5       redis:3.0.7
```

Once all the tasks are created and `RUNNING`, the actual number of tasks is
equal to the desired number:

```bash
$ docker service ls
ID            NAME    REPLICAS  IMAGE        COMMAND
4cdgfyky7ozw  redis   5/5       redis:3.0.7
```

### Create a service with a rolling update policy

```bash
$ docker service create \
  --replicas 10 \
  --name redis \
  --update-delay 10s \
  --update-parallelism 2 \
  redis:3.0.6
```

When you run a [service update](service_update.md), the scheduler updates a
maximum of 2 tasks at a time, with `10s` between updates. For more information,
refer to the [rolling updates
tutorial](../../swarm/swarm-tutorial/rolling-update.md).

### Set environment variables (-e, --env)

This sets environmental variables for all tasks in a service. For example:

```bash
$ docker service create --name redis_2 --replicas 5 --env MYVAR=foo redis:3.0.6
```

### Set metadata on a service (-l, --label)

A label is a `key=value` pair that applies metadata to a service. To label a
service with two labels:

```bash
$ docker service create \
  --name redis_2 \
  --label com.example.foo="bar"
  --label bar=baz \
  redis:3.0.6
```

For more information about labels, refer to [apply custom
metadata](../../userguide/labels-custom-metadata.md).

### Add volumes or bind-mounts

The following table describes the options for defining mounts in a service:

| Option                | Required          | Description
|:----------------------|:------------------|:--------------------------------------------------------------------------------------------------------------------
| **type**              |                   | The type of mount, can be either "volume", or "bind". Defaults to "volume" if no type is specified.<ul><li>`volume`: (default) mounts a [managed volume](volume_create.md) into the container.</li><li>`bind`: bind-mounts a directory or file from the host into the container.</li></ul>
| **src**               | `bind`&nbsp;only  | <ul><li>`type=volume`: Use `src` to specify the name of the volume (e.g., `src=my-volume`). If a volume with the given name does not exist, it is automatically created. If this option is omitted, an ephemeral volume with a random name is generated. Random names are guaranteed to be unique on the host, but may not be unique cluster-wide. Ephemeral volumes have the same lifecycle as the container it is attached to, and are destroyed when the *container* is destroyed (which is upon `service update`, or when scaling or re-balancing the service).</li><li>`type=bind`: Use `src` to specify host-path to bind mount (e.g., `src=/path/on/host/`). When using a bind-mount (`"type=bind"`), the `src` path must be specified as an absolute path, and *must* be a pre-existing path, or an error is produced.</li></ul>
| **source**            |                   | Alias for `src`.
| **dst**               | yes               | Mount path inside the container, for example `/some/path/in/container/`. If the path does not exist in the container's filesystem, the Engine creates a directory at the specified location before mounting the volume or bind-mount.
| **destination**       |                   | Alias for `dst`.
| **target**            |                   | Alias for `dst`.
| **readonly**          |                   | By default, the Engine mounts binds and volumes `read-write`. Pass the `readonly` option to mount the bind or volume `read-only` in the container.<br /><br />A value is optional:<ul><li>`true` or `1`: Default if you do not provide a value. Mounts the bind or volume read-only in the container.</li><li>`false` or `0`: Mounts the bind or volume read-write in the container.</li></ul>
| **ro**                |                   | Alias for `readonly`.

The following options can only be used for bind-mounts (`type=bind`);


| Option                | Description
|:----------------------|:--------------------------------------------------------------------------------------------------------------------
| **bind-propagation**  | Bind propagation options to set on the mount at runtime. Valid options are `shared`, `slave`, `private`, `rshared`, `rslave`, and `rprivate`. Defaults to `rprivate` if not specified. For volumes, bind propagation is not configurable, and also defaults to `rprivate`.


The following options can only be used for named volumes (`type=volume`);

| Option                | Description
|:----------------------|:--------------------------------------------------------------------------------------------------------------------
| **volume-driver**     | Name of the volume-driver plugin to use for the volume. Defaults to the ``"local"`` volume driver to create the volume if it does not exist.
| **volume-label**      | Custom metadata ("labels") to apply to the volume upon creation. Labels are provided as comma-separated list of key/value pairs, for example, `volume-label=hello=world`. For more information about labels, refer to [apply custom metadata](../../userguide/labels-custom-metadata.md).
| **volume-nocopy**     | By default, if you attach an empty volume to a container, the Engine propagates the files and directories that are present at the mount-path (`dst`) inside the container into the volume. Set `volume-nocopy` to disables copying files from the container's filesystem to the volume and mount the empty volume.<br /><br />A value is optional:<ul><li>`true` or `1`: Default if you do not provide a value. Disables copying.</li><li>`false` or `0`: Enables copying.</li></ul>
| **volume-opt**        | Volume driver-specific options to use when creating the volume. Options are provided as comma-separated list of key/value pairs, for example, `volume-opt=some-option=some-value,some-other-option=some-other-value`. For available options, refer to the documentation of the volume driver that is used.

#### Differences between "--mount" and "--volume"

The `--mount` flag features most options that are supported by the `-v` /
`--volume` flag for `docker run`. There are some differences;

- The `--mount` flag allows specifying a volume driver, and volume driver
  options *per volume*, without having to create volumes in advance. When using
  `docker run`, only a single volume driver can be specified (using the
  `--volume-driver` flag), which is shared by all volumes.
- The `--mount` flag allows specifying custom metadata ("labels") for the volume,
  without having to create the volume out of band.
- When using `type=bind`, the host-path must refer to an *existing* path on the
  host, and is not automatically created if the path does not exist. If the
  specified path does not exist on the host, an error is produced, and the
  service will fail to be deployed succesfully.
- The `--mount` flag does not allow you to relabel volumes with `Z` or `z`

#### Create a service using a named volume

The following example creates a service that uses a named volume:

```bash
$ docker service create \
  --name my-service \
  --replicas 3 \
  --mount type=volume,source=my-volume,destination=/path/in/container,volume-label="color=red",volume-label="shape=round" \
  nginx:alpine
```

For each replica of the service, the engine requests a volume named "my-volume"
from the default ("local") volume driver where the task is deployed. If the
volume does not exist, the engine creates a new volume and applies the "color"
and "shape" labels.

When the task is started, the volume is mounted on `/path/in/container/` inside
the container.

Be aware that the default ("local") volume is a locally scoped volume driver.
This means that depending on where a task is deployed, either that task gets a
*new* volume named "my-volume", or shares the same "my-volume" with other tasks
of the same service. Multiple containers writing to a single shared volume can
cause data corruption if the software running inside the container is not
designed to handle concurrent processes writing to the same location. Also take
into account that containers can be re-scheduled by the Swarm orchestrator and
be deployed on a different node.

#### Create a service that uses an anonymous (ephemeral) volume

The following command creates a service with three replicas with an anonymous 
volume on `/path/in/container`:

```bash
$ docker service create \
  --name my-service \
  --replicas 3 \
  --mount type=volume,destination=/path/in/container \
  nginx:alpine
```

In this example, no name (`source`) is specified for the volume, hence a new,
*randomly named* volume is created for each task. This guarantees that each task
gets its own volume, and volumes are not shared between tasks. Unnamed volumes
are considered "ephemeral", and are destroyed when the container is destroyed.

#### Create a service that uses a bind-mounted host directory

The following example bind-mounts a host directory at `/path/in/container` in
the containers backing the service:

```bash
$ docker service create \
  --name my-service \
  --mount type=bind,source=/path/on/host,destination=/path/in/container \
  nginx:alpine
```

### Set service mode (--mode)

You can set the service mode to "replicated" (default) or to "global". A
replicated  service runs the number of replica tasks you specify. A global
service runs on each active node in the swarm.

The following command creates a "global" service:

```bash
$ docker service create \
 --name redis_2 \
 --mode global \
 redis:3.0.6
```

### Specify service constraints (--constraint)

You can limit the set of nodes where a task can be scheduled by defining
constraint expressions. Multiple constraints find nodes that satisfy every
expression (AND match). Constraints can match node or Docker Engine labels as
follows:

| node attribute  | matches                   | example                                         |
|:----------------|:--------------------------|:------------------------------------------------|
| node.id         | node ID                   | `node.id == 2ivku8v2gvtg4`                      |
| node.hostname   | node hostname             | `node.hostname != node-2`                       |
| node.role       | node role: manager        | `node.role == manager`                          |
| node.labels     | user defined node labels  | `node.labels.security == high`                  |
| engine.labels   | Docker Engine's labels    | `engine.labels.operatingsystem == ubuntu 14.04` |

`engine.labels` apply to Docker Engine labels like operating system,
drivers, etc. Swarm administrators add `node.labels` for operational purposes by
using the [`docker node update`](node_update.md) command.

For example, the following limits tasks for the redis service to nodes where the
node type label equals queue:

```bash
$ docker service create \
  --name redis_2 \
  --constraint 'node.labels.type == queue' \
  redis:3.0.6
```

### Attach a service to an existing network (--network)

You can use overlay networks to connect one or more services within the swarm.

First, create an overlay network on a manager node the docker network create
command:

```bash
$ docker network create --driver overlay my-network

etjpu59cykrptrgw0z0hk5snf
```

After you create an overlay network in swarm mode, all manager nodes have
access to the network.

When you create a service and pass the --network flag to attach the service to
the overlay network:

$ docker service create \
  --replicas 3 \
  --network my-network \
  --name my-web \
  nginx

716thylsndqma81j6kkkb5aus
The swarm extends my-network to each node running the service.

Containers on the same network can access each other using
[service discovery](../../swarm/networking.md#use-swarm-mode-service-discovery).

### Publish service ports externally to the swarm (-p, --publish)

You can publish service ports to make them available externally to the swarm
using the `--publish` flag:

```bash
docker service create --publish <TARGET-PORT>:<SERVICE-PORT> nginx
```

For example:

```bash
docker service create --name my_web --replicas 3 --publish 8080:80 nginx
```

When you publish a service port, the swarm routing mesh makes the service
accessible at the target port on every node regardless if there is a task for
the service running on the node. For more information refer to
[Use swarm mode routing mesh](../../swarm/ingress.md).

## Related information

* [service inspect](service_inspect.md)
* [service ls](service_ls.md)
* [service rm](service_rm.md)
* [service scale](service_scale.md)
* [service ps](service_ps.md)
* [service update](service_update.md)

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