---
layout: docs
page_title: 'Task Driver Plugins: Remote Task Drivers'
description: >-
  Remote Task Drivers support cloud and other nonlocal task runtime
  environments.
---

# Remote Task Drivers

~> **Note:** Remote Task Driver support is experimental and subject to backward
incompatible changes between Nomad releases or deprecation. Please refer to the
[Upgrade Guide][upgrade] to find breaking changes.

~> **Known Bugs:** When a Nomad node running a remote task driver goes down,
another node must be available and able to run the replacement allocation in
order to take advantage of remote task driver's ability to avoid restarting
lost tasks. If a new node is not immediately available but started later,
it will start a new instance of the remote task instead of reconnecting to the
old one. Follow [#10592][gh-10592] for the fix.

Nomad 1.1.0 introduces support for Remote Task Drivers. Remote Task Drivers
allow custom task driver plugins to execute tasks using nonlocal runtimes such
as cloud container runtimes. Without this support, task driver plugins trying
to manage remote tasks would run into the following problems:

1. When [draining][drain] a node, Nomad stops all allocations on that node
   before rescheduling them.

2. When a node is `down`, Nomad reschedules all allocations onto other nodes.

These 2 behaviors are optimal for traditional task drivers where the task
process is colocated with the Nomad agent. If the Nomad node is down or
drained, the allocations should be considered down or be drained as well.

However these 2 behaviors do not apply to tasks executing on remote runtimes.
If the Nomad node managing them goes down, a new Nomad node should be able to
manage them without restarting the task. Likewise if the Nomad node managing
the remote task is drained, a new Nomad node should manage the remote task
without requiring it be stopped and restarted.

The Remote Task Driver feature in Nomad 1.1.0 improves these behaviors for
custom plugins that advertise the [`RemoteTasks` capability][remote-cap].

## Caveats

Due to the exerpimental nature there are a number of standard Nomad features
which Remote Task Drivers do not support by default.

### Resources

~> See [*Remote Task Drivers and Resources* #10549][gh-10549] on Github for
details.  Comments, ideas, and use cases welcome!

The [`resources`][resources] block has not been altered for remote task
drivers. Since remote tasks do not consume local resources, remote task drivers
should not use the existing `resources` block and instead implement their own
resource parameters in their [`task.config`][task-config] block.

Jobs using remote task drivers should use the minimum allowed resources in
their [`task.resources`][resources] block:

```hcl
resources {
  cpu    = 1
  memory = 10
}
```

### Nomad Client Features

Remote task drivers defer most Nomad client features to the driver plugin.

Since the allocation directory is local to the Nomad node, unless a remote task
driver is able to remotely mount or copy its contents, the following features
will be unavailable:

- [`artifact`][artifact] - artifacts are downloaded to the local Nomad
  allocation directory.
- [`dispatch_payload`][dispatch-payload] - dispatch payloads are written to the
  local Nomad allocation directory.
- [`ephemeral_disk`][ephemeral-disk] - ephemeral disks are local to the Nomad
  node and therefore not applicable to remote task drivers.
- [`template`][template] - templates are rendered in the local Nomad allocation
  directory.
- [`vault`][vault] - a secret token may be retrieved but the task driver may
  not place the token file in the expected location.
- [`volume`][volume] - volume and volue mounts assumed tasks have access to the
  Nomad node's local disk are unlikely to work with remote task drivers.

Furthermore since networking is completely handled by the remote runtime the
behavior of the following features is completely driver dependent:

- [`network`][network] - group networks are created on the local Nomad node,
  and task networks are up to the remote task driver to implement.
- [`connect`][connect] - since group networks and sidecars are local to the
  Nomad node, Consul Connect sidecars will not work as expected.

[artifact]: /nomad/docs/job-specification/artifact
[connect]: /nomad/docs/job-specification/connect
[dispatch-payload]: /nomad/docs/job-specification/dispatch_payload
[drain]: /nomad/docs/commands/node/drain
[ephemeral-disk]: /nomad/docs/job-specification/ephemeral_disk
[gh-10549]: https://github.com/hashicorp/nomad/issues/10549
[gh-10592]: https://github.com/hashicorp/nomad/issues/10592
[network]: /nomad/docs/job-specification/network
[remote-cap]: /nomad/docs/concepts/plugins/task-drivers#capabilities-capabilities-error
[resources]: /nomad/docs/job-specification/resources
[task-config]: /nomad/docs/job-specification/task#config
[template]: /nomad/docs/job-specification/template
[upgrade]: /nomad/docs/upgrade/upgrade-specific
[vault]: /nomad/docs/job-specification/vault
[volume]: /nomad/docs/job-specification/volume
