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docs | Drivers: Raw Exec | docs-devices-nvidia | The Raw Exec task driver simply fork/execs and provides no isolation. |
Raw Fork/Exec Driver
Name: raw_exec
The raw_exec
driver is used to execute a command for a task without any
isolation. Further, the task is started as the same user as the Nomad process.
As such, it should be used with extreme care and is disabled by default.
Task Configuration
task "webservice" {
driver = "raw_exec"
config {
command = "my-binary"
args = ["-flag", "1"]
}
}
The raw_exec
driver supports the following configuration in the job spec:
-
command
- The command to execute. Must be provided. If executing a binary that exists on the host, the path must be absolute. If executing a binary that is downloaded from anartifact
, the path can be relative from the allocations's root directory. -
args
- (Optional) A list of arguments to thecommand
. References to environment variables or any interpretable Nomad variables will be interpreted before launching the task.
Examples
To run a binary present on the Node:
task "example" {
driver = "raw_exec"
config {
# When running a binary that exists on the host, the path must be absolute/
command = "/bin/sleep"
args = ["1"]
}
}
To execute a binary downloaded from an artifact
:
task "example" {
driver = "raw_exec"
config {
command = "name-of-my-binary"
}
artifact {
source = "https://internal.file.server/name-of-my-binary"
options {
checksum = "sha256:abd123445ds4555555555"
}
}
}
Client Requirements
The raw_exec
driver can run on all supported operating systems. For security
reasons, it is disabled by default. To enable raw exec, the Nomad client
configuration must explicitly enable the raw_exec
driver in the client's
options:
client {
options = {
"driver.raw_exec.enable" = "1"
}
}
Client Options
-
driver.raw_exec.enable
- Specifies whether the driver should be enabled or disabled. -
driver.raw_exec.no_cgroups
- Specifies whether the driver should not use cgroups to manage the process group launched by the driver. By default, cgroups are used to manage the process tree to ensure full cleanup of all processes started by the task. The driver only uses cgroups when Nomad is launched as root, on Linux and when cgroups are detected.
Client Attributes
The raw_exec
driver will set the following client attributes:
driver.raw_exec
- This will be set to "1", indicating the driver is available.
Resource Isolation
The raw_exec
driver provides no isolation.
If the launched process creates a new process group, it is possible that Nomad will leak processes on shutdown unless the application forwards signals properly. Nomad will not leak any processes if cgroups are being used to manage the process tree. Cgroups are used on Linux when Nomad is being run with appropriate priviledges, the cgroup system is mounted and the operator hasn't disabled cgroups for the driver.