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1e07daa680
Updates Qemu, Java drivers to use go-getter to fetch binaries Adds remote artifact support for Exec, Raw Exec drivers
76 lines
2.3 KiB
Markdown
76 lines
2.3 KiB
Markdown
---
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layout: "docs"
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page_title: "Drivers: Exec"
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sidebar_current: "docs-drivers-exec"
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description: |-
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The Exec task driver is used to run binaries using OS isolation primitives.
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---
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# Isolated Fork/Exec Driver
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Name: `exec`
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The `exec` driver is used to simply execute a particular command for a task.
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However unlike [`raw_exec`](raw_exec.html) it uses the underlying isolation
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primitives of the operating system to limit the tasks access to resources. While
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simple, since the `exec` driver can invoke any command, it can be used to call
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scripts or other wrappers which provide higher level features.
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## Task Configuration
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The `exec` driver supports the following configuration in the job spec:
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* `command` - (Required) The command to execute. Must be provided.
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* `artifact_source` – (Optional) Source location of an executable artifact. Must be accessible
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from the Nomad client. If you specify an `artifact_source` to be executed, you
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must reference it in the `command` as show in the examples below
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* `args` - The argument list to the command, space seperated. Optional.
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## Client Requirements
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The `exec` driver can run on all supported operating systems but to provide
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proper isolation the client must be run as root on non-Windows operating systems.
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Further, to support cgroups, `/sys/fs/cgroups/` must be mounted.
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You must specify a `command` to be executed. Optionally you can specify an
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`artifact_source` to be downloaded as well. Any `command` is assumed to be present on the
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running client, or a downloaded artifact.
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## Examples
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To run a binary present on the Node:
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```
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config {
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command = "/bin/sleep"
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args = 1
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}
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```
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To execute a binary specified by `artifact_source`:
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```
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config {
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artifact_source = "https://dl.dropboxusercontent.com/u/1234/binary.bin"
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command = "$NOMAD_TASK_DIR/binary.bin"
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}
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```
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## Client Attributes
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The `exec` driver will set the following client attributes:
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* `driver.exec` - This will be set to "1", indicating the
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driver is available.
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## Resource Isolation
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The resource isolation provided varies by the operating system of
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the client and the configuration.
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On Linux, Nomad will use cgroups, namespaces, and chroot to isolate the
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resources of a process and as such the Nomad agent must be run as root.
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On Windows, the task driver will just execute the command with no additional
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resource isolation.
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