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d75cf587ef
Made small adjustment to make it clear that 0.8.7 would require the legacy syntax and that the deprecation notice was more about the legacy syntax becoming unsupported at some point after v0.9.0
146 lines
4.2 KiB
Markdown
146 lines
4.2 KiB
Markdown
---
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layout: "docs"
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page_title: "Drivers: Raw Exec"
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sidebar_current: "docs-drivers-raw-exec"
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description: |-
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The Raw Exec task driver simply fork/execs and provides no isolation.
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---
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# Raw Fork/Exec Driver
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Name: `raw_exec`
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The `raw_exec` driver is used to execute a command for a task without any
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isolation. Further, the task is started as the same user as the Nomad process.
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As such, it should be used with extreme care and is disabled by default.
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## Task Configuration
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```hcl
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task "webservice" {
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driver = "raw_exec"
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config {
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command = "my-binary"
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args = ["-flag", "1"]
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}
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}
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```
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The `raw_exec` driver supports the following configuration in the job spec:
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* `command` - The command to execute. Must be provided. If executing a binary
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that exists on the host, the path must be absolute. If executing a binary that
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is downloaded from an [`artifact`](/docs/job-specification/artifact.html), the
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path can be relative from the allocation's root directory.
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* `args` - (Optional) A list of arguments to the `command`. References
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to environment variables or any [interpretable Nomad
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variables](/docs/runtime/interpolation.html) will be interpreted before
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launching the task.
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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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task "example" {
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driver = "raw_exec"
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config {
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# When running a binary that exists on the host, the path must be absolute/
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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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```
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To execute a binary downloaded from an [`artifact`](/docs/job-specification/artifact.html):
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```
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task "example" {
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driver = "raw_exec"
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config {
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command = "name-of-my-binary"
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}
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artifact {
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source = "https://internal.file.server/name-of-my-binary"
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options {
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checksum = "sha256:abd123445ds4555555555"
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}
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}
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}
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```
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## Client Requirements
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The `raw_exec` driver can run on all supported operating systems. For security
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reasons, it is disabled by default. To enable raw exec, the Nomad client
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configuration must explicitly enable the `raw_exec` driver in the plugin's options:
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```
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plugin "raw_exec" {
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config {
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enabled = true
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}
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}
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```
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Nomad versions before v0.9 use the folowing client configuration. This configuration is
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also supported in Nomad v0.9.0, but is deprecated in favor of the plugin stanza:
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```
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client {
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options = {
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"driver.raw_exec.enable" = "1"
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}
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}
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```
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## Plugin Options
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* `enabled` - Specifies whether the driver should be enabled or disabled.
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Defaults to `false`.
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* `no_cgroups` - Specifies whether the driver should not use
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cgroups to manage the process group launched by the driver. By default,
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cgroups are used to manage the process tree to ensure full cleanup of all
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processes started by the task. The driver only uses cgroups when Nomad is
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launched as root, on Linux and when cgroups are detected.
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## Client Options
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~> Note: client configuration options will soon be deprecated. Please use
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[plugin options][plugin-options] instead. See the [plugin stanza][plugin-stanza] documentation for more information.
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* `driver.raw_exec.enable` - Specifies whether the driver should be enabled or
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disabled. Defaults to `false`.
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* `driver.raw_exec.no_cgroups` - Specifies whether the driver should not use
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cgroups to manage the process group launched by the driver. By default,
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cgroups are used to manage the process tree to ensure full cleanup of all
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processes started by the task. The driver only uses cgroups when Nomad is
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launched as root, on Linux and when cgroups are detected.
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## Client Attributes
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The `raw_exec` driver will set the following client attributes:
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* `driver.raw_exec` - This will be set to "1", indicating the driver is available.
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## Resource Isolation
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The `raw_exec` driver provides no isolation.
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If the launched process creates a new process group, it is possible that Nomad
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will leak processes on shutdown unless the application forwards signals
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properly. Nomad will not leak any processes if cgroups are being used to manage
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the process tree. Cgroups are used on Linux when Nomad is being run with
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appropriate privileges, the cgroup system is mounted and the operator hasn't
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disabled cgroups for the driver.
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[plugin-options]: #plugin-options
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[plugin-stanza]: /docs/configuration/plugin.html
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