Nomad Docs: Add new QEMU driver parameters

content/nomad/v1.11.x/content/docs/deploy/task-driver/qemu.mdx

@@ -43,22 +43,37 @@ way to retrieve the image being run.
 The `qemu` driver will set the following client attributes:
 
 - `driver.qemu` - Set to `1` if QEMU is found on the host node. Nomad determines
-  this by executing `qemu-system-x86_64 -version` on the host and parsing the output
-- `driver.qemu.version` - Version of `qemu-system-x86_64`, ex: `2.4.0`
+  this by executing the first found QEMU binary with `--version` on the client
+  and parsing the output. Nomad does not get the version of each individual QEMU
+  emulator.
+- `driver.qemu.version` - Version found running the command for `driver.qemu`;
+  for example: `2.4.0`
+- `driver.qemu.emulators` - A comma separated list of emulators detected on the client.
 
 Here is an example of using these properties in a job file:
 
 ```hcl
 job "docs" {
   # Only run this job where the qemu version is higher than 1.2.3.
   constraint {
-    attribute = "${driver.qemu.version}"
+    attribute = "${attr.driver.qemu.version}"
     operator  = ">"
     value     = "1.2.3"
   }
 }
 ```
 
+```hcl
+job "docs" {
+  # Only run this job where the the qemu-system-aarch64 emulator was detected.
+  constraint {
+    attribute = "${attr.driver.qemu.emulators}"
+    operator  = "set_contains"
+    value     = "aarch64"
+  }
+}
+```
+
 ## Plugin Options
 
 ```hcl
@@ -78,6 +93,10 @@ plugin "qemu" {
   including flags that provide the VM with access to host devices such
   as USB drives. Refer to the [QEMU documentation] for the available
   flags.
+- `emulators_allowlist` (`[]string`: `[]`) - Specifies the allowed emulators
+  tasks may use. When specified, Nomad only fingerprints this list and does not
+  allow tasks to run using other emulators. Defaults to fingerprinting and
+  allowing all emulators.
 
 ## Resource Isolation
 

content/nomad/v1.11.x/content/docs/job-declare/task-driver/qemu.mdx

@@ -14,8 +14,9 @@ great performance. Currently the `qemu` driver can map a set of ports from the
 host machine to the guest virtual machine, and provides configuration for
 resource allocation.
 
-The `qemu` driver can execute any regular `qemu` image (e.g. `qcow`, `img`,
-`iso`), and is currently invoked with `qemu-system-x86_64`.
+The `qemu` driver can execute any regular `qemu` image, such as `qcow`, `img`,
+and `iso`. Nomad uses the QEMU binary specified by the `emulator` parameter. For
+example, if you specify `x86_64d, Nomad uses `qemu-system-x86_64`.
 
 The driver requires the image to be accessible from the Nomad client via the
 [`artifact` downloader](/nomad/docs/job-specification/artifact).
@@ -31,6 +32,8 @@ task "webservice" {
 
   config {
     image_path        = "/path/to/my/linux.img"
+    emulator          = "x86_64"
+    machine_type      = "q35"
     accelerator       = "kvm"
     graceful_shutdown = true
     args              = ["-nodefaults", "-nodefconfig"]
@@ -40,10 +43,15 @@ task "webservice" {
 
 The `qemu` driver supports the following configuration in the job spec:
 
-- `image_path` - The path to the downloaded image. In most cases this will just
-  be the name of the image. However, if the supplied artifact is an archive that
-  contains the image in a subfolder, the path will need to be the relative path
-  (`subdir/from_archive/my.img`).
+- `image_path` - The path to the downloaded image. In most cases this is the
+  name of the image. However, if the supplied artifact is an archive that
+  contains the image in a subfolder, the path needs to be the relative path
+  (`subdir/from_archive/my.img`). Nomad gives this image an ID of "image0".
+
+- `emulator` `(string: "x86_64")` - The architecture of the QEMU emulator used to
+  run the virtual machine.
+
+- `machine_type` `(string: "pc")` - Used to select the emulated machine by name.
 
 - `drive_interface` - (Optional) This option defines on which type of interface
   the drive is connected. Available types are: `ide`, `scsi`, `sd`, `mtd`,

content/nomad/v1.11.x/content/docs/upgrade/upgrade-specific.mdx

@@ -14,6 +14,23 @@ used to document those details separately from the standard upgrade flow.
 
 ## Nomad 1.11.1
 
+#### Task config emulators
+
+We added `emulator` and `machine_type` to the task config.
+These default to the previously used values of `qemu-system-x86_64`, and `pc`.
+We also added the `emulators_allowlist` driver config, which defaults to
+allowing any emulator to run.
+
+#### `kvm` accelerator
+
+Previously, using the `kvm` accelerator required a machine type of `host`. This
+is no longer enforced. Nomad now uses the value for `machine_type`. Also, if
+using `resources.cores` with the `kvm` accelerator, Nomad set the `-smp` value
+to the `resources.cores` value. Nomad now only does this when you do not specify
+a custom `-smp` flag.g.
+
+#### QEMU driver
+
 The QEMU driver now uses host file paths for filesystem environment variables
 instead of relative container paths such as `/alloc` and `/local`. You may need
 to update job specs utilizing these variables to reflect the new values.