github.com/kardianos/nomad@v0.1.3-0.20151022182107-b13df73ee850/website/source/docs/drivers/qemu.html.md (about)

     1  ---
     2  layout: "docs"
     3  page_title: "Drivers: Qemu"
     4  sidebar_current: "docs-drivers-qemu"
     5  description: |-
     6    The Qemu task driver is used to run virtual machines using Qemu/KVM.
     7  ---
     8  
     9  # Qemu Driver
    10  
    11  Name: `qemu`
    12  
    13  The `Qemu` driver provides a generic virtual machine runner. Qemu can utilize
    14  the KVM kernel module to utilize hardware virtualization features and provide
    15  great performance. Currently the `Qemu` driver can map a set of ports from the
    16  host machine to the guest virtual machine, and provides configuration for
    17  resource allocation.
    18  
    19  The `Qemu` driver can execute any regular `qemu` image (e.g. `qcow`, `img`,
    20  `iso`), and is currently invoked with `qemu-system-x86_64`.
    21  
    22  ## Task Configuration
    23  
    24  The `Qemu` driver supports the following configuration in the job spec:
    25  
    26  * `image_source` - **(Required)** The hosted location of the source Qemu image. Must be accessible
    27  from the Nomad client, via HTTP.
    28  * `checksum` - **(Required)** The SHA256 checksum of the `qemu` image. If the
    29  checksums do not match, the `Qemu` diver will fail to start the image
    30  * `accelerator` - (Optional) The type of accelerator to use in the invocation.
    31   If the host machine has `Qemu` installed with KVM support, users can specify `kvm` for the `accelerator`. Default is `tcg`
    32  * `host_port` - **(Required)** Port on the host machine to forward to the guest
    33  VM
    34  * `guest_ports` - **(Optional)** Ports on the guest machine that are listening for
    35  traffic from the host. These ports match up with any `ReservedPorts` requested
    36  in the `Task` specification
    37  
    38  ## Client Requirements
    39  
    40  The `Qemu` driver requires Qemu to be installed and in your systems `$PATH`.
    41  The `image_source` must be accessible by the node running Nomad. This can be an
    42  internal source, private to your cluster, but it must be reachable by the client
    43  over HTTP.
    44  
    45  ## Client Attributes
    46  
    47  The `Qemu` driver will set the following client attributes:
    48  
    49  * `driver.qemu` - Set to `1` if Qemu is found on the host node. Nomad determines
    50  this by executing `qemu-system-x86_64 -version` on the host and parsing the output
    51  * `driver.qemu.version` - Version of `qemu-system-x86_64`, ex: `2.4.0`
    52  
    53  ## Resource Isolation
    54  
    55  Nomad uses Qemu to provide full software virtualization for virtual machine
    56  workloads. Nomad can use Qemu KVM's hardware-assisted virtualization to deliver
    57  better performance.
    58  
    59  Virtualization provides the highest level of isolation for workloads that
    60  require additional security, and resources use is constrained by the Qemu
    61  hypervisor rather than the host kernel. VM network traffic still flows through
    62  the host's interface(s).