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).