Overview: files
Advanced configuration (cfg-file) man page of qemu-init(5)
Basic configuration (rc-file)
The rc-file is required by each virtual machine handled by qemu-init. The format is KEY=VALUE . It will be read line sequential by qemud-cfg, lines starting with a '#\ ' will be ignored. If a value is empty or 0 (zero), the key will not be set. Exception: the keys NAME and TGTARCH MUST contain a valid value. There are a lot of comments and instructions for the keys in the rc-file itself.
The following table gives an overview and additional information1).
| Key | Severity | Description | |||
|---|---|---|---|---|---|
| Section 1: | NAME is the interface between qemu-init and qemu | ||||
| NAME | required | Set the <name> of the guest and the qemu option -name a) |
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| DESC | optional | optional, used by qemu-init for informational purposes only (extends NAME) | |||
| Section 2: | core settings for qemu | ||||
| TGTARCH | required | Set the target arch binary for qemu (default: qemu-system-x86_64 ) b) |
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| RUNAS | optional | Define a different user than SYSUSR to be used with qemu's option -runas (default: empty) |
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| DAEMON | recommended | Run in daemon mode, does set qemu's option -daemonize (default: true c)) |
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| KVM | recommended | Set the qemu option -enable-kvm (default: true c)) |
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| | |
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| Section 3: | options to control qemu-init | ||||
| BOOTDELAY | optional | Define timeout in seconds before the virtual machine starts - takes effect with “autostart” only | |||
| STOPDELAY | optional | Define timeout in seconds qemu-init will wait for shutdown of <name> (default: empty, lower values than 40 will be ignored) | |||
| PRECMD | optional | A command\ *) which will be executed before the virtual machine starts | |||
| POSTCMD | optional | A command\ *) which will be executed after the virtual machine was started | |||
| Section 4: | mainboard style qemu options | ||||
| RAM | recommended | Define the size of RAM (default: 2GB), set via qemu's option -m |
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| DISPLAY | recommended | Set the qemu option -display vnc:=<port> , commonly for administrative purposes (default, the <port> will be calculated) |
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| VNCKEYB | optional | Set a keyboard layout for vnc via qemu's option -k , takes effect with DISPLAY=“vnc” only |
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| Section 5: | default built-in hardware d) | ||||
| DSK | recommended | Use a harddisk with -drive file=<name>-sda.img,snapshot=off |
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| CDR | recommended | Create a CD-drive with qemu's option -drive media=cdrom,file=<VALUE> ; if <VALUE> is invalid, the drive is empty. |
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| NIC | recommended | Define a qemu network driver to create a tap device for bridged networking (default: virtio-net-pci)\ *) | |||
a)\ the qemu option -name should not be used elsewhere
b)\ if this differs from the host architecture, the qemu option -cpu have to be set in cfg-file accordingly
c)\ boolean variable: if not true it defaults to false; values to be true are: 1, on, y, yes (case insensitive)
d)\ key names in this section could be used multiple times, each key creates one device (DSK values couldn't be used twice)
qemu-init does set some qemu options2) automatically. Some depend on other keys of the rc-file, some are build-in defaults. If any of these qemu options appears in the cfg-file, it will not be used:
- the cpu will be set to
-cpu hostby - boot parameters are
-boot order=dc,menu=off -no-fd-bootchk - a mouse will be created automatically with
-usb -device usb-tabletif DISPLAY=“vnc”
Some more info to elected keys:
PRECMD / POSTCMD
Both keys works in the same way (simply replace pre by post). Single commands have to be quoted properly :
PRECMD="cp /usr/local/lib/ovmf-x64/OVMF_VARS-pure-efi.fd /tmp/my_vars.fd"
Multiple commands can be put in a batch file, one per line. A batch file does not require to have the executable bit set. It have to be defined with an absolute path is required:
PRECMD=/path/to/<name>-pre.cmd
Batch files could be shared between multiple guests. If a batch file belongs to a dedicated virtual machine only, it should be called <name>-pre.cmd (recommened).
NIC's
All NIC's defined in the rc-file will be handled as tap devices (for bridged networking). The host bridge device have to exist, and
- the default name of the bridge device is br0 on linux and bridge0 on (Free)BSD
- the number of NIC's is limited to 100 per guest
- qemu-init does calculate a unique mac address for all NIC's interfaces (prefix is always
DE:BE)
The qemu parameter to create a NIC is like:
-device virtio-net-pci,netdev=net0,mac=DE:AD:BE:EF:37:36 -netdev tap,id=net0,script=/usr/local/lib/qemud-br0
The driver virtio-net-pci comes from the rc-file. net0 will be increased by 1 for each NIC, script= is not set on (Free)BSD.