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NAME

hostctl — display or modify contents of the host's key-value store

SYNOPSIS

DESCRIPTION

The hostctl program provides a generic interface for accessing key-value stores on the system's host. It is primarily used for an abstracted way to exchange information with hypervisors that are supported by the pvbus(4) subsystem. When given the name of a specific key, hostctl will display the value or list the key names of the subtree. If the key is followed by a value, hostctl will write the new key-value pair to the key-value store.

The options are as follows:

-f device

Use device instead of the default /dev/pvbus0.

-i input

Read the new value for the specified key from the input file.

-o output

Save the returned value in the output file.

-q

Don't ask for confirmation of any default options.

-t

Print the type of the underlying driver.

Multiple hypervisor interfaces and key-value stores can be simultaneously available and reached through different device nodes.

FILES

/dev/pvbusu

pvbus(4) device unit u file.

EXAMPLES

The vmt(4) driver provides access to the “guestinfo” information that is available in VMware virtual machines:

# hostctl guestinfo.hostname
vm-111.example.com
# hostctl guestinfo.ip 192.168.100.111

The xen(4) driver provides access to the XenStore that is available in Xen virtual machines. The pvbus(4) layer abstracts it as a simple key-value interface:

# hostctl device/vif/0/mac
fe:e1:ba:d0:27:0f
# hostctl device/vif/0/description "My interface"

The XenStore is a virtual filesystem that also provides directories. The directory name can be specified as a key to return the contents, other keys, of the directory:

# hostctl device
vfb
vbd
vif
console

Access to the Hyper-V Key-Value Pair exchange interface is provided by the hyperv(4) driver. The pvbus(4) layer abstracts access to several pre-defined key pools: Auto, Guest, External and Guest/Parameters. Available keys can be listed and set:

# hostctl Auto/
FullyQualifiedDomainName
IntegrationServicesVersion
NetworkAddressIPv4
NetworkAddressIPv6
OSBuildNumber
OSName
OSMajorVersion
OSMinorVersion
OSVersion
ProcessorArchitecture
# hostctl Auto/FullyQualifiedDomainName `hostname`

SEE ALSO

pvbus(4)

HISTORY

The hostctl program first appeared in OpenBSD 5.9.

AUTHORS

The hostctl program was written by Reyk Floeter <reyk@openbsd.org>.