display or modify contents of the
host's key-value store
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
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
The options are as follows:
- Use device instead of the default /dev/pvbus0.
- Read the new value for the specified key from the input file.
- Save the returned value in the output file.
- Don't ask for confirmation of any default options.
- Print the type of the underlying driver.
Multiple hypervisor interfaces and key-value stores can be simultaneously available and reached through different device nodes.
- pvbus(4) device unit u file.
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`
hostctl program first appeared in
hostctl program was written by