virt-who [-d] [-i INTERVAL] [-o]
- -h, --help
show this help message and exit
- -d, --debug
Enable debugging output
- -o, --one-shot
Send the list of guest IDs and exit immediately
- -i INTERVAL, --interval=INTERVAL
Acquire and send guest information each N seconds; note that this option is recommendation only, requested interval might not been honoured and the actual interval might be longer or shorter depending on backend that is used.
- -p, --print
Print the host/guests association in JSON format to standard output
- -c, --config
Use configuration file directly (will override configuration from other files. 'global' and 'default' sections are not read in files passed in via this option, and are only read from /etc/virt-who.conf). Can be used multiple times. See virt-who-config(5) for details about configuration file format.
virt-who also reads environmental variables. They have the same name as command line arguments but upper-cased, with underscore instead of dash and prefixed with VIRTWHO_ (e.g. VIRTWHO_ONE_SHOT). Empty variables are considered as disabled, non-empty as enabled
virt-who has three modes how it can run:
- 1. one-shot mode
# virt-who -o
In this mode virt-who just sends the host to guest association to the server once and then exits.
- 2. interval mode
# virt-who -i INTERVAL
This is default mode. virt-who will listen to change events (if available) or do a polling with given interval, and will send the host to guest association when it changes. The default polling interval is 3600 seconds and can be changed using "-i INTERVAL" (in seconds).
- 3. print mode
# virt-who -p
This mode is similar to oneshot mode but the host to guest association is not send to server, but printed to standard output instead.
virt-who always writes error output to file /var/log/rhsm/rhsm.log. It also writes the same output to standard error output when started from command line.
virt-who can be started with option "-d" in all modes and with all backends. This option will enable verbose output with more information.
Virt-who may present security concerns in some scenarios because it needs access to every hypervisor in the environment. To minimize security risk, virt-who is a network client, not a server. It only does outbound connections to find and register new hypervisors and does not need access to any virtual machines. To further reduce risk, deploy virt-who in a small virtual machine with a minimal installation and lock it down from any unsolicited inbound network connections.
Here is a list of ports that need to be open for different hypervisors:
VMWare ESX/vCenter: 443/tcp
RHEV-M: 443/tcp or 8443/tcp (depending on version)
libvirt: depending on transport type, default (for remote connections) is qemu over ssh on port 22
local libvirt uses a local connection and doesn't need an open port
virt-who also needs to have access to Subscription Asset Manager, Satellite 5, or Satellite 6. Default port is 443/tcp. All the ports might be changed by system administrators.
Using the same network for machine running virt-who as for hypervisor management software instead of production VM networks is suggested.
Radek Novacek <rnovacek at redhat dot com>