weimarnetz / virsh-wrapper

A wrapper to use libvirt-tools in a multi user environment

wirt -- weimarnetz virtualization tool

Be bright and jovial among your guests to-night.
William Shakespeare, "Macbeth"

⚠️ (WIP) ⚠️

For end-user usage, see wirt CLI.

API

how it works?

• file-based: users on host write to their own config files
• pull-based: manager tool reads user's config and acts on it

config:

• endpoint: ~/virsh/ (folder in user's $HOME directory)

filesystem example

~/wirt
│
├── service                 # SERVICES (user can "send" commands to)
│   │ 
│   └── vm                  # vm resources
│       └── mymachine       # example: mymachine
│           ├── config      # settings.json to change
│           ├── destroy     # empty
│           ├── start       # empty
│           └── stop        # empty
│
├── info                    # INFO [host +w, user +r]
│   │
│   └── vm
│       └── mymachine
│           └── status.xml
│
└── logs                    # logs [host +w, user +r]
    │ 
    ├── history/...         # history dump (should be logfile later)
    └── vm
        ├── mymachine.log
        └── mymachine.log.1.tgz

in this version /logs and /info are to be written by the host and read by user, /service is the other way around.

Security

• security/rights management is all handled via unix user&group permissions
• authentication: not integrated in tool (since it's handled by OS)

Resources/Services

from an api perspective, the supported services are resources. for now, only virtual machines (vm) are supported.

Implementation/Node

• user can use cli tool (wirt), see <>.
• this tool can also do admin function (when the user runningn it has the rights)
• current: in the backend, a shell script reads and acts (via cron)
• new: same, but more modular
  • either virsh-wrapper stays monolithic and gets js helper scripts
  • or the main script is js and the virsh-wrapper gets more split up in commands

virsh-wrapper

A wrapper to use libvirt-tools in a multi user environment

###Users

• must be members of a specific group (e. g. vmguests)
• create a directory named virsh with subdirectories log and history
• for every virtual machine (domain) a subdirectory should be created, naming convention: dom-
• change group to vmguests for virsh and all subdirectories and grant read and write permissions to the group
• create a user named wrapper, also a member of vmguests and allow this user to sudo the script
• wrapper ALL=NOPASSWD=/path/to/virsh_wrapper.sh
• in a directory the user creates files named by the action
• for simple commands you only need to touch a file (e.g. start)
• the content of a file is used as parameter, except domain name
• files are processed in descending order of last change time (first in, first out)

###System

• a cronjob runs every x minutes and loops users and directories
• in case of errors a mail is sent to root and the user

Links

• virsh manpage: http://sancho.ccd.uniroma2.it/cgi-bin/man/man2html?virsh+1
• libvirt docs: http://libvirt.org/deployment.html