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OVIRT-VMCONSOLE

Copr build status

OUTLINE

ovirt-vmconsole enables secure access to virtual machine serial console. It uses SSH protocol to tunnel the console from customer to destination host.

Two components are available:

ovirt-vmconsole-host

ssh daemon implementation that runs on the host end enables trusted connections to access the consoles. Consoles are assumed to be unix domain sockets that are directly attached to qemu virtual serial.

ovirt-vmconsole-proxy

ssh daemon implementation that runs on the end user accessible host, users access the proxy, based on their public key the authorized consoles are fetch from a manager, once selected a connection to the host is established.

The ovirt-vmconsole package cannot be used as-is, it requires customization to fetch users' authorized keys and users' authorized consoles.

SERVICES

  • ovirt-vmconsole-host-sshd
  • ovirt-vmconsole-proxy-sshd

USAGE

Access to proxy by user is perform using the following command, a menu with the available consoles will be presented:

$ ssh -t -p 2222 ovirt-vmconsole@proxy-host connect

Access to specify console can be done using the following command:

$ ssh -t -p 2222 ovirt-vmconsole@proxy-host connect --vm-id=1E12DF323

List available consoles:

$ ssh -p 2222 ovirt-vmconsole@proxy-host list

Usage:

$ ssh -p 2222 ovirt-vmconsole@proxy-host -- --help

IMPLEMENTATION

ssh daemon implementation is based on system provided openssh, daemon is running under non privileged user. No root access is used.

INSTALLATION

PKI ARTIFACTS

PKI artifacts are located at:

/etc/pki/ovirt-vmconsole

Mode Owner File Notes
0644 root ca.pub
0600 ovirt-vmconsole host-ssh_host_rsa
0644 root host-ssh_host_rsa-cert.pub principal:fqdn
0600 ovirt-vmconsole proxy-ssh_host_rsa
0644 root proxy-ssh_host_rsa-cert.pub principal:fqdn
0600 ovirt-vmconsole proxy-ssh_user_rsa
0644 root proxy-ssh_user_rsa-cert.pub principal:ovirt-vmconsole-proxy

CONSOLES

By default consoles' usocks are assumed to be at:

/var/run/ovirt-vmconsole-console/

CONFIGURATION

Configuration is located at the following directory, Conf.d structure, sorted by file name, last wins.

/etc/ovirt-vmconsole/ovirt-vmconsole-{host,proxy}/conf.d

Packages should at least modify the following proxy configuration, refer to README.API:

  • key_list - get a list of authorized keys.
  • console_list - get a list of authorized consoles.

PROBLEM DETERMINATION

LOGS

Logs are sent to system log, if you enable debug make sure syslog daemon writes log records.

Enable log for specific user session can be done using:

$ ssh -t -p 2222 ovirt-vmconsole@proxy-host -- --debug connect

TEST

Create a socket s1 to emulate qemu, Ctrl-A to escape.

socat -,raw,echo=0,escape=1 UNIX-LISTEN:/var/run/ovirt-vmconsole-console/s1,user=ovirt-vmconsole

CUSTOMIZATION

It could be needed to change the TCP port the serial-console infrastructure uses to connect to emulated serial ports. This can be done manually, but it is not recommended way since it may easily broken by updates.

  1. Override on each virtualization host the default sshd options using the OPTIONS variable at:

    /etc/sysconfig/ovirt-vmconsole-host-sshd

  2. On the proxy host, edit

    /etc/sysconfig/ovirt-vmconsole-proxy-sshd

    You can create the file mentioned here and in the above bullet point if missing; check https://www.freedesktop.org/software/systemd/man/systemd.exec.html for further details.

  3. On the proxy host, also override the ssh options by dropping a new file in the /etc/ovirt-vmconsole/ovirt-vmconsole-proxy/conf.d/ directory, like

    /etc/ovirt-vmconsole/ovirt-vmconsole-proxy/conf.d/90-custom-options.conf

Use this option:

console_attach_ssh_args=""

  1. On the proxy host, SELinux should be customized:
# semanage port -a -t ovirt_vmconsole_proxy_port_t -p tcp XXX
  1. On each affected virtualization host, SELinux should be customized as well:
# semanage port -a -t ovirt_vmconsole_host_port_t -p tcp XXX