hypervisor

SmallStack Virtual Machine Hypervisor.

The hypervisor daemon manages virtual machines (VMs). Please read the SmallStack design document to understand the architecture.

Status page

The hypervisor provides a web interface on port 6976 which shows a status page, links to built-in dashboards and access to performance metrics and logs. If hypervisor is running on host myhost then the URL of the main status page is http://myhost:6976/. An RPC over HTTP interface is also provided over the same port.

Startup

Hypervisor is started at boot time, usually by one of the provided init scripts. The hypervisor process is baby-sat by the init script; if the process dies the init script will re-start it. It may be stopped with the command:

service hypervisor stop

which also kills the baby-sitting init script. It may be started with the command:

service hypervisor start

Usage

There are many command-line flags which may change the behaviour of hypervisor but many have defaults which should be adequate for most deployments. Built-in help is available with the command:

hypervisor -h

There are some sub-commands available for special maintenance:

• check-vms: check VM configuration and data files for consistency
• repair-vm-volume-allocations: repair the number of allocated blocks for VM volumes
• run: start the hypervisor. This is the same as not providing a subcommand
• stop: stop the hypervisor without shutting down VMs. The metadata, DHCP and TFTP services will stop
• stop-vms-on-next-stop: signal the hypervisor to cleanly shut down VMs on the next stop

Security

RPC access is restricted using TLS client authentication. Hypervisor expects a root certificate in the file /etc/ssl/CA.pem which it trusts to sign certificates which grant access to methods. It trusts the root certificate in the /etc/ssl/IdentityCA.pem file to sign identity-only certificates.

It also requires a certificate and key which grant it the ability to get images and objects from an imageserver. These should be in the files /etc/ssl/hypervisor/cert.pem and /etc/ssl/hypervisor/key.pem, respectively.

Control

The vm-control utility may be used to create, modify and destroy VMs.

The hyper-control utility is used to perform administrative tasks on the Hypervisor.