neicnordic/ganeti-os-nocloud

Synopsis

This is a cloud-init OS definition for Ganeti. It injects the meta-data and user-data directly into file system of the target host, to be picked up by the NoCloud data source.

This currently does not work with Rocky 9 cloud images. We have a solution/workaround to be committed soon which will require attaching an generated ISO image on first boot via command line options.

There are plans from the Ganeti project to develop two new providers:

• instance-simpleimage will deploy a fixed image.
• instance-cloudimage will deploy a cloud-init image using metad.

The latter should provide an attractive alternative to the current provider when available.

Usage

Preparation

Obtain cloud-init images for your guest Operating System. The image is expected to be in qcow2 format by default, but other formats supported by qemu-img can be selected by the OS variant definition.

Place the needed cloud-init images to /var/cache/ganeti-cloudimg and distribute them to all nodes. The expected file name of an image is specified in the corresponding configuration file found under /etc/ganeti/nocloud/variants/. To add a missing OS variant, create the configuration file and add the name to /etc/ganeti/nocloud/variants.list. The variant configuration supports the following variables:

• IMAGE_FILE is the filename of the image. This option is required.
• IMAGE_FORMAT is passed to the -f option of qemu-img, by default qcow2.
• IMAGE_DIR is the directory where to look for images, by default /var/cache/ganeti-cloudimg.

Next, put your cloud config data under /etc/ganeti/nocloud/user-data/. The OS creation script will look for ${OS_VARIANT}.yml then default.yml. You may find these cloud-config examples handy. Alternatively provide user data by setting the cloud_userdata OS parameter to a list of sources, see the documentation of this parameter below.

VM Creation

Once the needed image is in place, the VM can be created by specifying nocloud+variant as the OS, where variant is one of /etc/ganeti/nocloud/variants.list:

gnt-instance add -s 7G -o nocloud+ubuntu-18.04 vm1.example.org

Static Network Configuration

For static IP configuration, specify the network and ip parameters for the interface with e.g. --net 0:network=local,ip=172.16.0.20. Also, if you pass -O static_host_interface=0 then all IPs from the DNS A and AAAA records for the host will be added to the first interface, in which case the ip network parameter may be omitted. This allows creating IPv6-only VMs or VMs with multiple IP numbers.

If you also provide the name parameter, the generated network configuration will instruct cloud-init to rename the interface accordingly.

DNS configuration can be passed though the OS parameters dns_nameservers and dns_search which are comma-separated lists of IPs and domains, respectively.

OS Parameters

cloud_userdata

A comma-separate list of user-data sources. The sources will be merged using the cloud-init merging algorithm which can be configured with a merge_how key as documented on that page. The following kinds are supported:

• file:<path> includes the file at <path> on the Ganeti node, which can be absolute or relative to /etc/ganeti/nocloud/user-data.
• script:<path> includes the standard output of running <path> on the Ganeti node. The path is relative to /etc/ganeti/nocloud/user-data if not absolute. To run the script on the VM, use file:<path> instead.
• base64:<data> includes the base 64 decoding of <data>.
• <url> will be delivered to cloud-init as is, where schemes recognized as belonging to URLs include http, https, ftp, sftp, tftp, and scp.

An example user-data/default.yml for Ubuntu can be found in examples/ubuntu.

dns_nameservers and dns_search

Comma-separated lists of name servers and domains to search. These are added to all configured networks.

static_host_interface

If set to a Ganeti network interface number, this interface will be set up to handle the IPv4 and IPv6 addresses associated with the instance name according to DNS.