Support for Data URIs about ipxe HOT 5 OPEN

Related RFC for Data URLs: https://tools.ietf.org/html/rfc2397

It doesn't appear to require a maximum data size, but does specify that some applications that use URLs may impose length limits, so it seems like there is flexibility here to provide limits.

AWS user-data is limited to 16KB, a similar limitation here might make sense.

from ipxe.

What kind of content do you have in mind, and what is the maximum data size that would need to be supported?

from ipxe.

I'm also exploring this data-uri concept from the other side at tinkerbell/smee#110.

from ipxe.

Equinix Metal (formerly Packet) offers a IPXEScriptURL parameter during device creation. I have a gist conversation at https://gist.github.com/displague/5282172449a83c7b83821f8f8333a072 where I have been exploring the capabilities of this feature.

The contents of the data-uri, in this case, would be additional configuration, for example:

dhcp net0

kernel https://mirror.openshift.com/pub/openshift-v4/x86_64/dependencies/rhcos/pre-release/latest-4.6/rhcos-live-kernel-x86_64 console=ttyS1,115200n8 initrd=rhcos-live-initramfs.x86_64.img coreos.live.rootfs_url=http://mirror.openshift.com/pub/openshift-v4/x86_64/dependencies/rhcos/pre-release/latest-4.6/rhcos-live-rootfs.x86_64.img coreos.inst.install_dev=/dev/sda rd.net.timeout.carrier=30 coreos.inst.platform_id=packet

initrd https://mirror.openshift.com/pub/openshift-v4/x86_64/dependencies/rhcos/pre-release/latest-4.6/rhcos-live-initramfs.x86_64.img

boot

I don't know how large configurations like this typically get, in the gist I had several commented out lines and variable declarations that I've removed in this example.

1K seems like too little, does 4K seem sufficient? I can't imagine trying to shim binary images in as a data-uri.

Am I misrepresenting IPXE's role here? Is the existing HTTP support used for chaining additional configuration, or is it only used for pulling binary boot resources?

from ipxe.

You can chain into a different script yes: https://ipxe.org/cmd/chain
That is how the first script is loaded and executed, just that the chain is internal.
If you have a script, it would not make much sense to embed another script as data-uri

I could see a usage such as startnet.cmd when using wimboot,
Or maybe chainloaded configurations for other kernels.
But not as an embeded script inside a script.

Size might be an issue, on different levels, not sure how IPXEScriptURL is done, but if it is in dhcp packet, then you have a somewhat to small limit there.

from ipxe.