The API currently uses the obsolete containers endpoint instead of instances, and has no support for virtual-machines endpoint - https://documentation.ubuntu.com/lxd/en/latest/rest-api/#instances-containers-and-virtual-machines
There is a fork which already implemented this - https://github.com/turtle0x1/php-lxd
EDIT: Forked my own https://github.com/c0rn3j/php-lxd
The API currently uses the obsolete containers endpoint instead of instances, and has no support for virtual-machines endpoint - https://documentation.ubuntu.com/lxd/en/latest/rest-api/#instances-containers-and-virtual-machines
There is a fork which already implemented this - https://github.com/turtle0x1/php-lxd
EDIT: Forked my own https://github.com/c0rn3j/php-lxd