Added a minimal guide clarifying network based installation

Author: teclator

docs/user/guides/network.md

@@ -0,0 +1,95 @@
+# Agama Network installation
+
+The Agama installer ships as a Live ISO image generated by [kiwi-ng](https://osinside.github.io/kiwi/index.html).
+
+It can be booted directly from an USB stick, CD/DVD or from Network using the initrd and kernel extracted from the ISO as it is documented [here](https://osinside.github.io/kiwi/working_with_images/network_live_iso_boot.html#booting-a-live-iso-image-from-network).
+
+**Note:** As the remote boot process of a live ISO image places the ISO file into a ramdisk by default it is recommended to also extract the compressed root file system (squashfs.img).
+
+Once extracted, these files must be copied to an appropriate location accessible via FTP or HTTP.
+
+```bash
+sudo mount -oro,loop /srv/install/iso/agama-installer.iso /mnt
+sudo cp /mnt/boot/x86_64/loader/linux  /srv/tftpboot/boot/images/agama/x86_64/
+sudo cp /mnt/boot/x86_64/loader/initrd /srv/tftpboot/boot/images/agama/x86_64/
+sudo cp /mnt/LiveOS/squashfs.img /srv/tftpboot/boot/images/agama/x86_64/
+```
+
+How to set up a PXE server is out of scope of this document but some documentation for SLES can be found at [PXE Server](#pxe-server-documentation).
+
+## Important changes from YaST installer
+
+There are some important changes that affect the installation workflow and specially the [kernel boot options](#kernel-boot-options).
+
+- Linuxrc is not included and dracut takes care of booting the installer.
+- NetworkManager is the default network backend.
+
+We tried to provide some [compatibility with linuxrc options](https://agama-project.github.io/docs/user/reference/boot_options/linuxrc_compatibility) but we recommend to migrate to the dracut specific ones as not all the use cases are supported.
+
+## Kernel Boot Options
+
+As there is no linuxrc anymore the options given as kernel parameters should be replaced by [dracut](https://man7.org/linux/man-pages/man7/dracut.cmdline.7.html) specific ones like the network configuration and the installer sources.
+
+For Agama specific options check the [boot options](https://agama-project.github.io/docs/user/reference/boot_options) section.
+
+### Specify the installer image location
+
+It already requires network configuration enforcing rd.neednet=1.
+
+- `root=live:[http://192.168.0.1/agama/boot/x86_64/squashfs.img](http://192.168.0.1/agama/boot/x86_64/squashfs.img) ip=dhcp`
+
+  sets the Squashfs image or iso to be fetched by the livenet dracut module
+
+- `inst.installer_url=[http://192.168.0.1/agama/install/x86_84](http://192.168.0.1/agama/install/x86_84)`
+
+  sets the repositories to be used by the installer instead of the ones defined
+  in the product definition
+
+### Network configuration
+
+Network will be configured by dracut only if really required so, options like `root=live:<URL>` already requires it but not all of them do so, therefore, to ensure the network is configured by dracut set rd.neednet=1.
+
+**Note:** If an explicit network configuration is given using the `ip=` parameter Agama will disable the NetworkManager DHCP autosetup when starting the installer and mark the nm-initrd-generator generated connections to be persisted after the installation by default. To disable the copy of network the `inst.copy_network=0` parameter is available.
+
+### DHCP configuration
+
+- `ip=dhcp`
+
+  nm-initrd-generator will generate a profile using DHCP allowing multiple
+  devices to apply it at the same time.
+
+- `ip=enp1s0:dhcp`
+
+  the generated profile will be assigned to enp1s0 interface.
+
+- `ip=aa-bb-cc-dd-ee-ff:dhcp`
+
+  the generated profile will be assigned to the device with the specified mac address
+
+### DHCP static configuration
+
+- `ip=<client-IP>:[<peer>]:<gateway-IP>:<netmask>:<client_hostname>:<interface>:{none|off|dhcp|on|any|dhcp6|auto6|ibft}[:[<dns1>][:<dns2>]]`
+
+- `ip=10.144.136.45::10.144.136.254:24:agama1.suse.cz:enc800`
+
+  static configuration using a prefix length as the netmask.
+
+- `ip=192.168.100.228::192.168.100.1:255.255.255.0:agama.test:aa-bb-cc-dd-ee-ff`
+
+  the interface can be also a mac address
+
+### Use custom interface naming
+
+- `ifname=<interface>:<MAC>`
+
+  Assign network device name `<interface>` to the NIC with the MAC `<MAC>`.
+
+- `ifname=bootnet:AA:BB:CC:DD:EE:FF ip=bootnet:dhcp rd.neednet=1`
+
+**Note:** Agama will persist the renamed interface after the installation
+through a systemd network link file.
+
+## PXE Server Documentation
+
+For more information about setting up a PXE Boot Server on SUSE Linux Enterprise Server
+16.0 refer to [this guide](https://susedoc.github.io/doc-modular/main/html/SLE-PXE-server/index.html]).