View source for Packer installation

== Basic understanding ==

Alpine Linux installer is just a bunch of shell scripts, see [https://git.alpinelinux.org/alpine-conf/tree/setup-alpine.in setup-alpine.in] in [https://git.alpinelinux.org/alpine-conf/tree alpine-conf] repository. Understanding this is key to success.

== packer example boot_command ==

This is a part of 'boot_command' from [https://www.packer.io/docs/builders/qemu.html QEMU] builder:

 "boot_command": [
   "root<enter><wait>",
   "ifconfig eth0 up && udhcpc -i eth0<enter><wait5>",
   "wget http://{{ .HTTPIP }}:{{ .HTTPPort }}/answers<enter><wait>",
   "setup-alpine -f answers<enter><wait5>",
   "{{user `ssh_password`}}<enter><wait>",
   "{{user `ssh_password`}}<enter><wait5>",
   "<wait>y<enter><wait10>",
   "rc-service sshd stop<enter>",
   "mount /dev/vg0/lv_root /mnt<enter>",
   "echo 'PermitRootLogin yes' >> /mnt/etc/ssh/sshd_config<enter>",
   "umount /mnt<enter>",
   "reboot<enter>"
 ],

What it does is to mimic a human typing in "console" (VNC). Before running Alpine Linux installer (ie. 'setup-alpine') it does:

* logins in as 'root' (installation media doesn't require password)
* configures first network interfaces via DHCP
* gets 'answers' file from 'packer' built-in HTTP server to be able to start automated installation
* runs Alpine Linux 'setup-alpine' installer script with 'answers' file
* as 'setup-alpine' script asks to configure root password, it just does that
* after that, you can run whatever commands you want, but keep in mind that it is still installer media; you can 'reboot' into installed system and run 'provisioners'

The 'answer' file can be something like this:

 KEYMAPOPTS="us us"
 HOSTNAMEOPTS="-n alpine"
 INTERFACESOPTS="auto lo
 iface lo inet loopback
 
 auto eth0
 iface eth0 inet dhcp
 "
 DNSOPTS="-n 8.8.8.8"
 TIMEZONEOPTS="-z UTC"
 PROXYOPTS="none"
 APKREPOSOPTS="-1"
 SSHDOPTS="-c openssh"
 NTPOPTS="-c openntpd"
 DISKOPTS="-L -m sys /dev/vda"

== packer example provisioners ==

 "provisioners": [
   {
     "type": "shell",
     "scripts": [
       "{{ template_dir }}/../scripts/00_alpinelinux_base.sh",
       "{{ template_dir }}/../scripts/99_alpinelinux_base.sh"
     ]
   }
 ],

[[Category:Installation]]