Add ability to grow root partition + filesystem

arch.pkr.hcl

@@ -82,6 +82,20 @@ build {
         destination = "/mnt/etc/systemd/network/99-dhcp-wildcard.network"
     }
 
+    provisioner "file" {
+        source = "files/grow-root"
+        destination = "/usr/local/sbin/grow-root"
+    }
+
+    provisioner "shell" {
+        inline = ["chmod +x /usr/local/sbin/grow-root"]
+    }
+
+    provisioner "file" {
+        source = "files/grow-root.service"
+        destination = "/etc/systemd/system/grow-root.service"
+    }
+
     provisioner "shell" {
         pause_before = "10s"
         scripts = [

files/grow-root

@@ -0,0 +1,16 @@
+#!/bin/bash
+
+dev="$(findmnt -nfvo SOURCE -- "/")"
+
+# If it's a partition, expand that first using growpart.
+if [ "$(lsblk -ndo TYPE -- "$dev")" = part ]; then
+	disk="$(lsblk -ndpo PKNAME -- "$dev")"
+	partnum="${dev##*[!0-9]}"
+	growpart "$disk" "$partnum" || { [ $? -ne 1 ] && exit 1; }
+fi
+
+# Inform kernel of new partition
+partprobe
+
+# Expand the filesystem.
+resize2fs -- "$dev" || exit 1

files/grow-root.service

@@ -0,0 +1,9 @@
+[Unit]
+Description=Grows the root partition and filesystem to match disk size
+
+[Service]
+Type=oneshot
+ExecStart=/usr/local/sbin/grow-root
+
+[Install]
+WantedBy=multi-user.target

scripts/install_system.sh

@@ -4,8 +4,8 @@ set -eux
 pacman-key --init
 
 # Install the system
-pacstrap -K /mnt base linux linux-firmware rng-tools grub sudo \
-    openssh ufw git vim python-pip nomad nomad-driver-nspawn
+pacstrap -K /mnt base linux linux-firmware rng-tools grub parted sudo \
+    openssh ufw git vim cloud-utils python-pip nomad nomad-driver-nspawn
 
 # Clear the cache
 arch-chroot /mnt pacman -Scc --noconfirm