Alpine Linux (Virt) packer script

packer/alpine-linux-virt/.gitignore

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+output-qemu
+packer_cache

packer/alpine-linux-virt/README.md

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+# Packer for Alpine (Virt) GNS3 appliance
+
+This is the bare version of `Alpine Linux` installed from iso, no extra package added.
+
+Build in 1m12s on `macOS Monterey`.
+
+### Linux (untested)
+
+```bash
+packer build alpine.json
+```
+
+> :information_source: Uses `tcg` QEMU accelerator.
+
+
+### macOS (tested)
+
+```bash
+packer build -var-file macos.json alpine.json
+```
+
+> :information_source: Uses `hvf` QEMU accelerator. Actually much much faster than the default one, `packer` will fail on `macOS` without `hvf` (timing issue).

packer/alpine-linux-virt/alpine.json

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+{
+    "variables": {
+        "accelerator": "tcg"
+    },
+    "builders": [
+        {
+            "communicator": "none",
+            "type": "qemu",
+            "accelerator": "{{ user `accelerator` }}",
+            "use_default_display": true,
+            "iso_url": "https://dl-cdn.alpinelinux.org/alpine/v3.16/releases/x86_64/alpine-virt-3.16.2-x86_64.iso",
+            "iso_checksum": "6c7cb998ec2c8925d5a1239410a4d224b771203f916a18f8015f31169dd767a2",
+            "http_directory": "./files",
+            "vm_name": "alpine-virt-3.16.img",
+            "disk_size": "92M",
+            "format": "raw",
+            "qemu_img_args": {
+                "create": ["-o", "preallocation=off"]
+            },
+            "disk_interface": "virtio",
+            "disk_discard": "unmap",
+            "boot_wait": "15s",
+            "boot_key_interval": "20ms",
+            "boot_keygroup_interval": "100ms",
+            "boot_command": [
+                "root<enter>",
+                "ifconfig lo up<enter>",
+                "ifconfig eth0 up && udhcpc -i eth0<enter><wait5>",
+                "wget -q http://{{ .HTTPIP }}:{{ .HTTPPort }}/alpine.conf && setup-alpine -e -f alpine.conf<enter><wait><enter><wait500ms><enter><wait5><enter><wait500ms><enter><wait500ms>",
+                "wget -q http://{{ .HTTPIP }}:{{ .HTTPPort }}/install.sh && chmod +x install.sh && ./install.sh<enter><wait30s>",
+                "poweroff<enter>"
+            ]
+        }
+    ]
+}

packer/alpine-linux-virt/files/alpine.conf

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+KEYMAPOPTS=none
+HOSTNAMEOPTS=alpine
+DEVDOPTS=mdev
+INTERFACESOPTS="auto lo
+iface lo inet loopback
+
+auto eth0
+iface eth0 inet manual
+# DHCP
+#iface eth0 inet dhcp
+# Static
+#iface eth0 inet static
+#    address IP_ADDRESS/MASK
+#    gateway GW_IP_ADDRESS
+#    dns-nameserver DNS_IP_ADDRESS
+"
+TIMEZONEOPTS=UTC
+PROXYOPTS=none
+APKREPOSOPTS=-1
+SSHDOPTS=none
+NTPOPTS=none
+DISKOPTS=none
+#LBUOPTS=none
+APKCACHEOPTS=none

packer/alpine-linux-virt/files/install.sh

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+#!/bin/ash
+
+DRIVE="/dev/vda"
+
+# Format drive, from sector 2048 to end, bootable
+fdisk $DRIVE << EOS
+o
+n
+p
+1
+2048
+
+a
+1
+w
+EOS
+
+if [[ $? != 0 ]]; then
+    echo "Error while partitioning device" >&2
+    exit 1
+fi
+
+# Format partition without "64bit" and "has_journal" flags
+apk add e2fsprogs && mkfs.ext4 -O \^64bit,\^has_journal ${DRIVE}1 && mount ${DRIVE}1 /mnt -t ext4 && mkdir /mnt/boot && apk del e2fsprogs
+if [[ $? != 0 ]]; then
+    echo "Error somewhere while making filesystem or mounting partition" >&2
+    exit 1
+fi
+
+# Actually install Alpine Linux in mounted directory
+BOOT_SIZE=0 setup-disk -k virt -s 0 /mnt
+if [[ $? != 0 ]]; then
+    echo "Error while installing Alpine" >&2
+    exit 1
+fi
+
+# Install the MBR
+dd if=/mnt/usr/share/syslinux/mbr.bin of=/dev/vda
+if [[ $? != 0 ]]; then
+    echo "Error while fixing kernel path" >&2
+    exit 1
+fi
+
+# Fix kernel and initrd path, enable console on ttyS0
+sed -i.bkp 's_LINUX vmlinuz_LINUX /boot/vmlinuz_; s_INITRD initram_INITRD /boot/initram_; /APPEND/s/$/ console=ttyS0,115200/' /mnt/boot/extlinux.conf
+if [[ $? != 0 ]]; then
+    echo "Error while fixing kernel path" >&2
+    exit 1
+fi
+
+# Enable autologin on ttyS0
+sed -i.bkp 's/^ttyS0/#ttyS0/g' /mnt/etc/inittab && echo "ttyS0::respawn:/bin/login -f root" >> /mnt/etc/inittab
+if [[ $? != 0 ]]; then
+    echo "Error while enabling autologin on ttyS0" >&2
+    exit 1
+fi
+
+# Write 0
+dd if=/dev/zero bs=1M of=/mnt/zero ; rm -f /mnt/zero
+
+# fsck
+umount ${DRIVE}1 && apk add e2fsprogs && fsck.ext4 ${DRIVE}1
+if [[ $? != 0 ]]; then
+    echo "Couldn't fsck partition" >&2
+    exit 1
+fi

packer/alpine-linux-virt/macos.json

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+{
+    "accelerator": "hvf"
+}