From 5392080129b1093f36533e47c155f618c283ea57 Mon Sep 17 00:00:00 2001
From: Philip J Freeman <elektron@halo.nu>
Date: Sun, 4 May 2025 18:55:05 -0700
Subject: initial commit; demo ostree delta

---
 .gitignore       |  3 +++
 README.md        | 16 ++++++++++++++++
 make_rootfs.sh   | 57 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 ostree_commit.sh |  8 ++++++++
 ostree_delta.sh  |  7 +++++++
 5 files changed, 91 insertions(+)
 create mode 100644 .gitignore
 create mode 100644 README.md
 create mode 100755 make_rootfs.sh
 create mode 100755 ostree_commit.sh
 create mode 100755 ostree_delta.sh

diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..75b7505
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1,3 @@
+repo/
+rootfs/
+delta-update-file
diff --git a/README.md b/README.md
new file mode 100644
index 0000000..52266d8
--- /dev/null
+++ b/README.md
@@ -0,0 +1,16 @@
+# ostree-demo
+
+roughing out a quick demo to try out ostree for deploying ubuntu
+
+# delta test - adding nethack
+
+    sudo ./make_rootfs.sh
+    sudo ./make_rootfs.sh with-app
+
+    sudo ./ostree_commit.sh rootfs/20250504.182708/
+    sudo ./ostree_commit.sh rootfs/20250504.183218/
+
+    sudo ./ostree_delta.sh rootfs^ rootfs
+
+    du -sh delta-update-file 
+    60K     delta-update-file
diff --git a/make_rootfs.sh b/make_rootfs.sh
new file mode 100755
index 0000000..811c5cb
--- /dev/null
+++ b/make_rootfs.sh
@@ -0,0 +1,57 @@
+#!/bin/bash -xe
+
+IMAGE_VERSION=$( date +%Y%m%d.%H%M%S )
+
+function unmount_pseudo_filesystems(){
+	set +e
+	for dir in dev sys proc; do umount -v "$root"/"$dir"; done
+	set -e
+}
+
+function on_exit(){
+	set +e
+	unmount_pseudo_filesystems
+	umount -v "$root"
+}
+trap on_exit EXIT
+
+root=rootfs/"$IMAGE_VERSION"
+
+mkdir -p "$root"
+
+# bootstrap the OS
+
+debootstrap noble "$root"
+
+for dir in /proc /sys /dev; do
+	mount --bind "$dir" "$root"/"$dir"
+done
+
+export DEBIAN_FRONTEND=noninteractive
+
+chroot "$root" locale-gen en_US.UTF-8
+
+chroot "$root" apt-get update
+
+# Install a kernel and bootloader
+
+chroot "$root" apt-get -y --no-install-recommends install linux-generic-hwe-24.04 grub-efi
+
+if [ "$1" == "with-app" ]; then
+	# Install an application
+	chroot "$root" apt-get update
+	chroot "$root" apt-get install -y software-properties-common
+	chroot "$root" add-apt-repository -y universe
+	chroot "$root" apt-get update
+	chroot "$root" apt-get -y install nethack-console
+fi
+
+
+# Cleanup
+
+chroot "$root" apt-get clean
+
+unmount_pseudo_filesystems
+
+rm -rf "$root"/dev/*
+rm -rf "$root"/var/lib/apt/lists/*
diff --git a/ostree_commit.sh b/ostree_commit.sh
new file mode 100755
index 0000000..23a04e0
--- /dev/null
+++ b/ostree_commit.sh
@@ -0,0 +1,8 @@
+#!/bin/bash -xe
+
+ROOTFS_DIR=$1
+
+[ ! -d repo ] && \
+	ostree --repo=repo init
+
+ostree --repo=repo commit --branch=rootfs "$ROOTFS_DIR"
diff --git a/ostree_delta.sh b/ostree_delta.sh
new file mode 100755
index 0000000..2a23b56
--- /dev/null
+++ b/ostree_delta.sh
@@ -0,0 +1,7 @@
+#!/bin/bash -xe
+
+FROM_REF=$1
+TO_REF=$2
+
+ostree --repo=repo static-delta generate --min-fallback-size=0 \
+	--filename=delta-update-file --from="$FROM_REF" "$TO_REF"
-- 
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