Adds apt hooks to zfs snapshot before updates, and kernel updates.

020_zfs-apt-snapshot.sh

@@ -0,0 +1,38 @@
+#!/usr/bin/env bash
+
+POOL_NAME=rpool
+
+#  Create zfs snapshots before apt operations using apt hooks
+
+# 1. Create a Snapshot Script
+# Create /usr/local/sbin/snapPrepApt
+conf_print_snapPrepApt() {
+  cat <<EOF
+  #!/bin/bash
+DATE="'$(date +%F-%T)'"
+zfs snapshot -r ${POOL_NAME}@snap_pre_apt_$DATE
+EOF
+}
+conf_print_snapPrepApt | sudo tee /usr/local/sbin/snapPrepApt
+sudo chmod +x /usr/local/sbin/snapPrepApt
+
+# 2. Add Apt Hook
+# Create /etc/apt/apt.conf.d/90zfs-pre-apt-snapshot
+conf_print_apt_conf_d() {
+  cat <<EOF
+DPkg::Pre-Invoke {"/usr/local/sbin/snapPrepApt || true";};   
+EOF
+}
+conf_print_apt_conf_d | sudo tee /etc/apt/apt.conf.d/90zfs-pre-apt-snapshot
+chmod +x /etc/apt/apt.conf.d/90zfs-pre-apt-snapshot
+
+# 3. Kernel Updates
+# Use /etc/kernel/preinst.d/ to snapshot before kernel installation:
+conf_print_kernel_preinst_d() {
+  cat <<EOF
+#!/bin/bash
+DATE='$(date +%F-%T)'
+zfs snapshot -r ${POOL_NAME}@pre-kernel_${DATE}
+EOF
+}
+conf_print_kernel_preinst_d | sudo tee /etc/kernel/preinst.d/90zfs-pre-kernel-snapshot