From a3844b7ef67c8ad6f7109a26355d3dbc63c29a4a Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?R=C3=A2u=20Cao?= <raucao@kip.pe>
Date: Tue, 18 Oct 2022 18:45:17 +0200
Subject: [PATCH] WIP Add KVM host backup recipe

Add a recipe that configures scripts for live backups of VM images via
libvirt and borg.
---
 site-cookbooks/kosmos_kvm/files/backup_vm.sh  | 30 ++++++++++++++
 site-cookbooks/kosmos_kvm/recipes/backup.rb   | 40 +++++++++++++++++++
 .../templates/backup_all_vms.sh.erb           | 11 +++++
 3 files changed, 81 insertions(+)
 create mode 100644 site-cookbooks/kosmos_kvm/files/backup_vm.sh
 create mode 100644 site-cookbooks/kosmos_kvm/recipes/backup.rb
 create mode 100644 site-cookbooks/kosmos_kvm/templates/backup_all_vms.sh.erb

diff --git a/site-cookbooks/kosmos_kvm/files/backup_vm.sh b/site-cookbooks/kosmos_kvm/files/backup_vm.sh
new file mode 100644
index 0000000..96dbaea
--- /dev/null
+++ b/site-cookbooks/kosmos_kvm/files/backup_vm.sh
@@ -0,0 +1,30 @@
+#!/bin/bash
+# GENERATED BY CHEF
+# DO NOT EDIT
+set -e
+
+REPOSITORY=$BORG_REPO
+
+echo "Starting backup of VM: $1"
+
+echo "Dumping domain XML to /root/backups/vm_meta/$1.xml"
+virsh dumpxml --migratable $1 > /root/backups/vm_meta/$1.xml
+
+virsh snapshot-create-as --domain $1  \
+        --name hotswap.qcow2  \
+        --no-metadata         \
+        --atomic              \
+        --quiesce             \
+        --disk-only           \
+        --diskspec vda,snapshot=external
+
+borg create -v --stats  \
+        $REPOSITORY::$1_$(date +%F_%H-%M) \
+        /var/lib/libvirt/images/$1.qcow2  \
+        /root/backups/vm_meta
+
+echo "Pivoting base image back to original"
+virsh blockcommit $1 vda --pivot --base=/var/lib/libvirt/images/$1.qcow2
+
+echo "Removing snapshot image"
+rm /var/lib/libvirt/images/$1.hotswap.qcow2
diff --git a/site-cookbooks/kosmos_kvm/recipes/backup.rb b/site-cookbooks/kosmos_kvm/recipes/backup.rb
new file mode 100644
index 0000000..e8429b0
--- /dev/null
+++ b/site-cookbooks/kosmos_kvm/recipes/backup.rb
@@ -0,0 +1,40 @@
+#
+# Cookbook:: kosmos_kvm
+# Recipe:: backup
+#
+
+apt_package "borgbackup"
+
+borg_credentials = data_bag_item("credentials", "borg")
+
+file "/root/.ssh/borg_rsa" do
+  content borg_credentials["ssh_key"]
+  mode '0600'
+end
+
+bash "Add borg environment variables for bash" do
+  code <<-EOF
+          cat >>/root/.bashrc <<EOL
+
+# GENERATED BY CHEF
+export BORG_RSH='ssh -i /root/.ssh/borg_rsa'
+export BORG_PASSPHRASE=#{borg_credentials["passphrase"]}
+export BORG_REPO='#{borg_credentials["repository"]}'
+  EOF
+  not_if "grep -q BORG /root/.bashrc"
+end
+
+cookbook_file "/root/backups/backup_vm.sh" do
+  source "backup_vm.sh"
+  mode "0750"
+end
+
+# Search all guests and filter by presence on current host
+vm_domains = search(:node, "role:kvm_guest").map(&:name) \
+             & `virsh list --name`.strip.chomp.split("\n")
+
+template "/root/backups/backup_all_vms.sh" do
+  source "backup_all_vms.sh.erb"
+  mode '0750'
+  variables vm_domains: vm_domains
+end
diff --git a/site-cookbooks/kosmos_kvm/templates/backup_all_vms.sh.erb b/site-cookbooks/kosmos_kvm/templates/backup_all_vms.sh.erb
new file mode 100644
index 0000000..e1d443b
--- /dev/null
+++ b/site-cookbooks/kosmos_kvm/templates/backup_all_vms.sh.erb
@@ -0,0 +1,11 @@
+#!/bin/bash
+# GENERATED BY CHEF
+# DO NOT EDIT
+set -e
+
+echo "Backing up all VMs with kvm_guest chef role..."
+
+for domain in <%= @vm_domains.join(" ") %>
+do
+  /root/backups/backup_vm.sh $domain
+done