contrib: add a bash script to snapshort libvirt vms

This script is still 'work in progress' but could be used to make
snapshot of Libvirt VMs.
This can save some times when deploying again and again.

Signed-off-by: Guillaume Abrioux <gabrioux@redhat.com>

contrib/snapshot_vms.sh

@@ -0,0 +1,73 @@
+#!/bin/bash
+
+create_snapshots() {
+  local pattern=$1
+  for vm in $(sudo virsh list --all | awk "/${pattern}/{print \$2}"); do
+    sudo virsh shutdown "${vm}"
+    wait_for_shutoff "${vm}"
+    sudo virsh snapshot-create "${vm}"
+    sudo virsh start "${vm}"
+  done
+}
+
+delete_snapshots() {
+  local pattern=$1
+  for vm in $(sudo virsh list --all | awk "/${pattern}/{print \$2}"); do
+    for snapshot in $(sudo virsh snapshot-list "${vm}" --name); do
+      echo "deleting snapshot ${snapshot} (vm: ${vm})"
+      sudo virsh snapshot-delete "${vm}" "${snapshot}"
+    done
+  done
+}
+
+revert_snapshots() {
+  local pattern=$1
+  for vm in $(sudo virsh list --all | awk "/${pattern}/{print \$2}"); do
+    echo "restoring last snapshot for ${vm}"
+    sudo virsh snapshot-revert "${vm}" --current
+    sudo virsh start "${vm}"
+  done
+}
+
+wait_for_shutoff() {
+  local vm=$1
+  local retries=60
+  local delay=2
+
+  until test "${retries}" -eq 0
+  do
+    echo "waiting for ${vm} to be shut off... #${retries}"
+    sleep "${delay}"
+    let "retries=$retries-1"
+    local current_state=$(sudo virsh domstate "${vm}")
+    test "${current_state}" == "shut off" && return
+  done
+  echo couldnt shutoff "${vm}"
+  exit 1
+}
+
+while :; do
+    case $1 in
+        -d|--delete)
+            delete_snapshots "$2"
+            exit
+            ;;
+        -i|--interactive)
+            INTERACTIVE=TRUE
+            ;;
+        -s|--snapshot)
+            create_snapshots "$2"
+            ;;
+        -r|--revert)
+            revert_snapshots "$2"
+            ;;
+        --)
+            shift
+            break
+            ;;
+        *)
+            break
+    esac
+
+    shift
+done