merge - duplicity configuration in the control panel and disabling backups

Merges branch 'ponychicken-backup'.

management/backup.py

@@ -10,20 +10,27 @@
 
 import os, os.path, shutil, glob, re, datetime
 import dateutil.parser, dateutil.relativedelta, dateutil.tz
+import rtyaml
 
 from utils import exclusive_process, load_environment, shell, wait_for_service
 
-# Destroy backups when the most recent increment in the chain
-# that depends on it is this many days old.
-keep_backups_for_days = 3
-
 def backup_status(env):
-	# What is the current status of backups?
+	# Root folder
-	# Loop through all of the files in STORAGE_ROOT/backup/encrypted to
+	backup_root = os.path.join(env["STORAGE_ROOT"], 'backup')
-	# get a list of all of the backups taken and sum up file sizes to
-	# see how large the storage is.
 
+	# What is the current status of backups?
+	# Query duplicity to get a list of all backups.
+	# Use the number of volumes to estimate the size.
+	config = get_backup_config(env)
 	now = datetime.datetime.now(dateutil.tz.tzlocal())
+
+	# Are backups dissbled?
+	if config["target"] == "off":
+		return { }
+
+	backups = { }
+	backup_cache_dir = os.path.join(backup_root, 'cache')
+
 	def reldate(date, ref, clip):
 		if ref < date: return clip
 		rd = dateutil.relativedelta.relativedelta(ref, date)
@@ -34,27 +41,38 @@ def backup_status(env):
 		if rd.days == 1: return "%d day, %d hours" % (rd.days, rd.hours)
 		return "%d hours, %d minutes" % (rd.hours, rd.minutes)
 
-	backups = { }
+	# Get duplicity collection status and parse for a list of backups.
-	backup_root = os.path.join(env["STORAGE_ROOT"], 'backup')
+	def parse_line(line):
-	backup_dir = os.path.join(backup_root, 'encrypted')
+		keys = line.strip().split()
-	os.makedirs(backup_dir, exist_ok=True) # os.listdir fails if directory does not exist
+		date = dateutil.parser.parse(keys[1])
-	for fn in os.listdir(backup_dir):
+		return {
+			"date": keys[1],
+			"date_str": date.strftime("%x %X"),
+			"date_delta": reldate(date, now, "the future?"),
+			"full": keys[0] == "full",
+			"size": 0, # collection-status doesn't give us the size
+			"volumes": keys[2], # number of archive volumes for this backup (not really helpful)
+		}
+	collection_status = shell('check_output', [
+		"/usr/bin/duplicity",
+		"collection-status",
+		"--archive-dir", backup_cache_dir,
+		"--gpg-options", "--cipher-algo=AES256",
+		"--log-fd", "1",
+		config["target"],
+		],
+		get_env(env))
+	for line in collection_status.split('\n'):
+		if line.startswith(" full") or line.startswith(" inc"):
+			backup = parse_line(line)
+			backups[backup["date"]] = backup
+
+	# Look at the target to get the sizes of each of the backups. There is more than one file per backup.
+	for fn, size in list_target_files(config):
 		m = re.match(r"duplicity-(full|full-signatures|(inc|new-signatures)\.(?P<incbase>\d+T\d+Z)\.to)\.(?P<date>\d+T\d+Z)\.", fn)
-		if not m: raise ValueError(fn)
+		if not m: continue # not a part of a current backup chain
-
 		key = m.group("date")
-		if key not in backups:
+		backups[key]["size"] += size
-			date = dateutil.parser.parse(m.group("date"))
-			backups[key] = {
-				"date": m.group("date"),
-				"date_str": date.strftime("%x %X"),
-				"date_delta": reldate(date, now, "the future?"),
-				"full": m.group("incbase") is None,
-				"previous": m.group("incbase"),
-				"size": 0,
-			}
-
-		backups[key]["size"] += os.path.getsize(os.path.join(backup_dir, fn))
 
 	# Ensure the rows are sorted reverse chronologically.
 	# This is relied on by should_force_full() and the next step.
@@ -79,11 +97,11 @@ def backup_status(env):
 	# when the threshold is met.
 	deleted_in = None
 	if incremental_count > 0 and first_full_size is not None:
-		deleted_in = "approx. %d days" % round(keep_backups_for_days + (.5 * first_full_size - incremental_size) / (incremental_size/incremental_count) + .5)
+		deleted_in = "approx. %d days" % round(config["min_age_in_days"] + (.5 * first_full_size - incremental_size) / (incremental_size/incremental_count) + .5)
 
 	# When will a backup be deleted?
 	saw_full = False
-	days_ago = now - datetime.timedelta(days=keep_backups_for_days)
+	days_ago = now - datetime.timedelta(days=config["min_age_in_days"])
 	for bak in backups:
 		if deleted_in:
 			# Subsequent backups are deleted when the most recent increment
@@ -99,8 +117,6 @@ def backup_status(env):
 			bak["deleted_in"] = deleted_in
 
 	return {
-		"directory": backup_dir,
-		"encpwfile": os.path.join(backup_root, 'secret_key.txt'),
 		"tz": now.tzname(),
 		"backups": backups,
 	}
@@ -124,15 +140,48 @@ def should_force_full(env):
 		# (I love for/else blocks. Here it's just to show off.)
 		return True
 
+def get_passphrase(env):
+	# Get the encryption passphrase. secret_key.txt is 2048 random
+	# bits base64-encoded and with line breaks every 65 characters.
+	# gpg will only take the first line of text, so sanity check that
+	# that line is long enough to be a reasonable passphrase. It
+	# only needs to be 43 base64-characters to match AES256's key
+	# length of 32 bytes.
+	backup_root = os.path.join(env["STORAGE_ROOT"], 'backup')
+	with open(os.path.join(backup_root, 'secret_key.txt')) as f:
+		passphrase = f.readline().strip()
+	if len(passphrase) < 43: raise Exception("secret_key.txt's first line is too short!")
+	
+	return passphrase
+
+def get_env(env):
+	config = get_backup_config(env)
+	
+	env = { "PASSPHRASE" : get_passphrase(env) }
+	
+	if get_target_type(config) == 's3':
+		env["AWS_ACCESS_KEY_ID"] = config["target_user"]
+		env["AWS_SECRET_ACCESS_KEY"] = config["target_pass"]
+	
+	return env
+	
+def get_target_type(config):
+	protocol = config["target"].split(":")[0]
+	return protocol
+	
 def perform_backup(full_backup):
 	env = load_environment()
 
 	exclusive_process("backup")
-
+	config = get_backup_config(env)
 	backup_root = os.path.join(env["STORAGE_ROOT"], 'backup')
 	backup_cache_dir = os.path.join(backup_root, 'cache')
 	backup_dir = os.path.join(backup_root, 'encrypted')
 
+	# Are backups dissbled?
+	if config["target"] == "off":
+		return
+
 	# In an older version of this script, duplicity was called
 	# such that it did not encrypt the backups it created (in
 	# backup/duplicity), and instead openssl was called separately
@@ -169,17 +218,6 @@ def perform_backup(full_backup):
 	shell('check_call', ["/usr/sbin/service", "dovecot", "stop"])
 	shell('check_call', ["/usr/sbin/service", "postfix", "stop"])
 
-	# Get the encryption passphrase. secret_key.txt is 2048 random
-	# bits base64-encoded and with line breaks every 65 characters.
-	# gpg will only take the first line of text, so sanity check that
-	# that line is long enough to be a reasonable passphrase. It
-	# only needs to be 43 base64-characters to match AES256's key
-	# length of 32 bytes.
-	with open(os.path.join(backup_root, 'secret_key.txt')) as f:
-		passphrase = f.readline().strip()
-	if len(passphrase) < 43: raise Exception("secret_key.txt's first line is too short!")
-	env_with_passphrase = { "PASSPHRASE" : passphrase }
-
 	# Run a backup of STORAGE_ROOT (but excluding the backups themselves!).
 	# --allow-source-mismatch is needed in case the box's hostname is changed
 	# after the first backup. See #396.
@@ -192,10 +230,10 @@ def perform_backup(full_backup):
 			"--volsize", "250",
 			"--gpg-options", "--cipher-algo=AES256",
 			env["STORAGE_ROOT"],
-			"file://" + backup_dir,
+			config["target"],
-                        "--allow-source-mismatch"
+			"--allow-source-mismatch"
 			],
-			env_with_passphrase)
+			get_env(env))
 	finally:
 		# Start services again.
 		shell('check_call', ["/usr/sbin/service", "dovecot", "start"])
@@ -210,12 +248,12 @@ def perform_backup(full_backup):
 	shell('check_call', [
 		"/usr/bin/duplicity",
 		"remove-older-than",
-		"%dD" % keep_backups_for_days,
+		"%dD" % config["min_age_in_days"],
 		"--archive-dir", backup_cache_dir,
 		"--force",
-		"file://" + backup_dir
+		config["target"]
 		],
-		env_with_passphrase)
+		get_env(env))
 
 	# From duplicity's manual:
 	# "This should only be necessary after a duplicity session fails or is
@@ -227,13 +265,14 @@ def perform_backup(full_backup):
 		"cleanup",
 		"--archive-dir", backup_cache_dir,
 		"--force",
-		"file://" + backup_dir
+		config["target"]
 		],
-		env_with_passphrase)
+		get_env(env))
 
 	# Change ownership of backups to the user-data user, so that the after-bcakup
 	# script can access them.
-	shell('check_call', ["/bin/chown", "-R", env["STORAGE_USER"], backup_dir])
+	if get_target_type(config) == 'file':
+		shell('check_call', ["/bin/chown", "-R", env["STORAGE_USER"], backup_dir])
 
 	# Execute a post-backup script that does the copying to a remote server.
 	# Run as the STORAGE_USER user, not as root. Pass our settings in
@@ -241,7 +280,7 @@ def perform_backup(full_backup):
 	post_script = os.path.join(backup_root, 'after-backup')
 	if os.path.exists(post_script):
 		shell('check_call',
-			['su', env['STORAGE_USER'], '-c', post_script],
+			['su', env['STORAGE_USER'], '-c', post_script, config["target"]],
 			env=env)
 
 	# Our nightly cron job executes system status checks immediately after this
@@ -254,9 +293,9 @@ def perform_backup(full_backup):
 def run_duplicity_verification():
 	env = load_environment()
 	backup_root = os.path.join(env["STORAGE_ROOT"], 'backup')
+	config = get_backup_config(env)
 	backup_cache_dir = os.path.join(backup_root, 'cache')
-	backup_dir = os.path.join(backup_root, 'encrypted')
+
-	env_with_passphrase = { "PASSPHRASE" : open(os.path.join(backup_root, 'secret_key.txt')).read() }
 	shell('check_call', [
 		"/usr/bin/duplicity",
 		"--verbosity", "info",
@@ -264,9 +303,113 @@ def run_duplicity_verification():
 		"--compare-data",
 		"--archive-dir", backup_cache_dir,
 		"--exclude", backup_root,
-		"file://" + backup_dir,
+		config["target"],
 		env["STORAGE_ROOT"],
-	], env_with_passphrase)
+	], get_env(env))
+
+def list_target_files(config):
+	import urllib.parse
+	try:
+		p = urllib.parse.urlparse(config["target"])
+	except ValueError:
+		return "invalid target"
+
+	if p.scheme == "file":
+		return [(fn, os.path.getsize(os.path.join(p.path, fn))) for fn in os.listdir(p.path)]
+
+	elif p.scheme == "s3":
+		# match to a Region
+		import boto.s3
+		from boto.exception import BotoServerError
+		for region in boto.s3.regions():
+			if region.endpoint == p.hostname:
+				break
+		else:
+			raise ValueError("Invalid S3 region/host.")
+
+		bucket = p.path[1:].split('/')[0]
+		path = '/'.join(p.path[1:].split('/')[1:]) + '/'
+		if bucket == "":
+			raise ValueError("Enter an S3 bucket name.")
+
+		# connect to the region & bucket
+		try:
+			conn = region.connect(aws_access_key_id=config["target_user"], aws_secret_access_key=config["target_pass"])
+			bucket = conn.get_bucket(bucket)
+		except BotoServerError as e:
+			if e.status == 403:
+				raise ValueError("Invalid S3 access key or secret access key.")
+			elif e.status == 404:
+				raise ValueError("Invalid S3 bucket name.")
+			elif e.status == 301:
+				raise ValueError("Incorrect region for this bucket.")
+			raise ValueError(e.reason)
+
+		return [(key.name[len(path):], key.size) for key in bucket.list(prefix=path)]
+
+	else:
+		raise ValueError(config["target"])
+
+
+def backup_set_custom(env, target, target_user, target_pass, min_age):
+	config = get_backup_config(env, for_save=True)
+	
+	# min_age must be an int
+	if isinstance(min_age, str):
+		min_age = int(min_age)
+
+	config["target"] = target
+	config["target_user"] = target_user
+	config["target_pass"] = target_pass
+	config["min_age_in_days"] = min_age
+
+	# Validate.
+	try:
+		if config["target"] not in ("off", "local"):
+			# these aren't supported by the following function, which expects a full url in the target key,
+			# which is what is there except when loading the config prior to saving
+			list_target_files(config)
+	except ValueError as e:
+		return str(e)
+	
+	write_backup_config(env, config)
+
+	return "Updated backup config"
+	
+def get_backup_config(env, for_save=False):
+	backup_root = os.path.join(env["STORAGE_ROOT"], 'backup')
+
+	# Defaults.
+	config = {
+		"min_age_in_days": 3,
+		"target": "local",
+	}
+
+	# Merge in anything written to custom.yaml.
+	try:
+		custom_config = rtyaml.load(open(os.path.join(backup_root, 'custom.yaml')))
+		if not isinstance(custom_config, dict): raise ValueError() # caught below
+		config.update(custom_config)
+	except:
+		pass
+
+	# When updating config.yaml, don't do any further processing on what we find.
+	if for_save:
+		return config
+
+	# helper fields for the admin
+	config["file_target_directory"] = os.path.join(backup_root, 'encrypted')
+	config["enc_pw_file"] = os.path.join(backup_root, 'secret_key.txt')
+	if config["target"] == "local":
+		# Expand to the full URL.
+		config["target"] = "file://" + config["file_target_directory"]
+
+	return config
+
+def write_backup_config(env, newconfig):
+	backup_root = os.path.join(env["STORAGE_ROOT"], 'backup')
+	with open(os.path.join(backup_root, 'custom.yaml'), "w") as f:
+		f.write(rtyaml.dump(newconfig))
 
 if __name__ == "__main__":
 	import sys
@@ -274,6 +417,7 @@ if __name__ == "__main__":
 		# Run duplicity's verification command to check a) the backup files
 		# are readable, and b) report if they are up to date.
 		run_duplicity_verification()
+
 	else:
 		# Perform a backup. Add --full to force a full backup rather than
 		# possibly performing an incremental backup.

management/daemon.py

@@ -90,13 +90,19 @@ def json_response(data):
 def index():
 	# Render the control panel. This route does not require user authentication
 	# so it must be safe!
+
 	no_users_exist = (len(get_mail_users(env)) == 0)
 	no_admins_exist = (len(get_admins(env)) == 0)
+
+	import boto.s3
+	backup_s3_hosts = [(r.name, r.endpoint) for r in boto.s3.regions()]
+
 	return render_template('index.html',
 		hostname=env['PRIMARY_HOSTNAME'],
 		storage_root=env['STORAGE_ROOT'],
 		no_users_exist=no_users_exist,
 		no_admins_exist=no_admins_exist,
+		backup_s3_hosts=backup_s3_hosts,
 	)
 
 @app.route('/me')
@@ -402,6 +408,23 @@ def backup_status():
 	from backup import backup_status
 	return json_response(backup_status(env))
 
+@app.route('/system/backup/config', methods=["GET"])
+@authorized_personnel_only
+def backup_get_custom():
+	from backup import get_backup_config
+	return json_response(get_backup_config(env))
+
+@app.route('/system/backup/config', methods=["POST"])
+@authorized_personnel_only
+def backup_set_custom():
+	from backup import backup_set_custom
+	return json_response(backup_set_custom(env,
+		request.form.get('target', ''),
+		request.form.get('target_user', ''),
+		request.form.get('target_pass', ''),
+		request.form.get('min_age', '')
+	))
+
 # MUNIN
 
 @app.route('/munin/')
@@ -432,4 +455,3 @@ if __name__ == '__main__':
 
 	# Start the application server. Listens on 127.0.0.1 (IPv4 only).
 	app.run(port=10222)
-

management/templates/system-backup.html

@@ -5,17 +5,77 @@
 
 <h2>Backup Status</h2>
 
-<h3>Copying Backup Files</h3>
+<p>The box makes an incremental backup each night. By default the backup is stored on the machine itself, but you can also have it stored on Amazon S3</p>
 
-<p>The box makes an incremental backup each night. The backup is stored on the machine itself. You are responsible for copying the backup files off of the machine.</p>
+<h3>Configuration</h3>
 
-<p>Many cloud providers make this easy by allowing you to take snapshots of the machine's disk.</p>
+<form class="form-horizontal" role="form" onsubmit="set_custom_backup(); return false;">
+  <div class="form-group">
+    <label for="backup-target-type" class="col-sm-2 control-label">Backup to:</label>
+    <div class="col-sm-2">
+      <select class="form-control" rows="1" id="backup-target-type" onchange="toggle_form()">
+        <option value="off">Nowhere (Disable Backups)</option>
+        <option value="local">{{hostname}}</option>
+        <option value="s3">Amazon S3</option>
+      </select>
+    </div>
+  </div>
+  <div class="form-group backup-target-local">
+    <div class="col-sm-10 col-sm-offset-2">
+      <div>Backups are stored on this machine&rsquo;s own hard disk. You are responsible for periodically using SFTP (FTP over SSH) to copy the backup files from <tt id="backup-location"></tt> to a safe location. These files are encrypted, so they are safe to store anywhere.</div>
+    </div>
+  </div>
+  <div class="form-group backup-target-s3">
+    <div class="col-sm-10 col-sm-offset-2">
+      <div>Backups are stored in an Amazon Web Services S3 bucket. You must have an AWS account already.</div>
+    </div>
+  </div>
+  <div class="form-group backup-target-local backup-target-s3">
+    <label for="min-age" class="col-sm-2 control-label">How many days should backups be kept?</label>
+    <div class="col-sm-8">
+      <input type="number" class="form-control" rows="1" id="min-age">
+    </div>
+  </div>
+  <div class="form-group backup-target-s3">
+    <label for="backup-target-s3-host" class="col-sm-2 control-label">S3 Region</label>
+    <div class="col-sm-8">
+      <select class="form-control" rows="1" id="backup-target-s3-host">
+        {% for name, host in backup_s3_hosts %}
+          <option value="{{host}}">{{name}}</option>
+        {% endfor %}
+      </select>
+    </div>
+  </div>
+  <div class="form-group backup-target-s3">
+    <label for="backup-target-s3-path" class="col-sm-2 control-label">S3 Path</label>
+    <div class="col-sm-8">
+      <input type="text" placeholder="your-bucket-name/backup-directory" class="form-control" rows="1" id="backup-target-s3-path">
+    </div>
+  </div>
+  <div class="form-group backup-target-s3">
+    <label for="backup-target-user" class="col-sm-2 control-label">S3 Access Key</label>
+    <div class="col-sm-8">
+      <input type="text" class="form-control" rows="1" id="backup-target-user">
+    </div>
+  </div>
+  <div class="form-group backup-target-s3">
+    <label for="backup-target-pass" class="col-sm-2 control-label">S3 Secret Access Key</label>
+    <div class="col-sm-8">
+      <input type="text" class="form-control" rows="1" id="backup-target-pass">
+    </div>
+  </div>
+  <div class="form-group">
+    <div class="col-sm-offset-2 col-sm-11">
+      <button id="set-s3-backup-button" type="submit" class="btn btn-primary">Save</button>
+    </div>
+  </div>
+</form>
 
-<p>You can also use SFTP (FTP over SSH) to copy files from <tt id="backup-location"></tt>. These files are encrypted, so they are safe to store anywhere. Copy the encryption password from <tt id="backup-encpassword-file"></tt> also but keep it in a safe location.</p>
+<p> Copy the encryption password from <tt id="backup-encpassword-file"></tt> to a safe and secure location. You will need this file to decrypt backup files.</div></p>
 
-<h3>Current Backups</h3>
+<h3>Available Backups</h3>
 
-<p>The backup directory currently contains the backups listed below. The total size on disk of the backups is currently <span id="backup-total-size"></span>.</p>
+<p>The backup location currently contains the backups listed below. The total size of the backups is currently <span id="backup-total-size"></span>.</p>
 
 <table id="backup-status" class="table" style="width: auto">
   <thead>
@@ -27,8 +87,14 @@
   <tbody>
   </tbody>
 </table>
-
 <script>
+
+function toggle_form() {
+  var target_type = $("#backup-target-type").val();
+  $(".backup-target-local, .backup-target-s3").hide();
+  $(".backup-target-" + target_type).show();
+}
+
 function nice_size(bytes) {
   var powers = ['bytes', 'KB', 'MB', 'GB', 'TB'];
   while (true) {
@@ -46,19 +112,22 @@ function nice_size(bytes) {
 }
 
 function show_system_backup() {
+  show_custom_backup()
+  
   $('#backup-status tbody').html("<tr><td colspan='2' class='text-muted'>Loading...</td></tr>")
   api(
     "/system/backup/status",
     "GET",
     { },
     function(r) {
-      $('#backup-location').text(r.directory);
-      $('#backup-encpassword-file').text(r.encpwfile);
-
       $('#backup-status tbody').html("");
       var total_disk_size = 0;
 
-      if (r.backups.length == 0) {
+      if (typeof r.backups == "undefined") {
+        var tr = $('<tr><td colspan="3">Backups are turned off.</td></tr>');
+        $('#backup-status tbody').append(tr);
+        return;
+      } else if (r.backups.length == 0) {
         var tr = $('<tr><td colspan="3">No backups have been made yet.</td></tr>');
         $('#backup-status tbody').append(tr);
       }
@@ -83,4 +152,62 @@ function show_system_backup() {
       $('#backup-total-size').text(nice_size(total_disk_size));
     })
 }
+
+function show_custom_backup() {
+    $(".backup-target-local, .backup-target-s3").hide();
+    api(
+      "/system/backup/config",
+      "GET",
+      { },
+      function(r) {
+        if (r.target == "file://" + r.file_target_directory) {
+          $("#backup-target-type").val("local");
+        } else if (r.target == "off") {
+          $("#backup-target-type").val("off");
+        } else if (r.target.substring(0, 5) == "s3://") {
+          $("#backup-target-type").val("s3");
+	  var hostpath = r.target.substring(5).split('/');
+          var host = hostpath.shift();
+          $("#backup-target-s3-host").val(host);
+          $("#backup-target-s3-path").val(hostpath.join('/'));
+        }
+        $("#backup-target-user").val(r.target_user);
+        $("#backup-target-pass").val(r.target_pass);
+        $("#min-age").val(r.min_age_in_days);
+        $('#backup-location').text(r.file_target_directory);
+        $('#backup-encpassword-file').text(r.enc_pw_file);
+        toggle_form()
+      })
+}
+
+function set_custom_backup() {
+  var target_type = $("#backup-target-type").val();
+  var target_user = $("#backup-target-user").val();
+  var target_pass = $("#backup-target-pass").val();
+  
+  var target;
+  if (target_type == "local" || target_type == "off")
+    target = target_type;
+  else if (target_type == "s3")
+    target = "s3://" + $("#backup-target-s3-host").val() + "/" + $("#backup-target-s3-path").val();
+
+  var min_age = $("#min-age").val();
+  api(
+    "/system/backup/config",
+    "POST",
+    {
+      target: target,
+      target_user: target_user,
+      target_pass: target_pass,
+      min_age: min_age
+    },
+    function(r) {
+      // Responses are multiple lines of pre-formatted text.
+      show_modal_error("Backup configuration", $("<pre/>").text(r), function() { show_system_backup(); }); // refresh after modal
+    },
+    function(r) {
+      show_modal_error("Backup configuration (error)", r);
+    });
+  return false;
+}
 </script>

setup/management.sh

@@ -4,9 +4,13 @@ source setup/functions.sh
 
 # build-essential libssl-dev libffi-dev python3-dev: Required to pip install cryptography.
 apt_install python3-flask links duplicity libyaml-dev python3-dnspython python3-dateutil \
-	build-essential libssl-dev libffi-dev python3-dev
+	build-essential libssl-dev libffi-dev python3-dev python-pip
-hide_output pip3 install --upgrade rtyaml email_validator idna cryptography
+hide_output pip3 install --upgrade rtyaml email_validator idna cryptography boto
-	# email_validator is repeated in setup/questions.sh
+
+# duplicity uses python 2 so we need to use the python 2 package of boto
+hide_output pip install --upgrade boto
+
+# email_validator is repeated in setup/questions.sh
 
 # Create a backup directory and a random key for encrypting backups.
 mkdir -p $STORAGE_ROOT/backup