diff options
Diffstat (limited to 'byteback-backup')
| -rw-r--r-- | byteback-backup | 187 |
1 files changed, 187 insertions, 0 deletions
diff --git a/byteback-backup b/byteback-backup new file mode 100644 index 0000000..52a7d28 --- /dev/null +++ b/byteback-backup @@ -0,0 +1,187 @@ +#!/usr/bin/ruby +# +# Back up this system to a byteback-enabled server (just some command line +# tools and SSH setup). We aim to make sure this backups are easy, complete +# and safe for most types of hosting customer. +# +# See 'man byteback' for more information. + +require 'trollop' +require 'resolv' + +HOSTNAME = `hostname -f` + +@sources = ["/"] +@exclude = ["/swap.file", "/var/backups/localhost"] + +def error(message) + STDERR.print "*** #{message}\n" + exit 1 +end + +def verbose(message) + print "#{message}\n" +end + +opts = Trollop::options do + + opt :destination, "Backup destination (i.e. user@host:/path)", + :type => :string + + opt :source, "Source paths", + :type => :strings + + opt :verbose, "Show rsync command and progress" + + opt :retry_number, "Number of retries on error", + :type => :integer, + :default => 3 + + opt :retry_delay, "Wait number of seconds between retries", + :type => :integer, + :default => 1800 + + opt :ssh_key, "SSH key for connection", + :type => :string, + :default => "/etc/byteback/key" +end + +@ssh_key = opts[:ssh_key] +@verbose = opts[:verbose] ? "--verbose" : nil +@sources = opts[:source] if opts[:source] +@destination = opts[:destination] +@retry_number = opts[:retry_number] +@retry_delay = opts[:retry_delay] + +if !@destination && File.exists?("/etc/byteback/destination") + @destination = File.read("/etc/byteback/destination").chomp +end +error("Must suply --destination or put it into /etc/bytebackup/destination") unless @destination + +_dummy, @destination_user, @destination_host, colon, @destination_path = + /^(.*)?(?:@)([^:]+)(:)(.*)?$/.match(@destination).to_a + +error("Must be a remote path") unless colon + +# Validate & normalise source directories +# +error("No sources specified") if @sources.empty? +@sources = @sources.map do |s| + s = s.gsub(/\/+/,"/") + error("Can't read directory #{s}") unless File.readable?(s) + s +end + +# Guess destination for backup +# +if !@destination + guesses = [] + Resolv::DNS.open do |dns| + suffix = HOSTNAME.split(".")[2..-1].join(".") + ["byteback." + suffix].each do |name| + [Resolv::DNS::Resource::IN::AAAA, + Resolv::DNS::Resource::IN::A].each do |record_type| + next if !guesses.empty? # only care about first result + guesses += dns.getresources(name, record_type) + end + end + end + + if guesses.empty? + error "Couldn't guess at backup host, please specify --destination" + end + + # ick, do I really have to do this to get a string represnetation of + # the IP address? + # + guess = guesses.first.inspect + match = / (.*)>$/.match(guess)[1] + error "Result #{guesses} is not an IP" if !match + @destination = "byteback@#{match[1]}:#{HOSTNAME}/current/" + + verbose "Guessed destination=#{@destination} from #{guess}" +end + +# Test ssh connection is good before we start +# +error("Could not read ssh key #{@ssh_key}") unless File.readable?(@ssh_key) + +error("Could not connect to #{@destination}") unless system( + "ssh", + "-a", + "-i", + @ssh_key, + @destination.split(":")[0], + "byteback-receive", + "--ping", + "#{@verbose}" +) + +# Call rsync to copy certain sources, returns exit status (see man rsync) +# +def rsync(*sources) + # Default options include --inplace because we only care about consistency + # at the end of the job, and rsync will do more work for big files without + # it. + # + args = [ + "rsync", + "--archive", + "--numeric-ids", + "--delete", + "--inplace", + "--rsync-path", + "rsync --fake-super", + "--rsh", + "ssh -a -i #{@ssh_key} -l #{@destination_user}", + "--delete", + "--one-file-system", + "--relative" + ] + + args << "--verbose" if @verbose + args += @exclude.map { |x| ["--exclude", x] }.flatten + args += sources + args << @destination + + print args.map { |a| / /.match(a) ? "\"#{a}\"" : a }.join(" ")+"\n" if @verbose + system(*args) + + return $?.exitstatus +end + +RSYNC_EXIT_STATUSES_TO_RETRY_ON = [10,11,20,21,22,23,24,30] + +# Run the file copy, retrying if necessary +# +loop do + status = rsync(*@sources) + + if status === 0 + break + elsif RSYNC_EXIT_STATUSES_TO_RETRY_ON.include?(status) + if @retry_number > 0 + @retry_number -= 1 + sleep @retry_delay + redo + else + error("Maximum number of rsync retries reached") + end + else + error("Fatal rsync error occurred (#{status})") + end +end + +# Mark the backup as done on the other end +# +error("Backup could not be marked complete") unless system( + "ssh", + "-a", + "-i", + @ssh_key, + @destination.split(":")[0], + "sudo", + "byteback-snapshot", + "--snapshot", + "#{@verbose}" +) |