I’m setting up automated offsite backups from my NSLU2 to Amazon S3. With suprisingly little effort, I’ve managed to get a tool called s3sync running on the “slug” (as it’s known). s3sync is a Ruby script, so in order to run it, I had to install Ruby, which in turn meant that I had to replace the slug’s firmware with a different version of Linux, called Unslung. All of this worked pretty much as advertised in the tools’ respective documentation – for the details, see the previous posts in this series.
Having confirmed that s3sync worked as I’d expect it to, I needed to install it in a sensible place – I’d previously just put it in /tmp – set it up so that I could use SSL to encrypt the data while it was on its way to Amazon, and then write a script to synchronise at least one of the directories I want backed up. I’d then be able to test the script, schedule it, test the scheduling, and then I’d be done!
First things first – I was getting annoyed with not having some of my favourite packages installed on the slug, so:
# ipkg install less Installing less (394-2) to root... Downloading http://ipkg.nslu2-linux.org/feeds/unslung/cross/less_394-2_armeb.ipk Installing ncursesw (5.5-1) to root... Downloading http://ipkg.nslu2-linux.org/feeds/unslung/cross/ncursesw_5.5-1_armeb.ipk Installing ncurses (5.5-1) to root... Downloading http://ipkg.nslu2-linux.org/feeds/unslung/cross/ncurses_5.5-1_armeb.ipk Configuring less Configuring ncurses Configuring ncursesw # ipkg install bash Installing bash (3.1-1) to root... Downloading http://ipkg.nslu2-linux.org/feeds/unslung/cross/bash_3.1-1_armeb.ipk Installing readline (5.1-1) to root... Downloading http://ipkg.nslu2-linux.org/feeds/unslung/cross/readline_5.1-1_armeb.ipk Configuring bash Configuring readline # ls /opt/bin/bash # /opt/bin/bash bash-3.1#
So, I edited
/etc/passwd to make
/opt/bin/bash the shell for root, logged out, then logged back in again.
OK, the next task was to installing s3sync somewhere sensible: I felt that
/home/s3sync was a good enough place for the s3sync script itself and my own shell scripts, so I put everything there:
-bash-3.1# cd /home -bash-3.1# mkdir s3sync -bash-3.1# cd s3sync -bash-3.1# mv /tmp/s3sync/* . -bash-3.1# ls HTTPStreaming.rb README.txt README_s3cmd.txt S3.rb S3_s3sync_mod.rb S3encoder.rb s3cmd.rb s3sync.rb s3try.rb thread_generator.rb -bash-3.1#
Next, it was necessary to install some root certificates so that it could use SSL to transfer data. Working from John Eberly’s post on how he set up s3sync, I did the following:
-bash-3.1# mkdir certs -bash-3.1# cd certs -bash-3.1# wget http://mirbsd.mirsolutions.de/cvs.cgi/~checkout~/src/etc/ssl.certs.shar Connecting to mirbsd.mirsolutions.de[188.8.131.52]:80 -bash-3.1# sh ssl.certs.shar x - 00869212.0 x - 052e396b.0 x - 0bb21872.0
x - f4996e82.0 x - f73e89fd.0 x - ff783690.0 -bash-3.1#
And now I could put in scripts to upload to S3, based on John Eberly’s:
-bash-3.1# cat > upload.sh #!/opt/bin/bash # script to sync local directory up to s3 cd /home/s3sync export AWS_ACCESS_KEY_ID=<my key ID> export AWS_SECRET_ACCESS_KEY=<my secret key> export SSL_CERT_DIR=/home/s3sync/certs ./s3sync.rb -r --ssl --delete "/user data/Giles/Catalogue" <my key ID>.Backups:/remotefolder -bash-3.1# chmod 700 upload.sh
The chmod was required to stop non-root users (of whom I naturally have hordes on the slug :-) from being able to read the private key. Better to be safe than sorry. The directory I was syncing is a very small subdirectory of the area I want to back up to S3.
Next, a download script:
-bash-3.1# cat > download.sh #!/opt/bin/bash # script to sync "directory" down from s3 cd /home/s3sync export AWS_ACCESS_KEY_ID=<my key ID> export AWS_SECRET_ACCESS_KEY=<my secret key> export SSL_CERT_DIR=/home/s3sync/certs ./s3sync.rb -r --ssl --delete <my key ID>:/remotefolder/Catalogue/ /downloads/ -bash-3.1# chmod 700 download.sh -bash-3.1#
Next, I created the <my key ID>.Backups bucket using jets3t Cockpit, and then ran the upload script:
-bash-3.1# ./upload.sh -bash-3.1#
A quick check confirmed that the data had been uploaded. However, I found myself thinking – I’d like the tool to log a bit more than that. s3sync’s usage said that there was a “-v” option to run it in verbose mode, so I set that in the upload script and reran it. There was still no output, but I suspected that that was simply because there were no changes to upload… so I deleted the data from S3 using jets3t Cockpit, and reran. This time I got output:
-bash-3.1# ./upload.sh Create node 19_Ejiri.jpg Create node 22_Okabe.jpg Create node 29_The_Original_Hachiman_Shrine_at_Suna_Village.jpg Create node 47_Kameyama.jpg -bash-3.1#
Time to test the download script (adding the -v to it first):
-bash-3.1# mkdir /downloads/ -bash-3.1# ./download.sh Create node 19_Ejiri.jpg Create node 22_Okabe.jpg Create node 29_The_Original_Hachiman_Shrine_at_Suna_Village.jpg Create node 47_Kameyama.jpg -bash-3.1# ls -lrt /downloads/ -rwxrw---- 1 guest everyone 578008 Nov 14 22:30 19_Ejiri.jpg -rwxrw---- 1 guest everyone 607822 Nov 14 22:30 22_Okabe.jpg -rwxrw---- 1 guest everyone 563472 Nov 14 22:30 29_The_Original_Hachiman_Shrine_at_Suna_Village.jpg -rwxrw---- 1 guest everyone 681194 Nov 14 22:31 47_Kameyama.jpg -bash-3.1# ls -lrt /user\ data/Giles/Catalogue/ -rwxrw---- 1 guest everyone 607822 Mar 17 2005 22_Okabe.jpg -rwxrw---- 1 guest everyone 578008 Mar 17 2005 19_Ejiri.jpg -rwxrw---- 1 guest everyone 681194 Mar 17 2005 47_Kameyama.jpg -rwxrw---- 1 guest everyone 563472 Mar 17 2005 29_The_Original_Hachiman_Shrine_at_Suna_Village.jpg
Hooray! So, finally, I decided to try syncing up my entire “user data” share on an
cron job, set to execute very soon. I modified the
upload.sh script to point to the correct directory, and then edited
/etc/crontab, adding a line saying:
42 22 * * * root /home/s3sync/upload.sh &> /tmp/s3sync.log
And then I waited until 10:42pm by the slug’s time (which, incidentally, seemed to have drifted a minute or so since the previous evening). At 10:42pm, I checked what processes were running:
-bash-3.1# ps auxww PID TTY Uid Size State Command 1 root 1212 S /bin/init 2 root 0 S [keventd]
1628 ttyp1 root 2100 S -bash 1715 root 2036 S /opt/bin/bash /home/s3sync/upload.sh 1716 root 12856 S /opt/bin/ruby ./s3sync.rb -v -r --ssl --del 1718 ttyp1 root 1984 R ps auxww -bash-3.1#
Excellent. The logfile was there; nothing had been written yet, but checking the bucket showed that data was already being copied up. My best guess was that the logfile would be flushed at a later point.
At this point, all I could really do was wait – so it was time to leave the slug for the day, ready to check the next. If everything had synchronised up correctly – and a download to another machine worked – then I would be able to say that I’d completed the project :-)
Next: Scheduling part 2