S3cmd tool for Amazon Simple Storage Service (S3)

=================================================

Author:

Michal Ludvig <[email protected]>

S3tools / S3cmd project homepage:

http://s3tools.org

S3tools / S3cmd mailing lists:

* Announcements of new releases:

[email protected]

* General questions and discussion about usage

[email protected]

* Bug reports

[email protected]

Amazon S3 homepage:

http://aws.amazon.com/s3

!!!

!!! Please consult INSTALL file for installation instructions!

!!!

What is Amazon S3

-----------------

Amazon S3 provides a managed internet-accessible storage

service where anyone can store any amount of data and

retrieve it later again. Maximum amount of data in one

"object" is 5GB, maximum number of objects is not limited.

S3 is a paid service operated by the well known Amazon.com

internet book shop. Before storing anything into S3 you

must sign up for an "AWS" account (where AWS = Amazon Web

Services) to obtain a pair of identifiers: Access Key and

Secret Key. You will need to give these keys to S3cmd.

Think of them as if they were a username and password for

your S3 account.

Pricing explained

-----------------

At the time of this writing the costs of using S3 are (in USD):

$0.15 per GB per month of storage space used

plus

$0.10 per GB - all data uploaded

plus

$0.18 per GB - first 10 TB / month data downloaded

$0.16 per GB - next 40 TB / month data downloaded

$0.13 per GB - data downloaded / month over 50 TB

plus

$0.01 per 1,000 PUT or LIST requests

$0.01 per 10,000 GET and all other requests

If for instance on 1st of January you upload 2GB of

photos in JPEG from your holiday in New Zealand, at the

end of January you will be charged $0.30 for using 2GB of

storage space for a month, $0.20 for uploading 2GB

of data, and a few cents for requests.

That comes to slightly over $0.50 for a complete backup

of your precious holiday pictures.

In February you don't touch it. Your data are still on S3

servers so you pay $0.30 for those two gigabytes, but not

a single cent will be charged for any transfer. That comes

to $0.30 as an ongoing cost of your backup. Not too bad.

In March you allow anonymous read access to some of your

pictures and your friends download, say, 500MB of them.

As the files are owned by you, you are responsible for the

costs incurred. That means at the end of March you'll be

charged $0.30 for storage plus $0.09 for the download traffic

generated by your friends.

There is no minimum monthly contract or a setup fee. What

you use is what you pay for. At the beginning my bill used

to be like US$0.03 or even nil.

That's the pricing model of Amazon S3 in a nutshell. Check

Amazon S3 homepage at http://aws.amazon.com/s3 for more

details.

Needless to say that all these money are charged by Amazon

itself, there is obviously no payment for using S3cmd :-)

Amazon S3 basics

----------------

Files stored in S3 are called "objects" and their names are

officially called "keys". Since this is sometimes confusing

for the users we often refer to the objects as "files" or

"remote files". Each object belongs to exactly one "bucket".

To describe objects in S3 storage we invented a URI-like

schema in the following form:

s3://BUCKET

or

s3://BUCKET/OBJECT

Buckets

-------

Buckets are sort of like directories or folders with some

restrictions:

1) each user can only have 100 buckets at the most,

2) bucket names must be unique amongst all users of S3,

3) buckets can not be nested into a deeper hierarchy and

4) a name of a bucket can only consist of basic alphanumeric

characters plus dot (.) and dash (-). No spaces, no accented

or UTF-8 letters, etc.

It is a good idea to use DNS-compatible bucket names. That

for instance means you should not use upper case characters.

While DNS compliance is not strictly required some features

described below are not available for DNS-incompatible named

buckets. One more step further is using a fully qualified

domain name (FQDN) for a bucket - that has even more benefits.

* For example "s3://--My-Bucket--" is not DNS compatible.

* On the other hand "s3://my-bucket" is DNS compatible but

is not FQDN.

* Finally "s3://my-bucket.s3tools.org" is DNS compatible

and FQDN provided you own the s3tools.org domain and can

create the domain record for "my-bucket.s3tools.org".

Look for "Virtual Hosts" later in this text for more details

regarding FQDN named buckets.

Objects (files stored in Amazon S3)

-----------------------------------

Unlike for buckets there are almost no restrictions on object

names. These can be any UTF-8 strings of up to 1024 bytes long.

Interestingly enough the object name can contain forward

slash character (/) thus a "my/funny/picture.jpg" is a valid

object name. Note that there are not directories nor

buckets called "my" and "funny" - it is really a single object

name called "my/funny/picture.jpg" and S3 does not care at

all that it _looks_ like a directory structure.

The full URI of such an image could be, for example:

s3://my-bucket/my/funny/picture.jpg

Public vs Private files

-----------------------

The files stored in S3 can be either Private or Public. The

Private ones are readable only by the user who uploaded them

while the Public ones can be read by anyone. Additionally the

Public files can be accessed using HTTP protocol, not only

using s3cmd or a similar tool.

The ACL (Access Control List) of a file can be set at the

time of upload using --acl-public or --acl-private options

with 's3cmd put' or 's3cmd sync' commands (see below).

Alternatively the ACL can be altered for existing remote files

with 's3cmd setacl --acl-public' (or --acl-private) command.

Simple s3cmd HowTo

------------------

1) Register for Amazon AWS / S3

Go to http://aws.amazon.com/s3, click the "Sign up

for web service" button in the right column and work

through the registration. You will have to supply

your Credit Card details in order to allow Amazon

charge you for S3 usage.

At the end you should have your Access and Secret Keys

2) Run "s3cmd --configure"

You will be asked for the two keys - copy and paste

them from your confirmation email or from your Amazon

account page. Be careful when copying them! They are

case sensitive and must be entered accurately or you'll

keep getting errors about invalid signatures or similar.

Remember to add ListAllMyBuckets permissions to the keys

or you will get an AccessDenied error while testing access.

3) Run "s3cmd ls" to list all your buckets.

As you just started using S3 there are no buckets owned by

you as of now. So the output will be empty.

4) Make a bucket with "s3cmd mb s3://my-new-bucket-name"

As mentioned above the bucket names must be unique amongst

_all_ users of S3. That means the simple names like "test"

or "asdf" are already taken and you must make up something

more original. To demonstrate as many features as possible

let's create a FQDN-named bucket s3://public.s3tools.org:

~$ s3cmd mb s3://public.s3tools.org

Bucket 's3://public.s3tools.org' created

5) List your buckets again with "s3cmd ls"

Now you should see your freshly created bucket

~$ s3cmd ls

2009-01-28 12:34 s3://public.s3tools.org

6) List the contents of the bucket

~$ s3cmd ls s3://public.s3tools.org

~$

It's empty, indeed.

7) Upload a single file into the bucket:

~$ s3cmd put some-file.xml s3://public.s3tools.org/somefile.xml

some-file.xml -> s3://public.s3tools.org/somefile.xml [1 of 1]

123456 of 123456 100% in 2s 51.75 kB/s done

Upload a two directory tree into the bucket's virtual 'directory':

~$ s3cmd put --recursive dir1 dir2 s3://public.s3tools.org/somewhere/

File 'dir1/file1-1.txt' stored as 's3://public.s3tools.org/somewhere/dir1/file1-1.txt' [1 of 5]

File 'dir1/file1-2.txt' stored as 's3://public.s3tools.org/somewhere/dir1/file1-2.txt' [2 of 5]

File 'dir1/file1-3.log' stored as 's3://public.s3tools.org/somewhere/dir1/file1-3.log' [3 of 5]

File 'dir2/file2-1.bin' stored as 's3://public.s3tools.org/somewhere/dir2/file2-1.bin' [4 of 5]

File 'dir2/file2-2.txt' stored as 's3://public.s3tools.org/somewhere/dir2/file2-2.txt' [5 of 5]

As you can see we didn't have to create the /somewhere

'directory'. In fact it's only a filename prefix, not

a real directory and it doesn't have to be created in

any way beforehand.

8) Now list the bucket contents again:

~$ s3cmd ls s3://public.s3tools.org

DIR s3://public.s3tools.org/somewhere/

2009-02-10 05:10 123456 s3://public.s3tools.org/somefile.xml

Use --recursive (or -r) to list all the remote files:

~$ s3cmd ls s3://public.s3tools.org

2009-02-10 05:10 123456 s3://public.s3tools.org/somefile.xml

2009-02-10 05:13 18 s3://public.s3tools.org/somewhere/dir1/file1-1.txt

2009-02-10 05:13 8 s3://public.s3tools.org/somewhere/dir1/file1-2.txt

2009-02-10 05:13 16 s3://public.s3tools.org/somewhere/dir1/file1-3.log

2009-02-10 05:13 11 s3://public.s3tools.org/somewhere/dir2/file2-1.bin

2009-02-10 05:13 8 s3://public.s3tools.org/somewhere/dir2/file2-2.txt

9) Retrieve one of the files back and verify that it hasn't been

corrupted:

~$ s3cmd get s3://public.s3tools.org/somefile.xml some-file-2.xml

s3://public.s3tools.org/somefile.xml -> some-file-2.xml [1 of 1]

123456 of 123456 100% in 3s 35.75 kB/s done

~$ md5sum some-file.xml some-file-2.xml

39bcb6992e461b269b95b3bda303addf some-file.xml

39bcb6992e461b269b95b3bda303addf some-file-2.xml

Checksums of the original file matches the one of the

retrieved one. Looks like it worked :-)

To retrieve a whole 'directory tree' from S3 use recursive get:

~$ s3cmd get --recursive s3://public.s3tools.org/somewhere

File s3://public.s3tools.org/somewhere/dir1/file1-1.txt saved as './somewhere/dir1/file1-1.txt'

File s3://public.s3tools.org/somewhere/dir1/file1-2.txt saved as './somewhere/dir1/file1-2.txt'

File s3://public.s3tools.org/somewhere/dir1/file1-3.log saved as './somewhere/dir1/file1-3.log'

File s3://public.s3tools.org/somewhere/dir2/file2-1.bin saved as './somewhere/dir2/file2-1.bin'

File s3://public.s3tools.org/somewhere/dir2/file2-2.txt saved as './somewhere/dir2/file2-2.txt'

Since the destination directory wasn't specified s3cmd

saved the directory structure in a current working

directory ('.').

There is an important difference between:

get s3://public.s3tools.org/somewhere

and

get s3://public.s3tools.org/somewhere/

(note the trailing slash)

S3cmd always uses the last path part, ie the word

after the last slash, for naming files.

In the case of s3://.../somewhere the last path part

is 'somewhere' and therefore the recursive get names

the local files as somewhere/dir1, somewhere/dir2, etc.

On the other hand in s3://.../somewhere/ the last path

part is empty and s3cmd will only create 'dir1' and 'dir2'

without the 'somewhere/' prefix:

~$ s3cmd get --recursive s3://public.s3tools.org/somewhere /tmp

File s3://public.s3tools.org/somewhere/dir1/file1-1.txt saved as '/tmp/dir1/file1-1.txt'

File s3://public.s3tools.org/somewhere/dir1/file1-2.txt saved as '/tmp/dir1/file1-2.txt'

File s3://public.s3tools.org/somewhere/dir1/file1-3.log saved as '/tmp/dir1/file1-3.log'

File s3://public.s3tools.org/somewhere/dir2/file2-1.bin saved as '/tmp/dir2/file2-1.bin'

See? It's /tmp/dir1 and not /tmp/somewhere/dir1 as it

was in the previous example.

10) Clean up - delete the remote files and remove the bucket:

Remove everything under s3://public.s3tools.org/somewhere/

~$ s3cmd del --recursive s3://public.s3tools.org/somewhere/

File s3://public.s3tools.org/somewhere/dir1/file1-1.txt deleted

File s3://public.s3tools.org/somewhere/dir1/file1-2.txt deleted

...

Now try to remove the bucket:

~$ s3cmd rb s3://public.s3tools.org

ERROR: S3 error: 409 (BucketNotEmpty): The bucket you tried to delete is not empty

Ouch, we forgot about s3://public.s3tools.org/somefile.xml

We can force the bucket removal anyway:

~$ s3cmd rb --force s3://public.s3tools.org/

WARNING: Bucket is not empty. Removing all the objects from it first. This may take some time...

File s3://public.s3tools.org/somefile.xml deleted

Bucket 's3://public.s3tools.org/' removed

Hints

-----

The basic usage is as simple as described in the previous

section.

You can increase the level of verbosity with -v option and

if you're really keen to know what the program does under

its bonet run it with -d to see all 'debugging' output.

After configuring it with --configure all available options

are spitted into your ~/.s3cfg file. It's a text file ready

to be modified in your favourite text editor.

For more information refer to:

* S3cmd / S3tools homepage at http://s3tools.org

* Amazon S3 homepage at http://aws.amazon.com/s3

Enjoy!

Michal Ludvig

* [email protected]

* http://www.logix.cz/michal