Initial configuration steps on all platforms

Creating a file tree

If you haven’t got a file tree yet, you should create it now.

Make the directory for the file tree and fill it:

mkdir /srv/mytree
rsync .... /srv/mytree

Note that this file tree is a necessary prerequisite to running MirrorBrain, even though it intercepts the requests to those files and redirects them to mirrors.

Having said that, there is a way to get by without local files, which is by using the null-rsync (found in the source tree) tool instead of rsync to pull the files. null-rsync is used exactly as rsync, but it will create a pseudo file tree that requires very few local space. However, since those files are filled with zeroes (!), it is important to make sure that MirrorBrain never delivers content from those files. That is achieved by using the MirrorBrainFallback directive to define some mirrors that are always available and are guaranteed to have all those files. (The directive can be configured individually per directory in Apache config.) See the 2.11.0 release notes for details.

Note that if you do have the real files locally, you can automatically maintain cryptographic hashes of them in the database; running with pseudo files cuts on some very useful features. In addition, the local files are always available to deliver them directly, which is a good fallback behaviour for files that are not mirrored at all, files that have not arrived on any mirror just yet, and so on. Of course, you can also make sure that files are never delivered from the redirector (in other words, it redirects always).

Note

In summary: a tree with real files is required, if you want to serve any hashes, zsync, or torrents. But you can make sure that the content is always redirected. The “fake tree” that you can create with null-rsync is good only for pure redirection. (And Metalinks without hashes.) The server doesn’t know any content then; only file path, size, mtime, nothing else.

Creating mirrorbrain.conf

Create a configuration file named /etc/mirrorbrain.conf with the content below:

[general]
instances = main

[main]
dbuser = mirrorbrain
dbpass = 12345
dbdriver = postgresql
dbhost = 127.0.0.1
# optional: dbport = ...
dbname = mirrorbrain

[mirrorprobe]
# logfile = /var/log/mirrorbrain/mirrorprobe.log
# loglevel = INFO

Note

The database password in the above template is only a placeholder and you need to edit it: change it to the actual password, the one that you gave when you ran PostgreSQL’s createuser command. Likewise, make sure that you picked the same username.

Set the following permissions and privileges on the file:

sudo chmod 0640 /etc/mirrorbrain.conf
sudo chown root:mirrorbrain /etc/mirrorbrain.conf

Other possible options per MirrorBrain instance are:

scan_top_include

Directory names separated by spaces. Meaning: Scan only these directories, and ignore all other directories at the top level.

scan_exclude_rsync

Exclude list for rsync scans (same rules as for rsyncs option --exclude apply). Meaning: Ignore all directories or path names that match, everywhere in the tree.

scan_exclude

Exclude list for FTP scans. Meaning: Ignore all directories or path names that match, everywhere in the tree.

Testing the database admin tool

At this point, you should be able to type the following command without getting an error:

mb list

It’ll produce no output, but exit with 0. If it gives an error, something is wrong.

Note

Do this to verify that the previous steps have been completed successfully.

Likewise, the following command should not return any error, but rather displays its usage info. If so, the installation should be quite fine:

mb help

Also, the following should work (you might have to change the path to /usr/share/GeoIP for your system):

 % geoiplookup_continent -f /var/lib/GeoIP/GeoIP.dat www.slashdot.org
NA

The NA stands for North America and indicates that the GeoIP lookup works correctly.

Creating some mirrors

Collect a list of mirrors (their HTTP baseurl, and their rsync or FTP baseurl for scanning). For example:

http://ftp.isr.ist.utl.pt/pub/MIRRORS/ftp.suse.com/projects/
rsync://ftp.isr.ist.utl.pt/suse/projects/

http://ftp.kddilabs.jp/Linux/distributions/ftp.suse.com/projects/
rsync://ftp.kddilabs.jp/suse/projects/

Now you need to enter the mirrors into the database; it could be done using the “mb” mirrorbrain tool. (See ‘mb help new’ for full option list.):

mb new ftp.isr.ist.utl.pt \
       --http http://ftp.isr.ist.utl.pt/pub/MIRRORS/ftp.suse.com/projects/ \
       --rsync rsync://ftp.isr.ist.utl.pt/suse/projects/

mb new ftp.kddilabs.jp \
       --http http://ftp.kddilabs.jp/Linux/distributions/ftp.suse.com/projects/ \
       --rsync rsync://ftp.kddilabs.jp/suse/projects/

The tool automatically figures out the GeoIP location of each mirror by itself. But you could also specify them on the commandline.

If you want to edit a mirror later, use:

mb edit <identifier>

To simply display a mirror, you could use ‘mb show kddi’, for instance.

Finally, each mirror needs to be scanned and enabled:

mb scan --enable <identifier>

See the output of mb help for more commands. Refer to Maintaining the mirror database for a full reference documentation to the mb tool.

Setting up required cron jobs

Setting up mirror monitoring

Mirror monitoring needs to be set up to run automatically. Put this into /etc/crontab:

The following cron job is needed to check which mirrors are reachable. This command is responsible for checking the mirrors in short intervals, and marking them online/offline in the database:

* * * * *                 mirrorbrain   mirrorprobe

Setting up mirror scanning

Configure mirror scanning:

45 * * * *                mirrorbrain   mb scan --quiet --jobs 4 --all

Use more parallel scanners (-j|--jobs ...) if you have a beefy machine.

The --quiet option can be used twice (e.g. as -qq), which will totally silence the scanner, except for error messages. This means that you get a mail only when there is something wrong.

Maintenance

Another cron job is useful to remove unreferenced files from the database:

# Monday: database clean-up day...
30 1 * * mon              mirrorbrain   mb db vacuum

Keeping the GeoIP database uptodate

The GeoIP database is changed at least once a month, so a new copy should be downloaded regularly:

# update GeoIP database on Mondays
31 2 * * mon              root  sleep $(($RANDOM/1024)); /usr/bin/geoip-lite-update

(The ‘sleep’ is there so you can copy the line, don’t need to adjust the time, and still the GeoIP servers will not get a lot of simultaneous hits at exactly the same time. That’s all.)

Testing

TODO: describe how to test that the install was successful
(When testing, consider any excludes that you configured, and which might introduce confusion.)
  • Many HTTP clients can be used for testing, but cURL is a most helpful tool for that. Here are some examples.

    Showy the HTTP response code and the Location header pointing to the new location:

    curl -sI <url>

    Display the metalink:

    curl -s <url>.metalink

    Show a HTML list with the available mirrors:

    curl -s <url>?mirrorlist

Setting up logging

You may want to log more details than Apache normally logs into the access_log file. You can define a new log format that gives you an access_log, with details from MirrorBrain added:

LogFormat "%h %l %u %t \"%r\" %>s %b \"%{Referer}i\" \"%{User-Agent}i\" \
want:%{WANT}e give:%{GIVE}e r:%{MB_REALM}e %{X-MirrorBrain-Mirror}o \
%{MB_CONTINENT_CODE}e:%{MB_COUNTRY_CODE}e ASN:%{ASN}e P:%{PFX}e \
size:%{MB_FILESIZE}e %{Range}i" combined_redirect

This defines a new log format called “combined_redirect”, which you can use in your virtual hosts with the CustomLog directive.

Instead of:

CustomLog /var/log/apache2/myhost/access_log combined

you would use:

CustomLog /var/log/apache2/myhost/access_log combined_redirect

Creating hashes

First, add some configuration (example):

MirrorBrainMetalinkPublisher "openSUSE" http://download.opensuse.org

You need to create a directory where to store the hashes. For instance, /srv/hashes/srv/opensuse. Note that the full pathname to the filetree (/srv/opensuse) is part of this target path.

Make the directory owned by the mirrorbrain user.

Now, create the hashes with the following command. It is best run as unprivileged user (mirrorbrain):

mb makehashes /srv/opensuse -t /srv/hashes/srv/opensuse

Add the hashing command to /etc/crontab to be run every few hours. Alternatively, run it after changes in the file tree happen, coupled to some trigger etc.

Note

The path names used here need to match the DocumentRoot in Apache’s virtual host setup.

(This command was called metalink-hasher in previous releases of MirrorBrain.)

Optional things you might want

  • further things that you might want to configure:

    • mod_autoindex_mb, a replacement for the standard module mod_autoindex:

      a2dismod autoindex
      a2enmod autoindex_mb
      Add IndexOptions Mirrorlist
      # or IndexOptions +Mirrorlist, depending on your config (if you have options
      # that are inherited from above in the tree, and you just want to add this one here)
    • add a link to a CSS stylesheet for mirror lists:

      MirrorBrainMirrorlistStylesheet "http://static.opensuse.org/css/mirrorbrain.css"

      and for the autoindex:

      IndexStyleSheet "http://static.opensuse.org/css/mirrorbrain.css"

Configuring GeoIP

Note

It is better to use the larger GeoLiteCity database, instead of the minimal GeoIP database that contains only country information. With the more detailed info in the former database, a better mirror selection is achieved in many cases.

Edit /etc/apache2/conf.d/mod_geoip.conf:

<IfModule mod_geoip.c>
   GeoIPEnable On
   GeoIPDBFile /var/lib/GeoIP/GeoLiteCity.dat.updated
   #GeoIPOutput [Notes|Env|All]
   GeoIPOutput Env
</IfModule>

(Change GeoIPOutput All to GeoIPOutput Env)

Note that a caching mode like MMapCache needs to be used, when Apache runs with the worker MPM.In this case, use:

<IfModule mod_geoip.c>
   GeoIPEnable On
   GeoIPDBFile /var/lib/GeoIP/GeoLiteCity.dat.updated MMapCache
   GeoIPOutput Env
</IfModule>

Seting up automatic updates of the GeoIP database

New versions of the GeoIP database are released each month. You can set up a cron job to automatically fetch new updates as follows. If you do that, make sure to set the GeoIPDBFile path (see above) to /var/lib/GeoIP/GeoLiteCity.dat.updated:

# update GeoIP database on Mondays
31 2 * * mon   root    sleep $(($RANDOM/1024)); /usr/bin/geoip-lite-update

Creating a virtual host

Maybe create a DNS alias for your web host, if needed.

Note

A complete reference of all Apache directives can be found here.

The following snippet would create a new site as virtual host:

sudo sh -c "cat > /etc/apache2/sites-available/mirrorbrain << EOF
<VirtualHost 127.0.0.1>
    ServerName mirrors.example.org
    ServerAdmin webmaster@example.org
    DocumentRoot /var/www/downloads
    ErrorLog     /var/log/apache2/mirrors.example.org/error.log
    CustomLog    /var/log/apache2/mirrors.example.org/access.log combined
    <Directory /var/www/downloads>
        MirrorBrainEngine On
        MirrorBrainDebug Off
        FormGET On
        MirrorBrainHandleHEADRequestLocally Off
        MirrorBrainMinSize 2048
        MirrorBrainExcludeUserAgent rpm/4.4.2*
        MirrorBrainExcludeUserAgent *APT-HTTP*
        MirrorBrainExcludeMimeType application/pgp-keys
        Options FollowSymLinks Indexes
        AllowOverride None
        Order allow,deny
        Allow from all
    </Directory>
</VirtualHost>
EOF
"

Another example:

<VirtualHost your.host.name:80>
    ServerName samba.mirrorbrain.org

    ServerAdmin webmaster@example.org

    DocumentRoot /srv/samba/pub/projects

    ErrorLog     /var/log/apache/samba.mirrorbrain.org/logs/error_log
    CustomLog    /var/log/apache/samba.mirrorbrain.org/logs/access_log combined

    <Directory /srv/samba/pub/projects>
        MirrorBrainEngine On
        MirrorBrainDebug Off
        FormGET On
        MirrorBrainHandleHEADRequestLocally Off
        MirrorBrainMinSize 2048
        MirrorBrainExcludeUserAgent rpm/4.4.2*
        MirrorBrainExcludeUserAgent *APT-HTTP*
        MirrorBrainExcludeMimeType application/pgp-keys

        Options FollowSymLinks Indexes
        AllowOverride None
        Order allow,deny
        Allow from all
    </Directory>

</VirtualHost>

Make the log directory for the virtual host:

sudo mkdir /var/log/apache2/mirrors.example.org/

Enable the site:

sudo a2ensite mirrorbrain

Restart Apache, best while watching the error log:

sudo tail -f /var/log/apache2/error.log &
sudo /etc/init.d/apache2 restart