Archvsync ========= This is the central repository for the Debian mirror scripts. The scripts in this repository are written for the purposes of maintaining a Debian archive mirror (and shortly, a Debian bug mirror), but they should be easily generalizable. Currently the following scripts are available: * ftpsync - Used to sync an archive using rsync * runmirrors - Used to notify leaf nodes of available updates * dircombine - Internal script to manage the mirror user's $HOME on debian.org machines * typicalsync - Generates a typical Debian mirror * udh - We are lazy, just a shorthand to avoid typing the commands, ignore... :) Usage ===== For impatient people, short usage instruction: - Create a dedicated user for the whole mirror. - Create a seperate directory for the mirror, writeable by the new user. - Place the ftpsync script in the mirror user's $HOME/bin (or just $HOME) - Place the ftpsync.conf.sample into $HOME/etc as ftpsync.conf and edit it to suit your system. You should at the very least change the TO= and RSYNC_HOST lines. - Create $HOME/log (or wherever you point $LOGDIR to) - Setup the .ssh/authorized_keys for the mirror user and place the public key of your upstream mirror into it. Preface it with no-port-forwarding,no-X11-forwarding,no-agent-forwarding,no-pty,command="~/bin/ftpsync",from="IPADDRESS" and replace $IPADDRESS with that of your upstream mirror. - You are finished In order to receive different pushes or syncs from different archives, name the config file ftpsync-$ARCHIVE.conf and call the ftpsync script with the commandline "sync:archive:$ARCHIVE". Replace $ARCHIVE with a sensible value. If your upstream mirror pushes you using runmirrors bundled together with this sync script, you do not need to add the "sync:archive" parameter to the commandline, the scripts deal with it automatically. Debian mirror script minimum requirements ========================================= As always, you may use whatever scripts you want for your Debian mirror, but we *STRONGLY* recommend you to not invent your own. However, if you want to be listed as a mirror it *MUST* support the following minimal functionality: - Must perform a 2-stage sync The archive mirroring must be done in 2 stages. The first rsync run must ignore the index files. The correct exclude options for the first rsync run are: --exclude Packages* --exclude Sources* --exclude Release* --exclude ls-lR* The first stage must not delete any files. The second stage should then transfer the above excluded files and delete files that no longer belong on the mirror. Rationale: If archive mirroring is done in a single stage, there will be periods of time during which the index files will reference files not yet mirrored. - Must not ignore pushes whil(e|st) running. If a push is received during a run of the mirror sync, it MUST NOT be ignored. The whole synchronization process must be rerun. Rationale: Most implementations of Debian mirror scripts will leave the mirror in an inconsistent state in the event of a second push being received while the first sync is still running. It is likely that in the near future, the frequency of pushes will increase. - Should understand multi-stage pushes. The script should parse the arguments it gets via ssh, and if they contain a hint to only sync stage1 or stage2, then ONLY those steps SHOULD be performed. Rationale: This enables us to coordinate the timing of the first and second stage pushes and minimize the time during which the archive is desynchronized. This is especially important for mirrors that are involved in a round robin or GeoDNS setup. The minimum arguments the script has to understand are: sync:stage1 Only sync stage1 sync:stage2 Only sync stage2 sync:all Do everything. Default if none of stage1/2 are present. There are more possible arguments, for a complete list see the ftpsync script in our git repository. ftpsync ======= This script is based on the old anonftpsync script. It has been rewritten to add flexibilty and fix a number of outstanding issues. Some of the advantages of the new version are: - Nearly every aspect is configurable - Correct support for multiple pushes - Support for multi-stage archive synchronisations - Support for hook scripts at various points - Support for multiple archives, even if they are pushed using one ssh key - Support for multi-hop, multi-stage archive synchronisations Correct support for multiple pushes ----------------------------------- When the script receives a second push while it is running and syncing the archive it won't ignore it. Instead it will rerun the synchronisation step to ensure the archive is correctly synchronised. Scripts that fail to do that risk ending up with an inconsistent archive. Can do multi-stage archive synchronisations ------------------------------------------- The script can be told to only perform the first or second stage of the archive synchronisation. This enables us to send all the binary packages and sources to a number of mirrors, and then tell all of them to sync the Packages/Release files at once. This will keep the timeframe in which the mirrors are out of sync very small and will greatly help things like DNS RR entries or even the planned GeoDNS setup. Multi-hop, multi-stage archive synchronisations ----------------------------------------------- The script can be told to perform a multi-hop multi-stage archive synchronisation. This is basically the same as the multi-stage synchronisation explained above, but enables the downstream mirror to push his own staged/multi-hop downstreams before returning. This has the same advantage than the multi-stage synchronisation but allows us to do this over multiple level of mirrors. (Imagine one push going from Europe to Australia, where then locally 3 others get updated before stage2 is sent out. Instead of 4times transferring data from Europe to Australia, just to have them all updated near instantly). Can run hook scripts -------------------- ftpsync currently allows 5 hook scripts to run at various points of the mirror sync run. Hook1: After lock is acquired, before first rsync Hook2: After first rsync, if successful Hook3: After second rsync, if successful Hook4: Right before leaf mirror triggering Hook5: After leaf mirror trigger (only if we have slave mirrors; HUB=true) Note that Hook3 and Hook4 are likely to be called directly after each other. The difference is that Hook3 is called *every* time the second rsync succeeds even if the mirroring needs to re-run due to a second push. Hook4 is only executed if mirroring is completed. Support for multiple archives, even if they are pushed using one ssh key ------------------------------------------------------------------------ If you get multiple archives from your upstream mirror (say Debian, Debian-Backports and Volatile), previously you had to use 3 different ssh keys to be able to automagically synchronize them. This script can do it all with just one key, if your upstream mirror tells you which archive. See "Commandline/SSH options" below for further details. For details of all available options, please see the extensive documentation in the sample configuration file. Commandline/SSH options ======================= Script options may be set either on the local command line, or passed by specifying an ssh "command". Local commandline options always have precedence over the SSH_ORIGINAL_COMMAND ones. Currently this script understands the options listed below. To make them take effect they MUST be prepended by "sync:". Option Behaviour stage1 Only do stage1 sync stage2 Only do stage2 sync all Do a complete sync (default) mhop Do a multi-hop sync archive:foo Sync archive foo (if the file $HOME/etc/ftpsync-foo.conf exists and is configured) callback Call back when done (needs proper ssh setup for this to work). It will always use the "command" callback:$HOSTNAME where $HOSTNAME is the one defined in config and will happen before slave mirrors are triggered. So, to get the script to sync all of the archive behind bpo and call back when it is complete, use an upstream trigger of ssh $USER@$HOST sync:all sync:archive:bpo sync:callback Mirror trace files ================== Every mirror needs to have a 'trace' file under project/trace. The file format is as follows: The filename has to be the full hostname (eg. hostname -f), or in the case of a mirror participating in RR DNS (where users will never use the hostname) the name of the DNS RR entry, eg. security.debian.org for the security rotation) The content has (no leading spaces): Sat Nov 8 13:20:22 UTC 2008 Used ftpsync version: 42 Running on host: steffani.debian.org First line: Output of date -u Second line: Freeform text containing the program name and version Third line: Text "Running on host: " followed by hostname -f The third line MUST NOT be the DNS RR name, even if the mirror is part of it. It MUST BE the hosts own name. This is in contrast to the filename, which SHOULD be the DNS RR name. runmirrors ========== This script is used to tell leaf mirrors that it is time to synchronize their copy of the archive. This is done by parsing a mirror list and using ssh to "push" the leaf nodes. You can read much more about the principle behind the push at [1], essentially it tells the receiving end to run a pre-defined script. As the whole setup is extremely limited and the ssh key is not usable for anything else than the pre-defined script this is the most secure method for such an action. This script supports two types of pushes: The normal single stage push, as well as the newer multi-stage push. The normal push, as described above, will simply push the leaf node and then go on with the other nodes. The multi-staged push first pushes a mirror and tells it to only do a stage1 sync run. Then it waits for the mirror (and all others being pushed in the same run) to finish that run, before it tells all of the staged mirrors to do the stage2 sync. This way you can do a nearly-simultaneous update of multiple hosts. This is useful in situations where periods of desynchronization should be kept as small as possible. Examples of scenarios where this might be useful include multiple hosts in a DNS Round Robin entry. For details on the mirror list please see the documented runmirrors.mirror.sample file. [1] http://blog.ganneff.de/blog/2007/12/29/ssh-triggers.html