##(see the SpecSpec for an explanation)

 * '''Launchpad Entry''': UbuntuSpec:server-lucid-apt-mirror-ec2
 * '''Created''': NickBarcet
 * '''Contributors''': JamesTroup
 * '''Packages affected''': -

== Summary ==

Improve the way our mirrors works on EC2.  This is mainly an IS job.

== Release Note ==

Package mirrors on EC2 have been improve to provide more robustness and better service.

== Rationale ==

The current mirrors have the following problems: 
 * We assume that the mirror are not going to crash
 * Long time to recover from a crash
 * We need proper HA mirrors
 * From AWS SLA, you can loose a complete availability zone without a problem but mirrors withtin a round robin need to be completely in sync
    ==> we currently cannot guarantee this

== User stories ==

== Assumptions ==

== Design ==

Identical to what is offered today, just more robust

== Implementation ==

3 possible implementations to chose from:
 1. sync proxy type setup
   * a proxy within each zone, mirror syncing from it
   ==> has to be tested
   need 6 boxes total instead of 4
   
 1. LVM snapshots to make them sync transactionally
 
 1. Using squid (similar to 1) Peer squid in diffrent regions, upstream being archive.u.c

=== UI Changes ===

No UI

=== Code Changes ===



=== Migration ===

No user migration required

== Test/Demo Plan ==

== Unresolved issues ==



== BoF agenda and discussion ==
=== How does it work? ===
 * Can it work in S3 directly?
   * Problem with symlinks
   * never been looked at by IS
   * unappropriate packages for a ppa
   * would have been elegant to have a repo be directly in S3
   * would need to improve many things
    * need to add a methd to apt
    * need tools to update the mirror
    
 * plans for supporting fuse S3? -> scott moser

 [I tried creating an apt mirror in S3 using an rsync to an s3fs file system (fuse based).  It was taking days to do the initial copy so I abandoned it, but would be willing to provide steps to whoever is investigating this -- Eric Hammond] 

=== Problems ====

 * WE assume that the mirror are not going to crash
 * Long time to recover from a crash
 * We need proper HA mirrors
 * From AWS SLA, you can loose a complete region without a problem but mirrors withtin a round robin need to be completely in sync
    ==> we cannot guarantee this

  [Correction: The EC2 SLA assumes that an entire *availability zones* in a region can fail, but not an entire region --Eric Hammond]
  
=== Improvements ===
 * sync proxy type setup
   * a proxy within each zone, mirror syncing from it
   ==> has to be tested
   need 6 boxes total instead of 4
   
 * LVM snapshots to make them sync transactionally
 
 * Using squid (similar to 1) Peer squid in diffrent regions, upstream being archive.u.c
 
  * Should we talk with amazon ? Simon/Nick to try establish communitcation
  
  * Documentation ?? Not right now, but once it is in good shape, yes, it should
  
  * Would be usefull to have a recommandation for uec, but not basedon this work (not the same constraints -> not te same solution)
    Good candidate for a puppet reciepe


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