1 .. -*- coding: utf-8 -*-

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     3 Migrating cubicweb instances - benefits from a distributed architecture

     4 =======================================================================

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     6 Migrate apache & cubicweb

     7 -------------------------

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     9 **Aim** : do the migration for N cubicweb instances hosted on a server to another with no downtime.

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    11 **Prerequisites** : have an explicit definition of the database host (not default or localhost). In our case, the database is hosted on another host.

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    13 **Steps** :

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    15 1. *on new machine* : install your environment (*pseudocode*) ::

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    17      apt-get install cubicweb cubicweb-applications apache2

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    19 2. *on old machine* : copy your cubicweb and apache configuration to the new machine ::

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    21     scp /etc/cubicweb.d/ newmachine:/etc/cubicweb.d/

    22     scp /etc/apache2/sites-available/ newmachine:/etc/apache2/sites-available/

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    24 3. *on new machine* : start your instances ::

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    26      cubicweb start

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    28 4. *on new machine* : enable sites and modules for apache and start it, test it using by modifying your /etc/host file.

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    30 5. change dns entry from your oldmachine to newmachine

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    32 6. shutdown your *old machine* (if it doesn't host other services or your database)

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    34 7. That's it.

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    36 **Possible enhancements** : use right from the start a pound server behind your apache, that way you can add backends and smoothily migrate by shuting down backends that pound will take into account.

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    38