10. Migrating cubicweb instances - benefits from a distributed architecture¶
10.1. Migrate apache & cubicweb¶
Aim : do the migration for N cubicweb instances hosted on a server to another with no downtime.
Prerequisites : have an explicit definition of the database host (not default or localhost). In our case, the database is hosted on another host.
Steps :
on new machine : install your environment (pseudocode)
apt-get install cubicweb cubicweb-applications apache2
on old machine : copy your cubicweb and apache configuration to the new machine
scp /etc/cubicweb.d/ newmachine:/etc/cubicweb.d/ scp /etc/apache2/sites-available/ newmachine:/etc/apache2/sites-available/
on new machine : start your instances
cubicweb start
on new machine : enable sites and modules for apache and start it, test it using by modifying your /etc/host file.
change dns entry from your oldmachine to newmachine
shutdown your old machine (if it doesn’t host other services or your database)
That’s it.
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.