Tomo in production

[francois0690]

Hi,

I'm looking for best practice for using Tomo in a production environnement.

• Size of /var/www/my-app/releases/ folder

How do I use Tomo to delete all other folders except the currently used version?
(I can do it manually but I can do a mistake with rm command...)

• Multiple update for load-balancing

I have two front end Rails server for load balancing, I would like to push a new version to both at the same time.
Maybe can I open two terminals and run the following two commands at the same time?

tomo deploy --config .tomo/config_host1.rb
tomo deploy --config .tomo/config_host2.rb

• New release but same DB

I have another serveur for Posgresql only.
If I want to keep my data could you please confirm me that the best way to do that is to disable the run "rails:db_seed" task in the deploy do block in config.rb file?
This will not prevent eventual migrations but will not destroy the data.

All other advice to secure the process of updating a production application is welcome.

Thanks for Tomo !

[mattbrictson]

Hi @francois0690 ! Good questions.

How do I use Tomo to delete all other folders except the currently used version?

This happens automatically when the core:clean_releases task runs (it should be near the end of your deploy block). By default, it will keep the most recent 10 release folders and delete the older ones. If you want to keep only 1 release, add this setting to your .tomo/config.rb file:

set keep_releases: 1

Multiple update for load-balancing

Tomo is designed to deploy to multiple servers simultaneously. In your .tomo/config.rb, add a host line for each server, like this:

host "deployer@www1.example.com"
host "deployer@www2.example.com"

Now you can run tomo setup to set up both machines simultaneously, and tomo deploy to deploy to both simultaneously.

In practice, you will also want to use roles to avoid doubling-up on certain operations. For example, you probably only want database tasks like rails:db_migrate to run one on server, not both. One way to do that is to give one host a "primary" role (you can name the role whatever you want), and then tell tomo to only run those database tasks on the primary host. It would look like this:

host "deployer@www1.example.com", roles: ["primary"]
host "deployer@www2.example.com"

role :primary, runs: ["rails:db_*", "rails:console", "rails:log_tail"]

If I want to keep my data could you please confirm me that the best way to do that is to disable the run "rails:db_seed" task

Yes, there is no harm in removing the run "rails:db_seed" task from the deploy block. I would suggest you keep it in the setup block. That way, you can use tomo setup to initialize the database once, prior to your first deploy (the seeds will run during setup). After that, you can use tomo deploy multiple times and the seeds will not run if you remove that task from the deploy block.

All other advice to secure the process of updating a production application is welcome

As a general practice, I suggest writing your seeds so that they are idempotent. In my opinion, running rails db:seed should not delete or modify data. That is why the default config in tomo assumes that it is safe to run the seeds on every deploy.

[francois0690]

Great! Thank you for your answers! 👍 🙏 👏