Rails meetup deployments tricks

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Deployment:!tips and tricks

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Why?

Deployments are scary

Major cause of downtime

Wasted time

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About

@smathieu

“We only deploy 20 times per day”

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Tip #1

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Tip #2

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Have a staging server

rainforest @smathieu

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Tip #3

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Tip #4

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Deploying Without Downtime

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Migrations

Major challenge to get right

It gets harder with data

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ActiveRecord’s Column Cache

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Don’t delete columns

rename_column :users, :notes, :deprecated_notes_2014_01_01

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Adding Indexes

Slows on large tables

Locks the table

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Postgres

CREATE INDEX CONCURRENTLY

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MySQLPercona Toolkit:

http://www.percona.com/software/percona-toolkit

Facebook’s Online Schema Change:

https://www.facebook.com/notes/mysql-at-facebook/online-schema-change-for-mysql/

430801045932

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Renaming Columns

Don’t do it

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Tip #5

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Having a staging server is nice, but…

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… on demand staging is better

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And many more…

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Conclusion

Your CI should be the only thing deploying your code

No-Downtime Deployments are harder, but possible

Invest in your deployment processes

rainforest @smathieu

Questions?

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Links

https://github.com/jipiboily/fourchette

https://www.facebook.com/notes/mysql-at-facebook/online-schema-change-for-mysql/430801045932

http://www.percona.com/software/percona-toolkit