在生产上部署发布的最佳实践

Question

We have a production site with more than 350 running instances, so making the site down even for a short time is a big deal.
My question: After pushing our code to production, if there is any update on composer we have to update it, during this period the site will be down. So what is the best practice to update composer on production without making the site down while updating?

Answer 1

I strongly recommend you use a deployment system, like Capistrano ( https://github.com/capistrano/capistrano ).

Capistrano will per example clone your branch/commit into a dedicated folder, run scripts like Composer and if everything is fine, then it create/move a symlink to this folder.

It's transparent for your user.

And if anything goes wrong, you can ask Capistrano to "rollback", it will make the symlink point to the last working version (folder).

Answer 2

I suggests to use this approach to achieve almost zero down time: The root directory of the web server must be just a symbolic link.

• Create a new directory for every release and upload the files into it.
• Install your dependencies.
• Run your tests.
• Create a symbolic link as the root directory of the web server that points to the new release directory.

So you don't have to shutdown your website for coping and uploading files directly to the root directory. Just use symbolic links. Also in this way it is much easier to rollback to any old release.

Answer 3

I am using azure to host my websites and I noticed what they do is the following:

1. Pull the code from git to a staging folder
2. Install composer dependencies in this folder
3. Copy all contents for this folder to the live folder

By running the composer install on another folder the packages on live are always available. The only time a down time can occur is when you are copying the files to the live directory, but this will be very briefly.

Answer 4

You don't need either composer or git in production/stage servers.

This is the steps I follow:

1. Release: Use ci tool (like circleci, travis, etc.) to run your tests, but also to create a release build.

2. Deployment: Use a deployment tool (like chef, puppet, ansible), which would automate the release, ideally working beside some orchestration tool (like kubernetes, terraform,...)

Step 1: CI Release

(only in your release branch, ex: master)

1.1 composer archive

1.2 Uncompress into a distribution directory mkdir -p dist/ && tar -C dist/ -xf *.tar && cd dist

1.3 composer install --no-ansi --no-dev --no-interaction --no-progress --no-scripts --optimize-autoloader

1.4 Compress again with vendor repositories

1.5 Make a git release throw the api. You can use a tool like https://github.com/tcnksm/ghr or make your own code there

Step 2: Deployment

2.1 Download your code into /some/path/{release-version}

2.2 When finished, remove the actual symlink (if any) and create a new symlink to /some/path/{release-version}

2.3 Remove any previous versions to avoid memory issues