This workshop will be retired on May 1, 2025.
Heads up! To view this whole video, sign in with your Courses Plus account or enroll in your free 7-day trial. Sign In Enroll
Preview
Start a free Courses trial
to watch this video
Next we'll show you how to install Unicorn on your server, and configure your Rails app to use Unicorn instead of Puma in production.
On your server, in your Rails app directory, add the following to your Gemfile:
group :production do
gem 'unicorn', '~> 5.2'
end
Next, edit config/unicorn.rb:
working_directory "/home/deploy/guestbook"
pid "/home/deploy/guestbook/tmp/pids/unicorn.pid"
stderr_path "/home/deploy/guestbook/unicorn/unicorn.log"
stdout_path "/home/deploy/guestbook/unicorn/unicorn.log"
listen "/tmp/unicorn.guestbook.sock"
worker_processes 2
timeout 30
Modify config/nginx.conf to read:
upstream unicorn {
server unix:/tmp/unicorn.guestbook.sock fail_timeout=0;
}
server {
listen 80 default;
root /home/deploy/guestbook/public;
try_files $uri/index.html $uri @unicorn;
location @unicorn {
proxy_pass http://unicorn;
}
}
Run the following from your Rails app directory:
bundle install
mkdir unicorn
sudo service nginx restart
RAILS_ENV=production bundle exec unicorn -c config/unicorn.rb -D
At this point, if you type your server's address into your browser, you should see your app, but this time it will be running under Unicorn instead of Puma.
Related Discussions
Have questions about this video? Start a discussion with the community and Treehouse staff.
Sign upRelated Discussions
Have questions about this video? Start a discussion with the community and Treehouse staff.
Sign up
So we've got engine X forwarding
our apps traffic to Puma,
0:00
now let's get it working
with unicorn instead.
0:03
So I'm going to quit out
of the rail server here.
0:06
Unicorn is distributed as a Ruby gem, so
0:10
to install it am going to edit
our applications gem file.
0:12
Down here at the bottom I'm going
to add a new production group.
0:18
So that this only gets installed
on our production server.
0:22
So group symbol production
as well as block.
0:26
And in this block we will specify the gems
we want to install in production so
0:33
we want to install the gym unicorn.
0:36
And we're gonna use the total
walk of syntax here to lock that
0:42
two minor version 5.2, that's the current
one at the time of recording.
0:46
Okay Ctrl all to write that out for
in the filename Ctrl+x to exit and
0:52
now we need to run bundle
install to actually install it.
0:56
It will download Unicorn and
all its dependencies.
1:04
And when it returns to the prompts,
Unicorn will be installed.
1:09
Now, we need to set up
a configuration file for Unicorn.
1:12
Just like with Engine X, we're going to
set it up within our config subdirectory.
1:15
So we use the nano editor and will create
a new file in the config directory,
1:20
we're going to name it unicorn.rb.
1:25
We name the other file nginx.conf
because it was in nginxs format but
1:30
unicorn configuration files are plain ruby
files so we give this one a .rb extension.
1:36
Okay, so we've got a few directives
that we need to set up here first.
1:42
The first is going to be the working
directory option working_directory.
1:45
Again this is basically a Ruby method
call we're going to pass at string and
1:54
we'll specify the path to our Rails app.
1:59
So that's home/deploy/guestbook.
2:01
We're gonna need that route a few more
times, so I'm gonna copy that here.
2:11
Then we need to specify a file that
unicorn will write out its process ID to
2:18
so that we can shut the server
down if we need to.
2:22
So I'm going to use the pid directive and
2:25
specify that it should to a file
within our guest book app directory.
2:27
Within a PID's sub directory and
we're gonna name that fur
2:33
unicorn.pid.
2:38
Next we have a couple options for logging.
2:44
So I'm going to say that
errors should be logged to
2:48
a particular path with stderr_path.
2:51
We're going to have it write to a file
in our guestbook app directory again,
2:55
within a unicorn sub directory.
3:02
We'll name that unicorn.log And
3:07
then we'll use the STD out
path directive to have it
3:12
write standard output to the same
location to the same log file.
3:15
Okay, this next part is crucial.
3:21
So engine X is going to
communicate with unicorn and Gen X
3:23
is one process running on our Linux server
and the Unicorn server is another process.
3:28
In Linux processes communicate with each
other through sockets which is kind of
3:35
like a file except that one process
writes into this virtual file and
3:39
another process reads out of it.
3:43
So we're going to give unicorn
the listen directive and
3:45
tell it where it should listen for
requests.
3:49
And we're gonna give it the name
of the socket to listen on.
3:53
So we'll create a string that points
to a path in the tmp root directory.
3:55
And we're going to name that
socket unicorn.guestbook.sock.
4:02
Okay, so there's the socket that unicorn
is going to listen on will Set up ngenx to
4:10
write to that socket later.
4:14
Then we need to specify how many
unicorn processes it should start up.
4:18
For right now we're just going
to say worker_processes and
4:22
we'll just give it a number 2 for
right now.
4:29
And finally we should specify how long
it should give one of those processes to
4:32
respond before it terminates it.
4:36
Be that with the timeout directive and
we'll set that to 30 seconds for
4:38
right now.
4:42
Okay, let's save the file an exit.
4:47
Okay and with that configuration in
place we can try running the unicorn.
4:50
We're going to want to do that in
the production environment, so
4:53
I'll specify rails equals production.
4:56
Since we installed the unicorn through,
5:05
bundler we're going to want to run it
using bundlers So we use bundle exec.
5:06
The executable is named unicorn.
5:12
And next we're going to use the -c command
line flag to specify a configuration
5:17
file it should load.
5:21
We're going to want to use
the config directory unicorn.rb And
5:25
finally we'll use dash capital D to
specify that it should run as a demon,
5:31
that is, it should continue
running in the background.
5:35
If we try running this,
we'll see an error.
5:39
It says that the directory for
the P I D file isn't writeable and
5:43
that's because we forgot to create
that directory, so let's do that now.
5:47
So, we'll create a,
we'll make a directory and pids.
5:52
Here within our rails app directory.
5:56
If we try running it again and
6:00
will fail again because it says the
directory for unicorn.log isn't writable.
6:02
We forgot to create a unicorn
subdirectory as well.
6:06
So, add directory unicorn.
6:10
Okay let's try one more time.
6:14
And this time it kicks off successfully.
6:19
We've got unicorn running now but
6:22
if we try to visit our Rails app
we'll see 502 Bad Gateway again.
6:24
This is because engine x isn't set up to
communicate with unicorn via the socket we
6:27
told unicorn to listen on so
we're going to need to fix that now.
6:31
So I'm going to go back into
the nginx configuration file.
6:36
config/nginxx.conf.
6:41
And specify a socket that nginx
should write requests out to.
6:45
We're going to use the upstream directive.
6:50
We're going to name this
upstream location unicorn.
6:54
And then options for
6:58
that upstream location are here
within brackets, curly brackets.
7:00
And here we're going to use
the server directive and
7:04
we're going to specify the Unix
socket that it should write out to.
7:08
So unix:/tmp/unicorn.guestbook.sock.
7:12
Which is the same path that we specified
within the unicorn configuration.
7:22
And here at the end of the line
we're going to add one more option,
7:28
we're going to say fail
underscore timeout equals zero.
7:33
That fail timeout equals zero causes
engine X to always retry request if
7:40
it fails.
7:44
We need this because a unicorn
worker might get shut
7:45
down by the master process if
it takes too long to respond and
7:47
we don't want to lose the request so
that will cause engine X to retry it.
7:51
And now instead of forwarding requests
that it gets onto local host port 3000,
7:56
we want to get it to forwarded
on to our upstream location.
8:00
So we're going to have it forward
it to another HTTP server.
8:04
But we're going to have it go to
the unicorn upstream location.
8:09
So we use the same name as our
upstream directive http://unicorn.
8:12
Okay write that out save it, and
8:17
as always we need to restart engine x.
8:22
It will want our sudo password.
8:28
And now if we go to our host IP and
try to reload the root path.
8:35
We'll see our Rails app.
8:39
Nginx is successfully communicating
with Unicorn using the Unix socket.
8:41
You need to sign up for Treehouse in order to download course files.
Sign upYou need to sign up for Treehouse in order to set up Workspace
Sign up