Introduction to Ansible Transcripts
Chapter: Deployments
Lecture: Updating Config Files with the lineinfile Module
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0:00
We set up the WSGI server
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and now have Nginx serving as a reverse proxy.
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We grabbed our application dependencies from PyPI.
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One more step that we want to do to make sure
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that we can actually have a two-server deployment
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is tweak our database settings.
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Right now, Postgres, very same default settings
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only allow local connections.
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And so, we just want to update the configuration
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so that our web server can connect to the database server.
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We're just going to tweak one line
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in our Postgres configuration
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and that will do it for our deployment.
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So our web server is set
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so let's move into roles/database/tasks.
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And we'll add one task here.
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Allow connections from our web server.
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Could of used the lineinfile module
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and the lineinfile module checks to see
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if a specific line is in a file
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and if it is skips the step
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if it's not I'll make sure that line gets in there.
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It's super handy for tweaking configuration files
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and especially if you don't want to create
0:59
an entire template file yourself.
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First, we specify the path to the file that we want to modify.
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And modify the pg_hba.conf Postgres figuration file.
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We want this line to be present where we say
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insert this after this line.
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And our line should be
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and normally you'd set up a variable for this
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but in this case we're just going to put
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the IP address of our web server
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and we're going to trust it.
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Course, you should modify this for your own purposes
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but this is just an example so that you will be able
1:48
to use the lineinfile module as a task.
1:50
Finally, we need superuser privileges
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so set become yes on this.
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Now, I've tested this out and I have two separate windows.
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In the bottom window, we're going to log into the server.
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Let's take a look at that configuration file.
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So when we execute our playbook
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we are then going to have a line that is inserted here
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into the default configuration that allows our web server
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to connect to the database. We'll just start at the task.
2:36
Now we see that using the lineinfile module
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we can populate text into any files that we want
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whether that's a configuration file, readme file
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we don't always need to use templates to accomplish
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populating information into files.
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Again, for your own deployments
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you're going to to want to customize everything
2:51
that we've done here
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including adding additional security settings for Postgres.
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These examples were really to show you what you could do
2:57
with Ansible rather than teach you how to configure
3:00
a Postgres database or set up a Python application.
3:02
This was really just an example to learn more about Ansible.
