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In this video, you'll learn about Ansible playbooks.

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Playbooks provide a DevOps way for working with Ansible, for the simple reason that they

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define the desired state in YAML.

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And that's an example of configuration as code.

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The Ansible playbook command is used to compare the current state of the managed machine with

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the desired state, and if they don't match, the desired state is implemented.

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Use for instance the command ansible-playbook-i-inventory-u-student-k deploy-webserver.yaml.

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You can find this deploy-webserver.yaml in the course Git Repository.

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So let me show you.

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To access a playbook, we need access to the course Git Repository.

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Use git clone to https://github.com/.sandervanvugt/.linux+.

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Then you have a directory with the name linux+.

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And in that directory, use deploy-webserver.yaml.

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So what is this doing?

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This is a playbook written in YAML.

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So in YAML, indentation is important to identify relations between parent objects and child

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objects.

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Then we see a play header that is telling us that this playbook needs to be executed

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on all hosts.

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Then we see a list of tasks, which is identifying the package task where we want to install

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the latest version of the Apache 2 package.

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And the service task is calling the service module to make sure that the Apache 2 service

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will reach a state of started and will also be enabled to ensure that it will automatically

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be started if the target machine reboots.

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Then I'm using answerable playbook, minus i inventory.

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No need to specify any host names, because that is in the playbook itself.

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Minus use student, because we didn't specify any defaults.

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I'm giving the username of the remote user.

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And minus k will prompt for the sudo password on deploy-webserver.

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And then after entering the become password, oh no, it's telling me unable to parse Linux

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plus inventory.

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You know why?

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That is because the inventory file is not in the current directory.

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Now a simple change is to make that minus i dot dot slash inventory, because that is

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where my inventory file is.

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And now we can see that the playbook is running.

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And oh my goodness, what do we get?

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We get a couple of error messages on the remote Ubuntu machine.

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And the error messages include what?

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Well, it's telling me could not open log file and could not open log file.

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That is typically a permission-based problem.

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Let me show you what the problem is by giving you another example.

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I'm going to give you answerable all, minus i inventory, minus m command.

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Let me do a minus k as well, minus uppercase K for the become password.

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Then we use minus m command and minus a ls minus l slash root.

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I like this example to figure out if I have any permission issues.

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So it's prompting for the become password.

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And then I'm making the same mistake again.

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Well, that should be a quick fix.

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So it's prompting for the become password.

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And then I'm getting a permission denied.

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You know what is missing here?

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What is missing is the option minus b, minus b for become.

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Minus k prompts for the become password.

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That is a pseudo password, but it won't use it without the option minus b.

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So here you can see that the ls minus l root works with the minus b.

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And we need to do something similar on this playbook.

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So we make that minus b, minus uppercase K.

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And then after entering the become password, it is gathering facts.

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That is where it's discovering properties that can be used in playbook conditionals.

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It's installing the package.

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It's starting and enabling the service.

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And now we are all done.