136 lines
4.5 KiB
ReStructuredText
136 lines
4.5 KiB
ReStructuredText
Quick start
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===========
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We'll explain you a simple example to help you understand what Kapow! really does and why it is awesome.
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Scenario
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--------
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In this example we'll consider that our scenario is a corporate network like this:
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.. _quickstart_image:
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.. image:: /_static/network.png
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:align: center
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:width: 80%
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Our organization has an external host as a bridge between our intranet an the public Internet.
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**Our goal: our team need to check if the the host :samp:`Internal Machine` is alive.**
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Limitations and constrains
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--------------------------
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1. We **don't want** to **grant access** to the :samp:`External Host` to anybody.
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2. We **don't want** to manage VPNs or any similar solutions to access to *Internal Host* from the Internet.
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3. We **want to limit the actions** that an user can perform in our intranet when while it is checking if :samp:`Internal Host` is alive.
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4. We **want** the most standard way mechanism. Easy to use and that facilitates the automation.
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5. We **don't have budget** to invest in a custom solution.
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Study options
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-------------
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Alter analyze the problem and our goal we conclude that is enough **with a simple :samp:`ping` to samp:`Internal Host`.**
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So, then **we need analyze how to perform the ping.**
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Accessing via SSH
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+++++++++++++++++
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In this case we need to create a system user in samp:`External Host` for each user that needs to check if :samp:`Internal host` is alive and we also need to grant access to each user through :samp:`SSH` to the system.
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Conclusion: **Not good idea**
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Reasons:
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1. We need to manage users (violates our constrains)
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2. We need to access users to system (violates our constrains)
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3. We can't control the :samp:`ping` options the user choice to ping :samp:`Internal Host` (violates our constrains)
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Develop custom solution
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+++++++++++++++++++++++
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Oks, this approach could maybe be the more customizable for our organization but:
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1. We'll need to start a new project. Develop it, test it, manage it and maintain it.
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2. We need time for the development.
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3. We need money. Even we have developers in our organization, their time it's not free.
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Conclusion: **Not good idea**
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Reasons:
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1. Need to spend money (violates our constrains)
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2. Need to spend time (violates our constrains)
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Using Kapow! (Spoiler: the winner!)
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+++++++++++++++++++++++++++++++++++
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Oks, lets analyze Kapow! and check our constrains:
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1. Kapow! is Open Source. Them: **it's free**.
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2. By using kapow! we don't need to program our own solution. Them: **don't waste time**.
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3. By using Kapow! we can run any command in the :samp:`External Host` limiting the command parameters. Them: **it's safe**.
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4. By using Kapow! we can launch any system command as HTTP API easily. Them: **we don't need to grant login access to anybody to :samp:`External Host`**
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Conclusion: **Kapow! is the best choice**.
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Reasons: it cover all of our requirements.
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Using Kapow!
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------------
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Following the example of the :ref:`Scenario <quickstart_image>` we'll follow these steps:
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Install Kapow!
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++++++++++++++
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Follow :doc:`Install Kapow! <install_and_configure>`.
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Write ping.pow file
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+++++++++++++++++++
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Kapow! use plain text files to define the rules to expose the system command. For our example we need a file like that:
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.. code-block:: console
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$ cat ping.pow
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kapow route add /ping -c 'ping -c 1 10.10.10.100 | kapow set /response/body'
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Explanation:
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1. :samp:`kapow route add /ping` - adds a new HTTP API end-point at :samp:`/ping`.
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2. :samp:`-c` - after this parameter we write the system command that Kapow! will runs for each HTTP Request to :samp:`/ping`.
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3. :samp:`ping -c 1 10.10.10.100` - sends 1 ping package to the host *10.10.10.100*, i.e. :samp:`Internal Host`.
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4. :samp:`| kapow set /response/body` - sends the ping response to be the HTTP Response of HTTP End-point of :samp:`/ping`.
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Launch the service
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++++++++++++++++++
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At this point we only need to launch kapow! with :samp:`simple.pow`:
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.. code-block:: console
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$ kapow server ping.pow
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Consume the service
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+++++++++++++++++++
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Then we can call HTTP Service as any usual tool for the web. In this example we'll use :samp:`curl`:
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.. code-block:: console
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$ curl http://external.host/ping
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PING 10.10.100 (10.10.100): 56 data bytes
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64 bytes from 10.10.100: icmp_seq=0 ttl=55 time=1.425 ms
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Under the hoods
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++++++++++++++++
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To understand what's happening in the hoods with Kapow! lets see the picture:
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.. image:: /_static/sequence.png
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:align: center
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:width: 80%
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As you can see, Kapow! perform the *magic* between system commands and HTTP API.
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