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149 lines
4.1 KiB
ReStructuredText
149 lines
4.1 KiB
ReStructuredText
Systems Administration
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======================
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Fabric
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------
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`Fabric <http://docs.fabfile.org>`_ is a library for simplifying system administration tasks. While Chef
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and Puppet tend to focus on managing servers and system libraries,
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fabric is more focused on application level tasks such as deployment.
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Install Fabric:
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.. code-block:: bash
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$ pip install fabric
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The following code will create two tasks that we can use: ``memory_usage`` and
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``deploy``. The former will output the memory usage on each machine. The
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latter will ssh into each server, cd to our project directory, activate the
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virtual environment, pull the newest codebase, and restart the application
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server.
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::
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from fabric.api import cd, env, prefix, run, task
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env.hosts = ['my_server1', 'my_server2']
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@task
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def memory_usage():
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run('free -m')
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@task
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def deploy():
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with cd('/var/www/project-env/project'):
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with prefix('. ../bin/activate'):
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run('git pull')
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run('touch app.wsgi')
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With the previous code saved in a file named fabfile.py, we can check memory
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usage with:
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.. code-block:: bash
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$ fab memory_usage
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[my_server1] Executing task 'memory'
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[my_server1] run: free -m
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[my_server1] out: total used free shared buffers cached
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[my_server1] out: Mem: 6964 1897 5067 0 166 222
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[my_server1] out: -/+ buffers/cache: 1509 5455
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[my_server1] out: Swap: 0 0 0
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[my_server2] Executing task 'memory'
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[my_server2] run: free -m
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[my_server2] out: total used free shared buffers cached
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[my_server2] out: Mem: 1666 902 764 0 180 572
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[my_server2] out: -/+ buffers/cache: 148 1517
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[my_server2] out: Swap: 895 1 894
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and we can deploy with:
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.. code-block:: bash
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$ fab deploy
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Additional features include parallel execution, interaction with remote
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programs, and host grouping.
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`Fabric Documentation <http://docs.fabfile.org>`_
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Salt
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----
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`Salt <http://saltstack.org/>`_ is an open source infrastructure management tool.
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It supports remote command execution from a central point (master host) to multiple
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hosts (minions). It also supports system states which can be used to configure
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multiple servers using simple template files.
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Salt supports python versions 2.6 and 2.7 and can be installed via pip:
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.. code-block:: bash
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$ pip install salt
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After configuring a master server and any number of minion hosts, we can run arbitrary
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shell commands or use pre-built modules of complex commands on our minions.
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The following command lists all available minion hosts, using the ping module.
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.. code-block:: bash
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$ salt '*' test.ping
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The host filtering is acomplished by matching the minion id, or using the grains system.
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The `grains <http://docs.saltstack.org/en/latest/topics/targeting/grains.html>`_ system
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uses static host information like the operating system version or the CPU architecture to
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provide a host taxonomy for the salt modules.
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The following command lists all available minions running CentOS using the grains system:
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.. code-block:: bash
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$ salt -G 'os:CentOS' test.ping
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Salt also provides a state system. States can be used to configure the minion hosts.
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For example, when a minion host is ordered to read the following state file, will install
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and start the Apache server:
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.. code-block:: yaml
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apache:
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pkg:
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- installed
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service:
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- running
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State files can be written using YAML, the Jinja2 template system or pure python.
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`Salt Documentation <http://docs.saltstack.org/en/latest/index.html>`_
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Chef
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----
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.. todo:: Write about Chef
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`Chef Documentation
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<http://wiki.opscode.com/display/chef/Documentation>`_
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Puppet
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------
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.. todo:: Write about Puppet
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`Puppet Labs Documentation <http://docs.puppetlabs.com>`_
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Blueprint
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---------
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.. todo:: Write about Blueprint
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Buildout
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--------
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.. todo:: Write about Buildout
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`Buildout Website <http://www.buildout.org>`_
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