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Install chef server on redhat/centos

rpm -Uvh http://rbel.frameos.org/rbel6
yum -y install rubygem-chef-server
service iptables stop
setup-chef-server.sh
knife configure -i

Install chef client on redhat/centos

curl -L http://www.opscode.com/chef/install.sh | bash

Resources and Providers

In Chef, Resources represent a piece of system state and Providers are the underlying implementation which brings them into that state.

The chef-client runs in two stages

  1. The compilation phase The client examines each Recipe in order and adds its Resources to the ResourceCollection

  2. The execution phase The client iterates over the ResourceCollection, and performs the following:

  • Based on the Resource's "provider" attribute, a new instance of the specified Provider is created (if the attribute is not set, one is selected based on the local platform). The originating Resource is stored in the new Provider as the @new_resource instance variable and is accessible when writing LWPs as new_resource.name, for example.

  • The load_current_resource method is then called on the provider instance, giving it an opportunity to populate @current_resource with a new resource that represents the current state of the relevant part of the system.

  • For each action specified in @new_resource.actions, the action_ method that corresponds to each action is called(e.g. action :create will invoke the action_create method of the Provider instance.)

Errors

 Server doesn't support resource history, skipping resource report.

Loads cookbook components

  • Libraries
  • Providers
  • Resources
  • Attributes
  • Definitions
  • Recipes

The order is important because of where you can put things, and when things are available.

Provider is chosen by Chef::Platform

This is how platform specific providers are chosen like apt/yum, useradd, etc. It also contains logic to get the provider for the resource...

Chef::Platform finds the provider

  • Specifically named parameter
  • Platform assigned providers
  • Matching the resource name

Specifically named providers are like we saw earlier where the resource itself had the provider parameter. Platform assigned are the ones like apt/yum for packages. Matching the resource name is how LWRPs get chosen.

What is Definitions

Definetions allow you to create new Resources by stringing together existing resources.

tips from Darren Birkett

git clone https://github.com/rcbops/chef-cookbooks.git
cd chef-cookbooks
git checkout sprint
git submodule update --init

Delete cookbook use bulk

knife cookbook bulk delete .*
knife role bulk delete .*

Chef show some weird problem, finally find that it is coursed by full of disk

make chef-server listen to 127.0.0.1

vi /etc/sysconfig/chef-server
OPTIONS="-h 127.0.0.1"

Common Attributes

ignore_failure => If true, we will continue running the Recipese if this resource fails for any reason. (defaults to false)
provider       => The class name of a provider to use for this resource.
retries        => Number of times to cantch exceptions and retry the resource (defaults to 0). Requires Chef >= 0.10.4.
retry_delay    => Retry delay in seconds (defaults to 2). Requires Chef >= 0.10.4.
supports       => A hash of options that hint providers as to the capabilities of this resource.

examples

gem_package "syntax" do
  action :install
  ignore_failure true
end

Check network first

ruby_block "check_internet" do
  block do
    require 'socket'

    test_host = "www.google.com"
    test_port = "www"
    retries = 0

    begin
      s = TCPSocket.new(test_host, test_port)
      s.close

    rescue Errno::ETIMEDOUT
      if retries < 3
        retries += 1
        Chef::Log.logger.send("warn", "Unable to connect to #{test_host}:#{test_port}, retry ##{retries}")
        retry
      end
    end
  end
end