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slides/adding-a-new-node/01_slide.md

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+# Adding a New Node
+
+.notes These course materials are Copyright © 2010-2011 Opscode, Inc. All rights reserved.
+This work is licensed under a Creative Commons Attribution Share Alike 3.0 License. To view a copy of this license, visit http://creativecommons.org/licenses/by-sa/3.0/; or send a letter to Creative Commons, 171 2nd Street, Suite 300, San Francisco, California, 94105, USA.
+
+# Objectives
+
+At completion of this unit you should...
+
+* Be able to use knife to configure a new server.
+* Understand how search is used to integrate systems together.
+
+# Bootstrapping Chef
+
+The process of installing and initially running Chef is referred to as
+“Bootstrapping Chef”. The general steps are:
+
+* Update the local system’s package cache (OS dependent).
+* Install Ruby and RubyGems.
+* Install Chef as a RubyGem.
+* Copy the validation certificate file.
+* Create a Chef client configuration pointing at the right Chef Server.
+* Create a JSON file with the node’s initial Run List.
+* Run Chef using the JSON file.
+
+# Installing and Running Chef
+
+    sudo su -
+    apt-get update
+    apt-get install -y ruby ruby1.8-dev build-essential \
+      wget libruby-extras libruby1.8-extras
+    cd /tmp
+    wget http://production.cf.rubygems.org/rubygems/rubygems-1.3.7.tgz
+    tar zxf rubygems-1.3.7.tgz
+    cd rubygems-1.3.7
+    ruby setup.rb --no-format-executable
+
+    gem install ohai chef
+    mkdir /etc/chef
+    vi /etc/chef/validation.pem
+    vi /etc/chef/client.rb
+    vi /etc/chef/first-boot.json
+
+    sudo chef-client -j /etc/chef/first-boot.json
+
+# Bootstrap Sub-command
+
+Knife bootstrap will run a single script on a target host.
+
+Uses “bootstrap templates” by name. Several come with Chef.
+
+These are typically used to install Chef on the remote system and tell Chef to run with a particular run list.
+
+# Default Bootstrap Template
+
+    if [ ! -f /usr/bin/chef-client ]; then
+      apt-get update
+      apt-get install -y ruby ruby1.8-dev build-essential wget libruby-extras libruby1.8-extras
+      cd /tmp
+      wget http://production.cf.rubygems.org/rubygems/rubygems-1.3.7.tgz
+      tar zxf rubygems-1.3.7.tgz
+      cd rubygems-1.3.7
+      ruby setup.rb --no-format-executable
+    fi
+    gem install ohai --no-rdoc --no-ri --verbose
+    gem install chef --no-rdoc --no-ri --verbose <%= bootstrap_version_string %>
+    mkdir -p /etc/chef
+    (
+    cat <<'EOP'
+    <%= validation_key %>
+    EOP
+    ) > /tmp/validation.pem
+    awk NF /tmp/validation.pem > /etc/chef/validation.pem
+    rm /tmp/validation.pem
+    (
+    cat <<'EOP'
+    <%= config_content %>
+    EOP
+    ) > /etc/chef/client.rb
+    (
+    cat <<'EOP'
+    <%= { "run_list" => @run_list }.to_json %>
+    EOP
+    ) > /etc/chef/first-boot.json
+    <%= start_chef %>
+
+# Default Bootstrap Template
+
+[Default Bootstrap Template](https://github.com/opscode/chef/raw/master/chef/lib/chef/knife/bootstrap/ubuntu10.04-gems.erb)
+
+# Knife Bootstrap Templates
+
+The templates that come with Chef:
+
+* archlinux-gems
+* centos5-gems
+* fedora13-gems
+* ubuntu10.04-apt
+* ubuntu10.04-gems
+
+# Knife Bootstrap Customization
+
+The bootstrap “templates” are really just shell scripts.
+
+You can create your own bootstrap templates.
+
+Use `-d` to specify the distribution style.
+
+    ./.chef/bootstrap/DISTRO.erb
+    $HOME/.chef/bootstrap/DISTRO.erb
+
+# Knife Bootstrap
+
+    (
+    cat <<'EOP'
+    <%= config_content %>
+    EOP
+    ) > /etc/chef/client.rb
+
+Bootstrap scripts are processed as ERB templates.
+
+“`config_content`” comes from Bootstrap Context, which is a shortcut to
+using the Chef Config values from Knife.
+
+# Knife Bootstrap Usage
+
+    % knife bootstrap IPADDRESS -r 'role[webserver]' -x ubuntu -i ~/.ssh/ec2.pem
+
+    % knife bootstrap IPADDRESS -r 'role[webserver]' -x ubuntu -i ~/.ssh/ec2.pem -d ubuntu10.04-mine-gems
+
+# Integrate a New Node
+
+Integrating a new node into the infrastructure is easy with knife bootstrap.
+
+We’ll add a load balancer that will sit in front of the web server.
+
+# Add Load Balancer
+
+Presumably, the new system has been provisioned and has an OS installed on it, ready to SSH and be managed with Knife Bootstrap and Chef.
+
+# Load Balancer Cookbook
+
+The load balancer will need a cookbook to install and configure the load balancer software.
+
+Haproxy is the load balancer software.
+
+The cookbook is available from the Community Site.
+
+A new role will be created that will be applied with the “knife bootstrap” command.
+
+# Load Balancer Role
+
+    @@@ruby
+    name "lb"
+    description "web server load balancer"
+    run_list(
+      "recipe[haproxy::app_lb]"
+    )
+
+The `haproxy::app_lb` recipe will perform a search for web servers.
+
+# Bootstrap Load Balancer
+
+    knife bootstrap IPADDRESS -r 'role[lb]' -x ubuntu --sudo
+
+IPADDRESS is the IP of the target system. We can use FQDN here.
+
+Default Ubuntu installs enable the “ubuntu” user to sudo.
+
+# Haproxy Uses Search
+
+The app_lb recipe in the haproxy cookbook uses search.
+
+Any new nodes with “role[webserver]” will be automatically detected by
+the load balancer whenever it runs Chef.
+
+.notes When growing the infrastructure, new web servers can be created
+with the “webserver” role. Then run chef-client on the load balancer
+node and the new servers will be automatically added to the pool for
+haproxy.
+
+# Summary
+
+You should now be able to...
+
+* Use knife to configure a new server.
+* Describe how search is used to integrate systems together.
+
+# Lab Exercise
+
+## Adding a New Node