Chef-client: workstation and Node perspective

Chef-Client usage from the perspective of Administrator( chef workstation)

Run lists specify what recipes or roles the

node should run, along with the order they

should be run in

• Run lists are represented by an array

• Recipes are specified by “recipe[name]”

• Roles are specified by “role[name]”

1. Add new node
1. knife node 
2. Edit existing node for like editing run list
1. knife node edit target-node
            It'll open the node in text editor. Edit the run list and save it.
3. Create new client on chef-server with given key and role
1. knife client create backup --admin --file "$HOME/.chef/backup.pem"
2.           It will create new client named "backup" with admin privileges using backup.pem key.
3. ( Generally we create this user for taking chef-server backup)
4. Upload to chef-server
1. knife cookbook upload -a
   knife cookbook upload --all       Upload all cookbooks to chef-server
2. knife role from file roles/*.rb
           upload all roles on chef-server 
3. knife data bag create users     
          Create users databag
4. knife data bag from file [bag_name] [item_name.json]knife data bag from file [bag_name] [item1_name.json] [item2_name.json]
   knife data bag from file [bag_name] /path/to/[bag_name]/[item_name.json]knife data bag from file [bag_name] /path/to/[bag_name]/[item1_name.json] /path/to/[bag_name]/[item2_name.json]
   knife data bag from file [bag_name] /path/to/[bag_name]
   knife data bag from file [bag_name] --all
            # all data bag items assuming that data bags are in the ./data_bags/
   knife data bag from file --all           # all data bags assuming that data bags are in the ./data_bags/
            
5. Add run list to node
1. knife node run_list add target-node “role[base],role[monitoring]”
6. Remove run list from node
1. knife node run_list remove target-node “recipe[apache]”
7. Search clients with particular role
1. knife ssh "role:base"       
                Knife SSH performs a search for nodes on the Chef Server with the query "role:base".  Knife opens an SSH connection to the nodes' IP address (-a ipaddress or -
   a cloud.public_ipv4). 
2. The SSH session will connect as the user (-x 
3. opscode) with the password (-P opscode) 
4. to SSH and run on the node.
8. Run 'chef-client' 
1. Run the chef-client on all nodes
1. $ knife ssh 'name:*' 'sudo chef-client'
2. On  ALL nodes under role:base
1. knife ssh role:base "sudo chef-client" -x username -P password
3. On particular node (-a ipaddress or -a cloud.public_ipv4).
1. knife ssh role:base "sudo chef-client" -x USERNAME -P PASSWORD -a cloud.public_ipv4
9. Download, extract and upload cookbook
1. knife cookbook site download COOKBOOK
              Download cookbook from community.opscode.com
2.  tar -zxvf COOKBOOK*.tar.gz -C cookbooks
               Extract the download cookbook.tar.gz into cookbooks directory
3. less cookbooks/COOKBOOK/README.md
                 Read cookbook README.md
4.  less cookbooks/COOKBOOK/recipes/default.rb
                  Read default.rb recipe
5.  knife cookbook upload COOKBOOK
                  If everything is fine, then upload it on chef-server
10. Environments
1. Move Nodes
1. Nodes can be moved between environments, such as from a “dev” to a “production” environment by using the knife exec sub-command. For example:
      
   knife exec -E 'nodes.transform("chef_environment:dev") { |n| n.chef_environment("production") }'
2. Search Environments
1. Using knife command:
       knife search node "chef_environment:QA AND platform:centos"
2. Or, to include the same search in a recipe, use a code block similar to:
   

   qa_nodes = search(:node,"chef_environment:QA")
   qa_nodes.each do |qa_node|
       # Do useful work specific to qa nodes only
   end

Chef-Client usage from the perspective of  Node

1. Sync cookbook
1. sudo chef-client -Fdoc -lfatal
         It'll pull the latest cookbooks from chef-server and sync the system according to run list defined.

Important cookbooks:

apt, users, ssh_host_knows, build_essentials

References:

1. Chef Resources:  http://docs.opscode.com/chef/resources.html