Chef Basics /Installation and Configuration
Chef is used in infrastructure automation and helps in reducing manual and repetitive tasks for infrastructure management.
Uses Ruby encoding to develop basic building blocks like recipe and cookbooks.
Why Chef ?
a) used to automate the infrastructure provisioning
b) streamline the task of configuration and managing the company’s server.
c) capability to get integrated with any of the cloud technology.
d) does not make assumptions on the current status of a node. It uses its mechanisms to get the current status of machine.
Major Throwback
It needs constant babying so that people who are working should not mess up with others cookbooks.
Components of Chef
a)Attribute
They are settings stored in form of key-value pair — they are used to change the existing state or setting a particular infrastructure node
b) Recipe
collection of attributes which are used to manage the infrastructure.
They are loaded during Chef client run and compared with the existing attribute of the node and relevant action is taken
c) cookbook
collection of recipes . They are the basic building blocks which get uploaded to Chef server
d) Resource
It is the basic component of a recipe used to manage the infrastructure with different kind of states
There can be multiple resources in a recipe, which will help in configuring and managing the infrastructure. Some of common examples are package/service/user/group/template /file/directory
e) Metadata
It is used to manage the metadata about the package. This includes details like the name and details of the package. It also includes things such as dependency information that tells which cookbooks this cookbook needs to operate
f) Files
It’s a sub-directory within the cookbook
How Chef works ?
It is 3 tier client server model
a) Cook books are developed on chef workstation , (Usually a local machine )Work stations are installed command line utilities like knife , test kitchen
b) Knife help to upload cookbooks to Chef Server
c) All Chef nodes on which cookbook needs to be installed are registered to chef Server
Chef Node Components
Chef client is the key component of all the nodes, which helps in setting up the communication between the Chef server and Chef node . Install this at each node
Ohai — helps in getting the current state of any node at a given point of time.
Starting with Chef
Step 1 : Install Chef development kit in you host . Check if this is working via firing command
chef -v
You can use it locally or on a AWS/GCP . I am focusing on first approach by using it with Virtual Box and Vagrant , both of which are well known virtualization tools.
check if virtual box is installed
vboxmanage — version
Check if vagrant is installed
vagrant — version
Create a centos machine in vagrant using virtualbox
vagrant box add bento/centos-7.2 — provider=virtualbox
Bento is basically a chef project which provides baseline machines for chef development
Do vagrant init to start these vm
vagrant init bento/centos7.2 ; vagrant up
It will create a configuration file VagrantFile inside your current directory
This file is used to launch and manage your instance.
Connect to your machine via vagrant ssh (running vagrant up in logs will give ip to connect to) Now you can install chef development kit (cdk) inside it.
For RHEL 7 you can use following commands
wget https://packages.chef.io/files/stable/chefdk/4.6.35/el/7/chefdk-4.6.35-1.el7.x86_64.rpm
rpm -ivh chefdk-4.6.35–1.el7.x86_64.rpm
Chef also needs ruby to be installed . You can find the tutorial here for same
Once both are installed correctly you can check if both are installed correctl via using
which chef
which ruby
If everything works fine congrats you are now ready to write cookbooks
