Knowledge Base for IT Professionals, Teachers and Astronauts
When Berkshelf in the Chef Test Kitchen cannot resolve the cookbook dependencies, it displays the following error message during converge:
Unable to satisfy the following requirements
To help Berks to start a fresh calculation, delete the Berksfile.lock file and enter the following into the command window:
berks install
In the first part of the series, Beginner’s Guide to DevOps Engineering Part 1. we have already installed the DevOps development tools.
chef generate cookbook test
file '/Users/YOUR_USERNAME/Desktop/helloworld.txt' do content 'Hello world' end
file 'C:\\Users\\YOUR_USERNAME\\Desktop\\helloworld.txt' do content 'Hello world' end
cd testchef-client --local-mode recipes/default.rbWe will use Test Kitchen and Vagrant to launch virtual machines. Currently, only Linux images are available for Vagrant, so we will modify our recipe to select between Linux and Windows and act accordingly.
Open the default.rb recipe and update it to look like this
case node['os']
when 'linux'
file "/tmp/helloworld.txt" do
content 'This file was created by Chef!'
end
when 'windows'
file "C:\\Chef\\helloworld.txt" do
content 'This file was created by Chef!'
end
endEnter the following commands into the Bash window
kitchen listkitchen converge ubuntu
kichen login ubuntukitchen destroy ubuntuTo test your cookbook on a Windows virtual machine locally, create one for Vagrant. See Launch Windows instances locally with Chef Test Kitchen for the details.
Chef has a steep learning curve. Chef is not just scripting or programming, but you have to understand how Chef works to be able to use it to configure servers. There are many ways to do the same thing and there is not much documentation to recommend the best way. If you search Google, the problems usually have multiple solutions, and many times the “best” answer is selected based on personal preference. To get started, you should familiarize yourself with the tools, because you will use most of them during the development process.
In this guide I will use a Windows computer as a workstation, but all tools work on Mac and Linux computers.
Learn Vagrant to understand how Test Kitchen manages the test servers on your local machine or at AWS. You will not use vagrant directly, but Test Kitchen uses it to launch servers.
Working with AWS in Beginner’s Guide to DevOps Engineering part 3.
to the Tutorials page
DevOps engineering (Release engineering) is a relatively new profession. There is a very high demand for experienced DevOps engineers, because more and more large corporations want to migrate their data centers into the Cloud. In this series I will introduce you to the tools of the trade through the development of a Chef cookbook.
The tools of the DevOps engineers are new and most of them are in the active development phase with frequent releases. Some of the new versions have show stopping bugs in them, so it is a good idea to test all new versions of the tools before you uninstall the old one.
To work as a DevOps engineer you need a development environment with multiple tools. Luckily all of them are available for free and easy to set up.
You can do all development and testing on your workstation for free, but to see your scripts running in a real cloud, you can set up an account at a cloud provider. Amazon Web Services (AWS) offers a free tier where you can launch small server instances for free.
In this guide I will use a Windows computer as a workstation, but all tools work on Mac and Linux computers.
If you don’t have an Apple ID create one. You can obtain one without a credit card:
Create the opt folder in the root of the harddisk.
The Windows operating system already has a Remote Desktop Client
Download the Microsoft Remote Desktop app from the App Store
Install a good text editor. If you do not have a favorite, I recommend Notepad ++
Install iTerm2, a smart terminal emulator to issue Bash commands and log into Linux servers.
https://ruigomes.me/blog/perfect-iterm-osx-terminal-installation/
https://gist.github.com/kevin-smets/8568070
Certain commands need elevated rights to run, so we will set up the Bash window to run as administrator.
Download Virtual Box from https://www.virtualbox.org/wiki/Downloads and follow the instructions to install it.
At the time of writing this was the section where the installer files were referenced
Run the downloaded installer file and accept all default values.
The installer starts the application. You can close it, we will use other tools to start it in the future.
The default credentials of a Vagrant server are:
The Ruby Development Kit is need for certain Ruby gems, so install it.
ruby dk.rb initruby dk.rb installRuby is already a part of the operating system.
;C:\HashiCorp\Terraform
For more details see https://www.terraform.io/intro/getting-started/install.html
cd ~
ls .bash_profile
# PATH Export PATH=/opt/terraform:$PATH export PATH unset DYLD_LIBRARY_PATH
We will use this utility to display the Terraform graphs.
;C:\Program Files (x86)\GraphvizX.XX\bin
Set up the DevOps development environment in Beginner’s Guide to DevOps Engineering part 2.
to the Tutorials page
When you create an EC2 instance in Amazon Web Services (AWS) the security group (firewall) blocks all ports that are not explicitly opened. To make file sharing possible on Windows servers, open the following ports in the security group of the server:
When you execute a Chef recipe that calls a custom resource and the execution stops without any output from the custom resource, make sure the custom resource does not reference a misspelled property with the #{PROPERTY_NAME} syntax.
When you work in the graphical user interface (GUI) of your operating system, and want to copy the contents of a file to the clipboard, you can use the following commands:
On OS X run: cat FILE_NAME | pbcopy
On Linux run: cat FILE_NAME | xclip
On Windows (via Cygwin/Git Bash) run: cat FILE_NAME | clip
If a Chef cookbook is “frozen”, the cookbook is protected against accidental overwrite.
When someone tries to overwrite it the
“Version ... of cookbook COOKBOOK_NAME is frozen. Use --force to override"
message appears.
To check if a Chef cookbook is frozen on the Chef server execute the following command
knife cookbook show COOKBOOK_NAME latest | grep frozen
To upload a Chef cookbook and freeze it to prevent accidental overwrite
knife cookbook upload COOKBOOK_NAME --freeze
To overwrite a frozen cookbook upload it with
knife cookbook upload COOKBOOK_NAME --force
To freeze the referenced cookbooks when you upload them with BerkShelf upload them with
berks upload
(do not use the –no-freeze option)
If you have already installed Chef Client on a Windows box and want to upgrade to the latest version
choco upgrade chef-clientIf you work in the AWS environment and launch and terminate servers frequently the same IP is reused many times. When you try to connect to a new server with SSH and the IP address is already in the known_hosts file you will get the following error message.
@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
@ WARNING: REMOTE HOST IDENTIFICATION HAS CHANGED! @
@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
IT IS POSSIBLE THAT SOMEONE IS DOING SOMETHING NASTY!
Someone could be eavesdropping on you right now (man-in-the-middle attack)!
It is also possible that a host key has just been changed.
The fingerprint for the ECDSA key sent by the remote host is
SHA256:...
Please contact your system administrator.
Add correct host key in /c/Users/.../.ssh/known_hosts to get rid of this message.
Offending ECDSA key in /c/Users/.../.ssh/known_hosts:13
ECDSA host key for ... has changed and you have requested strict checking.
Host key verification failed.
The solution is to delete the line from the “c:/Users/YOUR_USER_NAME/.ssh/known_hosts” file that has the same IP address as the new server.
When you install a new version of ChefDK and try to run Test Kitchen converge you may get the following error message
>>>>>> ------Exception-------
>>>>>> Class: Kitchen::ActionFailed
>>>>>> Message: Failed to complete #create action: [SSL_connect returned=1 errno=0 state=SSLv3 read server certificate B: certificate verify failed
To solve the problem add the following to the Windows environment variables and open a new Command or Bash window for the change to take effect:
SSL_CERT_FILE=C:\opscode\chefdk\embedded\ssl\certs\cacert.pem