Create vSphere Template with Packer

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Author: Christoph Stoettner
Read in about 4 min · 781 words

Fountain pen and a notebook

Photo by Aaron Burden | Unsplash

The last months I built a lot of environments for tests with IBM Connections Componentpack, Rancher, plain Kubernetes, IBM Domino and some more. In former years, I deployed single virtual machines, cloned them and created snapshots to “easily” jump back in cases of errors. Then I found Packer , which helped me to automate the first virtual machines on my local notebook.

Now I use Packer to create templates for VMware vSphere, which then are deployed and multiplied with Terraform . Terraform needs some packages installed in the template, that it can provision virtual machines on vSphere.

  • Open VM-Tools

  • Perl

You can find all files and scripts on Gitlab.

The definition is simplified to make it better readable. As best practise I would recommend to add a variabe section to the packer file, so you avoid to type the same information over and over again.

In this article I just prepare the template. Working with Terraform will be covered in a future post.

One thing more, to install additional software on the provisioned servers later, I will use Ansible . Ansible needs ssh and Python .

First CentOS template

To create a template for CentOS, we start with a kickstart file, which is used by Packer to install and configure the template.

Create a root password

echo 'import crypt,getpass; \
  print crypt.crypt(getpass.getpass(), "$5$16_CHARACTER_SALT_HERE")' | python -

Replace $16_CHARACTER_SALT_HERE with 16 random characters.

Example to generate 16 random characters

openssl rand -base64 24 | cut -c-16

Kickstart File

You can find one in my GPN19 repo at Gitlab.com .

Simple kickstart file

install
lang en_US.UTF-8
keyboard de
timezone Europe/Berlin
auth --useshadow --enablemd5
services --enabled=NetworkManager,sshd
eula --agreed
ignoredisk --only-use=sda
reboot

bootloader --location=mbr
zerombr
clearpart --all --initlabel
part swap --asprimary --fstype="swap" --size=1024
part /boot --fstype xfs --size=200
part pv.01 --size=1 --grow
volgroup rootvg01 pv.01
logvol / --fstype xfs --name=lv01 --vgname=rootvg01 --size=1 --grow

authconfig --enableshadow --passalgo=sha256
rootpw --iscrypted $5$cnxfyyiayqjelmbt$4/Lq1vPDBp2BZznXcLukwVy4n0DPp6tX.PrCz7YA62B

%packages --nobase --ignoremissing
@core
%end

Packer JSON

To tell Packer how our template should be installed, start with following file :

{
  "builders": [  
    {
      "type": "vmware-iso",
      "boot_command": [
         "<tab> text ks=http://{{ .HTTPIP }}:{{ .HTTPPort }}/kickstart-de.cfg<enter>"
      ],
      "communicator": "ssh",
      "guest_os_type": "centos7-64",
      "http_directory": "http",
      "iso_checksum_type": "sha256",
      "iso_checksum_url": "http://ftp.halifax.rwth-aachen.de/centos/7.6.1810/isos/x86_64/sha256sum.txt",
      "iso_url": "http://ftp.halifax.rwth-aachen.de/centos/7.6.1810/isos/x86_64/CentOS-7-x86_64-Minimal-1810.iso",
      "ssh_username":"root",
      "ssh_password":"password",  
      "ssh_wait_timeout": "600s",
      "shutdown_command": "shutdown -P now",
      "version": 14
    }
  ],
  "provisioners": [ 
      {
          "type": "shell",
          "expect_disconnect": true,
          "execute_command": "sudo UPDATE=true bash '{{ .Path  }}'",
          "environment_vars": [
            "UPDATE=true"
          ],
          "scripts": [  
            "script/epel.sh",
            "script/kernel.sh",
            "script/sshd.sh",
            "script/vmtools.sh",
            "script/update.sh",
            "script/reboot.sh",
            "script/ansible.sh",
            "script/cleanup.sh"
          ]
      }
  ],
  "post-processors": [ 
      [
        {
            "type": "vsphere",  
            "cluster": "HMUC PWR HOSTS",
            "host": "vsphere.example.com",
            "datacenter": "HMUC",
            "resource_pool": "rp_hvie_devops",
            "username": "cstoettner@example.com",
            "password": "{{user `vsphere_password`}}",
            "datastore": "devops-01_sas_7.2k_raid10",
            "vm_name": "stoeps-centos-gpn19",
            "vm_folder": "devops",
            "vm_network": "vm-net-devops",
            "disk_mode": "thin",
            "insecure": "true",
            "overwrite": "true"
        },
        {
            "type": "vsphere-template",  
            "host": "vsphere.example.com",
            "insecure": "true",
            "datacenter": "HMUC",
            "username": "cstoettner@example.com",
            "password": "{{user `vsphere_password`}}",
            "folder": "/devops/templates"
        }
      ]
   ]
}
  • Builder (building the vmware itself)

  • Provisioner (run some scripts on the new deployed machine)

  • Post-Processor (upload to VMware vSphere)

  • The order is important, or Terraform can’t recognize the vm tools

  • Post-Processor to upload the VM to vSphere

  • Post-Processor to tag it as template

  • I set the root password to password in the kickstart

The kickstart file generates the user root with password password. During the deployment with Terraform I disable the password login with passwd -l root, so the root user needs to use a ssh-key for authentication.

Thanks to Nico for the tip with passwd --lock.

This configuration file uses a lot of default values from VMware, like disk space, cpu count and so on. All these can be changed later during our Terraform deployment.

Within the Provisioner part, I use some scripts, to add:

  • EPEL repository

  • Install open-vm-tools, perl, python

  • Update all installed packages

  • Update the kernel to the latest version (in the moment 5.1)

    • The original CentOS kernel is quite old and the Docker support needs some tweaks like the usage of device-mapper, that’s the main reason for the update
  • Reboot (important to do this after the open-vm-tools installation, because without Terraform will not recognize the tools and not deploy)

  • Cleanup (deleting host keys, repositories and so on)

During my talk at GPN19, someone pointed me to Systemd machine id . I always ignored this, but I added the delete command to the cleanup script and the create command into my Terraform file. Thanks for this hint!

Create the template

packer build -var vsphere_password=My_Vsphere_password centos.json

I use a variable for the password, because I always check-in my definition files to git and I don’t want to have passwords there in the history.

I created a video of the creation, please try the command yourself, or have a look at it.

Now our template is uploaded to vSphere. Using it within Terraform will be another post.

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