Terraform with cloud-init

[olivierlambert]

Hello!

Hmm likely a question for @ddelnano

[ddelnano]

@m4xm0rris Xen Orchestra's web application is doing this templating on the client side (reference). Since terraform already has a nice interface for templating (using its template_file data source), you can do the substitution yourself.

Here is an example below. Note: this code is not tested but was pulled from an internal project I have.

# template_file.tpl
#cloud-config

hostname: ${name}

# any other cloud-config you need
[...]

# vm.tf
data "template_file" "cloud_config" {
  template = file("${path.module}/template_file.tpl")
  vars = {
    name = "your_hostname_value"
  }
}

resource "xenorchestra_cloud_config" "cloud_config" {
  name = "cloud_config"
  # This performs the templating
  template = data.template_file.cloud_config.rendered
}

resource "xenorchestra_vm" "vm" {
  [ ... ]
  cloud_config = xenorchestra_cloud_config.cloud_config.template
  
}

Please share your terraform code if you would like more specific advice on how to recreate exactly what you are trying to do.

[m4xm0rris]

Thanks @ddelnano , that worked perfectly!

Appreciate the help!

[olivierlambert]

Interesting indeed, we should probably document this If you have time @ddelnano obviously

[m4xm0rris]

Just stumbled upon this provider too which may offer a more streamlined approach, not that I am familiar enough with Terraform yet to say this for sure: https://github.com/hashicorp/terraform-provider-cloudinit

[ddelnano]

I created terraform-provider-xenorchestra #181 to track updating the docs.

Cool, I didn't realize that there was a cloudinit terraform provider :). I'll be giving that a try and may use that in the examples if its better than using template_file directly.

[m4xm0rris]

@ddelnano Yeah, I only found it as template_file is deprecated apparently and as it hasn't seen any updates, I couldn't use the code you posted from my M1 Macbook

Anyways, thanks for the help!

[ddelnano]

@m4xm0rris it looks like there is a builtin function to do templating now (templatefile). Apologies, it's been a while since I've written any new templated terraform code.

[m4xm0rris]

In case anyone comes here looking for an example (as it took me days of banging head against the proverbial wall to get this working with templatefile function):

cloud_config.tftpl

#cloud-config
hostname: ${hostname}
user: ops-user
ssh_authorized_keys:
  - OPS_USER_SSH_KEY
manage_etc_hosts: true
fqdn: ${hostname}.${domain}
package_upgrade: true
users:
 - default

cloud_network_config.tftpl

#cloud-config
version: 1
config:
    - type: physical
      name: eth0
      subnets:
      - type: static
        address: '${ip}'
        netmask: '255.255.255.0'
        gateway: '10.1.50.1'

vm.tf

resource "xenorchestra_vm" "unc-lab" {
......
 cloud_config = templatefile("cloud_config.tftpl", {
  hostname = "unc-lab"
  domain = "morris.lan"
})
cloud_network_config = templatefile("cloud_network_config.tftpl", {
  ip = "10.1.55.34"
})
.......

Thanks @ddelnano for your help!

[ddelnano]

I was able to confirm that using the cloudinit data source does work with Xen Orchestra.

Here is the following terraform code that I used (essential pieces like SR and network are excluded for the example):

data "cloudinit_config" "cloud_config" {
  gzip = false
  base64_encode = false

  part {
    content_type = "text/cloud-config"
    content = <<EOF
users:
  - name: ddelnano
    sudo: ALL=(ALL) NOPASSWD:ALL
    ssh_import_id:
      - gh:ddelnano

packages:
- make
- build-essential

runcmd:
- echo 'this is a test'
EOF
  }
}

resource "xenorchestra_vm" "vm" {
  memory_max = 2147467264
  cpus = 1
  name_label = "XO terraform tutorial"
  template = data.xenorchestra_template.vm_template.id
  cloud_config = data.cloudinit_config.cloud_config.rendered

  network {
    network_id = data.xenorchestra_network.network.id
  }

  disk {
    sr_id = data.xenorchestra_sr.sr.id
    name_label = "VM root volume"
    size = 4294967296
  }
}

This creates a VM and runs the cloudinit I specified, however, it doesn't allow you to do any templating. So you would still need to use the templatfile function built into Terraform.

I'm going to update the docs to use the templatefile function since that is the most streamlined approach.

[ddelnano]

@m4xm0rris thanks for posting your solution. Would you mind reviewing my changes to the terraform registry documentation (here)?

Since I've been working with terraform long before Xen Orchestra, having your opinion on the documentation would be valuable

[ppikna97]

Hi, I have question to this topic. I figured out to use templatefiles in terraform to provision my VMs. But when I try to provision network alongside with userdata configuration (2 templatefiles) it did not work. It just apply network configuration. My use case was to firstly configure static networking and than install some packages, hostname and so on. I was resolving this few months ago, but did not understand how execution sequence works or if it is even possible. Cloud-init official documentation is not very clear.

I would appreciate any help with this.

[m4xm0rris]

@ddelnano Sir, the only thing I could point out from that pull request is the block in your vm.md where you are templating the variables in a separate block.

"

# Template the cloudinit if needed
template = templatefile("cloud_config.tftpl", {
  hostname = "your-hostname"
  domain = "your.domain.com"
})

"
I have no where near enough experience with Terraform to tell if makes any practical difference, but I am able to redner the template inline with the rest of my VM resource definition. eg.

cloud_network_config = templatefile("cloud_network_config.tftpl", {
   ip = "10.1.55.37"
   netmask = var.network["netmask"]
   gateway = var.network["gateway"]
 })

Just a little tidier IMO, but again have no idea if the way you have done this is better practice etc.

Thanks

[m4xm0rris]

@ppikna97 Hi! How are you calling the templates in your VM resources? As you can see above from my examples I'm simply pulling both user data and network inline with the rest of my config e.g.

cloud_config = templatefile("cloud_config.tftpl", {
  hostname = "bw-lab"
  domain = var.network["domain"]
})
cloud_network_config = templatefile("cloud_network_config.tftpl", {
  ip = "10.1.55.37"
  netmask = var.network["netmask"]
  gateway = var.network["gateway"]
})

[ppikna97]

@m4xm0rris thanks. I was using template_file data source with xenorchestra_cloud_config data source like this:

But I found answer to both of us... Some video linked me here templatefile vs template_file. Resulting that it is better to use templatefile function to match terraform version and for working with different data types. But in the essence templatefile and template_file do the same thing.

[m4xm0rris]

@ppikna97 Np, I was also using template_file originally but as its now deprecated there have been no builds released for M1 based Mac (leading/forcing me down the templatefile function route).

[bxen]

@m4xm0rris This was very helpful. Thank you!

[dydomby]

@m4xm0rris thanks, it helped much.

[olivierlambert]

Hello there!

If you think some extra doc would be important to avoid searching for the solution, please do so

[antoniolfdacruz]

Hi there!

Please, delete my question if it is considered bad in any way.

I am able to write terraform code that creates a vm in one of our xcp pools.

But can't undertand how I must configure the template in order to be able to pass cloud-init userdata and metadata.

I am using a simple VM install from ubuntu 20.04.5 ISO, turned into a template. It does not seem to load the yaml templates.

code_textalfcruz-adm@local.hcpa.ufrgs.br@volt-ampere:~/terraform-provider-xenorchestra-intro/mkxcpvm2n$ cat main.tf
# Infrastructure parametrization

variable "xoa_pool_name" {
  type        = string
  description = "Pool Name at HCPA's XCP-ng infrastructure managed by XenOrchestra"
  default     = "UAAPool01"
}

variable "xoa_template_name" {
  type        = string
  description = "Template name at the chosen XCP-ng pool (must be unique between all the HCPA's pools"
  #default     = "Ubuntu 20.04 LTS Focal Fossa (20211008u)"
  default = "template-ubuntu-20045"
}

variable "xoa_sr_name" {
  type        = string
  description = "Name of the Storage Resource to place the VM disk(s) at the chosen pool"
  default     = "EQL01UHAASR01"
}

variable "xoa_public_vlanid" {
  type        = string
  description = "The VLAN id of the public (first) network interface of this VM"
  default     = "VLAN702"
}

variable "xoa_private_vlanid" {
  type        = string
  description = "The VLAN id of the private (or second) network interface of this VM"
  default     = "VLAN902"
}

# VM parametrization

variable "vm_memory_max" {
  type        = number
  description = "VM's maximum memory (in bytes)"
  default     = 2147467264
}

variable "vm_cpus" {
  type        = number
  description = "VM's number of virtual CPU cores"
  default     = 4
}

variable "vm_name_label" {
  type        = string
  description = "The VM's name on the XCP-ng infrastructure (XOA and XCP console)"
  default     = "Terraformed at HCPA"
}

variable "vm_disk_name_label" {
  type        = string
  description = "The name of the first VM's disk"
  default     = "Filesystem root"
}

variable "vm_disk_size" {
  type        = number
  description = "The size of this VM's first disk (in bytes - default = template thick / size - 30GB)"
  default     = 32212254720
}

variable "vm_public_domain" {
  type        = string
  description = "Name of the local intranet domain"
  default     = "local.hcpa.ufrgs.br"
}

variable "vm_public_ipv4_address" {
  type        = string
  description = "The VM's public (first) interface IPv4 address"
  default     = "10.70.3.250"
}

variable "vm_public_ipv4_prefixlen" {
  type        = string
  description = "The number of network bits to use for the public IPv4 interface netmask"
  default     = "23"
}

variable "vm_public_ipv4_gateway" {
  type        = string
  description = "The IPv4 default gateway for the public interface"
  default     = "10.72.0.1"
}

# Gattering ambient facts

data "xenorchestra_pool" "pool" {
  name_label = var.xoa_pool_name
}

data "xenorchestra_template" "vm_template" {
  name_label = var.xoa_template_name
}

data "xenorchestra_sr" "sr" {
  name_label = var.xoa_sr_name
  pool_id    = data.xenorchestra_pool.pool.id
}

data "xenorchestra_network" "public_vlanid" {
  name_label = var.xoa_public_vlanid
  pool_id    = data.xenorchestra_pool.pool.id
}

data "xenorchestra_network" "private_vlanid" {
  name_label = var.xoa_private_vlanid
  pool_id    = data.xenorchestra_pool.pool.id
}

# Create cloudinit templates

data "template_file" "userdata" {
  template  = file("./cloud_userdata_cfg.yaml")
  vars      = {
    hostname = var.vm_name_label
    domain   = var.vm_public_domain
  }
}

data "template_file" "metadata" {
  template = file("./cloud_metadata_cfg.yaml")
  vars     = {
    hostname  = var.vm_name_label
    ip        = var.vm_public_ipv4_address
    prefixlen = var.vm_public_ipv4_prefixlen
    gateway   = var.vm_public_ipv4_gateway
  }
}

resource "xenorchestra_cloud_config" "userdataconfig" {
  name = "user data config"
  template = data.template_file.userdata.rendered
}

resource "xenorchestra_cloud_config" "metadataconfig" {
  name = "network data config"
  template = data.template_file.metadata.rendered
}

# VM creation

resource "xenorchestra_vm" "vm" {
#  cloud_config = templatefile("cloud_userdata_cfg.yaml", {
#    hostname = var.vm_name_label
#    domain   = var.vm_public_domain
#  })
#  cloud_network_config = templatefile("cloud_metadata_cfg.yaml", {
#    hostname  = var.vm_name_label
#    ip        = var.vm_public_ipv4_address
#    prefixlen = var.vm_public_ipv4_prefixlen
#    gateway   = var.vm_public_ipv4_gateway
#  })
  cloud_network_config = xenorchestra_cloud_config.metadataconfig.template
  cloud_config = xenorchestra_cloud_config.userdataconfig.template
  memory_max = var.vm_memory_max
  cpus       = var.vm_cpus
  name_label = var.vm_name_label
  template   = data.xenorchestra_template.vm_template.id

  network {
    network_id = data.xenorchestra_network.public_vlanid.id
  }

#  network {
#    network_id = data.xenorchestra_network.private_vlanid.id
#  }

  disk {
    sr_id      = data.xenorchestra_sr.sr.id
    name_label = var.vm_disk_name_label
    size       = var.vm_disk_size
  }
}

alfcruz-adm@local.hcpa.ufrgs.br@volt-ampere:~/terraform-provider-xenorchestra-intro/mkxcpvm2n$
alfcruz-adm@local.hcpa.ufrgs.br@volt-ampere:~/terraform-provider-xenorchestra-intro/mkxcpvm2n$ cat cloud_userdata_cfg.yaml
#cloud-config
groups:
  - aghuse: [aghu]

users:
  # seiseg and aghu / REDACTED | same public key
  - name: aghu
    uid: 1003
    gecos: AGHU Application Standard User
    passwd: <REDACTED>
    lock_passwd: true
    sudo: ['ALL=(ALL) NOPASSWD:ALL']
    groups: [aghuse]
    shell: /bin/bash
    homedir: /opt/aghu
    no_create_home: false

packages:
  - tree

runcmd:
  - sed -i -e "s/PARAMMYHOSTNAME/${hostname}/g" /etc/postfix/main.cf
  - sed -i -e "s/PARAMMYHOSTNAME/${hostname}/" /etc/puppetlabs/puppet/puppet.conf
  - /opt/ds_agent/dsa_control -r
  - /opt/ds_agent/dsa_control -a dsm://goodman.local.hcpa.ufrgs.br:4120/ "policyid:60"
  - systemctl disable networker
  -


alfcruz-adm@local.hcpa.ufrgs.br@volt-ampere:~/terraform-provider-xenorchestra-intro/mkxcpvm2n$ cat cloud_metadata_cfg.yaml
#cloud-config
local-hostname: ${hostname}
instance-id: ${hostname}
network:
  version: 2
  ethernets:
    ens192:
      dhcp4: false
      addresses:
        - ${ip}/${prefixlen}
      gateway4: ${gateway}
      nameservers:
        search: [local.hcpa.ufrgs.br, hcpa]
        addresses: [10.10.31.13, 10.10.31.14, 10.10.31.42]
growpart:
  mode: auto
  devices: ['/dev/sda2']
  ignore_growroot_disabled: true
wait-on-network:
  ipv4: true

alfcruz-adm@local.hcpa.ufrgs.br@volt-ampere:~/terraform-provider-xenorchestra-intro/mkxcpvm2n$