Question
How do I work with "count" and connection.host using Terraform?
- Posted on September 11, 2019
- TerraformDigitalOcean
Asked by Mowijo
Using this setup
me@mybox:~terraform -v
Terraform v0.12.8
+ provider.digitalocean v1.7.0
I try to create two droplets serving Nginx using this Terraform file
resource "digitalocean_droplet" "web" {
count = 2
name = "web-${count.index}"
image = "ubuntu-14-04-x64"
region = "fra1"
size = "512mb"
private_networking = true
ssh_keys = [
"${var.ssh_fingerprint}"
]
connection {
user = "root"
type = "ssh"
host = digitalocean_droplet.web[count.index].ipv4_address
private_key = "${file(var.pvt_key)}"
timeout = "2m"
}
provisioner "remote-exec" {
inline = [
"export PATH=$PATH:/usr/bin",
# install nginx
"sudo apt-get update",
"sudo apt-get -y install nginx",
"curl -sSL https://repos.insights.digitalocean.com/install.sh | sudo bash"
]
}
}
but get this error when running terraform plan
Error: Cycle: digitalocean_droplet.web[1], digitalocean_droplet.web[0]
If I change the specification of connection.host to foo terraform runs without errors. Of course, it becomes hard to run any commands on the host afterwards, so my question is this:
How do I specify the host address when using count variables?
Thanks in advance and have a nice day, Morten
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Rather than using the count, you can simplify this a bit by referencing self.ipv4_address and Terraform will do the right thing. self allows you to access attributes of the resource it is called from.
Putting this all together, you get:
resource "digitalocean_droplet" "web" {
count = 2
name = "web-${count.index}"
image = "ubuntu-14-04-x64"
region = "fra1"
size = "512mb"
private_networking = true
monitoring = true
ssh_keys = [
"${var.ssh_fingerprint}"
]
connection {
user = "root"
type = "ssh"
host = self.ipv4_address
private_key = "${file(var.pvt_key)}"
timeout = "2m"
}
provisioner "remote-exec" {
inline = [
"export PATH=$PATH:/usr/bin",
# install nginx
"sudo apt-get update",
"sudo apt-get -y install nginx",
"curl -sSL https://repos.insights.digitalocean.com/install.sh | sudo bash"
]
}
}
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Thank you a metric ton, asb! That did the trick.
As you might have guessed, I have just started my journey into Terraform and your help on this matter has been invaluable. Should your life bring you through Denmark, make sure to drop in for a serving of your favourite beverage!