I have a script that I need to run after my instance has been provisioned and the volumes have been attached:
resource "aws_instance" "controller" {
...
provisioner "remote-exec" {
connection {
type = "ssh"
user = "centos"
}
inline = [
"download and run script to verify environment"
]
}
}
resource "aws_ebs_volume" "controller-ebs-sdb" {
...
}
resource "aws_volume_attachment" "controller-volume-attachment-sdb" {
device_name = "/dev/sdb"
volume_id = "${aws_ebs_volume.controller-ebs-sdb.id}"
instance_id = "${aws_instance.controller.id}"
}
Currently the script is failing the environment because when it runs the volume has not been attached.
Is it possible to only run the remote-exec script after the volumes have been attached?
You can run a provisioner on any resource (consider the null_resource pattern for an extreme version of this) so the best thing here is to run it on the aws_volume_attachment resource:
# ...
resource "aws_volume_attachment" "controller-volume-attachment-sdb" {
device_name = "/dev/sdb"
volume_id = "${aws_ebs_volume.controller-ebs-sdb.id}"
instance_id = "${aws_instance.controller.id}"
provisioner "remote-exec" {
connection {
host = "${aws_instance.controller.public_ip}"
type = "ssh"
user = "centos"
}
inline = [
"download and run script to verify environment"
]
}
}
You can consider adding a trigger option in remote-exec. Other crude option is to add a sleep for some seconds or, the script can retry itself, or check the status/existence of the disk and then attempt.
Related
Is it possible to execute shell commands on Ubuntu OS using Terraform script?
I have to do some initial configuration before execution of Terraform scripts.
you could define a local-exec provisioner in your resource
provisioner "local-exec" {
command = "echo The server's IP address is ${self.private_ip}"
}
that will execute right after the resource is created, there are other types of provisioners see: https://www.terraform.io/language/resources/provisioners/syntax
Depends upon where your Ubuntu OS is, if its local then you can do something like this
resource "aws_instance" "web" {
# ...
provisioner "local-exec" {
command = "echo ${self.private_ip} >> private_ips.txt"
}
}
If its a remote resource for example an aws ec2 instance:
resource "aws_instance" "web" {
# ...
# Establishes connection to be used by all
# generic remote provisioners (i.e. file/remote-exec)
connection {
type = "ssh"
user = "root"
password = var.root_password
host = self.public_ip
}
provisioner "remote-exec" {
inline = [
"puppet apply",
"consul join ${aws_instance.web.private_ip}",
]
}
}
Also, if its an ec2-instance, one thing that is mostly used is defining a script using user_data which runs immediately after the resource is created with root privileges but only once and then will never run even if you reboot the instance. In terraform you can do something like this:
resource "aws_instance" "server" {
ami = "ami-123456"
instance_type = "t3.medium"
availability_zone = "eu-central-1b"
vpc_security_group_ids = [aws_security_group.server.id]
subnet_id = var.subnet1
private_ip = var.private-ip
key_name = var.key_name
associate_public_ip_address = true
tags = {
Name = "db-server"
}
user_data = <<EOF
mkdir abc
apt update && apt install nano
EOF
}
I have this below code when I run apply it gets a timeout. An instance is created but remote-exec commands don't work.
I am running this in the windows 10 machine.
Terraform version is v0.12.12 provider.aws v2.33.0
resource "aws_instance" "web" {
ami = "ami-54d2a63b"
instance_type = "t2.nano"
key_name = "terra"
tags = {
Name = "HelloWorld"
}
connection {
type = "ssh"
user = "ubuntu"
private_key = "${file("C:/Users/Vinayak/Downloads/terra.pem")}"
host = self.public_ip
}
provisioner "remote-exec" {
inline = [
"echo cat > test.txt"
]
}
}
Please try to change you host line to
host = "${self.public_ip}"
Letting people know the actual error message you are getting might help too. :)
I want to create x instances and run the same provisioner.
resource "aws_instance" "workers" {
ami = "ami-08d658f84a6d84a80"
count = 3
...
provisioner "remote-exec" {
scripts = ["setup-base.sh", "./setup-docker.sh"]
connection {
type = "ssh"
host = "${element(aws_instance.workers.*.public_ip, count.index)}"
user = "ubuntu"
private_key = file("${var.provisionKeyPath}")
agent = false
}
}
I think the host line confuses Terraform. Getting Error: Cycle: aws_instance.workers[2], aws_instance.workers[1], aws_instance.workers[0]
Since I upgrade my terraform version(0.12), I have been encountered the same problem as yours.
You need to use ${self.private_ip} for the host property in your connection object,
and the connection object should be located out of the provisioner "remote-exec"
Details are the below.
resource "aws_instance" "workers" {
ami = "ami-08d658f84a6d84a80"
count = 3
...
connection {
host = "${self.private_ip}"
type = "ssh"
user = "YOUR_USER_NAME"
private_key = "${file("~/YOUR_PEM_FILE.pem")}"
}
provisioner "remote-exec" {
scripts = ["setup-base.sh", "./setup-docker.sh"]
}
...
}
If you need to get more information, the below link is gonna be helping you.
https://github.com/hashicorp/terraform/issues/20286
I have a resource "aws_instance" which includes a provisioner "file". This all works as expected when the EC2 instance is not present at first.
How can I re-run the provisioner if the file is deleted from the VM?
resource "aws_instance" "example" {
ami = "ami-0b0a60c0a2bd40612"
instance_type = "t2.micro"
key_name = "secret"
security_groups = ["terraform-basic-ssh-http"]
provisioner "file" {
source = "install-nginx.sh"
destination = "/tmp/install-nginx.sh"
connection {
type = "ssh"
user = "ubuntu"
private_key = "${file("/local/path/to/my/key.pem")}"
}
}
provisioner "remote-exec" {
inline = [
"chmod +x /tmp/install-nginx.sh",
"/tmp/install-nginx.sh"
]
connection {
type = "ssh"
user = "ubuntu"
private_key = "${file("/local/path/to/mykey.pem")}"
}
}
}
You can also use the terraform taint command for that: terraform taint provisioner.file
If your resource is in a module, taint the provisioner with terraform taint -module=[MODULE_NAME] provisioner.file
This will let Terraform "recreate" the provisioner.
I am trying to set up a group of EC2s for an app using Terraform in AWS. After each server is created I want to mount the eNVM instance storage on each server using remote-exec. So create 3 servers and then mount the eNVM on each of the 3 servers
attempted to use null_resource but I am getting errors about 'resource depends on non-existent resource' or 'interpolation' errors
variable count {
default = 3
}
module "app-data-node" {
source = "some_git_source"
count = "${var.count}"
instance_size = "instance_data"
hostname_pattern = "app-data"
dns_domain = "${data.terraform_remote_state.network.dns_domain}"
key_name = "app-automation"
description = "Automation App Data Instance"
package_proxy = "${var.package_proxy}"
}
resource "null_resource" "mount_envm" {
# Only run this provisioner for app nodes
#count = "${var.count}"
depends_on = [
"null_resource.${module.app-data-node}"
]
connection {
host = "${aws_instance.i.*.private_ip[count.index]}"
user = "root"
private_key = "app-automation"
}
provisioner "remote-exec" {
inline = [
"sudo mkfs -t ext4 /dev/nvme0n1",
"sudo mkdir /data",
"sudo mount /dev/nvme0n1 /data"
]
}
}
3 EC2 instances each with eNVMs mounted on them.
You can use a null_resource to run the provisioner:
resource "null_resource" "provisioner" {
count = "${var.count}"
triggers {
master_id = "${element(aws_instance.my_instances.*.id, count.index)}"
}
connection {
#host = "${element(aws_instance.my_instances.*.private_ip, count.index)}"
host = "${element(aws_instance.my_instances.*.private_ip, count.index)}"
type = "ssh"
user = "..."
private_key = "..."
}
# set hostname
provisioner "remote-exec" {
inline = [
"sudo mkfs -t ext4 /dev/nvme0n1",
"sudo mkdir /data",
"sudo mount /dev/nvme0n1 /data"
]
}
}
This should do it for all instances at once as well.