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---
title: Terraform refactoring and state move
description: An example replacing a count with a for_each
date: 2022-01-03
tags:
- terraform
---
## Introduction
When I initialised my oracle cloud free tier infrastructure in [a previous blog article]({{< ref "getting_started_oci_free_tier.md" >}}), I made a mistake of using a `count` to iterate on a list of names for the instances I wished to spawn. The drawback of doing this is that I cannot reorder the items in this list, and deleting one instance could affect the other.
The solution to this is to change this `count` construct to a `for_each`. This way the state objects will no longer be indexed by the instance position in the list, they will be indexed by their names.
## What changes in the terraform code
Since in one of the resources I used the index to infer a fault domain id, I rewrote the list from this :
```hcl
oracle_amd64_instances_names = ["dalinar", "kaladin"]
```
to this :
```hcl
oracle_amd64_instances = {
dalinar = { "fault_domain_id" = 0 },
kaladin = { "fault_domain_id" = 1 },
}
```
Note that I renamed the variable in order to not miss anywhere it was used. Now for each resource that used this list with a `count` like the following :
```hcl
resource "oci_core_instance" "amd64-vms" {
count = length(var.oracle_amd64_instances_names)
compartment_id = var.oracle_tenancy_ocid
availability_domain = data.oci_identity_availability_domains.ads.availability_domains[0].name
fault_domain = data.oci_identity_fault_domains.fd.fault_domains[
count.index % length(data.oci_identity_fault_domains.fd.fault_domains)].name
display_name = var.oracle_amd64_instances_names[
count.index % length(var.oracle_amd64_instances_names)]
shape = "VM.Standard.E2.1.Micro"
preserve_boot_volume = false
create_vnic_details {
subnet_id = oci_core_subnet.adyxax-production.id
hostname_label = var.oracle_amd64_instances_names[count.index]
display_name = var.oracle_amd64_instances_names[count.index]
}
```
Such entries now becomes :
```hcl
resource "oci_core_instance" "amd64-vms" {
for_each = var.oracle_amd64_instances
compartment_id = var.oracle_tenancy_ocid
availability_domain = data.oci_identity_availability_domains.ads.availability_domains[0].name
fault_domain = data.oci_identity_fault_domains.fd.fault_domains[each.value["fault_domain_id"]].name
display_name = each.key
shape = "VM.Standard.E2.1.Micro"
preserve_boot_volume = false
create_vnic_details {
subnet_id = oci_core_subnet.adyxax-production.id
hostname_label = each.key
display_name = each.key
}
```
## How to migrate the state
To see which resources need to be migrated you can use `terraform state list` :
```sh
julien@nas ~/git/adyxax/adyxax.org/02-permanent-hosts (master *$%) $ terraform state list
data.cloudflare_zones.adyxax-eu
data.cloudflare_zones.adyxax-org
data.cloudflare_zones.asj-fr
data.hcloud_ssh_key.adyxax
data.oci_core_image.ol8
data.oci_core_vnic_attachments.amd64-vms-vnics[0]
data.oci_core_vnic_attachments.amd64-vms-vnics[1]
data.oci_identity_availability_domains.ads
data.oci_identity_fault_domains.fd
cloudflare_record.adyxax-org-oracle-amd64-vms-ipv4[0]
cloudflare_record.adyxax-org-oracle-amd64-vms-ipv4[1]
cloudflare_record.adyxax-org-oracle-amd64-vms-ipv6[0]
cloudflare_record.adyxax-org-oracle-amd64-vms-ipv6[1]
oci_core_instance.amd64-vms[0]
oci_core_instance.amd64-vms[1]
oci_core_internet_gateway.gw
oci_core_ipv6.amd64-vms-ipv6s[0]
oci_core_ipv6.amd64-vms-ipv6s[1]
oci_core_route_table.default-via-gw
oci_core_security_list.allow-all
oci_core_subnet.adyxax-production
oci_core_vcn.adyxax
```
Here we are interested with all the resources indexed with `0` and `1`. I migrated the state using the following commands :
```sh
terraform state mv data.oci_core_vnic_attachments.amd64-vms-vnics[0] \
data.oci_core_vnic_attachments.amd64-vms-vnics[\"dalinar\"]
terraform state mv data.oci_core_vnic_attachments.amd64-vms-vnics[1] \
data.oci_core_vnic_attachments.amd64-vms-vnics[\"kaladin\"]
terraform state mv cloudflare_record.adyxax-org-oracle-amd64-vms-ipv4[0] \
cloudflare_record.adyxax-org-oracle-amd64-vms-ipv4[\"dalinar\"]
terraform state mv cloudflare_record.adyxax-org-oracle-amd64-vms-ipv4[1] \
cloudflare_record.adyxax-org-oracle-amd64-vms-ipv4[\"kaladin\"]
terraform state mv cloudflare_record.adyxax-org-oracle-amd64-vms-ipv6[0] \
cloudflare_record.adyxax-org-oracle-amd64-vms-ipv6[\"dalinar\"]
terraform state mv cloudflare_record.adyxax-org-oracle-amd64-vms-ipv6[1] \
cloudflare_record.adyxax-org-oracle-amd64-vms-ipv6[\"kaladin\"]
terraform state mv oci_core_instance.amd64-vms[0] \
oci_core_instance.amd64-vms[\"dalinar\"]
terraform state mv oci_core_instance.amd64-vms[1] \
oci_core_instance.amd64-vms[\"kaladin\"]
terraform state mv oci_core_ipv6.amd64-vms-ipv6s[0] \
oci_core_ipv6.amd64-vms-ipv6s[\"dalinar\"]
terraform state mv oci_core_ipv6.amd64-vms-ipv6s[1] \
oci_core_ipv6.amd64-vms-ipv6s[\"kaladin\"]
```
Note the escaping of the quotes so that the shell does not interpret (and remove) these. We can make sure we did not do any mistake by running a plan and seeing that terraform does not report any changes :
```sh
No changes. Your infrastructure matches the configuration.
```
|
