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Julien Dessaux 2021-09-05 20:26:27 +02:00
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---
title: Getting started with Oracle Cloud Infrastructure
description: Oracle Cloud Infrastructure's always free tier is very generous
date: 2021-09-05
tags:
- terraform
---
## Introduction
Oracle Cloud Infrastructure provides quite a generous always free tier for you to use and test their cloud... or host some light services. But getting started was a little difficult with many pieces missing or incomplete in the examples, especially how to configure ipv6 on your instances.
The documentation is very good and exhaustive but information was scattered : the following should help you get started right after you create your oracle cloud infrastructure's account.
## Create your API access
In order to terraform your infrastructure, you are going to need to generate an api access which is composed of a key and several other things :
- Open the web console, click the top left menu and select `Identity & Security` then `Users`.
- Click your account
- Scroll to bottom left and select `API Keys`
- click `Add an api key`
- Select `Generic API Key Pair`, download the private key file then click `Add`
- Copy the information displayed for the next phase
## Terraform
### Provider configuration
Here is the relevant snippet from my `providers.tf` file :
```hcl
variable "oracle_tenancy_ocid" {}
variable "oracle_user_ocid" {}
variable "oracle_fingerprint" {}
provider "oci" {
tenancy_ocid = var.oracle_tenancy_ocid
user_ocid = var.oracle_user_ocid
fingerprint = var.oracle_fingerprint
private_key_path = "../tf-common/oracle_key.pem"
region = "eu-amsterdam-1"
}
variable "oracle_amd64_instances_names" {}
```
This goes along with a `terraform.tfvars` file that you should fill with the api access information you saved up earlier :
```hcl
oracle_tenancy_ocid = "XXXXX"
oracle_user_ocid = "YYYYY"
oracle_fingerprint = "ZZZZZ"
oracle_amd64_instances_names = ["dalinar", "kaladin"]
```
The last bit is how I name the two free instances I want to create, pick anything you like.
### Networking
Here is how to bootstrap a vcn and the associated objects for direct internet access. For simplicity I will leave the access lists opened, firewall rules really are a pain to write with terraform... I plan to keep on using iptables or shorewall on the hosts for now.
```hcl
resource "oci_core_vcn" "adyxax" {
compartment_id = var.oracle_tenancy_ocid
cidr_blocks = ["10.0.0.0/16"]
display_name = "adyxax"
dns_label = "adyxax"
is_ipv6enabled = true
}
resource "oci_core_internet_gateway" "gw" {
compartment_id = var.oracle_tenancy_ocid
vcn_id = oci_core_vcn.adyxax.id
enabled = true
display_name = "gw"
}
resource "oci_core_route_table" "default-via-gw" {
compartment_id = var.oracle_tenancy_ocid
vcn_id = oci_core_vcn.adyxax.id
display_name = "default-via-gw"
route_rules {
destination = "0.0.0.0/0"
destination_type = "CIDR_BLOCK"
network_entity_id = oci_core_internet_gateway.gw.id
}
route_rules {
destination = "::/0"
destination_type = "CIDR_BLOCK"
network_entity_id = oci_core_internet_gateway.gw.id
}
}
# protocol - Specify either all or an IPv4 protocol number : ICMP ("1"), TCP ("6"), UDP ("17"), and ICMPv6 ("58").·
resource "oci_core_security_list" "allow-all" {
compartment_id = var.oracle_tenancy_ocid
vcn_id = oci_core_vcn.adyxax.id
display_name = "allow-all"
egress_security_rules {
protocol = "all"
destination = "0.0.0.0/0"
}
ingress_security_rules {
protocol = "all"
source = "0.0.0.0/0"
}
egress_security_rules {
protocol = "all"
destination = "::/0"
}
ingress_security_rules {
protocol = "all"
source = "::/0"
}
}
resource "oci_core_subnet" "adyxax-production" {
cidr_block = cidrsubnet(oci_core_vcn.adyxax.cidr_blocks[0], 8, 0)
compartment_id = var.oracle_tenancy_ocid
vcn_id = oci_core_vcn.adyxax.id
display_name = "production"
dns_label = "production"
ipv6cidr_block = cidrsubnet(oci_core_vcn.adyxax.ipv6cidr_blocks[0], 8, 0)
security_list_ids = [oci_core_security_list.allow-all.id]
route_table_id = oci_core_route_table.default-via-gw.id
}
```
### Instances
Here is how to create the two always free tier instances. The tricky part was to understand how ipv6 addresses are like second class citizens on oracle cloud :
```hcl
data "oci_identity_availability_domains" "ads" {
compartment_id = var.oracle_tenancy_ocid
}
data "oci_identity_fault_domains" "fd" {
compartment_id = var.oracle_tenancy_ocid
availability_domain = data.oci_identity_availability_domains.ads.availability_domains[0].name
}
# taken from https://docs.oracle.com/en-us/iaas/images/all/?search=Oracle-Linux-8.4
data "oci_core_image" "ol8" {
image_id = "ocid1.image.oc1.eu-amsterdam-1.aaaaaaaaj46eslsa6ivgneyneypomtvzb6dmg22gtewy6opwiniuwgsdv7uq"
}
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 = true
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]
}
source_details {
boot_volume_size_in_gbs = 50
source_type = "image"
source_id = data.oci_core_image.ol8.id
}
metadata = {
"ssh_authorized_keys" : "ssh-ed25519 AAAAC3NzaC1lZDI1NTE5AAAAILOJV391WFRYgCVA2plFB8W8sF9LfbzXZOrxqaOrrwco"
}
}
data "oci_core_vnic_attachments" "amd64-vms-vnics" {
count = length(var.oracle_amd64_instances_names)
compartment_id = var.oracle_tenancy_ocid
instance_id = oci_core_instance.amd64-vms[count.index].id
}
resource "oci_core_ipv6" "amd64-vms-ipv6s" {
count = length(var.oracle_amd64_instances_names)
vnic_id = data.oci_core_vnic_attachments.amd64-vms-vnics[count.index].vnic_attachments[0].vnic_id
display_name = var.oracle_amd64_instances_names[count.index]
}
```
### Bonus : Provisionning cloudflare's dns
If like me you are managing your dns with cloudflare, here is how to provision the relevant records :
```hcl
resource "cloudflare_record" "adyxax-org-oracle-amd64-vms-ipv4" {
count = length(var.oracle_amd64_instances_names)
zone_id = lookup(data.cloudflare_zones.adyxax-org.zones[0], "id")
name = var.oracle_amd64_instances_names[count.index]
value = oci_core_instance.amd64-vms[count.index].public_ip
type = "A"
proxied = false
}
resource "cloudflare_record" "adyxax-org-oracle-amd64-vms-ipv6" {
count = length(var.oracle_amd64_instances_names)
zone_id = lookup(data.cloudflare_zones.adyxax-org.zones[0], "id")
name = var.oracle_amd64_instances_names[count.index]
value = oci_core_ipv6.amd64-vms-ipv6s[count.index].ip_address
type = "AAAA"
proxied = false
}
```
## Conclusion
Putting all of this together was an interesting experience, and I am satisfied that it works well. In the future I plan to add my own oci image based on alpine linux which is not available natively. I tried oracle linux and it is fine, but consumes way too much ram for my taste. For now I installed alpine linux using the instance's cloud console and [my procedure for that]({{< ref "docs/alpine/remote_install_iso" >}}).