Using Terraform to Manage Oracle Cloud Infrastructure

1© Pythian Services Inc., 2020
by Māris Elsiņš
TO MANAGE
ORACLE CLOUD INFRASTRUCTURE
USING TERRAFORM

Māris Elsiņš
Lead Database Consultant
✓ Oracle Databases
✓ Oracle e-Business Suite
✓ OCI
✓ AWS
✓ GCP
@MarisDBA
elsins@pythian.com

WHAT’S DIFFERENT IN THIS TERRAFORM TALK?

• Basics in 3 minutes + demo
• Terraform and OCI + demo
• A Few suggestions before you dive in!

BASICS IN 3 MINUTES

WHAT IS
• A tool for building, changing, and versioning infrastructure
• HashiCorp
• Open Source
• A Simple binary executable
• Manages Infrastructure as Code
• The cool stuff it provides

WHAT IS
• Configuration files describe the infrastructure
• Terraform language syntax (Declarative Language)
• Version controlled repeatable infrastructure

WHAT IS
• Resource Graph - determine dependencies and parallelize execution
• Execution Plans - verify the change before implementing it
• Change Automation - adjust the configuration files, and terraform will figure
out how to implement it
• DevOpsification

WHAT IS TERRAFORM
IMPORTANT CONCEPTS
• Providers - https://www.terraform.io/docs/providers/index.html
• Variables – provide parameters of the configuration
• Outputs – externalize the information
• Resources – describe what needs to be created
• Data Sources – Extract environment properties that are not maintained by
Terraform
• State files – The local metadata of the existing infrastructure
• Interpolation Syntax – refencing attributes from another resource
• Modules – reusability of existing code
d1
d2

TERRAFORM + OCI

STARTING WITH TERRAFORM + OCI
GETTING CONNECTED TO OCI
• Where to start?
• Getting Started with the Terraform Provider
https://docs.cloud.oracle.com/iaas/Content/API/SDKDocs/terraformgetstarted.htm
• Required Keys and OCIDs
https://docs.cloud.oracle.com/iaas/Content/API/Concepts/apisigningkey.htm
• Separation of impact areas in OCI
provider "oci" {
tenancy_ocid = "${var.tenancy_ocid}"
user_ocid = "${var.user_ocid}"
fingerprint = "${var.fingerprint}"
private_key_path = "${var.private_key_path}"
region = "${var.region}"
}

STARTING WITH TERRAFORM + OCI
GETTING CONNECTED TO OCI
• Where to start?
• Separation of impact areas in OCI
• Dedicated compartment(s) for all infra managed by Terraform
Policy: allow group OCITerra-Admins to manage all-resources in compartment OCITerra
• The rest is manually managed
• Object Storage bucket for terraform state?
• Administrative users, policies, etc….
provider "oci" {
tenancy_ocid = "${var.tenancy_ocid}"
user_ocid = "${var.user_ocid}"
fingerprint = "${var.fingerprint}"
private_key_path = "${var.private_key_path}"
region = "${var.region}"
}

BUILDING SOMETHING USEFUL
LET’S CREATE SOMETHING REAL
• What we’re building?
• Compartment
• VCN
• Security List
• Routing Table
• Internet Gateway
• Subnet
• Instance running nginx
• Requirements
• Used features

• Requirements
• Repeatable infrastructure
• Use the same code
• Different configurations
• NW
• Resource naming
• PROD protection
• Used features

d3
• Requirements
• Used features
• Terraform Workspaces
• A wrapper script

IMPORTING RESOURCES

IMPORTING RESOURCES
ADDING A MANUALLY CREATED RESOURCE
• Retrieve the OCID from OCI
• Create the placeholder resource in terraform configuration
• Import the resource metadata into the state file
terraform import placeholder_resource.name {ocid}
• Show the contents of the state file
terraform state show placeholder_resource.name
• Adjust the placeholder resource to add required attributes
• use the interpolation syntax to retrieve the attributes from other resources
• Check the terraform plan
terraform plan
d4

USING TERRAFORM IRL

USING TERRAFORM IRL
HOW TO START USING TERRAFORM IN YOUR PROJECTS?
• Start small
• Use an iterative approach
• Expand gradually
• Terraform-ing is a team effort
• Don’t Hardcode values in configuration files
• One large configuration defining DEV, UAT and PROD != OK

USING TERRAFORM IRL
• Start small
• Manual adjustments cause state issues
• Everyone needs to be familiar with the workflow, otherwise it will cause manual
actions (trouble)
• One large configuration defining DEV, UAT and PROD is NOT OK

USING TERRAFORM IRL
• Start small
• Utilize variables to make it possible to change aspects of the environment
• Variables simplify conversion into modules, thus improves reusability

USING TERRAFORM IRL
A FEW SUGGESTIONS BEFORE YOU DIVE IN
• Start small
• Reduced separation
• Inability to test the changes
• Decreased reliability and manageability of the configuration
• Break down the system in logical segments that are managed in separate TF
configurations!
• i.e. Core network, shared services
• References between different TF states are possible

USING TERRAFORM IRL
WHERE TO RUN THE TERRAFORM FROM?
• Running it from your workstation
• Possible, but error-prone in a team configuration…
• State needs to be shared (limitations of remote state with OCI)
• Does everyone have the right configuration files (did you forget to git pull?)
• A Deployment server

USING TERRAFORM IRL
WHERE TO RUN THE TERRAFORM FROM?
• Running it from your workstation?
• A Deployment server
• A single shared server, where terraform is executed from
• Additional infrastructure / backups, management
• More control over the configuration of terraform runs
• The “local” state supports locking and workspaces natively
• Editing should not be allowed on the deployment server (to avoid conflicts)
• Easier to integrate with other tools (Jenkins, Ansible, etc)

USING TERRAFORM IRL
PROTECT YOUR CRITICAL STUFF!
• Protecting the state files
• Corrupt/missing state can have severe impact
• State files can store sensitive information
• OCI’s support for remote state is weak at the moment
• Can use a file in an Object Storage Bucket
• Does not support several important features (workspaces, prefixes, limited locking)
• Alternative state storage options?
• Store state files on another cloud (AWS S3 Bucket)?
• Use a “deployment instance”and a “local” protected / encrypted / backed up state
on Block Storage or File Storage services.
• Plan code promotions carefully
• Protecting the PROD

USING TERRAFORM IRL
• Different versions of the same TF configuration code in different environments
• Modules vs. wrapper scripts that pulls the correct version
• Different architectures, but utilize the same terraform modules (different versions)
• Isolate the environments (ability to run destroy without affecting others) to reduce the
potential impact
• terraform workspaces
• Completely separated terraform configuration files (+use of modules)

USING TERRAFORM IRL
• accidents happen
• ‘terraform apply’ in the wrong environment can be very costly
• Build fail-safes (i.e. a wrapper *.sh to implement extra checks for PROD executions)
• Additional benefits possible, i.e. checking out the correct code version from the
repository, posting tags back to git, etc.

SUMMARY
• You will require an IaC solution when moving to Cloud
• Terraform is one good option
• Especially on OCI
• Planning is critical
• Protecting and sharing the state
• Critical resources
• All team effort
• All in or Fail
• It’s fun!
• At least for dinosaur DBAs like me

?
@MarisDBA
elsins@pythian.com

Using Terraform to Manage Oracle Cloud Infrastructure

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