Terraform for Dummies Part 6: Deploy Oracle DB System 21c Using Terraform

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Intro

What’s the point of moving a database to the Cloud if we can’t automatically deploy it. After blogging about web compute provisioning on AWS (Amazon Web Services), OCI (Oracle Cloud Infrastructure)Azure (Microsoft Azure), and GCP (Google Cloud Platform) using Terraform. The least I could do as a (future-ex) DBA is to Terraform Database provisioning in Oracle Cloud. On top of that, I also wanted to include a Bastion Service Session to connect to the DBCS instance in the Private Subnet.

terraform1

Here’s a link to my GitHub Repo linked to this lab: brokedba/terraform-provider-oci/database-system

 

Where do I find a good OCI Database Deployment Sample?
I explored the official Oracle Cloud GitHub Repository, but I couldn’t find a simple stack with no frills. I mean, when you want to deploy a database for the first time, you don’t want to spin 10 other app components that have nothing to do with your DB. I then decided to gather the bare minimum using a function called terraform import that will retro-engineer the code from an existing database and carried on from there.  

 

Overview and Topology

The above illustration shows the different components involved in this OCI Terraform Database Stack

  • VCN (Virtual Compound Network)

  • Database Cloud System 21c with 1 PDB

  • Bastion Service and Bastion session using port forwarding SSH  targeting the DB Instance

  • 2x Subnets

    • DB Subnet: Private / Linked to default Route Table

    • App Subnet: Public / Linked to the App Route Table

  • 2x Route Tables

    • Default Route Table >  Routes to NAT Gateway and Service Gateway

    • App Route Table   >  Routes to the Internet Gateway

  • 2x Security Lists

    • The Database Sec List Ports: Ingress 22/1521 from App Subnet

    • The App Sec List Ports “: Ingress 22/80/443, egress 1521

 

I.Terraform Setup

Windows: Download and run the installer from their website (32-bit ,64-bit)

Linux:  Download, unzip and move the binary to the local bin directory

$ wget https://releases.hashicorp.com/terraform/1.0.3/terraform_1.0.3_linux_amd64.zip
$ unzip terraform_1.0.3_linux_amd64.zip
$ mv terraform /usr/local/bin/
$ terraform --version
  Terraform v1.0.3

 

II. Clone the Repository

  • Pick an empty directory on your file system and issue the following command

$ git clone https://github.com/brokedba/terraform-examples.git
$ cd ~/terraform-examples/terraform-provider-oci/database-system
  • Run Terraform init which will install the OCI provider plugin automatically
$ terraform init
$ terraform -v | grep provider  
  + provider registry.terraform.io/hashicorp/oci v3.83.1   

 

III. Terraform Config Content

  • Let’s see what’s in the database-system directory. Here, only *.tf files matter along with tfvars
$ tree 
├── bastion.tf     ---> OCI Bastion terraform declaration code  ├── database.tf ---> OCI DBCS terraform declaration code  ├── datasources.tf ---> data source declaration code (i.e to fetch shape ocids) ├── terraform.tfvars ---> TF_environment_variables needed to authenticate to OCI
├── outputs.tf   ---> displays the DBCS/Bastion resources detail after the deploy
├── variables.tf ---> Resource variables needed for the deploy 
└── vcn.tf       ---> Our Networking terraform declaration code 
  • Adjust the required authentication parameters in terraform.tfvars according to your tenancy and DB info 

# Adapt the below variables to your own tenancy authentication configuration
$ vi terraform.tfvars  
export TF_VAR_tenancy_ocid="ocid1.tenancy.oc1..aaaaaaaa"        # change me 
export TF_VAR_user_ocid="ocid1.user.oc1..aaaaaaaa"              # change me 
export TF_VAR_compartment_ocid="ocid1.tenancy.oc1..aaaaaaaa"    # change me 
export TF_VAR_fingerprint=$(cat PATH_To_Fing/oci_api_key_fingerprint)# change me 
export TF_VAR_private_key_path=PATH_To_APIKEY/oci_api_key.pem        # change me 
export TF_VAR_ssh_public_key=$(cat PATH_To_PublicSSH/id_rsa.pub)     # change me export TF_VAR_region="ca-toronto-1"                                  # change me 
export TF_VAR_db_admin_password="DBwelcome2022##" 

$ . terraform.tfvars  

 

Terraform files OVERVIEW:

I will only show excerpts from the database.tf /output.tf to have an idea but all *.tf files are accessible on my Repo.

 

Database.tf

  • As shown in the below declaration, highlighted in green are variables and the grey ones are data source based
resource "oci_database_db_system" "MYDBSYS" {
availability_domain   = data.oci_identity_availability_domains.ad1.availability_domains[0].name
  compartment_id      = var.compartment_ocid
  database_edition    = var.db_edition
  db_home {
    database {
      admin_password = var.db_admin_password
      db_name        = var.db_name
      pdb_name       = var.pdb_name
      character_set  = var.character_set
      ncharacter_set = var.n_character_set
      db_workload    = var.db_workload
      db_backup_config {
        auto_backup_enabled     = var.db_auto_backup_enabled
        auto_backup_window      = var.db_auto_backup_window
        recovery_window_in_days = var.db_recovery_window_in_days
      }
    }
    db_version = var.db_version
  }
  shape                   = var.db_system_shape
  license_model           = var.license_model
  subnet_id               = oci_core_subnet.terraDB.id
  private_ip              = var.db_system_private_ip
  ssh_public_keys         = ["${var.ssh_public_key}"] 
  hostname                = var.hostname
  data_storage_size_in_gb = var.data_storage_size_in_gb
  node_count              = data.oci_database_db_system_shapes.db_system_shapes.db_system_shapes[0]["minimum_node_count"]
  display_name = var.db_system_display_name
}

All variables can of course be changed to your liking in the variables.tf

 

output.tf

  • Here we just grab any relevant information related to the DBCS and the Bastion service like the ssh command
#########################
##  DBCS INSTANCE OUTPUT
#########################

output "hostname" {
description = " id of created instances."
value       = oci_database_db_system.MYDBSYS.hostname
}

output "private_ip" {
description = "Private IPs of created instances."
value       = oci_database_db_system.MYDBSYS.private_ip
}
output "DB_STATE" {
  value = oci_database_db_system.MYDBSYS.state
}
output "DB_Version" {   value = oci_database_db_system.MYDBSYS.version
}
output "db_system_options" {
  value = oci_database_db_system.MYDBSYS.db_system_options
}

#########
# BASTION
#########
output "bastion_name" {
value = oci_bastion_session.mybastion_session.bastion_name
}

output "bastion_session_name" {
  value = oci_bastion_session.mybastion_session.display_name
}

output "bastion_session_state" {
  value = oci_bastion_session.mybastion_session.state
}

output "bastion_session_target_resource_details" {
  value = oci_bastion_session.mybastion_session.target_resource_details
}

output "bastion_session_ssh_connection" {
  value = oci_bastion_session.mybastion_session.ssh_metadata.command
}

 

IV. DBCS Stack Deployment

Make sure you copied the adjusted terraform-tfvars file and sourced it. You can then run the plan command (output is truncated for more readability) 

$ terraform plan
  ------------------------------------------------------------------------
   Terraform will perform the following actions:

  ... # VCN declaration 
# oci_bastion_bastion.mybastion will be created
+ resource "oci_bastion_bastion" "mybastion" { ...
# oci_bastion_session.mybastion_session will be created
+ resource "oci_bastion_session" "mybastion_session" {
  ...
     + target_resource_details {
       + session_type                               = "PORT_FORWARDING"
       + target_resource_display_name               = (known after apply)
       + target_resource_operating_system_user_name = (known after apply)
       + target_resource_port                       = 22
       + target_resource_private_ip_address         = "192.168.78.10"
     }
  }
# oci_core_subnet.terraApp will be created
+ resource "oci_core_subnet" "terraApp" { ...
# oci_core_subnet.terraDB will be created
+ resource "oci_core_subnet" "terraDB" {
    + availability_domain        = "gwmA:CA-TORONTO-1-AD-1"
    + cidr_block                 = "192.168.78.0/24"
...
# oci_core_virtual_network.vcnterra will be created
 + resource "oci_core_virtual_network" "vcnterra" {
    + cidr_block               = "192.168.64.0/20"
    + display_name             = "db-vcn"
    + dns_label                = "terravcn"
 ...}
..
# oci_database_db_system.MYDBSYS will be created
+ resource "oci_database_db_system" "MYDBSYS" {
   + availability_domain                     = "gwmA:CA-TORONTO-1-AD-1" 
   + database_edition                        = "STANDARD_EDITION"
   + data_storage_size_in_gb                 = 256
   + display_name                            = "DBCSDEMO"
   + hostname                                = "hopsdb-oci"
   + license_model                           = "LICENSE_INCLUDED"
   + private_ip                              = "192.168.78.10"
   + shape                                   = "VM.Standard2.4"
   + ssh_public_keys                         =[... 
   + db_home { 
       + db_version                   = "21.0.0.0"
       ...
       + database {
            + db_workload                    = "OLTP"
            + db_name                        = "MYCDB"
            + pdb_name                       = "PDB1"
            ...
            + db_backup_config { … 
            + backup_destination_details {
            }
         }
       }
   }  
   + db_system_options {
     + storage_management = (known after apply) }
 
Plan: 15 to add, 0 to change, 0 to destroy.
Changes to Outputs:
  + DB_STATE                                = (known after apply)
  + DB_Version                              = (known after apply)
  + Subnet_CIDR_DB                          = "192.168.78.0/24"
  + Subnet_Name_DB                          = "db-sub"
  + bastion_name                            = (known after apply)
  + bastion_session_name                    = "Session-Mybastion"
  + bastion_session_ssh_connection          = (known after apply)
  + bastion_session_state                   = (known after apply)
  + bastion_session_target_resource_details = [
  + db_system_options                       = (known after apply)
  + hostname                                = "hopsdb-oci"
  + private_ip                              = "192.168.78.10"
  + vcn_id                                  = (known after apply)
  + vcn_name                                = "db-vcn"

Now let’s provision our DBCS instance (output has been truncated for more visibility)

$ terraform apply -auto-approve
...
oci_core_virtual_network.vcnterra: Creation complete after 1s 

oci_core_security_list.terraApp_sl: Creation complete after 1s 

oci_core_internet_gateway.igtw: Creation complete after 1s 
oci_core_security_list.terra_sl: Creation complete after 1s 
oci_core_route_table.apprt: Creation complete after 1s 
oci_core_service_gateway.obj-svcgw: Creation complete 
oci_core_nat_gateway.natgw: Creation complete after 3s 

oci_core_default_route_table.rt: Creation complete after 0s 
oci_core_subnet.terraApp: Creation complete after 5s 
oci_core_subnet.terraDB: Creation complete after 5s 
oci_database_db_system.MYDBSYS: Creating...
oci_core_drg.drgw: Creation complete after 9s 
oci_core_drg_attachment.drgw_attachment: Creation complete after 15s 
oci_database_db_system.MYDBSYS: Creation complete after 50m58s 
Apply complete! Resources: 15 added, 0 changed, 0 destroyed

 

CONNECTION TO YOUR DBCA INSTANCE 

As mentioned earlier I included a bastion service session to remote log into the target database instance in the private subnet from my workstation through a port forwarding tunnel. Do you want to know the full SSH Command? Look no further! it is already displayed in my Terraform output after the apply >> bastion_session_ssh_connection

terraform2

SSH Connection Usage

  • The final ssh command will look like this, notice I added and run it in the background, so I won’t have to open another session to login to the Private DB instance. 

# ssh -i ~/.ssh/id_rsa_oci -N -L 22:192.168.78.10:22 -p 22 ocid1.bastionsession.oc1.ca-toronto-1.amaaaaaavr**a@host.bastion.ca-toronto-1.oci.oraclecloud.com &
  • Run the final ssh command to access the target resource using a sort of loopback where localhost is forwarded into the target instance IP through the opened proxy tunnel. 

# ssh -i  ~/.ssh/id_rsa_dbcs opc@localhost
[opc@hopsdb-oci ~]$  sudo dbcli describe-component --- target instance
System Version
---------------
22.1.1.1.0
Component                                Installed Version    Available Version
---------------------------------------- -------------------- --------------------
GI                                        21.1.0.0.0            21.5.0.0
DB                                        21.1.0.0.0            21.5.0.0


[opc@hopsdb-oci]$ sudo dbcli list-databases ID DB Name DB Type DB Version CDB Class Storage Status DbHomeID ------- ---------- -------- ----------- ----- ----- -------- ---------- ----------- a3** MYCDB Si 21.1.0.0.0 true Oltp ASM Configured 9a841-****

 

What you should know

Terraform registry Doc for the OCI Provider is not up to date i.e node_count in db_system resource is really required

terraform3

 

The list of valid releases will change and can break your deployment. (i.e 19.11.0.0 was recently dropped from the list) you may want to use the base release first.

 

CONCLUSION

  • We have demonstrated in this tutorial how to quickly deploy a Database instance using Terraform in OCI and leverage along with all necessary network resources

  • Remember that all user attributes in this exercise can be modified in the variables.tf file.

  • Adding a bastion service on top of the stack including the required ssh command to access the DBCS instance is a great value (port 1512 can also be forwarded to connect from SQL Developer)

  • From this stack, you can safely add new components via sub-modules or new resources in the .tf files

  • With this simple example, you have no excuse not to try a Terraform deployment for your Databases in OCI

  • You can also import the stack into your resource manager service or even pipeline them in Gitlab/GitHub or OCI DevOps  

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