Azure Multi-Region Cockroach Cluster

TLDR;

Start by creating an SSH Key in Azure (region does not matter). You'll supply the name of the key as a variable to the HCL (Hashicorp Configuration Language). This key will allow you to log in to all the compute instances created by this script.

Export the following in the session where you will run the HCL. An Enterprise license is required to run the CRDB Cluster in a multi-region configuration.

export TF_VAR_cluster_organization={CLUSTER ORG}
export TF_VAR_enterprise_license={LICENSE}

Run this Terraform Script

# See the appendix below to intall Terrafrom, the Azure CLI and logging in to Azure

git clone https://github.com/nollenr/AZURE-Terraform-CRDB-Multi-Region.git
cd AZURE-Terraform-CRDB-Multi-Region/

# if you intend to use enterprise features of the database 
export TF_VAR_cluster_organization={CLUSTER ORG}
export TF_VAR_enterprise_license={LICENSE}

Modify the terraform.tfvars to meet your needs

You'll need to change several variable values to meet your needs. For example, you may want different regions, Virtual Network CIDRs, etc.

terraform init
terraform plan
terraform apply

# To clean up
terraform destroy

It is important to understand that 15 instances will be created when this script is executed:

• 9 CRDB instances (3 nodes per region in 3 regions)
• 3 HA Proxy Nodes (1 HA Proxy per region)
• 3 APP Nodes (1 APP node per region)

For ARM Installs

• the version of CRDB must be 23.2.x and above

terraform.tfvars and vars.tf

Be careful in choosing values for variables in the teffaform.tfvars and vars.tf files. They must conform to Azure naming standards and be valid values for the types of objects being created. No checking is performed on the inputs.

Appendix

Making Sense of the TLS Certs Used in This HCL

There are a lot of TLS objects (see tls HCL file ). To help make sense of the objects and how they are used in CRDB and VM formation, I created this chart to help -- maybe it does, maybe it doesn't.

Variable	CRDB Name	TLS	TLS Name	Note
tls_private_key	ca.key	tls_private_key.crdb_ca_keys.private_key_pem	TLS Private Key PEM
tls_public_key	ca.pub	tls_private_key.crdb_ca_keys.public_key_pem	TLS Public Key PEM
tls_cert	ca.crt	tls_self_signed_cert.crdb_ca_cert.cert_pem	TLS Cert PEM
tls_self_signed_cert	ca.crt	tls_self_signed_cert.crdb_ca_cert.cert_pem	TLS Cert PEM	Duplicate of tls_cert for better naming
tls_user_cert	client.name.crt	tls_locally_signed_cert.user_cert.cert_pem
tls_locally_signed_cert	client.name.crt	tls_locally_signed_cert.user_cert.cert_pem		Duplicate of tls_user_cert for better naming
tls_user_key	client.name.key	tls_private_key.client_keys.private_key_pem

Replacing an instance from a module

To replace the app instance from the first VPC (vpc 0) terraform apply -replace=module.crdb-region-0.azurerm_linux_virtual_machine.app[0]