Move `pgsql_tier` subnet to the new Virtual Network from jenkins-infra/azure-net

[lemeurherve]

Follow-up of jenkins-infra/helpdesk#2924

Related: #227

azure/vnets.tf

Lines 54 to 70 in 6391800

	# "pgsql-tier" subnet is reserved as "delegated" for the pgsql server on the public network
	# Ref. https://docs.microsoft.com/en-us/azure/postgresql/flexible-server/concepts-networking
	resource "azurerm_subnet" "pgsql_tier" {
	name = "pgsql-tier"
	resource_group_name = data.azurerm_resource_group.public_prod.name
	virtual_network_name = data.azurerm_virtual_network.public_prod.name
	address_prefixes = ["10.0.3.0/24"]
	delegation {
	name = "pgsql"
	service_delegation {
	name = "Microsoft.DBforPostgreSQL/flexibleServers"
	actions = [
	"Microsoft.Network/virtualNetworks/subnets/join/action",
	]
	}
	}
	}

[dduportal]

There are a some requirements and consequences:

• Most probably, changing the subnet of a managed pgsql instance requires to.. recreate the instance. if it is the case, better to migrate the DB content to a freshly created new one in the new subnet.
• If we can migrate the subnet, then we'lkl have to ensure there is a network peering with the former public network, to allow prodpublick8s to communicate with the instance

[dduportal]

Current error on the build, due to infra.ci being in the "new private" network with no peering to the "old public" where the DB is hosted for now

[2023-01-19T18:08:42.577Z] Error: error detecting capabilities: error PostgreSQL version: dial tcp: lookup public.postgres.database.azure.com on <redacted>:53: no such host
[2023-01-19T18:08:42.577Z] 
[2023-01-19T18:08:42.577Z]   with postgresql_role.keycloak,
[2023-01-19T18:08:42.577Z]   on keycloak.jenkins.io.tf line 7, in resource "postgresql_role" "keycloak":
[2023-01-19T18:08:42.577Z]    7: resource "postgresql_role" "keycloak" {
[2023-01-19T18:08:42.577Z] 
[2023-01-19T18:08:42.577Z] 
[2023-01-19T18:08:42.577Z] Error: error detecting capabilities: error PostgreSQL version: dial tcp: lookup public.postgres.database.azure.com on <redacted>:53: no such host
[2023-01-19T18:08:42.577Z] 
[2023-01-19T18:08:42.577Z]   with postgresql_role.plugin_health,
[2023-01-19T18:08:42.577Z]   on plugin-health.jenkins.io.tf line 12, in resource "postgresql_role" "plugin_health":
[2023-01-19T18:08:42.577Z]   12: resource "postgresql_role" "plugin_health" {
[2023-01-19T18:08:42.577Z] 
[2023-01-19T18:08:42.577Z] 
[2023-01-19T18:08:42.577Z] Error: error detecting capabilities: error PostgreSQL version: dial tcp: lookup public.postgres.database.azure.com on <redacted>:53: no such host
[2023-01-19T18:08:42.577Z] 
[2023-01-19T18:08:42.577Z]   with postgresql_role.rating,
[2023-01-19T18:08:42.577Z]   on rating.jenkins.io.tf line 12, in resource "postgresql_role" "rating":
[2023-01-19T18:08:42.577Z]   12: resource "postgresql_role" "rating" {

[dduportal]

Done (as per

azure/postgres-public-db.tf

Lines 6 to 13 in ceaa67d

	# Dedicated subnet is reserved as "delegated" for the pgsql server on the public network
	# Ref. https://docs.microsoft.com/en-us/azure/postgresql/flexible-server/concepts-networking
	# Defined in https://github.com/jenkins-infra/azure-net/blob/main/vnets.tf
	data "azurerm_subnet" "public_db_vnet_postgres_tier" {
	name = "${data.azurerm_virtual_network.public_db.name}-postgres-tier"
	virtual_network_name = data.azurerm_virtual_network.public_db.name
	resource_group_name = data.azurerm_resource_group.public.name
	}

)