[CES-124] Add new Session Manager instance to AppGw backend pool

[Krusty93]

List of changes

Add new Session Manager instance to AppGw backend pool

Motivation and context

Split incoming traffic to the two Session Manager instances using round robin pattern

Type of changes

• Add new resources
• Update configuration to existing resources
• Remove existing resources

Env to apply

• DEV
• UAT
• PROD

Does this introduce a change to production resources with possible user impact?

• Yes, users may be impacted applying this change
• No

Does this introduce an unwanted change on infrastructure? Check terraform plan execution result

• Yes
• No

Other information

Depends On #1193

---

If PR is partially applied, why? (reserved to mantainers)

How to apply

After PR is approved

1. run deploy pipeline from Azure DevOps io-platform-iac-projects
2. select PR branch
3. wait for approval

[sonarcloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarCloud

[github-actions]

📖 Terraform Plan ('src/common/prod') - success

Terraform Plan

data.azurerm_linux_function_app.function_assets_cdn: Still reading... [10s elapsed]
data.azurerm_linux_function_app.function_cgn: Still reading... [10s elapsed]
data.azurerm_linux_function_app.eucovidcert: Still reading... [10s elapsed]
data.azurerm_linux_web_app.firmaconio_selfcare_web_app: Still reading... [10s elapsed]
module.application_gateway_weu.data.azurerm_linux_web_app.fims_op_app: Still reading... [10s elapsed]
data.azurerm_linux_function_app.app_messages[0]: Still reading... [10s elapsed]
data.azurerm_linux_function_app.app_messages[1]: Still reading... [10s elapsed]
data.azurerm_linux_function_app.function_profile[1]: Still reading... [10s elapsed]
data.azurerm_linux_function_app.function_profile[0]: Still reading... [10s elapsed]
data.azurerm_linux_function_app.function_assets_cdn: Still reading... [20s elapsed]
data.azurerm_linux_function_app.function_cgn: Still reading... [20s elapsed]
module.application_gateway_weu.data.azurerm_linux_web_app.cms_backoffice_app_itn: Still reading... [10s elapsed]
data.azurerm_linux_web_app.firmaconio_selfcare_web_app: Still reading... [20s elapsed]
module.application_gateway_weu.data.azurerm_linux_web_app.fims_op_app: Still reading... [20s elapsed]
data.azurerm_linux_function_app.app_messages[0]: Still reading... [20s elapsed]
data.azurerm_linux_function_app.app_messages[1]: Still reading... [20s elapsed]
data.azurerm_linux_function_app.function_profile[1]: Still reading... [20s elapsed]
data.azurerm_linux_function_app.function_profile[0]: Still reading... [20s elapsed]
module.application_gateway_weu.data.azurerm_linux_web_app.cms_backoffice_app_itn: Still reading... [20s elapsed]
module.application_gateway_weu.data.azurerm_linux_web_app.session_manager_03: Still reading... [10s elapsed]
data.azurerm_linux_function_app.io_sign_user: Still reading... [10s elapsed]
data.azurerm_linux_function_app.lollipop_function: Still reading... [10s elapsed]
module.application_gateway_weu.data.azurerm_linux_web_app.session_manager_04: Still reading... [10s elapsed]
module.application_gateway_weu.data.azurerm_linux_web_app.appservice_continua: Still reading... [10s elapsed]
data.azurerm_linux_function_app.wallet_user: Still reading... [10s elapsed]
data.azurerm_linux_function_app.services_app_backend_function_app: Still reading... [10s elapsed]
module.application_gateway_weu.data.azurerm_linux_web_app.appservice_selfcare_be: Still reading... [10s elapsed]
module.application_gateway_weu.data.azurerm_linux_web_app.session_manager_03: Still reading... [20s elapsed]
data.azurerm_linux_function_app.io_sign_user: Still reading... [20s elapsed]
module.application_gateway_weu.data.azurerm_linux_web_app.appservice_devportal_be: Still reading... [10s elapsed]
data.azurerm_linux_function_app.lollipop_function: Still reading... [20s elapsed]
module.application_gateway_weu.data.azurerm_linux_web_app.session_manager_04: Still reading... [20s elapsed]
module.application_gateway_weu.data.azurerm_linux_web_app.appservice_continua: Still reading... [20s elapsed]
data.azurerm_linux_function_app.wallet_user: Still reading... [20s elapsed]
data.azurerm_linux_function_app.services_app_backend_function_app: Still reading... [20s elapsed]
module.application_gateway_weu.data.azurerm_linux_web_app.appservice_selfcare_be: Still reading... [20s elapsed]
module.application_gateway_weu.data.azurerm_linux_web_app.appservice_devportal_be: Still reading... [20s elapsed]

Terraform used the selected providers to generate the following execution
plan. Resource actions are indicated with the following symbols:
  ~ update in-place

Terraform will perform the following actions:

  # module.application_gateway_weu.azurerm_web_application_firewall_policy.api_app will be updated in-place
  ~ resource "azurerm_web_application_firewall_policy" "api_app" {
        id                  = "/subscriptions/ec285037-c673-4f58-b594-d7c480da4e8b/resourceGroups/io-p-rg-external/providers/Microsoft.Network/applicationGatewayWebApplicationFirewallPolicies/io-p-waf-appgateway-api-app-policy"
        name                = "io-p-waf-appgateway-api-app-policy"
        tags                = {
            "CostCenter"  = "TS310 - PAGAMENTI & SERVIZI"
            "CreatedBy"   = "Terraform"
            "Environment" = "Prod"
            "Owner"       = "IO"
            "Source"      = "https://github.com/pagopa/io-infra"
        }
        # (4 unchanged attributes hidden)

      ~ policy_settings {
          ~ request_body_inspect_limit_in_kb          = 0 -> 128
            # (6 unchanged attributes hidden)
        }

        # (1 unchanged block hidden)
    }

  # module.application_gateway_weu.module.app_gw.azurerm_application_gateway.this will be updated in-place
  ~ resource "azurerm_application_gateway" "this" {
        id                                = "/subscriptions/ec285037-c673-4f58-b594-d7c480da4e8b/resourceGroups/io-p-rg-external/providers/Microsoft.Network/applicationGateways/io-p-appgateway"
        name                              = "io-p-appgateway"
        tags                              = {
            "CostCenter"  = "TS310 - PAGAMENTI & SERVIZI"
            "CreatedBy"   = "Terraform"
            "Environment" = "Prod"
            "Owner"       = "IO"
            "Source"      = "https://github.com/pagopa/io-infra"
        }
        # (7 unchanged attributes hidden)

      - backend_address_pool {
          - fqdns        = [
              - "io-p-weu-session-manager-app-03.azurewebsites.net",
            ] -> null
          - id           = "/subscriptions/ec285037-c673-4f58-b594-d7c480da4e8b/resourceGroups/io-p-rg-external/providers/Microsoft.Network/applicationGateways/io-p-appgateway/backendAddressPools/session-manager-app-address-pool" -> null
          - ip_addresses = [] -> null
          - name         = "session-manager-app-address-pool" -> null
        }
      + backend_address_pool {
          + fqdns        = [
              + "io-p-weu-session-manager-app-03.azurewebsites.net",
              + "io-p-weu-session-manager-app-04.azurewebsites.net",
            ]
          + id           = (known after apply)
          + ip_addresses = []
          + name         = "session-manager-app-address-pool"
        }

        # (86 unchanged blocks hidden)
    }

Plan: 0 to add, 2 to change, 0 to destroy.

Warning: Argument is deprecated

  with module.application_gateway_weu.azurerm_web_application_firewall_policy.api_app,
  on ../_modules/application_gateway/firewall.tf line 62, in resource "azurerm_web_application_firewall_policy" "api_app":
  62:         disabled_rules = [
  63:           "942100",
  64:           "942120",
  65:           "942190",
  66:           "942200",
  67:           "942210",
  68:           "942240",
  69:           "942250",
  70:           "942260",
  71:           "942330",
  72:           "942340",
  73:           "942370",
  74:           "942380",
  75:           "942430",
  76:           "942440",
  77:           "942450",
  78:         ]

`disabled_rules` will be removed in favour of the `rule` property in version
4.0 of the AzureRM Provider.

(and 50 more similar warnings elsewhere)

─────────────────────────────────────────────────────────────────────────────

Note: You didn't use the -out option to save this plan, so Terraform can't
guarantee to take exactly these actions if you run "terraform apply" now.