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Management TLS

Configuring Let's Encrypt certificates via Azure DNS for IaaS Console and OBS

This document explains how to configure cert-manager to issue Let's Encrypt certificates using the DNS-01 challenge with Azure DNS.

Azure DNS​

The playbook construct service hostnames from the inventory variables:

management_cluster:
  public: "119.15.114.17"

cluster_name: phoenix.bcn
cluster_public_domain: midocloud.net

For example, the IaaS Console host resolves to:

iaas_console_host: "console.{{ cluster_name }}.{{ cluster_public_domain }}"

which evaluates to console.phoenix.bcn.midocloud.net.

You must add a Recordset in Azure DNS for each service subdomain in your {{ cluster_public_domain }} DNS zone, pointing to {{ management_cluster.public }}:

SubdomainA record value
console.{{ cluster_name }}.{{ cluster_public_domain }}{{ management_cluster.public }}
grafana.{{ cluster_name }}.{{ cluster_public_domain }}{{ management_cluster.public }}
loki.{{ cluster_name }}.{{ cluster_public_domain }}{{ management_cluster.public }}
prometheus.{{ cluster_name }}.{{ cluster_public_domain }}{{ management_cluster.public }}

DNS Forwarding for Internal Domains​

OpenWrt dnsmasq forwards ACME challenge queries to a public resolver so cert-manager can publish TXT records to Azure DNS and Let's Encrypt can resolve them.

For example,

openwrt_dhcp_dnsmasq_server: ...
  - "/_acme-challenge.console.{{ cluster_name }}.{{ cluster_public_domain }}/1.1.1.1"
  - "/_acme-challenge.grafana.{{ cluster_name }}.{{ cluster_public_domain }}/1.1.1.1"
  - "/_acme-challenge.loki.{{ cluster_name }}.{{ cluster_public_domain }}/1.1.1.1"
  - "/_acme-challenge.prometheus.{{ cluster_name }}.{{ cluster_public_domain }}/1.1.1.1"

Base domains resolve internally via the management cluster's CoreDNS.

Prerequisites​

  • Azure subscription with DNS zones
  • A domain registered in Azure DNS

Step 1: Create an Azure DNS Zone​

Create a DNS zone in the Azure Portal and note the resource group name.

Step 2: Create a Service Principal​

SUSCRIPTION_ID=$(az account show --query id -o tsv)
RESOURCE_GROUP="<your-resource-group-name>"  # e.g., "DNS-Management"
APP_NAME="<your-app-name>" # e.g., "DNS-CertManager"

SP=$(az ad sp create-for-rbac \
  --name "$APP_NAME" \
  --role "Contributor" \
  --scopes /subscriptions/$SUSCRIPTION_ID/resourceGroups/$RESOURCE_GROUP)

AZURE_TENANT_ID=$(echo "$SP" | jq -r '.tenant')
AZURE_SP_CLIENT_ID=$(echo "$SP" | jq -r '.appId')
AZURE_SP_PASSWORD=$(echo "$SP" | jq -r '.password')

Step 3: Configure in Inventory​

Add these variables to your inventory:

iaas_console_cert_manager_email: "<your-email>"
iaas_console_cert_manager_azure_subscription_id: "$SUSCRIPTION_ID"
iaas_console_cert_manager_azure_tenant_id: "$AZURE_TENANT_ID"
iaas_console_cert_manager_azure_sp_client_id: "$AZURE_SP_CLIENT_ID"
iaas_console_cert_manager_azure_sp_password: !vault |
  <vault-encrypted-password>
iaas_console_cert_manager_azure_dns_resource_group: "$RESOURCE_GROUP"
iaas_console_tls_enabled: true
iaas_console_tls_cluster_issuer: "letsencrypt-staging"
obs_tls_enabled: true
obs_tls_cluster_issuer: "letsencrypt-staging"

Encrypt the service principal password with ansible-vault and replace <vault-encrypted-password> with the result.

Step 4: Point Your Domain to Azure DNS​

If your domain is registered elsewhere, update the NS records at your registrar to point to the Azure DNS name servers.

Deploy​

Running the IaaS Console deployment will automatically configure TLS using the Let's Encrypt staging environment, which has more flexible rate limits. Once you have verified that things are working, switch both iaas_console_tls_cluster_issuer and obs_tls_cluster_issuer to "letsencrypt-prod".