Zero-Touch TLS Provisioning automates the entire certificate lifecycle, from issuance to renewal, without manual intervention.
Let’s see this in action. Imagine a new service, user-api, needs to serve traffic over HTTPS. Traditionally, you’d manually generate a CSR, submit it to a CA, download the cert, and configure your web server. With zero-touch, this happens programmatically.
apiVersion: cert-manager.io/v1
kind: Issuer
metadata:
name: letsencrypt-prod
spec:
acme:
email: admin@example.com
server: https://acme-v02.api.letsencrypt.org/directory
privateKeySecretRef:
name: letsencrypt-prod-key
solvers:
- http01:
ingress:
class: nginx
This Issuer tells cert-manager (a Kubernetes-native certificate management tool) how to obtain certificates from Let’s Encrypt. It specifies the ACME protocol endpoint, an email for registration, and a Kubernetes Secret (letsencrypt-prod-key) to store the ACME account’s private key. The solvers section defines how cert-manager will prove ownership of the domain. Here, http01 is configured to use an Ingress controller of class nginx.
When you create a Certificate resource for user-api.example.com:
apiVersion: cert-manager.io/v1
kind: Certificate
metadata:
name: user-api-tls
spec:
secretName: user-api-tls-secret
dnsNames:
- user-api.example.com
issuerRef:
name: letsencrypt-prod
kind: Issuer
cert-manager intercepts this. It sees the issuerRef points to our letsencrypt-prod Issuer. It then initiates the ACME challenge. For http01, it will create an Ingress resource that temporarily serves a specific token at http://user-api.example.com/.well-known/acme-challenge/<token>. The Let’s Encrypt server queries this endpoint. If the response matches the token, Let’s Encrypt knows cert-manager controls the domain.
Upon successful validation, Let’s Encrypt issues a certificate. cert-manager receives it, stores it in the Kubernetes Secret named user-api-tls-secret, and your Ingress controller (configured to use user-api-tls-secret for TLS) automatically picks it up. The private key for the certificate is also generated and stored in user-api-tls-secret.
The real magic is renewal. cert-manager monitors the expiration date of certificates it manages. About 30 days before expiry, it will automatically re-initiate the ACME challenge and obtain a new certificate, updating the user-api-tls-secret in place. Your application experiences zero downtime during renewal because the Ingress controller seamlessly switches to the new certificate.
The core problem this solves is the operational burden and error-proneness of manual certificate management. This includes tracking expirations, generating CSRs, uploading keys to CAs, and reconfiguring services. Zero-touch provisioning turns this into a declarative, automated process within your infrastructure. cert-manager acts as the orchestrator, interacting with ACME-compatible Certificate Authorities (CAs) like Let’s Encrypt, Buypass, or even private CAs.
The solvers configuration is key to proving domain ownership. Beyond http01, cert-manager supports dns01 challenges. This method involves creating a specific TXT record in your DNS zone. For example, if you delegate DNS management to AWS Route 53, you’d configure cert-manager with AWS credentials and it would automatically create _acme-challenge.user-api.example.com TXT records. This is often preferred for internal services or when ingress-based challenges are difficult to implement.
The privateKeySecretRef is crucial. It’s not just for the ACME account key; cert-manager uses it to store the private key for the certificate itself once issued. This means the private key never leaves your cluster and is managed securely by Kubernetes Secrets.
The solvers section allows for multiple strategies. You can define an ingress solver which uses an existing Ingress resource to respond to challenges, or a webhook solver that integrates with external systems (like cloud provider DNS APIs) to solve challenges. This flexibility allows zero-touch provisioning to work in diverse environments.
A common point of confusion is how cert-manager integrates with your ingress controller. It doesn’t directly configure the ingress controller. Instead, it updates a Kubernetes Secret containing the TLS certificate and private key. Your ingress controller, which is already configured to watch for Ingress resources and associated Secrets, automatically detects the updated Secret and reloads its configuration to serve traffic with the new certificate.
When setting up cert-manager for the first time, ensure your Issuer or ClusterIssuer (a cluster-wide version) is correctly configured with a valid ACME server URL and your ACME account email. Misspellings or incorrect URLs are common initial stumbling blocks.
The next thing you’ll likely want to tackle is using multiple CAs or implementing more advanced ACME challenge types like dns01 for wildcard certificates.