As mentioned on Mastodon (https://mastodon.social/@dpom@fosstodon.org/113460954769241417) there seems to be no way to do it at the moment :(

Thanks, I’ll try that!

Sure. I import the certificates like this:

{ config, pkgs, inputs, ... }:
{
  security.pki.certificateFiles = [
    ./certificates/home.pem
  ];
}

where home.pem is a default PEM formatted certificate. It works fine to import the cert system wide this way.

If I enter the flake.nix and run a simple curl against the remote server I get the following, which is typical for a TLS certificate error.

curl https://webpage.home
curl: (35) OpenSSL/3.0.14: error:16000069:STORE routines::unregistered scheme

So it seems to me that the development shell does not pick up the certificates installed on the system. I can work around that by using an impure shell, but I think that this is not how nix should be used.

Thanks for the response. You are right, the config was at the wrong path. Unfortunately, the config itself does not work, too. After a bit of testing around this worked for me:

apiVersion: v1
kind: PersistentVolume
metadata:
  name: nix-cache-volume
spec:
  capacity:
    storage: 500Gi
  storageClassName: manual
  accessModes:
    - ReadWriteOnce
  hostPath:
    path: "/mnt/k8s/nix-cache" # Needs exists before PV is created!
  persistentVolumeReclaimPolicy: Retain
---
apiVersion: v1
kind: PersistentVolumeClaim
metadata:
  name: nix-cache-pvc
spec:
  accessModes:
    - ReadWriteOnce
  storageClassName: manual
  resources:
    requests:
      storage: 500Gi
---
apiVersion: apps/v1
kind: Deployment
metadata:
  name: nix-cache
spec:
  replicas: 1
  selector:
    matchLabels:
      app: nix-cache
  template:
    metadata:
      labels:
        app: nix-cache
        name: nix-cache
    spec:
      volumes:
        - name: nix-cache-storage
          persistentVolumeClaim:
            claimName: nix-cache-pvc
        - name: nix-cache-config
          configMap:
            name: nix-cache-config
      containers:
        - name: nix-cache
          image: nginx:1.27.0 
          ports:
            - containerPort: 80
          volumeMounts:
            - name: nix-cache-storage
              mountPath: /data
            - name: nix-cache-config
              mountPath: /etc/nginx/nginx.conf
              subPath: nginx.conf
              readOnly: true
          resources:
            limits:
              memory: "512Mi"
              cpu: "300m"
            requests:
              memory: "256Mi"
              cpu: "200m"
---
apiVersion: v1
kind: Service
metadata:
  name: nix-cache
spec:
  selector:
    app: nix-cache
  ports:
    - protocol: TCP
      port: 80
      targetPort: 80
---
apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
  name: nix-cache-ingress
  annotations:
    traefik.ingress.kubernetes.io/router.tls: "true"
spec:
  rules:
    - host: "nix-cache.raspi.home"
      http:
        paths:
          - pathType: Prefix
            path: "/"
            backend:
              service:
                name: nix-cache
                port:
                  number: 80
  tls:
    - secretName: nix-cache-raspi-home-tls
      hosts:
        - "nix-cache.raspi.home"
---
apiVersion: cert-manager.io/v1
kind: Certificate
metadata:
  name: nix-cache.raspi.home
spec:
  commonName: nix-cache.raspi.home
  dnsNames:
    - "nix-cache.raspi.home"
  secretName: nix-cache-raspi-home-tls
  issuerRef:
    name: ca-issuer
    kind: ClusterIssuer
---
apiVersion: v1
kind: ConfigMap
metadata:
  name: nix-cache-config
data:
  # See: https://www.channable.com/tech/setting-up-a-private-nix-cache-for-fun-and-profit
  nginx.conf: |
    events {
        worker_connections 1024;
    }
    http {
      proxy_cache_path /data/nginx/cache max_size=500G keys_zone=cache_zone:50m inactive=365d;
      proxy_cache cache_zone;
      proxy_cache_valid 200 365d;
      proxy_cache_use_stale error timeout invalid_header updating http_500 http_502 http_504 http_403 http_404 http_429;
      proxy_ignore_headers X-Accel-Expires Expires Cache-Control Set-Cookie;
      proxy_cache_lock on;

      server {
          listen 80;

          server_name nix-cache.raspi.home;

          location /nix-cache-info {
              return 200 "StoreDir: /nix/store\nWantMassQuery: 1\nPriority: 41\n";
          }

          location / {
              proxy_set_header Host $proxy_host;
              proxy_pass https://cache.nixos.org;
          }
      }
    }

The config is an adaption from this blog post: https://www.channable.com/tech/setting-up-a-private-nix-cache-for-fun-and-profit