argo-cd/docs/operator-manual/ingress.md

Ingress Configuration

Argo CD runs both a gRPC server (used by the CLI), as well as a HTTP/HTTPS server (used by the UI). Both protocols are exposed by the argocd-server service object on the following ports:

• 443 - gRPC/HTTPS
• 80 - HTTP (redirects to HTTPS)

There are several ways how Ingress can be configured.

kubernetes/ingress-nginx

Option 1: SSL-Passthrough

Argo CD serves multiple protocols (gRPC/HTTPS) on the same port (443), this provides a challenge when attempting to define a single nginx ingress object and rule for the argocd-service, since the nginx.ingress.kubernetes.io/backend-protocol annotation accepts only a single value for the backend protocol (e.g. HTTP, HTTPS, GRPC, GRPCS).

In order to expose the Argo CD API server with a single ingress rule and hostname, the nginx.ingress.kubernetes.io/ssl-passthrough annotation must be used to passthrough TLS connections and terminate TLS at the Argo CD API server.

apiVersion: extensions/v1beta1
kind: Ingress
metadata:
  name: argocd-server-ingress
  annotations:
    kubernetes.io/ingress.class: nginx
    nginx.ingress.kubernetes.io/force-ssl-redirect: "true"
    nginx.ingress.kubernetes.io/ssl-passthrough: "true"
spec:
  rules:
  - host: argocd.example.com
    http:
      paths:
      - backend:
          serviceName: argocd-server
          servicePort: https

The above rule terminates TLS at the Argo CD API server, which detects the protocol being used, and responds appropriately. Note that the nginx.ingress.kubernetes.io/ssl-passthrough annotation requires that the --enable-ssl-passthrough flag be added to the command line arguments to nginx-ingress-controller.

SSL-Passthrough with cert-manager and Let's Encrypt

apiVersion: extensions/v1beta1
kind: Ingress
metadata:
  name: argocd-server-ingress
  namespace: argocd
  annotations:
    cert-manager.io/cluster-issuer: letsencrypt-prod
    kubernetes.io/ingress.class: nginx
    kubernetes.io/tls-acme: "true"
    nginx.ingress.kubernetes.io/ssl-passthrough: "true"
    # If you encounter a redirect loop or are getting a 307 response code 
    # then you need to force the nginx ingress to connect to the backend using HTTPS.
    #
    # nginx.ingress.kubernetes.io/backend-protocol: "HTTPS"
spec:
  rules:
  - host: argocd.example.com
    http:
      paths:
      - backend:
          serviceName: argocd-server
          servicePort: https
        path: /
  tls:
  - hosts:
    - argocd.example.com
    secretName: argocd-secret # do not change, this is provided by Argo CD

Option 2: Multiple Ingress Objects And Hosts

Since ingress-nginx Ingress supports only a single protocol per Ingress object, an alternative way would be to define two Ingress objects. One for HTTP/HTTPS, and the other for gRPC:

HTTP/HTTPS Ingress:

apiVersion: extensions/v1beta1
kind: Ingress
metadata:
  name: argocd-server-http-ingress
  annotations:
    kubernetes.io/ingress.class: "nginx"
    nginx.ingress.kubernetes.io/force-ssl-redirect: "true"
    nginx.ingress.kubernetes.io/backend-protocol: "HTTP"
spec:
  rules:
  - http:
      paths:
      - backend:
          serviceName: argocd-server
          servicePort: http
    host: argocd.example.com
  tls:
  - hosts:
    - argocd.example.com
    secretName: argocd-secret # do not change, this is provided by Argo CD

gRPC Ingress:

apiVersion: extensions/v1beta1
kind: Ingress
metadata:
  name: argocd-server-grpc-ingress
  annotations:
    kubernetes.io/ingress.class: "nginx"
    nginx.ingress.kubernetes.io/backend-protocol: "GRPC"
spec:
  rules:
  - http:
      paths:
      - backend:
          serviceName: argocd-server
          servicePort: https
    host: grpc.argocd.example.com
  tls:
  - hosts:
    - grpc.argocd.example.com
    secretName: argocd-secret # do not change, this is provided by Argo CD

The API server should then be run with TLS disabled. Edit the argocd-server deployment to add the --insecure flag to the argocd-server command:

spec:
  template:
    spec:
      name: argocd-server
      containers:
      - command:
        - /argocd-server
        - --staticassets
        - /shared/app
        - --repo-server
        - argocd-repo-server:8081
        - --insecure

The obvious disadvantage to this approach is that this technique requires two separate hostnames for the API server -- one for gRPC and the other for HTTP/HTTPS. However it allows TLS termination to happen at the ingress controller.

Traefik (v2.0)

Traefik can be used as an edge router and provide TLS termination within the same deployment.

It currently has an advantage over NGINX in that it can terminate both TCP and HTTP connections on the same port meaning you do not require multiple ingress objects and hosts.

The API server should be run with TLS disabled. Edit the argocd-server deployment to add the --insecure flag to the argocd-server command.

apiVersion: traefik.containo.us/v1alpha1
kind: IngressRoute
metadata:
  name: argocd-server-ingress
spec:
  entryPoints:
    - websecure
  routes:
    - match: Host(`argocd.example.com`)
      kind: Rule
      services:
        - name: argocd-server
          port: 80
  tls:
    certResolver: default
    options: {}

AWS Application Load Balancers (ALBs) And Classic ELB (HTTP Mode)

ALBs and Classic ELBs don't fully support HTTP2/gRPC, which is used by the argocd CLI. Thus, when using an AWS load balancer, either Classic ELB in passthrough mode is needed, or NLBs.

$ argocd login <host>:<port> --grpc-web

Authenticating through multiple layers of authenticating reverse proxies

ArgoCD endpoints may be protected by one or more reverse proxies layers, in that case, you can provide additional headers through the argocd CLI --header parameter to authenticate through those layers.

$ argocd login <host>:<port> --header 'x-token1:foo' --header 'x-token2:bar' # can be repeated multiple times
$ argocd login <host>:<port> --header 'x-token1:foo,x-token2:bar' # headers can also be comma separated

UI Base Path

If the Argo CD UI is available under a non-root path (e.g. /argo-cd instead of /) then the UI path should be configured in the API server. To configure the UI path add the --basehref flag into the argocd-server deployment command:

spec:
  template:
    spec:
      name: argocd-server
      containers:
      - command:
        - /argocd-server
        - --staticassets
        - /shared/app
        - --repo-server
        - argocd-repo-server:8081
        - --basehref
        - /argo-cd

NOTE: The flag --basehref only changes the UI base URL. The API server will keep using the / path so you need to add a URL rewrite rule to the proxy config. Example nginx.conf with URL rewrite:

worker_processes 1;

events { worker_connections 1024; }

http {

    sendfile on;

    server {
        listen 443;

        location /argo-cd {
            rewrite /argo-cd/(.*) /$1  break;
            proxy_pass         https://localhost:8080;
            proxy_redirect     off;
            proxy_set_header   Host $host;
            proxy_set_header   X-Real-IP $remote_addr;
            proxy_set_header   X-Forwarded-For $proxy_add_x_forwarded_for;
            proxy_set_header   X-Forwarded-Host $server_name;
            # buffering should be disabled for api/v1/stream/applications to support chunked response
            proxy_buffering off;
        }
    }
}