• Failed build model due to couldn't auto-discover subnets: unable to discover at least one subnet

    2 min read

    Using an ALB controller we might face the following error while creating Ingress objects:

    $ kubectl describe ingress pet2cattle -n pet2cattle
    Name:             pet2cattle
    Namespace:        pet2cattle
    Address:          
    Default backend:  default-http-backend:80 (<error: endpoints "default-http-backend" not found>)
    Rules:
      Host                        Path  Backends
      ----                        ----  --------
      admin-site.pet2cattle.com  
                                  /   ssl-redirect:use-annotation (<error: endpoints "ssl-redirect" not found>)
                                  /   pet2cattle:http (10.103.202.36:9000)
    Annotations:                  alb.ingress.kubernetes.io/actions.ssl-redirect:
                                    {"Type": "redirect", "RedirectConfig": { "Protocol": "HTTPS", "Port": "443", "StatusCode": "HTTP_301"}}
                                  alb.ingress.kubernetes.io/group.name: pet2cattle
                                  alb.ingress.kubernetes.io/listen-ports: [{"HTTP":80},{"HTTPS":443}]
                                  alb.ingress.kubernetes.io/scheme: internal
                                  alb.ingress.kubernetes.io/target-type: ip
                                  kubernetes.io/ingress.class: alb
                                  meta.helm.sh/release-name: pet2cattle
                                  meta.helm.sh/release-namespace: pet2cattle
    
    Events:
      Type     Reason            Age                 From     Message
      ----     ------            ----                ----     -------
      Warning  FailedBuildModel  16m (x19 over 38m)  ingress  Failed build model due to couldn't auto-discover subnets: unable to discover at least one subnet
    

    This message is telling us that the ALB controller is no able to find the subnets of the requested type. We will have to check the following:

    12/07/2021

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  • ALB Ingress: redirect traffic to HTTPS

    2 min read

    One of the beauties of using an ALB Ingress controller on AWS is that you can configure SSL certificates for your Ingress by just defining you want to use HTTPS

    apiVersion: extensions/v1beta1
    kind: Ingress
    metadata:
      annotations:
        kubernetes.io/ingress.class: alb
        alb.ingress.kubernetes.io/listen-ports: '[{"HTTP":80},{"HTTPS":443}]'
    

    But this is going to serve the same content using HTTP and HTTPS. Configuring a SSL redirect it is also pretty straightforward but involves two steps:

    22/03/2021

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From pet to cattle
Treat your kubernetes clusters like cattle, not pets