• Template complexity: can't evaluate field Values in type interface {}

    2 min read

    Working with templates can be challenging since, at the end of the day, we are mixing two languages: The template language and the language on which the template itself is written. Doing so we are getting the complexity of one language in addition of the complexity of the other language. That's maybe the main reason why, sometimes, it can be challenging to spot a issues when templates are involved. For example, helm uses templates for generating the appropriate Kubernetes objects, this is one of the errors you might encounter:

    $ helm template  . --debug 
    install.go:172: [debug] Original chart version: ""
    install.go:189: [debug] CHART PATH: /home/pet2cattle/git/spinnaker/helm-spinnaker
    
    
    Error: template: spinnaker/templates/hooks/install-using-hal.yaml:15:28: executing "spinnaker/templates/hooks/install-using-hal.yaml" at <include (print $.Template.BasePath "/configmap/halyard-config.yaml") .>: error calling include: template: spinnaker/templates/configmap/halyard-config.yaml:120:54: executing "spinnaker/templates/configmap/halyard-config.yaml" at <.Values.serviceAccount.spinnaker.enable>: can't evaluate field Values in type interface {}
    helm.go:81: [debug] template: spinnaker/templates/hooks/install-using-hal.yaml:15:28: executing "spinnaker/templates/hooks/install-using-hal.yaml" at <include (print $.Template.BasePath "/configmap/halyard-config.yaml") .>: error calling include: template: spinnaker/templates/configmap/halyard-config.yaml:120:54: executing "spinnaker/templates/configmap/halyard-config.yaml" at <.Values.serviceAccount.spinnaker.enable>: can't evaluate field Values in type interface {}
    

    The error itself looks challenging at first glance, the lines that causes this message are the following:

    {{- range $index, $context := .Values.kubeConfig.contexts }}
    (...)
        $HAL_COMMAND config provider kubernetes account $PROVIDER_COMMAND {{ $context }} --docker-registries dockerhub \
                    --context {{ $context }} {{ if .Values.serviceAccount.spinnaker.enable }}--service-account true{{ end }} \
    (...)
    {{- end }}
    

    Can you spot the mistake?

    02/04/2021

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  • Use kubie to simplify changes between kubernetes contexts and namespaces

    2 min read

    On another post we talked about how to change kubernetes context using kubectl and there's another post for setting a default namespace for a given context. kubie is a tool that helps trying to make it easier

    17/03/2021

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  • kubectl: set a given namespace as your default

    2 min read

    When you need to work on some specific namespace it is quite annoying yo have to specify at each kubectl command the same namespace over and over again. It's much easier to change the current context to use another namespace by default.

    25/01/2021

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  • Change kubectl context to use another k8s cluster

    2 min read

    When you have on your .kube/config several clusters, you can choose to which cluster you want to connect by setting the appropriate context.

    22/12/2020

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