Puppet apt::source adding unwanted 'bionic' repository entry on Ubuntu 18.04

Question

I'm trying to get an Ubuntu 18.04 instance configured via Puppet as a Kubernetes master node. In order to install the kublet, kubeadm, and kubectl packages on the Ubuntu 18.04 server, I have a manifest defined on a Puppet master server in which I'm trying to add the Kubernetes repository via Puppet's apt module. The relevant chunk of the manifest is as follows:

include apt

class kubernetes {
    file { '/opt/apt-key.gpg':
        source => [
            "https://packages.cloud.google.com/apt/doc/apt-key.gpg"
        ]
    }

    apt::key { 'kubernetes-repository':
        id => '54A647F9048D5688D7DA2ABE6A030B21BA07F4FB',
        source => 'https://packages.cloud.google.com/apt/doc/apt-key.gpg',
    }

    apt::source { 'kubernetes':
        comment => 'This is the kubernetes repository',
        location => 'http://apt.kubernetes.io/',
        repos => 'kubernetes-xenial main',
        key => {
            'id' => '54A647F9048D5688D7DA2ABE6A030B21BA07F4FB',
        },
        include => {
            'deb' => true,
        },
    }

    package { 'kubelet':
        ensure => installed,
    }

    package { 'kubeadm':
        ensure => installed,
    }

    package { 'kubectl':
        ensure => installed,
    }
}

node 'buildserver.mycompany.com' {
    include kubernetes
}

On the Ubuntu 18.04 server I perform the following to apply the manifest:

sudo puppet agent -t

I get the following output:

Info: Using configured environment 'production'
Info: Retrieving pluginfacts
Info: Retrieving plugin
Info: Retrieving locales
Info: Loading facts
Info: Caching catalog for buildserver.mycompany.com
Info: Applying configuration version '1549042128'
Error: Execution of '/usr/bin/apt-get -q -y -o DPkg::Options::=--force-confold install kubelet' returned 100: Reading package lists...
Building dependency tree...
Reading state information...
E: Unable to locate package kubelet
Error: /Stage[main]/Kubernetes/Package[kubelet]/ensure: change from 'purged' to 'present' failed: Execution of '/usr/bin/apt-get -q -y -o DPkg::Options::=--force-confold install kubelet' returned 100: Reading package lists...
Building dependency tree...
Reading state information...
E: Unable to locate package kubelet
Error: Execution of '/usr/bin/apt-get -q -y -o DPkg::Options::=--force-confold install kubeadm' returned 100: Reading package lists...
Building dependency tree...
Reading state information...
E: Unable to locate package kubeadm
Error: /Stage[main]/Kubernetes/Package[kubeadm]/ensure: change from 'purged' to 'present' failed: Execution of '/usr/bin/apt-get -q -y -o DPkg::Options::=--force-confold install kubeadm' returned 100: Reading package lists...
Building dependency tree...
Reading state information...
E: Unable to locate package kubeadm
Error: Execution of '/usr/bin/apt-get -q -y -o DPkg::Options::=--force-confold install kubectl' returned 100: Reading package lists...
Building dependency tree...
Reading state information...
E: Unable to locate package kubectl
Error: /Stage[main]/Kubernetes/Package[kubectl]/ensure: change from 'purged' to 'present' failed: Execution of '/usr/bin/apt-get -q -y -o DPkg::Options::=--force-confold install kubectl' returned 100: Reading package lists...
Building dependency tree...
Reading state information...
E: Unable to locate package kubectl
Notice: /Stage[main]/Kubernetes/Apt::Source[kubernetes]/Apt::Setting[list-kubernetes]/File[/etc/apt/sources.list.d/kubernetes.list]/ensure: defined content as '{md5}a0ab4048dbab52eed3aa72b3b6b533cf'
Info: /Stage[main]/Kubernetes/Apt::Source[kubernetes]/Apt::Setting[list-kubernetes]/File[/etc/apt/sources.list.d/kubernetes.list]: Scheduling refresh of Class[Apt::Update]
Info: Class[Apt::Update]: Scheduling refresh of Exec[apt_update]
Notice: /Stage[main]/Apt::Update/Exec[apt_update]/returns: Hit:1 http://archive.ubuntu.com/ubuntu bionic InRelease
Notice: /Stage[main]/Apt::Update/Exec[apt_update]/returns: Get:3 http://archive.ubuntu.com/ubuntu bionic-updates InRelease [88.7 kB]
Notice: /Stage[main]/Apt::Update/Exec[apt_update]/returns: Ign:2 https://packages.cloud.google.com/apt bionic InRelease
Notice: /Stage[main]/Apt::Update/Exec[apt_update]/returns: Err:4 https://packages.cloud.google.com/apt bionic Release
Notice: /Stage[main]/Apt::Update/Exec[apt_update]/returns:   404  Not Found [IP: 172.217.6.14 443]
Notice: /Stage[main]/Apt::Update/Exec[apt_update]/returns: Get:5 http://archive.ubuntu.com/ubuntu bionic-backports InRelease [74.6 kB]
Notice: /Stage[main]/Apt::Update/Exec[apt_update]/returns: Get:6 http://archive.ubuntu.com/ubuntu bionic-security InRelease [88.7 kB]
Notice: /Stage[main]/Apt::Update/Exec[apt_update]/returns: Reading package lists...
Notice: /Stage[main]/Apt::Update/Exec[apt_update]/returns: E: The repository 'http://apt.kubernetes.io bionic Release' does not have a Release file.
Error: /Stage[main]/Apt::Update/Exec[apt_update]: Failed to call refresh: '/usr/bin/apt-get update' returned 100 instead of one of [0]
Error: /Stage[main]/Apt::Update/Exec[apt_update]: '/usr/bin/apt-get update' returned 100 instead of one of [0]
Info: Class[Kubernetes]: Unscheduling all events on Class[Kubernetes]
Notice: Applied catalog in 4.19 seconds

It turns out that apt::source is creating the expected /etc/apt/sources.list.d/kubernetes.list file, but the entry for the repository in this file has an unwanted 'bionic' repository added to it. The entry in the file looks like this:

deb http://apt.kubernetes.io/ bionic kubernetes-xenial main

But I was expecting it to look like this:

deb http://apt.kubernetes.io/ kubernetes-xenial main

What can I do to prevent this 'bionic' repository from making it into the resulting file?

Answer 1

It turns out that the module is doing exactly what it's supposed to do. Passing in an empty string for the 'release' value in apt::source fixed my issue. The template that generates the /etc/apt/sources.list.d/kubernetes.list file (source.list.epp) prefixes the provided 'release' value prior to the provided list of repositories. On Ubuntu 18.04, when no 'release' value is provided it appears to resolve to 'bionic', which is how it was ending up in the file. Now my manifest looks like this:

apt::source { 'kubernetes':
    comment => 'This is the kubernetes repository',
    location => 'http://apt.kubernetes.io/',
    release => '',
    repos => 'kubernetes-xenial main',
    key => {
        'id' => '54A647F9048D5688D7DA2ABE6A030B21BA07F4FB',
    },
    include => {
        'deb' => true,
    },
}

 [<%- if ($opt_architecture) {%>arch=<%= $opt_architecture %><% } %><%if ($opt_architecture and $allow_unsigned) {%> <% }%><% if ($allow_unsigned) {%>trusted=yes<% } %>] <%- } %> <%= $location %> <%= $release %> <%= $repos %>