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Configure network proxy using YTT with Tanzu Kubernetes Grid (TKG)

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I was doing some work with Tanzu Kubernetes Grid (TKG) 1.2 using my TKG Demo Appliance Fling and the environment that I was working in did not have direct internet access, which is usually the case for most Production environment. I needed to have outbound connectivity from the TKG Worker Nodes so that they could pull down a set of containers as part of attaching to our Tanzu Mission Control (TMC) service.

Luckily, there was an HTTP proxy server that I could use for this connectivity and we just need to update our TKG templates so the TKG worker nodes will have the proxy settings. In the past, when needing to apply such customizations such as adding a network proxy to TKG, it meant I had to manually edit the TKG Dev/Prod YAML files. As previously shared, Tanzu Kubernetes Grid (TKG) 1.2 now uses the YAML Templating Tool (YTT) tool for customizing TKG plans.

Although the TKG documentation provides an example for YTT template example, it did not actually cover the TKG Worker Nodes which is what I needed but also that I needed to add a command into the postKubeadmCommands for the network proxy to be activated. The issue is that this section no longer exists in the base template like it did in previous versions of TKG and required some additional YTT annotation to get this working.

Here is the complete working ~/.tkg/providers/infrastructure-vsphere/ytt/proxy_nameserver.yaml template that adds the respective HTTP(S) proxy server and No Proxy settings.

#@ load("@ytt:overlay", "overlay")

#@overlay/match by=overlay.subset({"kind":"KubeadmControlPlane"})
---
apiVersion: controlplane.cluster.x-k8s.io/v1alpha3
kind: KubeadmControlPlane
spec:
  kubeadmConfigSpec:
    preKubeadmCommands:
    #! Add HTTP_PROXY to containerd configuration file
    #@overlay/append
    - echo $'[Service]\nEnvironment="HTTP_PROXY=http://1.2.3.4:3128/"' > /etc/systemd/system/containerd.service.d/http-proxy.conf
    #@overlay/append
    - echo 'Environment="HTTPS_PROXY=http://1.2.3.4:3128"' >> /etc/systemd/system/containerd.service.d/http-proxy.conf
    #@overlay/append
    - echo 'Environment="NO_PROXY=localhost,192.168.4.0/24,192.168.3.0/24,registry.rainpole.io,10.2.224.4,.svc,100.64.0.0/13,100.96.0.0/11"' >> /etc/systemd/system/containerd.service.d/http-proxy.conf
    #@overlay/match missing_ok=True
    postKubeadmCommands:
    #@overlay/append
    - systemctl restart containerd

#@overlay/match by=overlay.subset({"kind":"KubeadmConfigTemplate"})
---
apiVersion: bootstrap.cluster.x-k8s.io/v1alpha3
kind: KubeadmConfigTemplate
spec:
  template:
    spec:
      preKubeadmCommands:
      #! Add HTTP_PROXY to containerd configuration file
      #@overlay/append
      - echo $'[Service]\nEnvironment="HTTP_PROXY=http://1.2.3.4:3128/"' > /etc/systemd/system/containerd.service.d/http-proxy.conf
      #@overlay/append
      - echo 'Environment="HTTPS_PROXY=http://1.2.3.4:3128"' >> /etc/systemd/system/containerd.service.d/http-proxy.conf
      #@overlay/append
      - echo 'Environment="NO_PROXY=localhost,192.168.4.0/24,192.168.3.0/24,registry.rainpole.io,10.2.224.4,.svc,100.64.0.0/13,100.96.0.0/11"' >> /etc/systemd/system/containerd.service.d/http-proxy.conf
      #@overlay/match missing_ok=True
      postKubeadmCommands:
      #@overlay/append
      - systemctl restart containerd

Tanzu Kubernetes Grid (TKG) Demo Appliance 1.2.0

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Happy to share that the Tanzu Kubernetes Grid (TKG) Demo Appliance Fling has been updated to support the latest TKG 1.2.0 release which just came out a couple of weeks ago. The TKG Workshop Guide has been updated to reflect all new TKG 1.2 changes along with an updated vSphere Content Library containing all the OVA required to get started. As mentioned in the workshop guide, you can use either a VMware Cloud on AWS SDDC (1-Node) or a vSphere 6.7 Update 3/vSphere 7.0+ environment.

The most notable change with this version is actually within TKG itself which now uses kube-vip to replace the functionality that the HAProxy VM used to provide. What this means when deploying either a TKG Management or Workload Cluster is that you will need to specify an IP Address which will be used for the Virtual IP endpoint of the K8s Cluster as shown in the screenshot below.

tkg init -i vsphere -p dev --name tkg-mgmt --vsphere-controlplane-endpoint-ip 192.168.2.10


Using the TKG Demo Appliance, you can deploy both v1.19.1 and v1.18.8 K8s Clusters. To exercise a TKG Cluster upgrade workflow, you just have to run these three simple commands:

export VSPHERE_TEMPLATE=photon-3-kube-v1.18.8_vmware.1
tkg create cluster tkg-cluster-01 --plan=dev --kubernetes-version=v1.18.8+vmware.1 --vsphere-controlplane-endpoint-ip 192.168.2.11
tkg upgrade cluster tkg-cluster-01


There has been a lot of demand for TKG on VMware Cloud on AWS, so that is where I have spent the bulk of my testing not to mention where it was originally developed. You can also deploy the TKG Demo Appliance in an on-premises vSphere environment running 6.7 Update 3 or newer.

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Customizing Kubernetes cluster template (Dev/Prod) plans in Tanzu Kubernetes Grid 1.2

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With previous releases of Tanzu Kubernetes Grid (TKG), if you needed to apply special OS customizations that were applied to the deployed Control Plane and Worker Node VMs, such as injecting commands to handle network proxy or dealing with insecure container registry, your only option was to hand edit the default TKG Dev/Prod YAML templates. Not only was this error prone but because the templates can change from each release, it was difficult to manage and test until you attempted a deployment.

One of the newest features with the release of TKG 1.2 is official support for customizing the Kubernetes (K8s) Cluster Templates Plans using YTT (YAML Templating Tooling) which allows users to provide custom data that can then be patched/overlay to an existing YAML file. YTT itself is part of a larger toolset for building, creating and configuring deployments for K8s called Carvel. The Domain Specific Language (DSL) that YTT uses was not exactly intuitive but since the official TKG documentation had an example to start with, I was able to mostly figure my way through along with some tips from the #carvel Slack channel.

So what was I trying to do? I was working on updating my TKG Demo Appliance Fling to the latest 1.2 release and part of the setup required adding an entry to /etc/hosts file on all TKG VMs that are deployed. Instead of directly messing with the YAML templates, there is now a new "overlay" YAML file in ~/.tkg/providers/infrastructure-vsphere/ytt/vsphere-overlay.yaml which can be used to make such changes.

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