gubernat -> a docker-compose alternative, ...

Gubernat means steer (latin).

About

Gubernat is an approach to establish a production ready small kubernetes cluster.

The main goal in creating gubernat was: replace docker-compose in a portable open and upgradable way that is compatible with standard kubernetes configs and maintains a small footprint.

It will typically run on a single server. But it's good practice to have the opportunity to scale it up to a redundant configuration without too much effort.

So we created a simple installation procedure for kubernetes 1.16+, flannel as networking layer, the kubernetes-dashboard, helm and the standard nginx ingress configuration.

For persistent storage we are using local storage with explicit persitent volume allocation.

NEWS

Our first attempt on Raspbian (Raspberry PI 4)!

After this you have a running kubernetes cluster on a Raspbi!

Follow the work in directory raspbian

Components

Base OS: centos 7
kubernetes 1.16.2
standard k8s nginx ingress
helm 2
local storage provisioning
flannel network layer
kubernetes dashboard on port 32433

Installation

Base installation of CentOS 7 minimal
After the base installation I made a pair of very small shell scripts to aid the install:

[CONFIG] -> open it to configure your interface/IP address and hostname
1-repo.sh -> add kubernetes repo and install packages
2-system-setup.sh -> disable swap, disable selinux
3-network-setup.sh -> customize firewalld, setting hostname
4-kubeadm-run.sh -> install base cluster with kubeadm
5-post-install.sh -> install network plugin, ingress and dashboard
6-install-helm.sh -> install helm for deployment of packaged apps

Accessing the Dashboard

Execute the script dashboard-login-infos.sh and get the parameter for dashboard login.

The dashboard is always listening on port 32443 with SSL and a private certificate. That means:

https://myfamous-minicluster-hostname.cloud:32443

Getting login info for your cluster

You can copy the admin.conf in your local kube environment. As normal user:

mkdir -p ~/.kube
sudo cp /etc/kubernetes/admin.conf ~/.kube/
sudo chown $USER ~/.kube/admin.conf

Now you should put something like export KUBECONFIG=~/.kube/admin.conf in your shell startup.

You can now validate your login with kubectl config get-contexts

Tests

There is a small test deployment in the tests folder.

qnipp/gubernat