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Assuming you have Vagrant 2.0+ installed with virtualbox, libvirt/qemu or vmware, but is untested) you should be able to launch a 3 node Kubernetes cluster by simply running `vagrant up`. This will spin up 3 VMs and install kubernetes on them. Once they are completed you can connect to any of them by running `vagrant ssh k8s-[1..3]`.
To give an estimate of the expected duration of a provisioning run: On a dual core i5-6300u laptop with an SSD, provisioning takes around 13 to 15 minutes, once the container images and other files are cached. Note that libvirt/qemu is recommended over virtualbox as it is quite a bit faster, especially during boot-up time.
For proper performance a minimum of 12GB RAM is recommended. It is possible to run a 3 node cluster on a laptop with 8GB of RAM using the default Vagrantfile, provided you have 8GB zram swap configured and not much more than a browser and a mail client running. If you decide to run on such a machine, then also make sure that any tmpfs devices, that are mounted, are mostly empty and disable any swapfiles mounted on HDD/SSD or you will be in for some serious swap-madness. Things can get a bit sluggish during provisioning, but when that's done, the system will actually be able to perform quite well.
You can override the default settings in the `Vagrantfile` either by directly modifying the `Vagrantfile` or through an override file. In the same directory as the `Vagrantfile`, create a folder called `vagrant` and create `config.rb` file in it. An example of how to configure this file is given below.
By default, Vagrant uses Ubuntu 18.04 box to provision a local cluster. You may use an alternative supported operating system for your local cluster.
Customize `$os` variable in `Vagrantfile` or as override, e.g.,:
echo '$os = "flatcar-stable"' >> vagrant/config.rb
The supported operating systems for vagrant are defined in the `SUPPORTED_OS` constant in the `Vagrantfile`.
Kubespray can take quite a while to start on a laptop. To improve provisioning speed, the variable 'download_run_once' is set. This will make kubespray download all files and containers just once and then redistributes them to the other nodes and as a bonus, also cache all downloads locally and re-use them on the next provisioning run. For more information on download settings see [download documentation](/docs/downloads.md).
The following is an example of setting up and running kubespray using `vagrant`. For repeated runs, you could save the script to a file in the root of the kubespray and run it by executing 'source <name_of_the_file>.
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# use virtualenv to install all python requirements
VENVDIR=venv
virtualenv --python=/usr/bin/python3.7 $VENVDIR
source $VENVDIR/bin/activate
pip install -r requirements.txt
# prepare an inventory to test with
INV=inventory/my_lab
rm -rf ${INV}.bak &> /dev/null
mv ${INV} ${INV}.bak &> /dev/null
cp -a inventory/sample ${INV}
rm -f ${INV}/hosts.ini
# customize the vagrant environment
mkdir vagrant
cat << EOF > vagrant/config.rb
\$instance_name_prefix = "kub"
\$vm_cpus = 1
\$num_instances = 3
\$os = "centos-bento"
\$subnet = "10.0.20"
\$network_plugin = "flannel"
\$inventory = "$INV"
\$shared_folders = { 'temp/docker_rpms' => "/var/cache/yum/x86_64/7/docker-ce/packages" }
EOF
# make the rpm cache
mkdir -p temp/docker_rpms
vagrant up
# make a copy of the downloaded docker rpm, to speed up the next provisioning run
scp kub-1:/var/cache/yum/x86_64/7/docker-ce/packages/* temp/docker_rpms/
# copy kubectl access configuration in place
mkdir $HOME/.kube/ &> /dev/null
ln -s $PWD/$INV/artifacts/admin.conf $HOME/.kube/config
sudo ln -s $PWD/$INV/artifacts/kubectl /usr/local/bin/kubectl
export PATH=$PATH:$PWD/$INV/artifacts
If a vagrant run failed and you've made some changes to fix the issue causing the fail, here is how you would re-run ansible:
ansible-playbook -vvv -i .vagrant/provisioners/ansible/inventory/vagrant_ansible_inventory cluster.yml
```
If all went well, you check if it's all working as expected:
NAME STATUS ROLES AGE VERSION
kub-1 Ready control-plane,master 4m37s v1.22.5
kub-2 Ready control-plane,master 4m7s v1.22.5
kub-3 Ready <none> 3m7s v1.22.5
kubectl get pods --all-namespaces -o wide
Which should yield something like the following:
$ kubectl get pods --all-namespaces -o wide
NAMESPACE NAME READY STATUS RESTARTS AGE IP NODE NOMINATED NODE READINESS GATES
kube-system coredns-8474476ff8-m2469 1/1 Running 0 2m45s 10.233.65.2 kub-2 <none> <none>
kube-system coredns-8474476ff8-v5wzj 1/1 Running 0 2m41s 10.233.64.3 kub-1 <none> <none>
kube-system dns-autoscaler-5ffdc7f89d-76tnv 1/1 Running 0 2m43s 10.233.64.2 kub-1 <none> <none>
kube-system kube-apiserver-kub-1 1/1 Running 1 4m54s 10.0.20.101 kub-1 <none> <none>
kube-system kube-apiserver-kub-2 1/1 Running 1 4m33s 10.0.20.102 kub-2 <none> <none>
kube-system kube-controller-manager-kub-1 1/1 Running 1 5m1s 10.0.20.101 kub-1 <none> <none>
kube-system kube-controller-manager-kub-2 1/1 Running 1 4m33s 10.0.20.102 kub-2 <none> <none>
kube-system kube-flannel-9xgf5 1/1 Running 0 3m10s 10.0.20.102 kub-2 <none> <none>
kube-system kube-flannel-l8jbl 1/1 Running 0 3m10s 10.0.20.101 kub-1 <none> <none>
kube-system kube-flannel-zss4t 1/1 Running 0 3m10s 10.0.20.103 kub-3 <none> <none>
kube-system kube-multus-ds-amd64-bhpc9 1/1 Running 0 3m2s 10.0.20.103 kub-3 <none> <none>
kube-system kube-multus-ds-amd64-n6vl8 1/1 Running 0 3m2s 10.0.20.102 kub-2 <none> <none>
kube-system kube-multus-ds-amd64-qttgs 1/1 Running 0 3m2s 10.0.20.101 kub-1 <none> <none>
kube-system kube-proxy-2x4jl 1/1 Running 0 3m33s 10.0.20.101 kub-1 <none> <none>
kube-system kube-proxy-d48r7 1/1 Running 0 3m33s 10.0.20.103 kub-3 <none> <none>
kube-system kube-proxy-f45lp 1/1 Running 0 3m33s 10.0.20.102 kub-2 <none> <none>
kube-system kube-scheduler-kub-1 1/1 Running 1 4m54s 10.0.20.101 kub-1 <none> <none>
kube-system kube-scheduler-kub-2 1/1 Running 1 4m33s 10.0.20.102 kub-2 <none> <none>
kube-system nginx-proxy-kub-3 1/1 Running 0 3m33s 10.0.20.103 kub-3 <none> <none>
kube-system nodelocaldns-cg9tz 1/1 Running 0 2m41s 10.0.20.102 kub-2 <none> <none>
kube-system nodelocaldns-htswt 1/1 Running 0 2m41s 10.0.20.103 kub-3 <none> <none>
kube-system nodelocaldns-nsp7s 1/1 Running 0 2m41s 10.0.20.101 kub-1 <none> <none>
local-path-storage local-path-provisioner-66df45bfdd-km4zg 1/1 Running 0 2m54s 10.233.66.2 kub-3 <none> <none>