3ce260cb9a
Rework the kubelet.sh script by adding an explicit step which waits for the configuration to be valid, either by finding appropriate metadata or by waiting explicitly for kubelet.conf to be created (e.g. by kubeadm) before launching kubelet. The previous construct was implicitly waiting for kubelet.conf to be created since kubelet fails if that file is not present. Pull the set of start of day yaml files to be applied (currently just weave) out of the kubelet image and into the LinuxKit yaml by providing a directory which is searched for *.yaml after init. Signed-off-by: Ian Campbell <ijc@docker.com>
Kubernetes and LinuxKit
This project aims to demonstrate how one can create minimal and immutable Kubernetes OS images with LinuxKit.
Make sure to cd projects/kubernetes first.
Build OS images:
make build-vm-images
By default this will build images using Docker Engine for execution. To instead use cri-containerd use:
make build-vm-images KUBE_RUNTIME=cri-containerd
Boot Kubernetes master OS image using hyperkit on macOS: or qemu on Linux:
./boot.sh
Get IP address of the master:
ip addr show dev eth0
Login to the kubelet container:
./ssh_into_kubelet.sh <master-ip>
Manually initialise master with kubeadm:
kubeadm-init.sh
Once kubeadm exits, make sure to copy the kubeadm join arguments,
and try kubectl get nodes from within the master.
If you just want to run a single node cluster with jobs running on the master, you can use:
kubectl taint nodes --all node-role.kubernetes.io/master- --kubeconfig /etc/kubernetes/admin.conf
To boot a node use:
./boot.sh <n> [<join_args> ...]
More specifically, to start 3 nodes use 3 separate shells and run this:
shell1> ./boot.sh 1 --token bb38c6.117e66eabbbce07d 192.168.65.22:6443
shell2> ./boot.sh 2 --token bb38c6.117e66eabbbce07d 192.168.65.22:6443
shell3> ./boot.sh 3 --token bb38c6.117e66eabbbce07d 192.168.65.22:6443
Platform specific information
MacOS
The above instructions should work as is.
Linux
By default linuxkit run uses user mode networking which does not
support access from the host. To workaround this you can use port
forwarding e.g.
KUBE_RUN_ARGS="-publish 2222:22" ./boot.sh
ssh -o StrictHostKeyChecking=no -o UserKnownHostsFile=/dev/null -p 2222 root@localhost
However you will not be able to run worker nodes since individual instances cannot see each other.
To enable networking between instance unfortunately requires root
privileges to configure a bridge and setup the bridge mode privileged
helper.
See http://wiki.qemu.org/Features/HelperNetworking for details in brief you will need:
-
To setup and configure a bridge (including e.g. DHCP etc) on the host. (You can reuse a bridge created by e.g.
virt-mananger) -
To set the
qemu-bridge-helpersetuid root. The location differs by distro, it could be/usr/lib/qemu/qemu-bridge-helperor/usr/local/libexec/qemu-bridge-helperor elsewhere. You need tochmod u+s «PATH». -
List the bridge created in the first step in
/etc/qemu/bridge.confwith a line likeallow br0(if your bridge is calledbr0). -
Set
KUBE_NETWORKING=bridge,«name»e.g.KUBE_NETWORKING="bridge,br0" ./boot.sh KUBE_NETWORKING="bridge,br0" ./boot.sh 1 «options»
Configuration
The boot.sh script has various configuration variables at the top
which can be overridden via the environment e.g.
KUBE_VCPUS=4 ./boot.sh