I have done a good amount of work with Kubernetes in the last year or so. I created a fairly substantial set of Ansible playbooks and workflows, called Sk8ts, which would deploy Kubernetes to AWS. It would create networks, gateways, instances, setup clusters, etc. But to be honest I only went about 85% as far as I should have and ran out of time to spend on it. Further, perhaps creating my own distribution is not a great idea, though I certainly learned a lot about Ansible, AWS, and k8s.
I mention my work in Sk8ts because it was essentially a 3rd party installer or distribution. I also need to add to the context of this post the fact that I have spent years working on OpenStack, which does not have a specific, project led installer, and some people consider this to be a problem. Whether or not large, complicated infrastructure systems like OpenStack and Kubernetes have official installers is a bit of a conundrum.
While OpenStack does not have an official installer, Kubernetes does: Kubedadm. So in this post I will look at deploying Kubernetes 1.6 with Kubeadm. Please note that Kubeadm is not production ready yet. But someday…
K8s needs somewhere to run. I have an OpenStack cloud that I can create networks and instances in.
I’ve created four nodes to deploy k8s to. I’ve done this a few times so I kept the command around. For reference it’s below. I’ll use the first node as the master and the other three as the workers. The m1.medium flavor just has 4GB of memory, so they are not that large resource-wise.
#!/bin/bash
NET=cee24724-e062-4370-ba9f-57bed80f32cd
openstack server create \
--image xenial \
--key-name curtis \
--flavor m1.medium \
--min 4 \
--max 4 \
--nic net-id=$NET \
k8s
Just note that that will boot four instances. :)
Once the instances have been created, we can install the k8s and docker packages.
$ os server list
+--------------------------------------+-------+--------+---------------------------------------------------+------------+
| ID | Name | Status | Networks | Image Name |
+--------------------------------------+-------+--------+---------------------------------------------------+------------+
| 5da0a8b9-9635-47ba-b381-f3f10b569523 | k8s-4 | ACTIVE | k8s-vxlan=10.50.0.16 | xenial |
| b033b2f6-b7b1-4f62-81c6-cc486320880a | k8s-3 | ACTIVE | k8s-vxlan=10.50.0.13 | xenial |
| 9a4f75d9-20ba-4be0-8daf-7b9a5b6ae289 | k8s-2 | ACTIVE | k8s-vxlan=10.50.0.17 | xenial |
| edfccc19-98da-463a-b0d4-a779ff19e12a | k8s-1 | ACTIVE | k8s-vxlan=10.50.0.11 | xenial |
+--------------------------------------+-------+--------+---------------------------------------------------+------------+
Above are the four k8s-x instances. Now I’ll ssh into k8s-1 and install the k8s and docker packages. To do the install I’ll just a script.
ubuntu@k8s-1:~$ cat kube-install.sh
#!/bin/bash
apt-get update
apt-get install \
apt-transport-https \
ca-certificates \
curl \
software-properties-common
apt-add-repository \
"deb http://apt.kubernetes.io/ kubernetes-xenial main"
add-apt-repository \
"deb [arch=amd64] https://download.docker.com/linux/ubuntu \
$(lsb_release -cs) \
stable"
apt-get update
apt-get install docker-ce -y --allow-unauthenticated
apt-get install -y kubelet kubeadm kubectl kubernetes-cni --allow-unauthenticated
That will insecurely install various packages. I’m not getting any GPG keys, etc.
ubuntu@k8s-1:~$ sudo bash kube-install.sh
sudo: unable to resolve host k8s-1
Get:1 http://security.ubuntu.com/ubuntu xenial-security InRelease [102 kB]
SNIP!
Setting up docker-ce (17.03.1~ce-0~ubuntu-xenial) ...
Processing triggers for libc-bin (2.23-0ubuntu7) ...
Processing triggers for systemd (229-4ubuntu17) ...
Processing triggers for ureadahead (0.100.0-19) ...
Reading package lists... Done
Building dependency tree
Reading state information... Done
The following additional packages will be installed:
ebtables socat
The following NEW packages will be installed:
ebtables kubeadm kubectl kubelet kubernetes-cni socat
0 upgraded, 6 newly installed, 0 to remove and 10 not upgraded.
Need to get 43.2 MB of archives.
After this operation, 323 MB of additional disk space will be used.
WARNING: The following packages cannot be authenticated!
kubernetes-cni kubelet kubectl kubeadm
Authentication warning overridden.
Get:5 http://nova.clouds.archive.ubuntu.com/ubuntu xenial/main amd64 ebtables amd64 2.0.10.4-3.4ubuntu1 [79.6 kB]
Get:6 http://nova.clouds.archive.ubuntu.com/ubuntu xenial/universe amd64 socat amd64 1.7.3.1-1 [321 kB]
Get:1 https://packages.cloud.google.com/apt kubernetes-xenial/main amd64 kubernetes-cni amd64 0.5.1-00 [5,560 kB]
Get:2 https://packages.cloud.google.com/apt kubernetes-xenial/main amd64 kubelet amd64 1.6.4-00 [18.3 MB]
Get:3 https://packages.cloud.google.com/apt kubernetes-xenial/main amd64 kubectl amd64 1.6.4-00 [9,659 kB]
Get:4 https://packages.cloud.google.com/apt kubernetes-xenial/main amd64 kubeadm amd64 1.6.4-00 [9,234 kB]
Fetched 43.2 MB in 4s (10.4 MB/s)
Selecting previously unselected package ebtables.
(Reading database ... 54160 files and directories currently installed.)
Preparing to unpack .../ebtables_2.0.10.4-3.4ubuntu1_amd64.deb ...
Unpacking ebtables (2.0.10.4-3.4ubuntu1) ...
Selecting previously unselected package kubernetes-cni.
Preparing to unpack .../kubernetes-cni_0.5.1-00_amd64.deb ...
Unpacking kubernetes-cni (0.5.1-00) ...
Selecting previously unselected package socat.
Preparing to unpack .../socat_1.7.3.1-1_amd64.deb ...
Unpacking socat (1.7.3.1-1) ...
Selecting previously unselected package kubelet.
Preparing to unpack .../kubelet_1.6.4-00_amd64.deb ...
Unpacking kubelet (1.6.4-00) ...
Selecting previously unselected package kubectl.
Preparing to unpack .../kubectl_1.6.4-00_amd64.deb ...
Unpacking kubectl (1.6.4-00) ...
Selecting previously unselected package kubeadm.
Preparing to unpack .../kubeadm_1.6.4-00_amd64.deb ...
Unpacking kubeadm (1.6.4-00) ...
Processing triggers for systemd (229-4ubuntu17) ...
Processing triggers for ureadahead (0.100.0-19) ...
Processing triggers for man-db (2.7.5-1) ...
Setting up ebtables (2.0.10.4-3.4ubuntu1) ...
update-rc.d: warning: start and stop actions are no longer supported; falling back to defaults
Setting up kubernetes-cni (0.5.1-00) ...
Setting up socat (1.7.3.1-1) ...
Setting up kubelet (1.6.4-00) ...
Setting up kubectl (1.6.4-00) ...
Setting up kubeadm (1.6.4-00) ...
Processing triggers for systemd (229-4ubuntu17) ...
Processing triggers for ureadahead (0.100.0-19) ...
Nice. Now we have all the k8s packages and Docker installed. I should note that the Docker version we are getting is perhaps not supported by k8s. I believe k8s is only validated on Docker 1.11 or 1.12. Frankly I’m not sure how to get that version any more, as Docker has split out into a community and enterprise versions. The k8s install does seem to work with this version though.
ubuntu@k8s-1:~$ dpkg --list docker-ce
Desired=Unknown/Install/Remove/Purge/Hold
| Status=Not/Inst/Conf-files/Unpacked/halF-conf/Half-inst/trig-aWait/Trig-pend
|/ Err?=(none)/Reinst-required (Status,Err: uppercase=bad)
||/ Name Version Architecture Description
+++-=====================================-=======================-=======================-===============================================================================
ii docker-ce 17.03.1~ce-0~ubuntu-xen amd64 Docker: the open-source application container engine
So I’m getting 17.02-1-ce…??? Honestly, I don’t know what that version means.
Now I can use kubeadm.
ubuntu@k8s-1:~$ sudo kubeadm init
sudo: unable to resolve host k8s-1
[kubeadm] WARNING: kubeadm is in beta, please do not use it for production clusters.
[init] Using Kubernetes version: v1.6.4
[init] Using Authorization mode: RBAC
[preflight] Running pre-flight checks
[preflight] WARNING: docker version is greater than the most recently validated version. Docker version: 17.03.1-ce. Max validated version: 1.12
[preflight] WARNING: hostname "k8s-1" could not be reached
[preflight] WARNING: hostname "k8s-1" lookup k8s-1 on 10.50.0.1:53: no such host
[certificates] Generated CA certificate and key.
[certificates] Generated API server certificate and key.
[certificates] API Server serving cert is signed for DNS names [k8s-1 kubernetes kubernetes.default kubernetes.default.svc kubernetes.default.svc.cluster.local] and IPs [10.96.0.1 10.50.0.11]
[certificates] Generated API server kubelet client certificate and key.
[certificates] Generated service account token signing key and public key.
[certificates] Generated front-proxy CA certificate and key.
[certificates] Generated front-proxy client certificate and key.
[certificates] Valid certificates and keys now exist in "/etc/kubernetes/pki"
[kubeconfig] Wrote KubeConfig file to disk: "/etc/kubernetes/admin.conf"
[kubeconfig] Wrote KubeConfig file to disk: "/etc/kubernetes/kubelet.conf"
[kubeconfig] Wrote KubeConfig file to disk: "/etc/kubernetes/controller-manager.conf"
[kubeconfig] Wrote KubeConfig file to disk: "/etc/kubernetes/scheduler.conf"
[apiclient] Created API client, waiting for the control plane to become ready
[apiclient] All control plane components are healthy after 23.025086 seconds
[apiclient] Waiting for at least one node to register
[apiclient] First node has registered after 4.505916 seconds
[token] Using token: bdc910.dac015f93ad5a064
[apiconfig] Created RBAC rules
[addons] Created essential addon: kube-proxy
[addons] Created essential addon: kube-dns
Your Kubernetes master has initialized successfully!
To start using your cluster, you need to run (as a regular user):
sudo cp /etc/kubernetes/admin.conf $HOME/
sudo chown $(id -u):$(id -g) $HOME/admin.conf
export KUBECONFIG=$HOME/admin.conf
You should now deploy a pod network to the cluster.
Run "kubectl apply -f [podnetwork].yaml" with one of the options listed at:
http://kubernetes.io/docs/admin/addons/
You can now join any number of machines by running the following on each node
as root:
kubeadm join --token bdc910.dac015f93ad5a064 10.50.0.11:6443
There are a bunch of containers running.
ubuntu@k8s-1:~$ sudo docker ps
sudo: unable to resolve host k8s-1
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
bf36a19d1d61 gcr.io/google_containers/kube-proxy-amd64@sha256:44cc08e7e8a2089eb8dfad6b692e9ece5994d6e6cff07fc9e9b1273cab0f6c6a "/usr/local/bin/ku..." 2 minutes ago Up 2 minutes k8s_kube-proxy_kube-proxy-jvdkl_kube-system_fbc037b7-4864-11e7-acb2-fa163ef42293_0
9bda7bb1a3f2 gcr.io/google_containers/pause-amd64:3.0 "/pause" 2 minutes ago Up 2 minutes k8s_POD_kube-proxy-jvdkl_kube-system_fbc037b7-4864-11e7-acb2-fa163ef42293_0
d5a926f598ef gcr.io/google_containers/kube-scheduler-amd64@sha256:57661c79890b01ef2ff183ed4b467ca470efc4fb8d0517cd29abe49e72f6d904 "kube-scheduler --..." 2 minutes ago Up 2 minutes k8s_kube-scheduler_kube-scheduler-k8s-1_kube-system_3145edd89dab0492bdacc0dd589d0e90_0
95faeb5d116b gcr.io/google_containers/kube-controller-manager-amd64@sha256:a93d4c26d71de94861f78cf5ea62600e4952685d580e2774c630ea206b7c18ee "kube-controller-m..." 2 minutes ago Up 2 minutes k8s_kube-controller-manager_kube-controller-manager-k8s-1_kube-system_8d185204c4cf91dd9e76230d0642391b_0
fc4c977e5061 gcr.io/google_containers/etcd-amd64@sha256:d83d3545e06fb035db8512e33bd44afb55dea007a3abd7b17742d3ac6d235940 "etcd --listen-cli..." 2 minutes ago Up 2 minutes k8s_etcd_etcd-k8s-1_kube-system_7075157cfd4524dbe0951e00a8e3129e_0
c3d248897b53 gcr.io/google_containers/kube-apiserver-amd64@sha256:6d5aa429c2b0806e4b6d1d179054d6deee46eec0aabe7bd7bd6abff97be36ae7 "kube-apiserver --..." 2 minutes ago Up 2 minutes k8s_kube-apiserver_kube-apiserver-k8s-1_kube-system_76f5cdc7dab34e6c8b32d96a42cc51e8_0
8482b6284833 gcr.io/google_containers/pause-amd64:3.0 "/pause" 2 minutes ago Up 2 minutes k8s_POD_kube-scheduler-k8s-1_kube-system_3145edd89dab0492bdacc0dd589d0e90_0
4016d11d968d gcr.io/google_containers/pause-amd64:3.0 "/pause" 2 minutes ago Up 2 minutes k8s_POD_kube-controller-manager-k8s-1_kube-system_8d185204c4cf91dd9e76230d0642391b_0
ebc0ef82e638 gcr.io/google_containers/pause-amd64:3.0 "/pause" 2 minutes ago Up 2 minutes k8s_POD_kube-apiserver-k8s-1_kube-system_76f5cdc7dab34e6c8b32d96a42cc51e8_0
045d7c8d75ba gcr.io/google_containers/pause-amd64:3.0 "/pause" 2 minutes ago Up 2 minutes k8s_POD_etcd-k8s-1_kube-system_7075157cfd4524dbe0951e00a8e3129e_0
Now we need a networking plugin. By default kubeadm is ready to use weave. This is amazingly simple.
root@k8s-1:/etc/kubernetes# kubectl --kubeconfig ./admin.conf apply -f https://git.io/weave-kube-1.6
clusterrole "weave-net" created
serviceaccount "weave-net" created
clusterrolebinding "weave-net" created
daemonset "weave-net" created
This will modify the networking on the host.
root@k8s-1:/etc/kubernetes# ip ad sh
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1
link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
inet 127.0.0.1/8 scope host lo
valid_lft forever preferred_lft forever
inet6 ::1/128 scope host
valid_lft forever preferred_lft forever
2: ens3: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1450 qdisc pfifo_fast state UP group default qlen 1000
link/ether fa:16:3e:f4:22:93 brd ff:ff:ff:ff:ff:ff
inet 10.50.0.11/24 brd 10.50.0.255 scope global ens3
valid_lft forever preferred_lft forever
inet6 fe80::f816:3eff:fef4:2293/64 scope link
valid_lft forever preferred_lft forever
3: docker0: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc noqueue state DOWN group default
link/ether 02:42:59:52:32:1d brd ff:ff:ff:ff:ff:ff
inet 172.17.0.1/16 scope global docker0
valid_lft forever preferred_lft forever
4: datapath: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1376 qdisc noqueue state UNKNOWN group default qlen 1
link/ether a2:29:39:a0:df:49 brd ff:ff:ff:ff:ff:ff
inet6 fe80::a029:39ff:fea0:df49/64 scope link
valid_lft forever preferred_lft forever
6: weave: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1376 qdisc noqueue state UP group default qlen 1000
link/ether 9a:80:36:0d:7c:64 brd ff:ff:ff:ff:ff:ff
inet 10.32.0.1/12 scope global weave
valid_lft forever preferred_lft forever
inet6 fe80::9880:36ff:fe0d:7c64/64 scope link
valid_lft forever preferred_lft forever
7: dummy0: <BROADCAST,NOARP> mtu 1500 qdisc noop state DOWN group default qlen 1000
link/ether ee:ec:e0:cc:a1:9e brd ff:ff:ff:ff:ff:ff
9: vethwe-datapath@vethwe-bridge: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1376 qdisc noqueue master datapath state UP group default qlen 1000
link/ether 2e:9b:d3:2f:66:21 brd ff:ff:ff:ff:ff:ff
inet6 fe80::2c9b:d3ff:fe2f:6621/64 scope link
valid_lft forever preferred_lft forever
10: vethwe-bridge@vethwe-datapath: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1376 qdisc noqueue master weave state UP group default qlen 1000
link/ether 9e:1d:61:4f:c1:71 brd ff:ff:ff:ff:ff:ff
inet6 fe80::9c1d:61ff:fe4f:c171/64 scope link
valid_lft forever preferred_lft forever
11: vxlan-6784: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 65485 qdisc noqueue master datapath state UNKNOWN group default qlen 1000
link/ether 8e:12:6f:d6:0c:1d brd ff:ff:ff:ff:ff:ff
inet6 fe80::8c12:6fff:fed6:c1d/64 scope link
valid_lft forever preferred_lft forever
13: vethweplc205ec0@if12: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1376 qdisc noqueue master weave state UP group default
link/ether 62:6f:d0:66:4a:2b brd ff:ff:ff:ff:ff:ff link-netnsid 0
inet6 fe80::606f:d0ff:fe66:4a2b/64 scope link
valid_lft forever preferred_lft forever
Note the weave components.
There are also weave containers created.
root@k8s-1:/etc/kubernetes# docker ps | grep weave
fa0eaddf9b6e weaveworks/weave-npc@sha256:d4b37edd345b42fdc4cd4fdc9398233db035916c7ad04f2a99fb8230b1d2f6e9 "/usr/bin/weave-npc" About a minute ago Up About a minute k8s_weave-npc_weave-net-8n654_kube-system_889073fd-4865-11e7-acb2-fa163ef42293_0
f3e22468fc86 weaveworks/weave-kube@sha256:0445da5b752a50133133e2d4d6383e622f4a06a3c744268740238c23ae05c594 "/home/weave/launc..." About a minute ago Up About a minute k8s_weave_weave-net-8n654_kube-system_889073fd-4865-11e7-acb2-fa163ef42293_0
3953f0b070dd gcr.io/google_containers/pause-amd64:3.0 "/pause" About a minute ago Up About a minute k8s_POD_weave-net-8n654_kube-system_889073fd-4865-11e7-acb2-fa163ef42293_0
I’ll ssh into the other nodes and install the k8s and docker packages.
ubuntu@k8s-2:~$ sudo bash kube-install.sh
SNIP!
Now they can join via kubeadm.
ubuntu@k8s-2:~$ sudo kubeadm join --token bdc910.dac015f93ad5a064 10.50.0.11:6443
sudo: unable to resolve host k8s-2
[kubeadm] WARNING: kubeadm is in beta, please do not use it for production clusters.
[preflight] Running pre-flight checks
[preflight] WARNING: docker version is greater than the most recently validated version. Docker version: 17.03.1-ce. Max validated version: 1.12
[preflight] WARNING: hostname "k8s-2" could not be reached
[preflight] WARNING: hostname "k8s-2" lookup k8s-2 on 10.50.0.1:53: no such host
[discovery] Trying to connect to API Server "10.50.0.11:6443"
[discovery] Created cluster-info discovery client, requesting info from "https://10.50.0.11:6443"
[discovery] Cluster info signature and contents are valid, will use API Server "https://10.50.0.11:6443"
[discovery] Successfully established connection with API Server "10.50.0.11:6443"
[bootstrap] Detected server version: v1.6.4
[bootstrap] The server supports the Certificates API (certificates.k8s.io/v1beta1)
[csr] Created API client to obtain unique certificate for this node, generating keys and certificate signing request
[csr] Received signed certificate from the API server, generating KubeConfig...
[kubeconfig] Wrote KubeConfig file to disk: "/etc/kubernetes/kubelet.conf"
Node join complete:
* Certificate signing request sent to master and response
received.
* Kubelet informed of new secure connection details.
Run 'kubectl get nodes' on the master to see this machine join.
We can see there are two nodes now.
root@k8s-1:/etc/kubernetes# kubectl --kubeconfig ./admin.conf get nodes
NAME STATUS AGE VERSION
k8s-1 Ready 16m v1.6.4
k8s-2 Ready 5m v1.6.4
Now I’ll add the other nodes.
root@k8s-1:/etc/kubernetes# kubectl --kubeconfig ./admin.conf get nodes
NAME STATUS AGE VERSION
k8s-1 Ready 21m v1.6.4
k8s-2 Ready 10m v1.6.4
k8s-3 Ready 1m v1.6.4
k8s-4 NotReady 7s v1.6.4
Great, now we have a k8s cluster of four nodes that was deployed by kubeadm.
So how do we know this is even working? Lets deploy the socks shop app.
root@k8s-1:/etc/kubernetes# kubectl --kubeconfig ./admin.conf create namespace sock-shop
namespace "sock-shop" created
root@k8s-1:/etc/kubernetes# kubectl --kubeconfig ./admin.conf apply -n sock-shop -f "https://github.com/microservices-demo/microservices-demo/blob/master/deploy/kubernetes/complete-demo.yaml?raw=true"
Warning: kubectl apply should be used on resource created by either kubectl create --save-config or kubectl apply
namespace "sock-shop" configured
namespace "zipkin" created
deployment "carts-db" created
service "carts-db" created
deployment "carts" created
service "carts" created
deployment "catalogue-db" created
service "catalogue-db" created
deployment "catalogue" created
service "catalogue" created
deployment "front-end" created
service "front-end" created
deployment "orders-db" created
service "orders-db" created
deployment "orders" created
service "orders" created
deployment "payment" created
service "payment" created
deployment "queue-master" created
service "queue-master" created
deployment "rabbitmq" created
service "rabbitmq" created
deployment "shipping" created
service "shipping" created
deployment "user-db" created
service "user-db" created
deployment "user" created
service "user" created
the namespace from the provided object "zipkin" does not match the namespace "sock-shop". You must pass '--namespace=zipkin' to perform this operation.
the namespace from the provided object "zipkin" does not match the namespace "sock-shop". You must pass '--namespace=zipkin' to perform this operation.
the namespace from the provided object "zipkin" does not match the namespace "sock-shop". You must pass '--namespace=zipkin' to perform this operation.
the namespace from the provided object "zipkin" does not match the namespace "sock-shop". You must pass '--namespace=zipkin' to perform this operation.
the namespace from the provided object "zipkin" does not match the namespace "sock-shop". You must pass '--namespace=zipkin' to perform this operation.
This might take a while to complete in terms of downloading docker images and such.
We can ask for the port information.
root@k8s-1:/etc/kubernetes# kubectl --kubeconfig ./admin.conf -n sock-shop get svc front-end
NAME CLUSTER-IP EXTERNAL-IP PORT(S) AGE
front-end 10.96.97.28 <nodes> 80:30001/TCP 55s
We can access the socks shop page…
root@k8s-1:/etc/kubernetes# curl localhost:30001 | head
% Total % Received % Xferd Average Speed Time Time Time Current
Dload Upload Total Spent Left Speed
0 0 0 0 0 0 0 0 --:--:-- --:--:-- --:--:-- 0<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="utf-8">
<meta name="robots" content="all,follow">
<meta name="googlebot" content="index,follow,snippet,archive">
<meta name="viewport" content="width=device-width, initial-scale=1">
<meta name="description" content="WeaveSocks Demo App">
100 8688 100 8688 0 0 314k 0 --:--:-- --:--:-- --:--:-- 326k
curl: (23) Failed writing body (248 != 744)
k8s has changed a lot since I was using it in version 1.4. I’m quite behind. :)
I’m curious to see if kubeadm will catch on and actually be the best way to deploy and manage k8s. There are many other (competing?) projects.
I was inspired to try kubeadm by this heptio blog post in which they discuss how they don’t want to be k8s distribution.
…we need to be careful: distributions can be a dangerous path for a community. Each distributor has strong incentives to deliver differentiated experiences, and differentiated capabilities. As they develop a customer following their customers clamor for features. The community cannot move as fast as they could and so they deliver a patch. And somewhere a fairy dies. The community gets fragmented one really great customer request at a time. You end up with semantic divergence, and a community ‘dark ages’ period happens until a conquering empire emerges to pull it all together.
I don’t know if kubeadm can deploy k8s in a way that every single organization will be happy with. But we shall see.
At the very least, it’s an easy way to get a test/dev k8s install.