Add CIDR for microcluster Network Interface Configuration

[mateoflorido]

Overview

Infer the address for the microcluster by specifying a CIDR in the address flag.

Rationale

This allows us to have configuration in the ClusterAPI resources (where individual node IPs are not known yet) to choose the network interface that will be used by microcluster.

Testing

Bootstrapping

root@kcp-1:/k8s# k8s bootstrap --address 10.20.30.0/24
Bootstrapping the cluster. This may take a few seconds, please wait.
Bootstrapped a new Kubernetes cluster with node address "10.20.30.241:6400".
The node will be 'Ready' to host workloads after the CNI is deployed successfully.

root@kcp-1:/k8s# ip a
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000
    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
55: eth0@if56: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP group default qlen 1000
    link/ether 00:16:3e:5d:e3:df brd ff:ff:ff:ff:ff:ff link-netnsid 0
    inet 10.45.248.89/24 metric 100 brd 10.45.248.255 scope global dynamic eth0
       valid_lft 3503sec preferred_lft 3503sec
    inet6 fe80::216:3eff:fe5d:e3df/64 scope link
       valid_lft forever preferred_lft forever
57: eth1@if58: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP group default qlen 1000
    link/ether 00:16:3e:68:18:bb brd ff:ff:ff:ff:ff:ff link-netnsid 0
    inet 10.20.30.241/24 brd 10.20.30.255 scope global dynamic eth1
       valid_lft 3522sec preferred_lft 3522sec
    inet6 fe80::216:3eff:fe68:18bb/64 scope link
       valid_lft forever preferred_lft forever

Joining

root@kcp-3:~# k8s join-cluster eyJuYW1lIjoia2NwLTMiLCJzZWNyZXQiOiI5NzE0MmIxZDU3MGFkZTlmYzU2ZGE4ZGU4M2Q5Y2NlZDI2ZWM3ZjdkMjg0MGE0ZTZmZmM5ZTcyNWI0YzQ0OGExIiwiZmluZ2VycHJpbnQiOiI0MWJjYTVhZGVhMTZlZDJkNjgzYTY2MmY2M2EyYTJiNTEzMjlmNDkwNzllMjJiZjY0M2ZlN2NmNTlhOWZkZmVlIiwiam9pbl9hZGRyZXNzZXMiOlsiMTAuMjAuMzAuMjQxOjY0MDAiLCIxMC4yMC4zMC4xMTI6NjQwMCJdfQ== --address 10.20.30.0/24
Joining the cluster. This may take a few seconds, please wait.
Cluster services have started on "kcp-3".
Please allow some time for initial Kubernetes node registration.

microcluster running on the specified CIDR:

Netid  State   Recv-Q  Send-Q          Local Address:Port      Peer Address:Port  Process
tcp    LISTEN  0       4096             10.20.30.126:6400           0.0.0.0:*      users:(("k8sd",pid=1705,fd=12))

[mateoflorido]

Test with CIDR and ports:

root@kcp-1:~# k8s bootstrap --address 10.20.30.0/24:9875
Bootstrapping the cluster. This may take a few seconds, please wait.
Bootstrapped a new Kubernetes cluster with node address "10.20.30.86:9875".
The node will be 'Ready' to host workloads after the CNI is deployed successfully.
root@kcp-1:~# ss -tulpn | grep k8sd
tcp   LISTEN 0      4096         10.20.30.86:9875       0.0.0.0:*    users:(("k8sd",pid=1643,fd=11))
root@kcp-2:~# k8s join-cluster eyJuYW1lIjoia2NwLTIiLCJzZWNyZXQiOiJjZTk1ZmJjN2Y1YTM1YmE0ODg1YTlkNzA1ZTE5MmUyNDFiMDM2OTkyODU2NGU4YzA5NzcyZDkzZTMzNDI5ZDIxIiwiZmluZ2VycHJpbnQiOiIxMDA2NWEzM2FlNjA3ZmJlMWVkMTE3OGVjMjU5OWVlZGU0MGVhMWY5OTZhYTM4MmRjNWM5OGQwNGQ5Yjg0ZWU2Iiwiam9pbl9hZGRyZXNzZXMiOlsiMTAuMjAuMzAuODY6OTg3NSJdfQ== --address 10.20.30.0/24:9875
Joining the cluster. This may take a few seconds, please wait.
Cluster services have started on "kcp-2".
Please allow some time for initial Kubernetes node registration.

root@kcp-2:~# k8s kubectl get no -A -o wide
NAME    STATUS   ROLES                  AGE     VERSION   INTERNAL-IP    EXTERNAL-IP   OS-IMAGE             KERNEL-VERSION     CONTAINER-RUNTIME
kcp-1   Ready    control-plane,worker   11m     v1.30.1   10.20.30.86    <none>        Ubuntu 22.04.4 LTS   6.5.0-35-generic   containerd://1.6.32
kcp-2   Ready    control-plane,worker   5m41s   v1.30.1   10.20.30.138   <none>        Ubuntu 22.04.4 LTS   6.5.0-35-generic   containerd://1.6.32
root@kcp-2:~# ss -tulpn | grep k8sd
tcp   LISTEN 0      4096         10.20.30.138:9875       0.0.0.0:*    users:(("k8sd",pid=1681,fd=12))

[neoaggelos]

Excellent work, almost there!

[neoaggelos]

Just a final change and this should be good to go! Nice work @mateoflorido !

[neoaggelos]

final note on style, then we're good to merge

[bschimke95]

Great work Mateo! Only add some minor unittests for the new util function and we are good to go!

[bschimke95]

LGTM, nicely done!