MacVlan network with kubernetes - docker

Question

I setup the kubernetes cluster using k3s. I have one master and two nodes. I created docker macvlan network on one of the node.
I want to achieve below mentioned scenario.
Assign IP to container/pod.(user defined IP, not cluster IP).
q1.Is there any alternative option for docker macvlan?
q2.Can we run command on node (not on pod/container)? (while deploying the pod/service)
q3.can we create kubernetes network with user defined IP? (I don`t think LB/NP/Ingress will help for user defined IP, correct me if I am wrong!)

Answer 1

Kubernetes has its own very specialized network implementation. It can't easily assign a unique externally accessible IP address to each process the way the Docker MacVLAN setup can. Kubernetes also can't reuse the Docker networking infrastructure. Generally the cluster takes responsibility for assigning IP addresses to pods and services, and you can't specify them yourself.
So, in Kubernetes:
You can't manually assign IP addresses to things;
The cluster-internal IP addresses aren't directly accessible from outside the cluster;
The Kubernetes constructs can only launch containers on arbitrarily chosen nodes (possibly with some constraints; possibly on every node), but you don't usually launch a container on a single specific node, and you can't run a non-container command on a node.
Given what you're describing, a more general-purpose cluster automation tool like Salt Stack, Ansible, or Chef might meet your needs better. This will let you launch processes directly on managed nodes, and if those are server-type processes, they'll be accessible using the host's IP address as normal.

Answer 2

You can look into MetalLB, specifically into the Layer2 & Local traffic policy
(https://metallb.universe.tf/usage/)
You cannot assign IPs to the Pods but when you'll create a service type LoadBalancer (for example a http routing service like Traefik), MetalLB will help bind that service to the IP of the node.
As an example, you can see the external IP of the service Trafik is reported as my node's address - 192.168.1.201
NAME STATUS ROLES AGE VERSION INTERNAL-IP EXTERNAL-IP OS-IMAGE KERNEL-VERSION CONTAINER-RUNTIME
node02 Ready <none> 8d v1.20.2+k3s1 192.168.1.202 <none> Alpine Linux v3.13 5.10.10-0-virt containerd://1.4.3-k3s1
node01 Ready control-plane,master 8d v1.20.2+k3s1 192.168.1.201 <none> Alpine Linux v3.13 5.10.10-0-virt containerd://1.4.3-k3s1
For q2:
Of course you can, k8s doesn't take over the node. You ssh into it and run whatever you like.
For q1:
No.
NAMESPACE NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S)
default service/kubernetes ClusterIP 10.43.0.1 <none> 443/TCP
kube-system service/kube-dns ClusterIP 10.43.0.10 <none> 53/UDP,53/TCP,9153/TCP
kube-system service/metrics-server ClusterIP 10.43.254.20 <none> 443/TCP
kube-system service/traefik LoadBalancer 10.43.130.1 192.168.1.201 80:31666/TCP,443:31194/TCP,8080:31199/TCP
default service/whoami ClusterIP 10.43.61.10 <none> 80/TCP