Kube-Vip as a daemonset

In Hybrid mode kube-vip will manage a virtual IP address that is passed through it's configuration for a Highly Available Kubernetes cluster, it will also "watch" services of type:LoadBalancer and once their spec.LoadBalancerIP is updated (typically by a cloud controller) it will advertise this address using BGP/ARP.

Note about Daemonsets

The "hybrid" mode is now the default mode in kube-vip from 0.2.3 onwards, and allows both modes to be enabled at the same time.

If the Kubernetes installer allows for adding a Virtual IP as an additional SAN to the API server certificate then we can apply kube-vip to the cluster once the first node has been brought up.

Unlike generating the static manifest there are a few more things that may need configuring, this page will cover most scenarios.

Create the RBAC settings

As a daemonSet runs within the Kubernetes cluster it needs the correct access to be able to watch Kubernetes services and other objects. In order to do this we create a User, Role, and a binding.. we can apply this with the command:

kubectl apply -f https://kube-vip.io/manifests/rbac.yaml

Generating a Manifest

This section only covers generating a simple BGP configuration, as the main focus is will be on additional changes to the manifest. For more examples we can look at here.

Note: Pay attention if using the "static" examples, as the manifest subcommand should use daemonset and NOT pod.

Set configuration details

export VIP=192.168.0.40

export INTERFACE=<interface>

Configure to use a container runtime

The easiest method to generate a manifest is using the container itself, below will create an alias for different container runtimes.

containerd

alias kube-vip="ctr run --rm --net-host docker.io/plndr/kube-vip:0.3.0 vip"

Docker

alias kube-vip="docker run --network host --rm plndr/kube-vip:0.3.0"

BGP Example

This configuration will create a manifest that will start kube-vip providing controlplane and services management. Unlike ARP, all nodes in the BGP configuration will advertise virtual IP addresses.

Note we bind the address to lo as we don't want multiple devices that have the same address on public interfaces. We can specify all the peers in a comma seperate list in the format of address:AS:password:multihop.

Note 2 we pass the --inCluster flag as this is running as a daemonSet within the Kubernetes cluster and therefore will have access to the token inside the running pod.

Note 2 we pass the --taint flag as we're deploying kube-vip as both a daemonset and as advertising controlplane, we want to taint this daemonset to only run on the worker nodes.

export INTERFACE=lo

kube-vip manifest daemonset \
    --interface $INTERFACE \
    --vip $VIP \
    --controlplane \
    --services \
    --inCluster \
    --taint \
    --bgp \
    --bgppeers 192.168.0.10:65000::false,192.168.0.11:65000::false

Generated Manifest

apiVersion: apps/v1
kind: DaemonSet
metadata:
  creationTimestamp: null
  name: kube-vip-ds
  namespace: kube-system
spec:
  selector:
    matchLabels:
      name: kube-vip-ds
  template:
    metadata:
      creationTimestamp: null
      labels:
        name: kube-vip-ds
    spec:
      containers:
      - args:
        - manager
        env:
        - name: vip_arp
          value: "false"
        - name: vip_interface
          value: lo
        - name: port
          value: "6443"
        - name: vip_cidr
          value: "32"
        - name: cp_enable
          value: "true"
        - name: cp_namespace
          value: kube-system
        - name: svc_enable
          value: "true"
        - name: bgp_enable
          value: "true"
        - name: bgp_peers
          value: "192.168.0.10:65000::false,192.168.0.11:65000::false"
        - name: vip_address
          value: 192.168.0.40
        image: plndr/kube-vip:0.2.3
        imagePullPolicy: Always
        name: kube-vip
        resources: {}
        securityContext:
          capabilities:
            add:
            - NET_ADMIN
            - SYS_TIME
      hostNetwork: true
      serviceAccountName: kube-vip
      nodeSelector:
        node-role.kubernetes.io/master: "true"
      tolerations:
      - effect: NoSchedule
        key: node-role.kubernetes.io/master
  updateStrategy: {}

Manifest Overview

• nodeSelector - Ensures that this particular daemonset only runs on control plane nodes
• serviceAccountName: kube-vip - this specifies the user in the rbac that will give us the permissions to get/update services.
• hostNetwork: true - This pod will need to modify interfaces (for VIPs)
• env {...} - We pass the configuration into the kube-vip pod through environment variables.

K3s overview (on packet)

Step 1: TIDY (best if something was running before)

rm -rf /var/lib/rancher /etc/rancher ~/.kube/*; ip addr flush dev lo; ip addr add 127.0.0.1/8 dev lo; mkdir -p /var/lib/rancher/k3s/server/manifests/

Step 2: Get rbac

curl https://kube-vip.io/manifests/rbac.yaml > /var/lib/rancher/k3s/server/manifests/rbac.yaml

Step 3: Generate kube-vip (get EIP from CLI or UI)

export EIP=x.x.x.x
export INTERFACE=lo

kube-vip manifest daemonset \
  --interface $INTERFACE \
  --vip $EIP \
  --controlplane \
  --services \
  --inCluster \
  --taint \
  --bgp \
  --packet \
  --provider-config /etc/cloud-sa/cloud-sa.json | tee /var/lib/rancher/k3s/server/manifests/vip.yaml

NOTE: the —provider-config actually comes from the secret we apply in step 5 (this will leave kube-vip waiting to start)

Step 4: Up Cluster

K3S_TOKEN=SECRET k3s server --cluster-init --tls-san $EIP --no-deploy servicelb --disable-cloud-controller

Step 5: Add CCM

alias k="k3s kubectl" k apply -f ./secret.yaml

(^ https://github.com/packethost/packet-ccm/blob/master/deploy/template/secret.yaml)

k apply -f https://gist.githubusercontent.com/thebsdbox/c86dd970549638105af8d96439175a59/raw/4abf90fb7929ded3f7a201818efbb6164b7081f0/ccm.yaml

Step 6: Demo !

k apply -f https://k8s.io/examples/application/deployment.yaml k expose deployment nginx-deployment --port=80 --type=LoadBalancer --name=nginx

Step 7 watch and test:

k get svc --watch