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KubeArmor and Cilium on Debian 11 (Bullseye)

Overview

This user journey guides you to install and verify the compatibility of Kuberarmor and Cilium on Debian 11 (Bullseye) with 5.10 Kernel Version by applying policies on kubernetes workloads.

Step 1: Install etcd in control plane VM

Install etcd using below command:

sudo apt-get install etcd

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Once etcd is installed, configure the following values in /etc/default/etcd as shown below.

ETCD_LISTEN_CLIENT_URLS=http://0.0.0.0:2379
ETCD_ADVERTISE_CLIENT_URLS=http://0.0.0.0:2379

Restart & check the etcd status:

sudo service etcd restart
sudo service etcd enable
sudo service etcd status

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Step 2: Install KVM-Service in control plane

Download the latest RPM Package

wget https://github.com/kubearmor/kvm-service/releases/download/0.1/kvmservice_0.1_linux-amd64.deb

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dpkg -i kvmservice_0.1_linux-amd64.deb 

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systemctl status kvmservice

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Step 3: Install Karmor in control plane

curl -sfL https://raw.githubusercontent.com/kubearmor/kubearmor-client/main/install.sh | sudo sh -s -- -b /usr/local/bin

Step 4: Onboard VMs using Karmor

cat kvmpolicy1.yaml
apiVersion: security.kubearmor.com/v1
kind: KubeArmorVirtualMachine
metadata:
  name: testvm1
  labels:
    name: vm1
    vm: true

Run this command to add the VMs:

karmor vm add kvmpolicy1.yaml 

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To see the onboarded VM’s

karmor vm list

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Step 5: Generate installation scripts for configured worker VMs

Generate VM installation scripts for the configured VM by running the following command:

karmor vm --kvms getscript -v testvm1

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Step 6: Execute the installation script in VMs

Note: Docker needs to install before running the script.

Install pre-requisites:

sudo apt install bpfcc-tools linux-headers-$(uname -r)
vi testvm1.sh

Comment the following line on the script and save it:

#sudo docker run --name kubearmor $DOCKER_OPTS $KUBEARMOR_IMAGE $KUBEARMOR_OPTS

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Execute the installation script:

Copy the generated installation scripts to appropriate VMs using scp or rsync method and execute the scripts to run Cilium.

The script downloads Cilium Docker images and run them as containers in each VM. Cilium running in each VM connects to the KVM-Service control plane to register themselves and receive information about other VMs in the cluster, labels, IPs and configured security policies.

Execute the script on worker VM by running the following command:

./testvm1.sh

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Note: Make sure the kvm-service is running on control plane VM & To onboard more worker VM repeat Step 4, Step 5 & Step 6.

You can verify by running following command:

sudo docker ps

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Step 7: Install Kubearmor on worker VMs

Download the latest release of KubeArmor

wget https://github.com/kubearmor/KubeArmor/releases/download/v0.3.1/kubearmor_0.3.1_linux-amd64.deb

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dpkg -i kubearmor_0.3.1_linux-amd64.deb 

Note: While installing if you get the following error,

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Run the following command:

$apt --fix-broken install    to fix the error & 
reinstall $dpkg -i kubearmor_0.3.1_linux-amd64.deb 

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Start & check the status of Kubearmor:

sudo systemctl start kubearmor
sudo systemctl enable kubearmor
sudo systemctl status kubearmor

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Step 8: Apply and Verify Kubearmor system policy

cat khp-example-vmname.yaml
apiVersion: security.kubearmor.com/v1
kind: KubeArmorHostPolicy
metadata:
  name: khp-02
spec:
  severity: 5
  file:
    matchPaths:
    - path: /proc/cpuinfo
  action:
    Block

Run this command to apply the policy:

karmor vm --kvms policy add khp-example-vmname.yaml

Step 9: Policy Violation

With the above mentioned policy enforced in the VM, if a user tries to access /proc/cpuinfo file, user will see permission denied error and karmor log will show the alert log for blocking the file access as shown below.

cat /proc/cpuinfo

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Verifying Policy Violation Logs:

karmor log

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Step 10: Apply and Verify Cilium network policy

1. Allow connectivity with the control plane ( and port 2379)

cat vm-allow-control-plane.yaml
kind: CiliumNetworkPolicy
metadata:
  name: "vm-allow-control-plane"
spec:
  description: "Policy to allow traffic to kv-store"
  nodeSelector:
    matchLabels:
      name: vm1
  egress:
  - toCIDR:
    - 10.138.0.5/32
    toPorts:
    - ports:
      - port: "2379"
        protocol: TCP

2. For SSH connectivity allow port 22 and 169.254.169.254 port 80

cat vm-allow-ssh.yaml
kind: CiliumNetworkPolicy
metadata:
  name: "vm-allow-ssh"
spec:
  description: "Policy to allow SSH"
  nodeSelector:
    matchLabels:
      name: vm1
  egress:
  - toPorts:
    - ports:
      - port: "22"
        protocol: TCP
  - toCIDR:
    - 169.254.169.254/32
    toPorts:
    - ports:
      - port: "80"
        protocol: TCP

3. This policy block the DNS access in VM

cat vm-dns-visibility.yaml
kind: CiliumNetworkPolicy
metadata:
  name: "vm-dns-visibility"
spec:
  description: "Policy to enable DNS visibility"
  nodeSelector:
    matchLabels:
      name: vm1
  egress:
  - toPorts:
    - ports:
      - port: "53"
        protocol: ANY
      rules:
        dns:
        - matchPattern: "*"

4. This policy allow access of “www.google.co.in” alone in VM

cat vm-allow-www.google.co.in.yaml
kind: CiliumNetworkPolicy
metadata:
  name: "vm-allow-www.google.co.in"
spec:
  description: "Policy to allow traffic to www.google.co.in"
  nodeSelector:
    matchLabels:
      name: vm1
  egress:
  - toFQDNs:
    - matchName: www.google.co.in
    toPorts:
    - ports:
      - port: "80"
        protocol: TCP
      - port: "443"
        protocol: TCP

Run this command to apply the policy:

karmor vm --kvms policy add vm-allow-control-plane.yaml
karmor vm --kvms policy add vm-allow-ssh.yaml 
karmor vm --kvms policy add vm-dns-visibility.yaml 
karmor vm --kvms policy add vm-allow-www-google-co-in.yaml 

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Step 11: Policy Violation

curl http://www.google.co.in/

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curl https://go.dev/

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Verifying Policy Violation Logs:

docker exec -it cilium hubble observe -f -t policy-verdict

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