Add Flatcar and Cilium kube-proxy-free architecture

README.md

@@ -1,9 +1,9 @@
 # Kubernetes Security Baseline
 
 An auditable, GitOps-managed Kubernetes security baseline: local k3d for a
-fast reproducible demo, optional Terraform + Ansible for a cloud K3s host, CIS
-Benchmark checks in CI, Kyverno admission policies, and Falco runtime
-detection.
+fast reproducible demo, optional Flatcar plus Terraform and Ansible for a cloud
+K3s host, Cilium eBPF networking, CIS Benchmark checks in CI, Kyverno
+admission policies, and Falco runtime detection.
 
 ## Phase 1: provision a local cluster
 
@@ -22,8 +22,10 @@ Delete the lab with `k3d cluster delete security-baseline`.
 ## Production-style option
 
 `terraform/cloud-cluster/` and `ansible/bootstrap-k3s.yml` provide an optional,
-documented AWS path. It requires your own AWS credentials, an existing EC2 key
-pair, an Ubuntu AMI ID for the chosen region, and a tightly scoped admin CIDR.
+documented AWS path. It uses Flatcar as the host OS, disables Flannel and
+kube-proxy, and installs Cilium as the CNI and eBPF service datapath. It
+requires your own AWS credentials, an existing EC2 key pair, a Flatcar AMI ID
+for the chosen region, and a tightly scoped admin CIDR.
 It is not needed for the portfolio demo and is not run in CI.
 
 ## Build status
@@ -31,6 +33,7 @@ It is not needed for the portfolio demo and is not run in CI.
 - [x] Phase 1: local k3d definition and optional Terraform/Ansible path
 - [ ] Phase 2: ArgoCD app-of-apps deployment (scaffolded; runtime verification pending)
 - [x] Phase 3: kube-bench CI scan
+- [ ] Architecture revision: Flatcar hosts and Cilium kube-proxy replacement (configured; runtime verification pending)
 - [ ] Phase 4: Kyverno policy set and CIS mapping
 - [ ] Phase 5: Falco rules and webhook alerting
 - [ ] Phase 6: test workloads and evidence capture

ansible/bootstrap-k3s.yml

@@ -1,5 +1,5 @@
 ---
-- name: Harden host and install K3s
+- name: Configure Flatcar host and install K3s
   hosts: k3s_servers
   become: true
   gather_facts: true
@@ -7,44 +7,22 @@
   vars:
     k3s_version: "v1.30.6+k3s1"
     k3s_install_url: "https://get.k3s.io"
+    k3s_api_server_port: 6443
 
   pre_tasks:
-    - name: Require a supported Ubuntu release
+    - name: Require Flatcar Linux
       ansible.builtin.assert:
         that:
-          - ansible_distribution == "Ubuntu"
-          - ansible_distribution_version is version("22.04", ">=")
-        fail_msg: "This playbook expects Ubuntu 22.04 or newer."
+          - ansible_distribution == "Flatcar"
+        fail_msg: "This playbook expects Flatcar Linux. Use the Ubuntu fallback playbook if needed."
 
   tasks:
-    - name: Install host security prerequisites
-      ansible.builtin.apt:
-        name:
-          - apparmor
-          - apparmor-utils
-          - curl
-          - ca-certificates
-          - unattended-upgrades
-        state: present
-        update_cache: true
-
-    - name: Ensure unattended security upgrades are enabled
-      ansible.builtin.service:
-        name: unattended-upgrades
-        state: started
-        enabled: true
-
-    - name: Disable swap for Kubernetes node
+    - name: Disable swap if a swap device is present
       ansible.builtin.command: swapoff -a
       changed_when: false
+      failed_when: false
 
-    - name: Remove swap entries from fstab
-      ansible.builtin.replace:
-        path: /etc/fstab
-        regexp: '^([^#].*\sswap\s+.*)$'
-        replace: '# Disabled for Kubernetes: \1'
-
-    - name: Set restrictive SSH password authentication
+    - name: Set restrictive SSH authentication
       ansible.builtin.copy:
         dest: /etc/ssh/sshd_config.d/60-k8s-baseline.conf
         owner: root
@@ -53,23 +31,62 @@
         content: |
           PasswordAuthentication no
           PermitRootLogin no
-      notify: Restart ssh
+      notify: Restart sshd
+
+    - name: Create K3s configuration directory
+      ansible.builtin.file:
+        path: /etc/rancher/k3s
+        state: directory
+        owner: root
+        group: root
+        mode: '0750'
+
+    - name: Configure K3s for Cilium kube-proxy replacement
+      ansible.builtin.copy:
+        dest: /etc/rancher/k3s/config.yaml
+        owner: root
+        group: root
+        mode: '0600'
+        content: |
+          write-kubeconfig-mode: "0600"
+          flannel-backend: none
+          disable-network-policy: true
+          disable-kube-proxy: true
+          disable:
+            - traefik
+          https-listen-port: {{ k3s_api_server_port }}
+
+    - name: Download pinned K3s installer
+      ansible.builtin.get_url:
+        url: "{{ k3s_install_url }}"
+        dest: /var/lib/rancher/k3s-install.sh
+        owner: root
+        group: root
+        mode: '0700'
 
     - name: Install pinned K3s server
-      ansible.builtin.shell: |
-        curl -sfL {{ k3s_install_url }} | INSTALL_K3S_VERSION={{ k3s_version }} sh -s - server --write-kubeconfig-mode 600
-      args:
+      ansible.builtin.command:
+        cmd: /var/lib/rancher/k3s-install.sh server
         creates: /usr/local/bin/k3s
+      environment:
+        INSTALL_K3S_VERSION: "{{ k3s_version }}"
 
     - name: Enable and start K3s
-      ansible.builtin.service:
+      ansible.builtin.systemd:
         name: k3s
         state: started
         enabled: true
+        daemon_reload: true
+
+    - name: Wait for K3s API port
+      ansible.builtin.wait_for:
+        host: 127.0.0.1
+        port: "{{ k3s_api_server_port }}"
+        timeout: 120
 
   handlers:
-    - name: Restart ssh
-      ansible.builtin.service:
-        name: ssh
+    - name: Restart sshd
+      ansible.builtin.systemd:
+        name: sshd
         state: restarted
 

argocd/README.md

@@ -34,3 +34,8 @@ kubectl -n argocd get secret argocd-initial-admin-secret \
 
 The initial admin secret is for local bootstrap only. A later hardening phase
 should replace this with SSO/RBAC and remove the bootstrap credential.
+
+For a kube-proxy-free Cilium cluster, install Cilium before ArgoCD using the
+profile in `local-quickstart/cilium.md` or the Flatcar cloud bootstrap. The
+Cilium Application is stored under `argocd/optional-apps/` and is not watched
+by the default root app until the cluster is ready for it.

argocd/optional-apps/cilium.yaml

@@ -0,0 +1,25 @@
+apiVersion: argoproj.io/v1alpha1
+kind: Application
+metadata:
+  name: cilium
+  namespace: argocd
+  annotations:
+    argocd.argoproj.io/sync-wave: "-4"
+spec:
+  project: default
+  sources:
+    - repoURL: https://helm.cilium.io/
+      chart: cilium
+      targetRevision: 1.20.0
+      helm:
+        valueFiles:
+          - $values/cilium/cilium-values.yaml
+    - repoURL: https://git.swaphb.com/swaphb/kubernetes-security-baseline-lab.git
+      targetRevision: main
+      ref: values
+  destination:
+    server: https://kubernetes.default.svc
+    namespace: kube-system
+  # Apply this Application manually only after bootstrapping a kube-proxy-free
+  # cluster and replacing the API endpoint placeholder.
+

cilium/cilium-values.yaml

@@ -0,0 +1,23 @@
+# Cilium is the CNI, network-policy engine, and eBPF service datapath for the
+# production-style K3s profile. Set this endpoint before bootstrapping a
+# cluster because kube-proxy is intentionally disabled.
+kubeProxyReplacement: true
+k8sServiceHost: "127.0.0.1"
+k8sServicePort: 6443
+
+ipam:
+  mode: kubernetes
+
+routingMode: tunnel
+tunnelProtocol: vxlan
+
+hubble:
+  enabled: true
+  relay:
+    enabled: true
+  ui:
+    enabled: true
+
+operator:
+  replicas: 1
+

local-quickstart/cilium.md

@@ -0,0 +1,40 @@
+# Cilium local profile
+
+The standard k3d profile is the default quick start. This profile is for
+demonstrating Cilium with kube-proxy replacement.
+
+Create it with:
+
+```bash
+k3d cluster create --config local-quickstart/k3d-cilium-cluster-config.yaml
+```
+
+Before installing Cilium, set the API server endpoint in a temporary values
+file. The endpoint must be reachable directly from every node. Do not use the
+Kubernetes service VIP because kube-proxy is disabled during bootstrap.
+
+```bash
+kubectl config current-context
+kubectl get nodes -o wide
+cp cilium/cilium-values.yaml /tmp/cilium-values.yaml
+# Replace REPLACE_WITH_API_SERVER_DNS_OR_PRIVATE_IP with the reachable API endpoint.
+helm repo add cilium https://helm.cilium.io/
+helm repo update
+helm upgrade --install cilium cilium/cilium \
+  --namespace kube-system \
+  --version 1.20.0 \
+  --values /tmp/cilium-values.yaml
+kubectl -n kube-system rollout status daemonset/cilium --timeout=300s
+kubectl -n kube-system get pods -l k8s-app=cilium
+```
+
+Install ArgoCD only after Cilium is Ready. Apply
+`argocd/optional-apps/cilium.yaml` manually after the endpoint is configured;
+it is intentionally outside the root app-of-apps watched directory until the
+cluster has been bootstrapped without kube-proxy.
+
+Delete the profile with:
+
+```bash
+k3d cluster delete security-baseline-cilium
+```

local-quickstart/k3d-cilium-cluster-config.yaml

@@ -0,0 +1,32 @@
+apiVersion: k3d.io/v1alpha5
+kind: Simple
+metadata:
+  name: security-baseline-cilium
+
+# This is an advanced local profile. The standard k3d profile remains the
+# lowest-friction quick start and keeps Flannel enabled.
+servers: 1
+agents: 2
+
+options:
+  k3s:
+    extraArgs:
+      - arg: --flannel-backend=none
+        nodeFilters:
+          - server:*
+      - arg: --disable-network-policy
+        nodeFilters:
+          - server:*
+      - arg: --disable-kube-proxy
+        nodeFilters:
+          - server:*
+      - arg: --disable=traefik
+        nodeFilters:
+          - server:*
+  k3d:
+    wait: true
+    timeout: 180s
+  kubeconfig:
+    updateDefaultKubeconfig: true
+    switchCurrentContext: true
+

terraform/cloud-cluster/README.md

@@ -1,10 +1,10 @@
 # Optional production-style path
 
-This directory provisions one encrypted Ubuntu EC2 host with a deliberately
+This directory provisions one encrypted Flatcar EC2 host with a deliberately
 small network surface. It is a scaffold for the documented cloud path; the
 local k3d path remains the primary, cost-free portfolio demo.
 
-The AWS account, region, AMI, SSH key pair, and administrator CIDR are inputs,
+The AWS account, region, Flatcar AMI, SSH key pair, and administrator CIDR are inputs,
 not repository values. Do not commit a real `terraform.tfvars` file or private
 keys. The security group intentionally exposes SSH and the Kubernetes API only
 to `admin_cidr`; add any public application ports explicitly when needed.
@@ -21,7 +21,7 @@ terraform apply
 terraform output -raw public_ip
 ```
 
-Then run `ansible/bootstrap-k3s.yml` against the output IP. `terraform destroy`
+Then run `ansible/bootstrap-k3s.yml` against the output IP. Configure the
+Cilium API endpoint before installing Cilium. `terraform destroy`
 removes the lab resources when finished. This path is not required for the
 portfolio demo and is not invoked by CI.
-

terraform/cloud-cluster/terraform.tfvars.example

@@ -3,5 +3,4 @@ availability_zone = null
 instance_type    = "t3.medium"
 ssh_key_name     = "replace-with-existing-key-pair"
 admin_cidr       = "203.0.113.10/32"
-ami_id           = "replace-with-ubuntu-22.04-ami-for-your-region"
-
+ami_id           = "replace-with-flatcar-stable-ami-for-your-region"

terraform/cloud-cluster/variables.tf

@@ -27,7 +27,6 @@ variable "admin_cidr" {
 }
 
 variable "ami_id" {
-  description = "Ubuntu 22.04 LTS AMI ID for the selected region."
+  description = "Flatcar Stable AMI ID for the selected region and architecture."
   type        = string
 }
-