## Context
The mailserver container had `capabilities.add = ["NET_ADMIN"]`. Upstream
docker-mailserver docs say the capability is only needed by Fail2ban to
run iptables ban actions. Fail2ban is DISABLED in this stack
(`ENABLE_FAIL2BAN=0`, see line ~68) — CrowdSec owns the brute-force
policy at the LB layer. The capability was therefore unused ballast and
a minor attack-surface reduction opportunity. Addresses code-4mu.
## This change
Replaces the explicit `capabilities { add = ["NET_ADMIN"] }` block with
an empty `security_context {}`. Post-rollout verification
(`supervisorctl status`) confirms every service we actually run is
healthy — dovecot, postfix, rspamd, rsyslog, postsrsd, changedetector,
cron, mailserver. Every STOPPED entry was already disabled.
The inline comment documents the revert trigger: check
`kubectl logs -c docker-mailserver` for permission-denied patterns and
restore the capability if observed.
## Test Plan
### Automated
```
$ kubectl get pod -n mailserver -l app=mailserver -o jsonpath='{.items[0].spec.containers[?(@.name=="docker-mailserver")].securityContext}'
{"allowPrivilegeEscalation":true,"privileged":false,"readOnlyRootFilesystem":false,"runAsNonRoot":false}
$ kubectl rollout status deployment/mailserver -n mailserver
deployment "mailserver" successfully rolled out
$ kubectl exec -n mailserver -c docker-mailserver deployment/mailserver -- \
supervisorctl status | grep RUNNING
changedetector RUNNING ...
cron RUNNING ...
dovecot RUNNING ...
mailserver RUNNING ...
postfix RUNNING ...
postsrsd RUNNING ...
rspamd RUNNING ...
rsyslog RUNNING ...
```
### Observation window
EmailRoundtripFailing + EmailRoundtripStale alerts continue to run
every 20 min. If no alert fires in the 24h post-rollout window
(through ~2026-04-20 10:40 UTC), the change is considered safe and
this commit stands. Otherwise revert this commit.
## What is NOT in this change
- readOnlyRootFilesystem (separate hardening, out of scope)
- runAsNonRoot (docker-mailserver needs root for Postfix)
- Removing privilege-escalation defaults (container needs those for
chowning mail spool at startup)
Closes: code-4mu
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
|
||
|---|---|---|
| .beads | ||
| .claude | ||
| .git-crypt | ||
| .github | ||
| .planning | ||
| .woodpecker | ||
| ci | ||
| cli | ||
| diagram | ||
| docs | ||
| modules | ||
| playbooks | ||
| scripts | ||
| secrets | ||
| stacks | ||
| state/stacks | ||
| .gitattributes | ||
| .gitignore | ||
| .sops.yaml | ||
| AGENTS.md | ||
| config.tfvars | ||
| CONTRIBUTING.md | ||
| LICENSE.txt | ||
| MEMORY.md | ||
| README.md | ||
| setup-monitoring.sh | ||
| terragrunt.hcl | ||
| tiers.tf | ||
This repo contains my infra-as-code sources.
My infrastructure is built using Terraform, Kubernetes and CI/CD is done using Woodpecker CI.
Read more by visiting my website: https://viktorbarzin.me
Documentation
Full architecture documentation is available in docs/ — covering networking, storage, security, monitoring, secrets, CI/CD, databases, and more.
Adding a New User (Admin)
Adding a new namespace-owner to the cluster requires three steps — no code changes needed.
1. Authentik Group Assignment
In the Authentik admin UI, add the user to:
kubernetes-namespace-ownersgroup (grants OIDC group claim for K8s RBAC)Headscale Usersgroup (if they need VPN access)
2. Vault KV Entry
Add a JSON entry to secret/platform → k8s_users key in Vault:
"username": {
"role": "namespace-owner",
"email": "user@example.com",
"namespaces": ["username"],
"domains": ["myapp"],
"quota": {
"cpu_requests": "2",
"memory_requests": "4Gi",
"memory_limits": "8Gi",
"pods": "20"
}
}
usernamekey must match the user's Forgejo username (for Woodpecker admin access)namespaces— K8s namespaces to create and grant admin access todomains— subdomains underviktorbarzin.mefor Cloudflare DNS recordsquota— resource limits per namespace (defaults shown above)
3. Apply Stacks
vault login -method=oidc
cd stacks/vault && terragrunt apply --non-interactive
# Creates: namespace, Vault policy, identity entity, K8s deployer role
cd ../platform && terragrunt apply --non-interactive
# Creates: RBAC bindings, ResourceQuota, TLS secret, DNS records
cd ../woodpecker && terragrunt apply --non-interactive
# Adds user to Woodpecker admin list
What Gets Auto-Generated
| Resource | Stack |
|---|---|
| Kubernetes namespace | vault |
Vault policy (namespace-owner-{user}) |
vault |
| Vault identity entity + OIDC alias | vault |
| K8s deployer Role + Vault K8s role | vault |
| RBAC RoleBinding (namespace admin) | platform |
| RBAC ClusterRoleBinding (cluster read-only) | platform |
| ResourceQuota | platform |
| TLS secret in namespace | platform |
| Cloudflare DNS records | platform |
| Woodpecker admin access | woodpecker |
New User Onboarding
If you've been added as a namespace-owner, follow these steps to get started.
1. Join the VPN
# Install Tailscale: https://tailscale.com/download
tailscale login --login-server https://headscale.viktorbarzin.me
# Send the registration URL to Viktor, wait for approval
ping 10.0.20.100 # verify connectivity
2. Install Tools
Run the setup script to install kubectl, kubelogin, Vault CLI, Terraform, and Terragrunt:
# macOS
bash <(curl -fsSL https://k8s-portal.viktorbarzin.me/setup/script?os=mac)
# Linux
bash <(curl -fsSL https://k8s-portal.viktorbarzin.me/setup/script?os=linux)
3. Authenticate
# Log into Vault (opens browser for SSO)
vault login -method=oidc
# Test kubectl (opens browser for OIDC login)
kubectl get pods -n YOUR_NAMESPACE
4. Deploy Your First App
# Clone the infra repo
git clone https://github.com/ViktorBarzin/infra.git && cd infra
# Copy the stack template
cp -r stacks/_template stacks/myapp
mv stacks/myapp/main.tf.example stacks/myapp/main.tf
# Edit main.tf — replace all <placeholders>
# Store secrets in Vault
vault kv put secret/YOUR_USERNAME/myapp DB_PASSWORD=secret123
# Submit a PR
git checkout -b feat/myapp
git add stacks/myapp/
git commit -m "add myapp stack"
git push -u origin feat/myapp
After review and merge, an admin runs cd stacks/myapp && terragrunt apply.
5. Set Up CI/CD (Optional)
Create .woodpecker.yml in your app's Forgejo repo:
steps:
- name: build
image: woodpeckerci/plugin-docker-buildx
settings:
repo: YOUR_DOCKERHUB_USER/myapp
tag: ["${CI_PIPELINE_NUMBER}", "latest"]
username:
from_secret: dockerhub-username
password:
from_secret: dockerhub-token
platforms: linux/amd64
- name: deploy
image: hashicorp/vault:1.18.1
commands:
- export VAULT_ADDR=http://vault-active.vault.svc.cluster.local:8200
- export VAULT_TOKEN=$(vault write -field=token auth/kubernetes/login
role=ci jwt=$(cat /var/run/secrets/kubernetes.io/serviceaccount/token))
- KUBE_TOKEN=$(vault write -field=service_account_token
kubernetes/creds/YOUR_NAMESPACE-deployer
kubernetes_namespace=YOUR_NAMESPACE)
- kubectl --server=https://kubernetes.default.svc
--token=$KUBE_TOKEN
--certificate-authority=/var/run/secrets/kubernetes.io/serviceaccount/ca.crt
-n YOUR_NAMESPACE set image deployment/myapp
myapp=YOUR_DOCKERHUB_USER/myapp:${CI_PIPELINE_NUMBER}
Useful Commands
# Check your pods
kubectl get pods -n YOUR_NAMESPACE
# View quota usage
kubectl describe resourcequota -n YOUR_NAMESPACE
# Store/read secrets
vault kv put secret/YOUR_USERNAME/myapp KEY=value
vault kv get secret/YOUR_USERNAME/myapp
# Get a short-lived K8s deploy token
vault write kubernetes/creds/YOUR_NAMESPACE-deployer \
kubernetes_namespace=YOUR_NAMESPACE
Important Rules
- All changes go through Terraform — never
kubectl apply/edit/patchdirectly - Never put secrets in code — use Vault:
vault kv put secret/YOUR_USERNAME/... - Always use a PR — never push directly to master
- Docker images: build for
linux/amd64, use versioned tags (not:latest)
git-crypt setup
To decrypt the secrets, you need to setup git-crypt.
- Install git-crypt.
- Setup gpg keys on the machine
git-crypt unlock
This will unlock the secrets and will lock them on commit