nixos-servers/TODO.md

# TODO: Automated Host Deployment Pipeline

## Vision

Automate the entire process of creating, configuring, and deploying new NixOS hosts on Proxmox from a single command or script.

**Desired workflow:**
```bash
./scripts/create-host.sh --hostname myhost --ip 10.69.13.50
# Script creates config, deploys VM, bootstraps NixOS, and you're ready to go
```

**Current manual workflow (from CLAUDE.md):**
1. Create `/hosts/<hostname>/` directory structure
2. Add host to `flake.nix`
3. Add DNS entries
4. Clone template VM manually
5. Run `prepare-host.sh` on new VM
6. Add generated age key to `.sops.yaml`
7. Configure networking
8. Commit and push
9. Run `nixos-rebuild boot --flake URL#<hostname>` on host

## The Plan

### Phase 1: Parameterized OpenTofu Deployments ✅ COMPLETED

**Status:** Fully implemented and tested

**Implementation:**
- Locals-based structure using `for_each` pattern for multiple VM deployments
- All VM parameters configurable with smart defaults (CPU, memory, disk, IP, storage, etc.)
- Automatic DHCP vs static IP detection based on `ip` field presence
- Dynamic outputs showing deployed VM IPs and specifications
- Successfully tested deploying multiple VMs simultaneously

**Tasks:**
- [x] Create module/template structure in terraform for repeatable VM deployments
- [x] Parameterize VM configuration (hostname, CPU, memory, disk, IP)
- [x] Support both DHCP and static IP configuration via cloud-init
- [x] Test deploying multiple VMs from same template

**Deliverable:** ✅ Can deploy multiple VMs with custom parameters via OpenTofu in a single `tofu apply`

**Files:**
- `terraform/vms.tf` - VM definitions using locals map
- `terraform/outputs.tf` - Dynamic outputs for all VMs
- `terraform/variables.tf` - Configurable defaults
- `terraform/README.md` - Complete documentation

---

### Phase 2: Host Configuration Generator ✅ COMPLETED

**Status:** ✅ Fully implemented and tested
**Completed:** 2025-02-01

**Goal:** Automate creation of host configuration files

**Implementation:**
- Python CLI tool packaged as Nix derivation
- Available as `create-host` command in devShell
- Rich terminal UI with configuration previews
- Comprehensive validation (hostname format/uniqueness, IP subnet/uniqueness)
- Jinja2 templates for NixOS configurations
- Automatic updates to flake.nix and terraform/vms.tf

**Tasks:**
- [x] Create Python CLI with typer framework
  - [x] Takes parameters: hostname, IP, CPU cores, memory, disk size
  - [x] Generates `/hosts/<hostname>/` directory structure
  - [x] Creates `configuration.nix` with proper hostname and networking
  - [x] Generates `default.nix` with standard imports
  - [x] References shared `hardware-configuration.nix` from template
- [x] Add host entry to `flake.nix` programmatically
  - [x] Text-based manipulation (regex insertion)
  - [x] Inserts new nixosConfiguration entry
  - [x] Maintains proper formatting
- [x] Generate corresponding OpenTofu configuration
  - [x] Adds VM definition to `terraform/vms.tf`
  - [x] Uses parameters from CLI input
  - [x] Supports both static IP and DHCP modes
- [x] Package as Nix derivation with templates
- [x] Add to flake packages and devShell
- [x] Implement dry-run mode
- [x] Write comprehensive README

**Usage:**
```bash
# In nix develop shell
create-host \
  --hostname test01 \
  --ip 10.69.13.50/24 \  # optional, omit for DHCP
  --cpu 4 \               # optional, default 2
  --memory 4096 \         # optional, default 2048
  --disk 50G \            # optional, default 20G
  --dry-run               # optional preview mode
```

**Files:**
- `scripts/create-host/` - Complete Python package with Nix derivation
- `scripts/create-host/README.md` - Full documentation and examples

**Deliverable:** ✅ Tool generates all config files for a new host, validated with Nix and Terraform

---

### Phase 3: Bootstrap Mechanism ✅ COMPLETED

**Status:** ✅ Fully implemented and tested
**Completed:** 2025-02-01

**Goal:** Get freshly deployed VM to apply its specific host configuration

**Implementation:** Systemd oneshot service that runs on first boot after cloud-init

**Approach taken:** Systemd service (variant of Option A)
- Systemd service `nixos-bootstrap.service` runs on first boot
- Depends on `cloud-config.service` to ensure hostname is set
- Reads hostname from `hostnamectl` (set by cloud-init via Terraform)
- Runs `nixos-rebuild boot --flake git+https://git.t-juice.club/torjus/nixos-servers.git#${hostname}`
- Reboots into new configuration on success
- Fails gracefully without reboot on errors (network issues, missing config)
- Service self-destructs after successful bootstrap (not in new config)

**Tasks:**
- [x] Create bootstrap service module in template2
  - [x] systemd oneshot service with proper dependencies
  - [x] Reads hostname from hostnamectl (cloud-init sets it)
  - [x] Checks network connectivity via HTTPS (curl)
  - [x] Runs nixos-rebuild boot with flake URL
  - [x] Reboots on success, fails gracefully on error
- [x] Configure cloud-init datasource
  - [x] Use ConfigDrive datasource (Proxmox provider)
  - [x] Add cloud-init disk to Terraform VMs (disks.ide.ide2.cloudinit)
  - [x] Hostname passed via cloud-init user-data from Terraform
- [x] Test bootstrap service execution on fresh VM
- [x] Handle failure cases (flake doesn't exist, network issues)
  - [x] Clear error messages in journald
  - [x] No reboot on failure
  - [x] System remains accessible for debugging

**Files:**
- `hosts/template2/bootstrap.nix` - Bootstrap service definition
- `hosts/template2/configuration.nix` - Cloud-init ConfigDrive datasource
- `terraform/vms.tf` - Cloud-init disk configuration

**Deliverable:** ✅ VMs automatically bootstrap and reboot into host-specific configuration on first boot

---

### Phase 4: Secrets Management Automation

**Challenge:** sops needs age key, but age key is generated on first boot

**Current workflow:**
1. VM boots, generates age key at `/var/lib/sops-nix/key.txt`
2. User runs `prepare-host.sh` which prints public key
3. User manually adds public key to `.sops.yaml`
4. User commits, pushes
5. VM can now decrypt secrets

**Proposed solution:**

**Option A: Pre-generate age keys**
- [ ] Generate age key pair during `create-host-config.sh`
- [ ] Add public key to `.sops.yaml` immediately
- [ ] Store private key temporarily (secure location)
- [ ] Inject private key via cloud-init write_files or Terraform file provisioner
- [ ] VM uses pre-configured key from first boot

**Option B: Post-deployment secret injection**
- [ ] VM boots with template, generates its own key
- [ ] Fetch public key via SSH after first boot
- [ ] Automatically add to `.sops.yaml` and commit
- [ ] Trigger rebuild on VM to pick up secrets access

**Option C: Separate secrets from initial deployment**
- [ ] Initial deployment works without secrets
- [ ] After VM is running, user manually adds age key
- [ ] Subsequent auto-upgrades pick up secrets

**Decision needed:** Option A is most automated, but requires secure key handling

---

### Phase 5: DNS Automation

**Goal:** Automatically generate DNS entries from host configurations

**Approach:** Leverage Nix to generate zone file entries from flake host configurations

Since most hosts use static IPs defined in their NixOS configurations, we can extract this information and automatically generate A records. This keeps DNS in sync with the actual host configs.

**Tasks:**
- [ ] Add optional CNAME field to host configurations
  - [ ] Add `networking.cnames = [ "alias1" "alias2" ]` or similar option
  - [ ] Document in host configuration template
- [ ] Create Nix function to extract DNS records from all hosts
  - [ ] Parse each host's `networking.hostName` and IP configuration
  - [ ] Collect any defined CNAMEs
  - [ ] Generate zone file fragment with A and CNAME records
- [ ] Integrate auto-generated records into zone files
  - [ ] Keep manual entries separate (for non-flake hosts/services)
  - [ ] Include generated fragment in main zone file
  - [ ] Add comments showing which records are auto-generated
- [ ] Update zone file serial number automatically
- [ ] Test zone file validity after generation
- [ ] Either:
  - [ ] Automatically trigger DNS server reload (Ansible)
  - [ ] Or document manual step: merge to master, run upgrade on ns1/ns2

**Deliverable:** DNS A records and CNAMEs automatically generated from host configs

---

### Phase 6: Integration Script

**Goal:** Single command to create and deploy a new host

**Tasks:**
- [ ] Create `scripts/create-host.sh` master script that orchestrates:
  1. Prompts for: hostname, IP (or DHCP), CPU, memory, disk
  2. Validates inputs (IP not in use, hostname unique, etc.)
  3. Calls host config generator (Phase 2)
  4. Generates OpenTofu config (Phase 2)
  5. Handles secrets (Phase 4)
  6. Updates DNS (Phase 5)
  7. Commits all changes to git
  8. Runs `tofu apply` to deploy VM
  9. Waits for bootstrap to complete (Phase 3)
  10. Prints success message with IP and SSH command
- [ ] Add `--dry-run` flag to preview changes
- [ ] Add `--interactive` mode vs `--batch` mode
- [ ] Error handling and rollback on failures

**Deliverable:** `./scripts/create-host.sh --hostname myhost --ip 10.69.13.50` creates a fully working host

---

### Phase 7: Testing & Documentation

**Tasks:**
- [ ] Test full pipeline end-to-end
- [ ] Create test host and verify all steps
- [ ] Document the new workflow in CLAUDE.md
- [ ] Add troubleshooting section
- [ ] Create examples for common scenarios (DHCP host, static IP host, etc.)

---

## Open Questions

1. **Bootstrap method:** Cloud-init runcmd vs Terraform provisioner vs Ansible?
2. **Secrets handling:** Pre-generate keys vs post-deployment injection?
3. **DNS automation:** Auto-commit or manual merge?
4. **Git workflow:** Auto-push changes or leave for user review?
5. **Template selection:** Single template2 or multiple templates for different host types?
6. **Networking:** Always DHCP initially, or support static IP from start?
7. **Error recovery:** What happens if bootstrap fails? Manual intervention or retry?

## Implementation Order

Recommended sequence:
1. Phase 1: Parameterize OpenTofu (foundation for testing)
2. Phase 3: Bootstrap mechanism (core automation)
3. Phase 2: Config generator (automate the boilerplate)
4. Phase 4: Secrets (solves biggest chicken-and-egg)
5. Phase 5: DNS (nice-to-have automation)
6. Phase 6: Integration script (ties it all together)
7. Phase 7: Testing & docs

## Success Criteria

When complete, creating a new host should:
- Take < 5 minutes of human time
- Require minimal user input (hostname, IP, basic specs)
- Result in a fully configured, secret-enabled, DNS-registered host
- Be reproducible and documented
- Handle common errors gracefully

---

## Notes

- Keep incremental commits at each phase
- Test each phase independently before moving to next
- Maintain backward compatibility with manual workflow
- Document any manual steps that can't be automated