# pgdb1 Decommissioning Plan

## Overview

Decommission the pgdb1 PostgreSQL server. The only consumer was Open WebUI on gunter, which has been migrated to use a local PostgreSQL instance.

## Pre-flight Verification

Before proceeding, verify that gunter is no longer using pgdb1:

1. Check Open WebUI on gunter is configured for local PostgreSQL (not 10.69.13.16)
2. Optionally: Check pgdb1 for recent connection activity:
   ```bash
   ssh pgdb1 'sudo -u postgres psql -c "SELECT * FROM pg_stat_activity WHERE datname IS NOT NULL;"'
   ```

## Files to Remove

### Host Configuration
- `hosts/pgdb1/default.nix`
- `hosts/pgdb1/configuration.nix`
- `hosts/pgdb1/hardware-configuration.nix`
- `hosts/pgdb1/` (directory)

### Service Module
- `services/postgres/postgres.nix`
- `services/postgres/default.nix`
- `services/postgres/` (directory)

Note: This service module is only used by pgdb1, so it can be removed entirely.

### Flake Entry
Remove from `flake.nix` (lines 131-138):
```nix
pgdb1 = nixpkgs.lib.nixosSystem {
  inherit system;
  specialArgs = {
    inherit inputs self;
  };
  modules = commonModules ++ [
    ./hosts/pgdb1
  ];
};
```

### Vault AppRole
Remove from `terraform/vault/approle.tf` (lines 69-73):
```hcl
"pgdb1" = {
  paths = [
    "secret/data/hosts/pgdb1/*",
  ]
}
```

### Monitoring Rules
Remove from `services/monitoring/rules.yml` the `postgres_down` alert (lines 359-365):
```yaml
- name: postgres_rules
  rules:
    - alert: postgres_down
      expr: node_systemd_unit_state{instance="pgdb1.home.2rjus.net:9100", name="postgresql.service", state="active"} == 0
      for: 5m
      labels:
        severity: critical
```

### Utility Scripts
Delete `rebuild-all.sh` entirely (obsolete script).

## Execution Steps

### Phase 1: Verification
- [ ] Confirm Open WebUI on gunter uses local PostgreSQL
- [ ] Verify no active connections to pgdb1

### Phase 2: Code Cleanup
- [ ] Create feature branch: `git checkout -b decommission-pgdb1`
- [ ] Remove `hosts/pgdb1/` directory
- [ ] Remove `services/postgres/` directory
- [ ] Remove pgdb1 entry from `flake.nix`
- [ ] Remove postgres alert from `services/monitoring/rules.yml`
- [ ] Delete `rebuild-all.sh` (obsolete)
- [ ] Run `nix flake check` to verify no broken references
- [ ] Commit changes

### Phase 3: Terraform Cleanup
- [ ] Remove pgdb1 from `terraform/vault/approle.tf`
- [ ] Run `tofu plan` in `terraform/vault/` to preview changes
- [ ] Run `tofu apply` to remove the AppRole
- [ ] Commit terraform changes

### Phase 4: Infrastructure Cleanup
- [ ] Shut down pgdb1 VM in Proxmox
- [ ] Delete the VM from Proxmox
- [ ] (Optional) Remove any DNS entries if not auto-generated

### Phase 5: Finalize
- [ ] Merge feature branch to master
- [ ] Trigger auto-upgrade on DNS servers (ns1, ns2) to remove DNS entry
- [ ] Move this plan to `docs/plans/completed/`

## Rollback

If issues arise after decommissioning:
1. The VM can be recreated from template using the git history
2. Database data would need to be restored from backup (if any exists)

## Notes

- pgdb1 IP: 10.69.13.16
- The postgres service allowed connections from gunter (10.69.30.105)
- No restic backup was configured for this host