---
title: "VM 106 (docker-home) Right-Sizing Runbook"
description: "Runbook for right-sizing VM 106 from 16 GB/8 vCPU to 6 GB/4 vCPU — pre-checks, resize commands, and post-resize validation."
type: runbook
domain: server-configs
tags: [proxmox, infra-audit, right-sizing, docker-home]
---

# VM 106 (docker-home) Right-Sizing Runbook

## Context

Infrastructure audit (2026-04-02) found VM 106 severely overprovisioned:

| Resource | Allocated | Actual Usage | Target |
|----------|-----------|--------------|--------|
| RAM | 16 GB | 1.1–1.5 GB | 6 GB (4× headroom) |
| vCPUs | 8 (2 sockets × 4 cores) | load 0.12/core | 4 (1 socket × 4 cores) |

**Services**: Pi-hole, Nginx Proxy Manager, Portainer

## Pre-Check Results (2026-04-03)

Automated checks were run before resizing. **All clear.**

### Container memory limits

```bash
docker inspect pihole nginx-proxy-manager_app_1 portainer \
  | python3 -c "import json,sys; c=json.load(sys.stdin); \
    [print(x['Name'], 'MemoryLimit:', x['HostConfig']['Memory']) for x in c]"
```

Result:
```
/pihole MemoryLimit: 0
/nginx-proxy-manager_app_1 MemoryLimit: 0
/portainer MemoryLimit: 0
```

`0` = no limit — no containers will OOM at 6 GB.

### Docker Compose memory reservations

```bash
grep -rn 'memory\|mem_limit\|memswap' /home/cal/container-data/*/docker-compose.yml
```

Result: **no matches** — no compose-level memory reservations.

### Live memory usage at audit time

```
total: 15 GiB  used: 1.1 GiB  free: 6.8 GiB  buff/cache: 7.7 GiB
Pi-hole:  463 MiB
NPM:      367 MiB
Portainer:  12 MiB
Total containers: ~842 MiB
```

## Resize Procedure

Brief downtime: Pi-hole and NPM will be unavailable during shutdown.
Manticore runs Pi-hole 2 (10.10.0.226) for HA DNS — clients fail over automatically.

### Step 1 — Shut down the VM

```bash
ssh proxmox "qm shutdown 106 --timeout 60"
# Wait for shutdown
ssh proxmox "qm status 106"   # Should show: status: stopped
```

### Step 2 — Apply new hardware config

```bash
# Reduce RAM: 16384 MB → 6144 MB
ssh proxmox "qm set 106 --memory 6144"

# Reduce vCPUs: 2 sockets × 4 cores → 1 socket × 4 cores (8 → 4 vCPUs)
ssh proxmox "qm set 106 --sockets 1 --cores 4"

# Verify
ssh proxmox "qm config 106 | grep -E 'memory|cores|sockets'"
```

Expected output:
```
cores: 4
memory: 6144
sockets: 1
```

### Step 3 — Start the VM

```bash
ssh proxmox "qm start 106"
```

Wait ~30 seconds for Docker to come up.

### Step 4 — Verify services

```bash
# Pi-hole DNS resolution
ssh pihole "docker exec pihole dig google.com @127.0.0.1 | grep -E 'SERVER|ANSWER'"

# NPM — check it's running
ssh pihole "docker ps --filter name=nginx-proxy-manager --format '{{.Status}}'"

# Portainer
ssh pihole "docker ps --filter name=portainer --format '{{.Status}}'"

# Memory usage post-resize
ssh pihole "free -h"
```

### Step 5 — Monitor for 24h

Check memory doesn't approach the 6 GB limit:

```bash
ssh pihole "free -h && docker stats --no-stream --format 'table {{.Name}}\t{{.MemUsage}}'"
```

Alert threshold: if `used` exceeds 4.5 GB (75% of 6 GB), consider increasing to 8 GB.

## Rollback

If services fail to come up after resizing:

```bash
# Restore original allocation
ssh proxmox "qm set 106 --memory 16384 --sockets 2 --cores 4"
ssh proxmox "qm start 106"
```

## Related

- [Maintenance Reboot Runbook](maintenance-reboot.md) — VM 106 is Tier 2 (shut down after apps, before databases)
- Issue: cal/claude-home#19
