blumeops/plans/k8s-migration/P5.1_docker_migration.md

Phase 5.1: Migrate Minikube from QEMU2 to Docker Driver

Goal: Replace the qemu2 driver with docker to fix remote API access and simplify volume mounts

Status: Complete (2026-01-21) - Cluster running, ArgoCD deployed, apps synced

Prerequisites: Phase 5 complete

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Background

Original Problem (Podman → QEMU2)

During Phase 6 (Kiwix/Transmission migration), we discovered that the podman driver has fundamental limitations that prevent mounting external volumes:

1. SMB CSI driver fails with "Operation not permitted" - the rootless container lacks kernel-level mount capabilities
2. minikube mount fails - 9p mount gets "permission denied" inside the podman VM
3. hostPath volumes only work for paths inside the minikube container, not the macOS host

We migrated to QEMU2 to get a full VM with kernel capabilities.

New Problem (QEMU2 → Docker)

The QEMU2 driver introduced a new problem: the Kubernetes API server is inside the VM at 192.168.105.2:6443, and Tailscale's TCP proxy cannot forward to it properly:

• TCP connections succeed (nc -zv works)
• TLS handshake times out
• Root cause unknown, but likely related to Tailscale serve's handling of non-localhost upstreams

Additionally, the volume mount solution with QEMU2 was complex:

• Required NFS mount from sifaka → indri
• Then minikube mount to pass through to VM
• Two LaunchAgents/LaunchDaemons for persistence
• macOS GUI approval required for network access

Why Docker?

The docker driver solves both problems:

1. API Server on localhost: Docker Desktop handles port forwarding from container to localhost automatically, so tailscale serve --tcp=443 tcp://localhost:PORT works

2. Simpler volume mounts: Docker Desktop has built-in macOS file sharing. Paths shared with Docker are accessible inside containers.

3. Official Tailscale recommendation: Tailscale's own Kubernetes guide uses minikube with the docker driver.

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Implementation Summary

Infrastructure Changes

1. Docker Desktop installed (manual via brew install --cask docker)

   • Configured with 12GB memory in Docker Desktop settings
   • Kubernetes option disabled (using minikube instead)

2. Docker minikube cluster created:

   minikube start \
     --driver=docker \
     --container-runtime=docker \
     --cpus=6 \
     --memory=11264 \
     --disk-size=200g \
     --apiserver-names=k8s.tail8d86e.ts.net,indri \
     --apiserver-port=6443 \
     --listen-address=0.0.0.0
   

3. Tailscale serve configured for k8s API:

   • API server on localhost (port is dynamic with docker driver)
   • tailscale serve --service=svc:k8s --tcp=443 tcp://localhost:<PORT>

4. Remote kubectl access working from gilbert:

   • Created mise-tasks/ensure-minikube-indri-kubectl-config script
   • Fetches certs from indri and sets up ~/.kube/minikube-indri/config.yml

Ansible Roles Updated

• ansible/roles/minikube/ - docker driver, removed qemu2/NFS/socket_vmnet
• ansible/roles/tailscale_serve/ - removed svc:k8s (minikube role handles dynamic port)
• Containerd registry mirrors configured for zot pull-through cache

ArgoCD Bootstrap

All apps deployed and synced from feature/p5.1-qemu2-migration branch:

App	Status	Notes
tailscale-operator	Healthy	Manages Tailscale ingresses
argocd	Healthy	Self-managed
cloudnative-pg	Healthy	PostgreSQL operator
blumeops-pg	Progressing	PostgreSQL cluster starting
grafana	Progressing	Needs grafana-admin secret
grafana-config	Healthy	Dashboards and ingress
miniflux	Progressing	Needs miniflux-config secret
devpi	Progressing	Starting up

Secrets Still Needed

After PR merge, apply these secrets manually:

# Grafana admin password
op inject -i argocd/manifests/grafana-config/secret-admin.yaml.tpl | kubectl --context=minikube-indri apply -f -

# Miniflux config
op inject -i argocd/manifests/miniflux/secret.yaml.tpl | kubectl --context=minikube-indri apply -f -

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Technical Notes

API Server Port

With docker driver, the API server port is dynamic - Docker maps a random host port to 6443 inside the container.

The minikube ansible role queries the port after cluster start and configures tailscale serve accordingly.

Registry Mirror Configuration

Containerd uses /etc/containerd/certs.d/<registry>/hosts.toml files. The ansible role configures mirrors for:

• registry.tail8d86e.ts.net (private images)
• docker.io
• ghcr.io
• quay.io

ProxyClass Renamed

Changed from crio-compat to default - the old name was misleading since we're no longer using CRI-O.

Volume Mounts for P6 (Kiwix/Transmission)

Solution: Direct NFS from pods to sifaka ✅ TESTED AND WORKING

Docker NATs outbound traffic through indri's LAN IP (192.168.1.50), so sifaka's NFS exports need to allow 192.168.1.0/24.

Sifaka NFS exports configured:

• 192.168.1.0/24 - Docker containers via indri NAT
• 100.64.0.0/10 - Tailscale clients

Pods can mount NFS directly:

volumes:
  - name: torrents
    nfs:
      server: sifaka
      path: /volume1/torrents

No LaunchAgents, no minikube mount, no SMB CSI driver needed.

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Verification Checklist

• Docker Desktop installed and running on indri
• QEMU2 minikube deleted
• Docker minikube running (6 CPUs, 11GB RAM)
• API server accessible on localhost
• Tailscale serve configured for svc:k8s
• Remote kubectl access working from gilbert
• Ansible roles updated for docker driver
• socket_vmnet stopped
• ArgoCD deployed and synced
• All apps synced to feature branch
• Apply app secrets (grafana-admin, miniflux-db, devpi-root, eblume, borgmatic)
• Verify all apps healthy after secrets applied
• Miniflux database restored from borgmatic backup
• Merge PR and reset apps to main branch
• mise run indri-services-check passes

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Post-Merge Steps

After PR is merged:

# Reset all blumeops apps to main branch
argocd app set apps --revision main
argocd app set argocd --revision main
argocd app set blumeops-pg --revision main
argocd app set devpi --revision main
argocd app set grafana-config --revision main
argocd app set miniflux --revision main
argocd app set tailscale-operator --revision main

# Sync all apps
argocd app sync apps
argocd app sync argocd
argocd app sync tailscale-operator
argocd app sync blumeops-pg
argocd app sync grafana-config
argocd app sync miniflux
argocd app sync devpi

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Rollback Plan

If Docker driver doesn't work:

1. Delete Docker minikube: minikube delete
2. Recreate QEMU2 cluster (restore old ansible config from git)
3. Accept the Tailscale TCP forwarding limitation and use SSH tunnel for remote kubectl