🌐 Expanding to Multi-Cloud: Provisioning Oracle Linux 10 on Google Cloud's $0 Always Free Tier & Joining K3s

Why settle for one free cloud provider when you can build an automated, resilient multi-cloud Kubernetes cluster across Oracle Cloud (OCI) and Google Cloud Platform (GCP) — completely for $0/month?

In this post, I walk through the end-to-end process of:

Provisioning an Oracle Linux Server 10.1 instance on Google Cloud’s Always Free Tier (gce10).
Applying kernel and daemon memory hardening to reclaim ~250 MB of RAM.
Joining gce10 as a worker node into our central K3s Kubernetes cluster across a secure WireGuard mesh.
Running a head-to-head performance benchmark comparing Apple Silicon M1, OCI Ampere ARM (arm10), GCP Intel Xeon (gce10), and OCI AMD EPYC (amd10/amd11).

🏛️ 1. Multi-Cloud K3s Kubernetes Fleet Architecture

Our fleet previously lived entirely in OCI Tokyo. Adding gce10 in GCP Iowa (us-central1) creates a geo-distributed cross-cloud presence with a dedicated US edge outpost.

flowchart TD
    subgraph OCI APAC Region [Oracle Cloud Infrastructure - Tokyo]
        AMD10["amd10 (OCI AMD 1GB)<br>• Caddy Ingress Gateway<br>• Public IPv4: 152.70.101.162<br>• Google SSO Forward-Auth & WireGuard Hub"]
        AMD11["amd11 (OCI AMD 1GB • K3s Worker)<br>• Pod CIDR: 10.42.1.0/24<br>• Navidrome, VietCalendar, FileBrowser"]
        ARM10["arm10 (OCI Ampere ARM 10GB • K3s Master)<br>• Pod CIDR: 10.42.0.0/24<br>• PostgreSQL 18 + pgvector, VictoriaMetrics"]
    end

    subgraph GCP US-Central Region [Google Cloud Platform - Iowa]
        GCE10["gce10 (GCP e2-micro 1GB • K3s Worker)<br>• Pod CIDR: 10.42.2.0/24 (Flannel over WireGuard)<br>• Public IPv4: 136.111.37.17<br>• Vector Log Shipper & US Edge Bridge"]
    end

    AMD10 <-->|Internal VCN| ARM10
    AMD10 <-->|Internal VCN| AMD11
    GCE10 <-->|WireGuard Mesh wg0 (10.10.0.4 <-> 10.10.0.1)| AMD10
    GCE10 <-->|Cross-Cloud Flannel vxlan / Pod Routing| ARM10

🎁 2. Google Cloud Always Free Tier: Rules & Gotchas

Google Cloud provides one of the most generous persistent free tiers, but you must configure your VM strictly within these boundaries to avoid unexpected billing:

Parameter	Always Free Limit	Our Selected Config	Gotcha to Avoid
Machine Type	1 non-preemptible `e2-micro` / month	`e2-micro` (2 vCPU, 1 GB RAM)	Do NOT pick `e2-small` or `e2-medium`.
Region	`us-central1`, `us-east1`, or `us-west1`	`us-central1-a` (Iowa)	Non-US regions (Singapore, Tokyo) are NOT free!
Boot Disk	Up to 30 GB Standard Persistent Disk	30 GB `pd-standard`	Do NOT choose `pd-balanced` or `pd-ssd`.
Outbound Egress	1 GB/month to all destinations	Standard egress	Bulk media streaming will exceed 1 GB.

Provisioning Command via gcloud CLI

gcloud compute instances create gce-free-vm \
    --project=vietcalendar \
    --zone=us-central1-a \
    --machine-type=e2-micro \
    --image-family=oracle-linux-10 \
    --image-project=oracle-linux-cloud \
    --boot-disk-size=30GB \
    --boot-disk-type=pd-standard \
    --boot-disk-auto-delete \
    --metadata-from-file=ssh-keys=/path/to/ssh-keys.txt \
    --tags=http-server,https-server

🧠 3. Memory Optimization Playbook on a 1 GB Enterprise VM

Oracle Linux 10 boots with the Unbreakable Enterprise Kernel (UEK 6.12) and standard enterprise daemons. Out-of-the-box, it consumed ~600 MiB of RAM, leaving only ~350 MiB for user workloads.

Here is how we reclaimed memory and stabilized the baseline before starting K3s:

Step 1: Disable `kdump` & Reclaim Kernel `crashkernel` RAM

sudo systemctl disable --now kdump
sudo grubby --update-kernel=ALL --remove-args="crashkernel crash_kexec_post_notifiers"

Step 2: Decommission Heavy & Redundant Background Daemons

Google Guest Agent Suite (~81 MiB freed): Masked google-guest-agent-manager, google-guest-compat-manager, and core_plugin.
Redundant Linux Daemons (~60 MiB freed): Masked firewalld, tuned, google-osconfig-agent, rsyslog, rngd, dtprobed, auditd, and rpcbind.

Step 3: Setup 2.0 GB Swapfile with Low Swappiness

sudo dd if=/dev/zero of=/swapfile bs=1M count=2048
sudo chmod 600 /swapfile
sudo mkswap /swapfile
sudo swapon /swapfile
echo '/swapfile none swap sw 0 0' | sudo tee -a /etc/fstab
echo 'vm.swappiness=10' | sudo tee /etc/sysctl.d/99-swap.conf
sudo sysctl -p /etc/sysctl.d/99-swap.conf

☸️ 4. Joining K3s Kubernetes Over a WireGuard Mesh

With gce10 connected to amd10 over WireGuard (10.10.0.4 $\leftrightarrow$ 10.10.0.1), we joined gce10 to the master on arm10 (10.0.0.216):

curl -sfL https://get.k3s.io | INSTALL_K3S_SKIP_SELINUX_RPM=true \
  INSTALL_K3S_VERSION='v1.36.3+k3s1' \
  K3S_URL='https://10.0.0.216:6443' \
  K3S_TOKEN='<MASTER_NODE_TOKEN>' \
  sh -s - agent \
  --node-name gce10 \
  --node-ip 10.10.0.4 \
  --node-external-ip 136.111.37.17 \
  --flannel-iface wg0

Verification on `arm10` Master

NAME    STATUS   ROLES           AGE    VERSION        INTERNAL-IP   EXTERNAL-IP     OS-IMAGE                   KERNEL-VERSION
amd11   Ready    worker          3d6h   v1.36.3+k3s1   10.0.0.10     <none>          Oracle Linux Server 10.2   6.12.0-204.92.4.4.3.el10uek.x86_64
arm10   Ready    control-plane   3d6h   v1.36.3+k3s1   10.0.0.216    <none>          Oracle Linux Server 10.2   6.12.0-204.92.4.4.3.el10uek.aarch64
gce10   Ready    worker          2m     v1.36.3+k3s1   10.10.0.4     136.111.37.17   Oracle Linux Server 10.1   6.12.0-202.76.4.1.el10uek.x86_64

The cluster’s vector daemonset instantly scheduled onto gce10 (Pod IP: 10.42.2.2), immediately harvesting logs and streaming them back to VictoriaLogs on arm10!

⚡ 5. The 5-Node Benchmark Showdown

We ran an identical, standardized benchmark suite across 5 environments:

🍎 Apple MacBook Air (M1, 8 Cores, 16 GB Unified Memory)
🚀 arm10 (OCI Ampere Altra ARM64, 2 OCPUs, 10.9 GB RAM)
🌐 gce10 (GCP Intel Xeon x86_64, 2 vCPUs, 1 GB RAM)
🛡️ amd10 (OCI AMD EPYC 7551 x86_64, 2 vCPUs, 1 GB RAM)
🛡️ amd11 (OCI AMD EPYC 7551 x86_64, 2 vCPUs, 1 GB RAM)

A. CPU Compute (Prime Calculation — Lower is Faster)

Node	Processor	Single-Core Time	2-Core Multi-Thread	Relative Speed
🍎 Mac (M1)	Apple M1 (ARM64)	0.028 s 🏆	0.192 s	6.4x faster than AMD
`arm10`	Ampere Altra (ARM64)	0.049 s 🥈	0.211 s	3.6x faster than AMD
`gce10`	Intel Xeon (x86_64)	0.066 s 🥉	0.194 s 🥇	3.0x faster than AMD
`amd10`	AMD EPYC 7551 (x86_64)	0.178 s	0.587 s	Baseline
`amd11`	AMD EPYC 7551 (x86_64)	0.201 s	0.600 s	Baseline

B. Direct Disk I/O (Bypassing RAM Cache — Higher is Better)

Node	Direct Write (128 MB)	Direct Read (128 MB)	Storage Medium
🍎 Mac (M1)	464.8 MB/s 🏆	13,724 MB/s 🏆	Apple Internal PCIe NVMe SSD
`gce10`	87.2 MB/s 🥇	140.6 MB/s 🥇	GCP Standard Persistent Disk (30 GB)
`amd10`	47.5 MB/s 🥈	73.5 MB/s 🥈	OCI Block Storage (50 GB)
`amd11`	27.7 MB/s	49.8 MB/s	OCI Block Storage (50 GB)
`arm10`	17.7 MB/s	10.0 MB/s	OCI Block Storage (Active cluster I/O)

🎯 6. Fleet Specialization Matrix

arm10 (OCI ARM 10 GB): The Core Engine. Houses our PostgreSQL 18 database with pgvector, Spring Boot microservices, VictoriaMetrics TSDB, and K3s control plane.
gce10 (GCP Intel 1 GB): The US Outpost & Worker. High single-core clock speed, fast 140 MB/s storage I/O, and K3s worker node in North America.
amd10 & amd11 (OCI AMD 1 GB): The Gatekeepers & Shields.
- Caddy Ingress & TLS Termination: Caddy uses < 30 MB RAM and < 2% CPU to handle all public domain routing.
- 2 Free Dedicated Public IPv4s: OCI includes static public IPs for free.
- Zero-Trust Bastion & WireGuard Mesh: Encrypted overlay networking between private subnets and cross-cloud nodes.

🏛️ 1. Multi-Cloud K3s Kubernetes Fleet Architecture#

🎁 2. Google Cloud Always Free Tier: Rules & Gotchas#

Provisioning Command via gcloud CLI#

🧠 3. Memory Optimization Playbook on a 1 GB Enterprise VM#

Step 1: Disable kdump & Reclaim Kernel crashkernel RAM#

Step 2: Decommission Heavy & Redundant Background Daemons#

Step 3: Setup 2.0 GB Swapfile with Low Swappiness#

☸️ 4. Joining K3s Kubernetes Over a WireGuard Mesh#

Verification on arm10 Master#

⚡ 5. The 5-Node Benchmark Showdown#

A. CPU Compute (Prime Calculation — Lower is Faster)#

B. Direct Disk I/O (Bypassing RAM Cache — Higher is Better)#

🎯 6. Fleet Specialization Matrix#