Deployment/Kubernetes/Requirements

guidedeploymentCARE 3.0+

This page lists what an operator needs in place before deploying Care. The reference deployment is a small, self-hosted Kubernetes cluster provisioned with kubeadm and managed as infrastructure-as-code with [https://opentofu.org/ OpenTofu]. Everything below is distilled from the deployment repository ([https://github.com/ohcnetwork/deployment-k8 ohcnetwork/deployment-k8]); none of it requires a managed cloud platform, though the same shapes apply if you adapt them to one.

Read the reference architecture first if you want the bigger picture of how these pieces fit together.

Infrastructure

The reference is a two-node cluster on a shared network — one primary node and one secondary (failover) node — with replicated storage between them so the secondary can take over if the primary fails.

Requirement	Reference value	Notes
Nodes	At least 2 Linux hosts	One primary, one secondary/failover. Generalize the hostnames; the repo expects primary_node_name and secondary_node_name as inputs.
Network	Shared L2/L3 network between nodes	Each node also needs a routable IP (primary_node_ip, secondary_node_ip).
Kubernetes	Provisioned with kubeadm	The reference pins a specific kubernetesVersion in kubeadm.yaml; match the deployer's expected version rather than assuming "latest".
Pod / service networking	Cilium CNI	Pod and service subnets are set in the cluster config.
Storage	Per-node volumes, replicated	The reference separates fast (SSD) and bulk (HDD) data paths, e.g. primary_ssd_data_path, primary_hdd_data_path, secondary_ssd_data_path. Replication across nodes is what gives the failover node a usable copy of the data.
Swap	Permitted (not disabled)	The reference kubelet config runs with swap enabled in a limited mode rather than forcing it off.

📝 Note

The architecture notes describe storage replication as still evolving (RAID-with-replicas per volume is the target). Treat cross-node data replication as something you must design and verify for your environment, not as a turnkey feature.

Workstation tooling

You drive the deployment from an operator workstation that can reach the cluster's Kubernetes API. Install the following before you begin:

• ☐ kubectl — to talk to the cluster.
• ☐ kubeadm — to bootstrap the control plane and join nodes.
• ☐ OpenTofu (tofu) — the infrastructure is defined as Tofu modules and applied per stack.
• ☐ Helm — several components are installed as Helm charts.
• ☐ Cilium CLI — to install and inspect the CNI.
• ☐ Python 3 — the deployer (deployer.py, driven via make) is a Python program.
• ☐ The deployer's Python dependency — install it into your environment:

pip install -r requirements.txt

This installs [https://typer.tiangolo.com/ Typer] (typer>=0.9.0), which the make targets use to wrap Tofu and kubectl runs. For example, the repo exposes targets such as make apply-tofu-<stack>, make apply-k8-<stack>, and make check-k8-cluster.

💡 Tip

Use a Python virtual environment for the deployer so its dependency does not collide with other tools on your workstation.

External dependencies

These services are not part of the cluster bootstrap but the deployment expects them to exist (or be provisioned alongside it).

Dependency	Purpose	Reference choice
Container registry	Hosts the images the cluster pulls, including the locally built Care frontend image	The reference self-hosts a registry using [https://zotregistry.dev/ zot]. Any OCI-compatible registry works.
S3-compatible object storage	Off-site target for backups (Postgres, OpenSearch, object-store syncs)	Any S3-compatible endpoint — for example [https://min.io/ MinIO] or DigitalOcean Spaces. Keep the endpoint and credentials as your own secrets.
DNS	Resolves the public and internal hostnames for each service (Care API, Care frontend, object store, Odoo, Metabase, monitoring)	The repo takes both public and local domain names per service as inputs.
TLS certificates	HTTPS termination at the ingress	[https://letsencrypt.org/ Let's Encrypt]; a pre-fetched wildcard certificate is the intended approach so the ingress can terminate TLS for every subdomain.

⚠️ Warning

Do not copy hardcoded node names, internal domains, object-storage endpoints, or any credentials out of the deployment repository. Those are one operator's environment. Substitute your own values — for example <primary-node>, your-domain.example, <s3-endpoint> — and keep secrets out of version control.

What gets deployed

The cluster runs Care plus its data stores and a few adjacent applications. Use this table to size your nodes and storage. "Persistent" means the component needs a persistent volume that survives pod restarts and is included in backups; "non-persistent" means it can be recreated from scratch with no data loss.

Component	Shape	Storage	Backups
Care backend	Multiple web workers + Celery workers + a Celery scheduler	None (stateless)	N/A
Care frontend	Served via nginx; image built locally and pushed to the registry	None (stateless)	N/A
PostgreSQL (Care)	Production mode, single primary	Persistent	Daily/configurable, to disk and optionally to S3-compatible storage
Redis	Cache/broker, non-persistent mode	None	None
OpenSearch	Single node, minimal configuration	Persistent	Daily/configurable, to external media
Object store	Self-hosted S3-compatible store for uploads, audit logs, and public data	Persistent	Incremental syncs to external storage
Odoo	Web workers + Celery workers (with autoscaling)	Via its database	See Odoo Postgres
PostgreSQL (Odoo)	Dedicated instance, same hardening as Care's Postgres	Persistent	Daily/configurable, to external media
Metabase	Analytics app (with autoscaling)	Via its database	See Metabase Postgres
PostgreSQL (Metabase)	Dedicated instance, same hardening as Care's Postgres	Persistent	Daily/configurable backups of its volume

Alongside the application components, the cluster also provides:

• ☐ Load balancing — in front of the cluster, with separate load balancing for the object store and for Metabase where that isolation helps.
• ☐ WAF / firewall routing — at the ingress, so traffic is filtered before it reaches application pods.
• ☐ Central logging — file-based logging to a persistent volume, with the ability to pipe logs to external destinations.

ℹ️ Info

The deployment also targets auto-restore: a fresh cluster should be rebuildable from the backups above. That capability depends on every persistent component having a working, tested backup. Confirm your backups restore before you rely on them — see day-2 operations.

Before you proceed

You are ready to start provisioning the cluster once you can check every box:

• ☐ Two (or more) Linux nodes are reachable on a shared network, with their IPs and data paths chosen.
• ☐ Your workstation has kubectl, kubeadm, tofu, helm, and the Cilium CLI installed.
• ☐ Python 3 is available and pip install -r requirements.txt has succeeded.
• ☐ A container registry is reachable (self-hosted or managed).
• ☐ An S3-compatible bucket and credentials exist for backups.
• ☐ DNS records and a TLS certificate (e.g. a Let's Encrypt wildcard) are ready for your domains.

Related

Open Healthcare Network's flagship product: an open-source, FHIR-native electronic medical record (EMR) and healthcare operating system.