kubernetes

Temporal Workflow Resource Calculator

Calculate Kubernetes resource requirements for a self-hosted Temporal workflow engine. Size the History, Matching, Frontend, and Worker services plus the PostgreSQL persistence layer.

Self-Hosting Temporal on Kubernetes

Temporal is a durable execution engine for long-running workflows. Self-hosting on Kubernetes gives you full control but requires understanding how each service scales.

Service Roles

Service	Role	Scales With
Frontend	API gateway, gRPC for SDK	Request rate
History	Workflow state machine	Active workflow count
Matching	Task queue management	Activity worker count
Worker	Background maintenance	Workflow throughput

Active Workflow Count

The key sizing metric is steady-state active workflows — calculated by Little's Law:

active = (workflows_per_day / 1440) × avg_duration_minutes

Example: 10,000/day at 5 min average = 34 active at any time.

History Service Sharding

Temporal shards workflow state across 512 default shards (configurable). The History service instance count should be 2–8 for most workloads. Each shard holds a subset of workflow histories in memory.

PostgreSQL Schema

Temporal uses two PostgreSQL databases:

›temporal: workflow execution state, task queues, timers
›temporal_visibility: search attributes, workflow list queries

Recommended PostgreSQL setup: connection pooling via PgBouncer (transaction mode), and a read replica for visibility queries.

Helm Chart Deployment

bash

helm repo add temporal https://go.temporal.io/helm-charts
helm install temporal temporal/temporal \
  --set server.replicaCount=1 \
  --set cassandra.enabled=false \
  --set postgresql.enabled=true \
  --set elasticsearch.enabled=false

Key Terms

Full glossary →

Temporal

A durable workflow orchestration platform. Temporal persists workflow state in a database (PostgreSQL or Cassandra), enabling long-running, fault-tolerant business processes to survive process restarts.

etcd

A distributed key-value store used by Kubernetes to store all cluster state and configuration. etcd is the single source of truth for the entire cluster.

kubeadm

A tool for bootstrapping Kubernetes clusters. It automates the setup of control plane components and joining worker nodes, following Kubernetes best practices.

Frequently Asked Questions

What are the Temporal server components?

Temporal server has 4 services: Frontend (API gateway, handles SDK connections), History (workflow state machine, most memory-intensive), Matching (task queue management, connects workers to tasks), and Worker (internal background maintenance). Each can be scaled independently.

Why is the History service the most memory-intensive?

The History service stores the entire event history of every in-flight workflow in memory as a cache. Each workflow generates ~20–100 events (ActivityScheduled, ActivityCompleted, etc.). With 1,000 active workflows × 20 events × 1 KB each = 20 MB minimum — plus the History service shard cache, which can be 2–10× larger.

Should I use PostgreSQL or Cassandra for Temporal persistence?

PostgreSQL for most deployments under 100k workflows/day. It's easier to operate, backup, and restore. Cassandra is designed for Temporal's horizontally sharded architecture at massive scale (millions of executions). Unless you're at that scale, PostgreSQL is the right choice.

Can I run Temporal on a single node Kubernetes cluster?

Yes, for development. Use the temporalio/helm-charts with the 'server' chart and configure all 4 services to run as a single deployment with SQLite or a local PostgreSQL. For production, always separate services and use a managed PostgreSQL (or at minimum a PostgreSQL StatefulSet with persistent storage).

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