Cyclos on GKE Autopilot

Cyclos is a feature-rich banking and payment platform used by microfinance institutions, credit unions, and complementary currency networks. This module deploys Cyclos on GKE Autopilot on top of the App_GKE foundation, which provisions and manages the shared Google Cloud and Kubernetes infrastructure.

This guide focuses on the cloud services Cyclos uses and how to explore and operate them from the Google Cloud Console and the command line. For the mechanics common to every GKE application — Workload Identity, ingress, autoscaling, CI/CD, Cloud Armor, IAP, Binary Authorization, VPC Service Controls, backups, and the deployment lifecycle — refer to the App_GKE foundation guide rather than repeating them here.

---

1. Overview

Cyclos runs as a Java/Tomcat web workload. The deployment wires together a focused set of Google Cloud services:

Capability	Google Cloud service	Notes
Compute	GKE Autopilot	Java/Tomcat pods, 2 vCPU / 4 GiB recommended, horizontally autoscaled
Database	Cloud SQL for PostgreSQL 15	Required — Cyclos does not support MySQL or SQL Server
Object storage	Cloud Storage	A dedicated file-storage bucket (<prefix>-cyclos-storage) for uploaded files and media
Secrets	Secret Manager	Auto-generated database password; ROOT_PASSWORD for superuser extension setup
Ingress	Cloud Load Balancing	External LoadBalancer, optional custom domain + managed certificate

Sensible defaults worth knowing up front:

• PostgreSQL 15 is mandatory. Cyclos requires six specific PostgreSQL extensions (pg_trgm, uuid-ossp, cube, earthdistance, postgis, unaccent). MySQL and SQL Server are not supported.
• PostgreSQL extensions are installed automatically by the db-init job before Cyclos starts — you do not need to enable them manually.
• GCS file storage is mandatory. Cyclos uses Google Cloud Storage as its file content manager (cyclos.storedFileContentManager = gcs). NFS is disabled for the Cyclos container; the GCS bucket name is injected automatically.
• max_instance_count defaults to 1. Cyclos Community Edition requires Hazelcast configuration to scale horizontally. Increase only after configuring clustering.
• Schema management on startup. Cyclos creates and migrates its own PostgreSQL schema on first boot (cyclos.db.managed = true). First-deploy startup takes 2–5 minutes while extensions are created and the schema is initialised.
• Health probes target /api. The /api endpoint returns HTTP 200 only once Cyclos is fully initialised, making it the most reliable probe path.

---

2. Google Cloud Services & How to Explore Them

All commands assume you have run gcloud container clusters get-credentials <cluster> --region <region> --project <project> and that PROJECT, REGION, and NAMESPACE are set. The namespace and other identifiers are reported in the deployment Outputs.

A. GKE Autopilot — the Cyclos workload

Cyclos pods are scheduled on Autopilot, which bills for the CPU/memory the pods actually request. Horizontal Pod Autoscaling sizes the deployment between the minimum and maximum replica counts.

• Console: Kubernetes Engine → Workloads → select the Cyclos workload to see pods, revisions, and events. Kubernetes Engine → Services & Ingress shows the external IP.
• CLI:

  kubectl get pods,svc,hpa -n "$NAMESPACE"
  kubectl logs -n "$NAMESPACE" deploy/<service-name> --tail=100
  kubectl describe hpa -n "$NAMESPACE"          # current vs target utilisation

See App_GKE for how Autopilot, scaling, and the workload type (Deployment vs StatefulSet) are managed.

B. Cloud SQL for PostgreSQL 15

Cyclos stores all application data (accounts, transactions, members) in a managed Cloud SQL for PostgreSQL 15 instance. On first deploy, an initialization Job connects as the postgres superuser, creates the application database and user, and installs all six required PostgreSQL extensions. Subsequent starts use the application user.

• Console: SQL → select the instance for connections, backups, flags, and metrics.
• CLI:

  gcloud sql instances list --project "$PROJECT"
  gcloud sql instances describe <instance-name> --project "$PROJECT"
  # Open an interactive shell to inspect schema/data:
  gcloud sql connect <instance-name> --user=cyclos --database=cyclos --project "$PROJECT"
  # Inside psql — confirm required extensions are installed:
  # \dx

The instance name, database name, user, and the Secret Manager secret holding the password are all surfaced in the Outputs. For the connection model, automated backups, and password rotation, see App_GKE.

C. Cloud Storage — file content manager

Cyclos stores all uploaded files, profile photos, and transaction attachments in a dedicated Cloud Storage bucket provisioned as part of the deployment. The bucket name is derived from the deployment resource prefix and injected automatically as cyclos.storedFileContentManager.bucketName. The workload service account is granted access automatically.

• Console: Cloud Storage → Buckets → look for <prefix>-cyclos-storage.
• CLI:

  gcloud storage buckets list --project "$PROJECT" --filter="name:cyclos-storage"
  gcloud storage ls gs://<cyclos-storage-bucket>/
  # Confirm the bucket env var is injected into the pod:
  kubectl exec -n "$NAMESPACE" deploy/<service-name> -- \
    sh -c 'echo $cyclos__storedFileContentManager__bucketName'

See App_GKE for GCS Fuse mount options and CMEK.

D. Secret Manager

The Cyclos database password and the PostgreSQL superuser (ROOT_PASSWORD) are stored as Secret Manager secrets and injected into pods at runtime; plaintext never appears in configuration. The db-init job uses ROOT_PASSWORD to install extensions; Cyclos uses DB_PASSWORD to connect at runtime.

• Console: Security → Secret Manager.
• CLI:

  gcloud secrets list --project "$PROJECT"
  gcloud secrets versions access latest --secret=<secret-name> --project "$PROJECT"

The database password secret name is in the Outputs. See App_GKE for the Secret Store CSI integration and rotation.

E. Networking & ingress

By default the workload is exposed through an external Cloud Load Balancing IP. A custom domain with a Google-managed certificate can be enabled, and a static IP can be reserved so the address survives redeploys.

• Console: Network services → Load balancing; VPC network → IP addresses.
• CLI:

  kubectl get ingress,svc -n "$NAMESPACE"
  gcloud compute addresses list --project "$PROJECT"

See App_GKE for custom domains, Cloud CDN, and static IP details.

F. Cloud Logging & Monitoring

Pod stdout/stderr flow to Cloud Logging; GKE and Cloud SQL metrics flow to Cloud Monitoring. Optional uptime checks and alert policies are available.

• Console: Logging → Logs Explorer; Monitoring → Dashboards / Alerting.
• CLI:

  gcloud logging read \
    'resource.type="k8s_container" AND resource.labels.namespace_name="'"$NAMESPACE"'"' \
    --project "$PROJECT" --limit 50

---

3. Cyclos Application Behaviour

• First-deploy database setup. The db-init job runs as the PostgreSQL superuser and idempotently: creates the cyclos database user, creates the application database, installs all six required extensions (pg_trgm, uuid-ossp, cube, earthdistance, postgis, unaccent), and grants the necessary privileges. It is safe to re-run.

• Schema management on startup. Cyclos creates and evolves its own PostgreSQL schema on startup (cyclos.db.managed = true). First-deploy startup takes 2–5 minutes while the schema is built. Subsequent starts are faster but still validate the schema.

• JVM heap sizing. Set the CYCLOS_OPTIONS environment variable to cap JVM heap usage — for example { CYCLOS_OPTIONS = "-Xmx3g" } for a 4 GiB memory limit. Without this, the JVM can consume all available container memory and be OOMKilled.

  # Confirm CYCLOS_OPTIONS is set on the running pod:
  kubectl exec -n "$NAMESPACE" deploy/<service-name> -- env | grep CYCLOS_OPTIONS

• Health probe path. The startup and liveness probes both target /api, which returns HTTP 200 only once Cyclos is fully initialised and the schema is applied. Using a different path (such as /) results in a 302 redirect and the probe never passes.

• Single-instance default. Cyclos Community Edition defaults to one replica (max_instance_count = 1). Increasing the count without Hazelcast clustering configuration causes non-atomic transaction processing and potential data corruption.

• Hazelcast clustering (optional). For multi-replica deployments, set workload_type = "StatefulSet" and configure Hazelcast discovery via environment_variables. The bundled hazelcast.xml uses Kubernetes DNS discovery via the CLUSTER_K8S_DNS environment variable.

• Email delivery. Cyclos sends transactional email (notifications, password resets) via SMTP. Configure SMTP settings through environment_variables:

  environment_variables = {
    SMTP_HOST  = "smtp.sendgrid.net"
    SMTP_PORT  = "587"
    SMTP_USER  = "apikey"
    SMTP_SSL   = "true"
    EMAIL_FROM = "noreply@yourbank.example.com"
  }

  Use secret_environment_variables for SMTP_PASSWORD.

---

4. Configuration Variables

Variables are grouped exactly as they appear on the deployment platform. Only settings specific to or notable for Cyclos are listed; every other input is inherited from App_GKE with its standard behaviour and defaults.

Group 1 — Project & Identity

Variable	Default	Description
project_id	(required)	Target Google Cloud project.
region	us-central1	Region for the workload and regional resources.

Group 2 — Deployment Environment

Variable	Default	Description
tenant_deployment_id	demo	Short suffix that makes resource names unique per environment.
support_users	[]	Emails granted project access and monitoring alerts.
resource_labels	{}	Labels applied to all resources for cost/ownership tracking.

Group 3 — Application Identity

Variable	Default	Description
application_name	cyclos	Base name for resources. Do not change after first deploy.
application_display_name	Cyclos Community Edition	Friendly name shown in GKE workload annotations and the platform UI.
application_description	Cyclos Community Edition on GKE Autopilot	Workload description annotation.
application_version	4.16.17	Cyclos image version tag. Increment to trigger a new image pull and rollout.
display_name	Cyclos Community Edition	Name passed to Cyclos_Common for the application config object.
description	Cyclos Banking System on GKE	Description passed to Cyclos_Common.

Group 4 — Runtime & Scaling

Variable	Default	Description
deploy_application	true	Set false to provision infrastructure only.
container_resources	{ cpu_limit = "1000m", memory_limit = "2Gi" }	Full resource spec. Override to at least "2000m" CPU and "2Gi" memory. "4Gi" recommended for production.
cpu_limit	2000m	Convenience variable passed to Cyclos_Common. Overridden by container_resources in practice.
memory_limit	4Gi	Convenience variable passed to Cyclos_Common. Overridden by container_resources in practice.
min_instance_count	1	Minimum replicas. Keep ≥ 1 to avoid slow JVM cold starts.
max_instance_count	1	Maximum replicas. Keep 1 unless Hazelcast clustering is configured.
container_port	8080	Cyclos/Tomcat listens on port 8080.
enable_cloudsql_volume	false	Cloud SQL Auth Proxy sidecar. Cyclos defaults to direct TCP — enable only if verified needed.
enable_vertical_pod_autoscaling	false	Let Autopilot tune resource requests automatically.

Group 5 — Environment Variables & Secrets

Variable	Default	Description
environment_variables	{}	Extra non-secret settings. SMTP and CYCLOS_OPTIONS are configured here. Core Cyclos vars are injected automatically.
secret_environment_variables	{}	Map of env var → Secret Manager secret name.

Group 6 — GKE Backend & Cluster

Variable	Default	Description
service_type	LoadBalancer	How the Service is exposed.
session_affinity	ClientIP	Sticky routing for consistent session handling.
workload_type	null	Auto-selects Deployment. Set StatefulSet only with Hazelcast clustering.
network_tags	["nfsserver"]	Node/pod tags; retained for firewall rule compatibility.

Group 7 — StatefulSet

Variable	Default	Description
stateful_pvc_enabled	null	Enable per-pod PVCs. For Cyclos, only relevant with local file store (default is GCS).
stateful_pvc_size	10Gi	Storage per PVC.
stateful_pvc_mount_path	/data	Container path for the PVC.
stateful_pvc_storage_class	standard-rwo	Kubernetes StorageClass.
stateful_headless_service	null	Create a headless Service for stable DNS — required for Hazelcast.
stateful_pod_management_policy	null	OrderedReady or Parallel.
stateful_update_strategy	null	RollingUpdate or OnDelete.
stateful_fs_group	0	fsGroup GID for volume ownership.

Group 8 — Resource Quota

Variable	Default	Description
enable_resource_quota	false	Cap namespace CPU/memory/object counts.
quota_memory_requests / quota_memory_limits	""	Must use binary units (4Gi, 8192Mi) — bare integers are read as bytes and block scheduling.

Group 9 — Reliability Policies

Variable	Default	Description
enable_pod_disruption_budget	false	Protect availability during node upgrades. Enable only when min_instance_count > 1.
pdb_min_available	1	Minimum pods available during disruptions.
enable_topology_spread	false	Spread pods across zones.

Group 10 — Observability & Health

Variable	Default	Description
startup_probe	HTTP /api, 90s delay, 60s period, 5 failures	Cyclos-specific startup probe. Increase failure_threshold to 10 for first-deploy schema creation.
liveness_probe	HTTP /api, 120s delay, 60s period, 3 failures	Cyclos-specific liveness probe.
uptime_check_config	{ enabled = false, path = "/" }	Cloud Monitoring uptime check.
alert_policies	[]	Optional metric alert policies.

Group 11 — Jobs & Scheduled Tasks

Variable	Default	Description
initialization_jobs	[]	Leave empty to use the built-in db-init job (creates extensions, user, and database).
cron_jobs	[]	Scheduled Kubernetes CronJobs.
additional_services	[]	Sidecar or helper services deployed alongside Cyclos.

Group 12 — CI/CD & GitHub Integration

Standard App_GKE Cloud Build / Cloud Deploy integration — see App_GKE. Key inputs: enable_cicd_trigger, github_repository_url, github_token, enable_cloud_deploy.

Group 13 — NFS

Variable	Default	Description
enable_nfs	false	NFS is not used by the Cyclos container (GCS is the file store). Set true only if you need NFS provisioned for other jobs.

Group 14 — Cloud Storage & Artifact Registry

Variable	Default	Description
create_cloud_storage	true	Provision the additional data bucket.
storage_buckets	[{ name_suffix = "data" }]	Additional GCS buckets (the primary cyclos-storage bucket is provisioned automatically).
gcs_volumes	[]	GCS Fuse mounts.
manage_storage_kms_iam / enable_artifact_registry_cmek	false	CMEK options.

Group 16 — Database Backend

Variable	Default	Description
database_type	POSTGRES	Cloud SQL engine. Cyclos requires PostgreSQL. Do not change to MySQL or NONE.
db_name	cyclos	PostgreSQL database name forwarded to Cyclos_Common's own db-init job and injected into the app config. Immutable after first deploy.
db_user	cyclos	Application user forwarded to Cyclos_Common. Immutable after first deploy.
database_password_length	32	Generated password length (16–64).
enable_auto_password_rotation	false	Zero-downtime DB password rotation.

Note: application_database_name / application_database_user (defaults gkeappdb / gkeappuser) are a separate pair forwarded to the App_GKE foundation's own database provisioning. Cyclos's actual database/user (as connected to by the app) is driven by db_name / db_user above, provisioned by Cyclos_Common's db-init job — leave the application_database_* pair at its defaults.

Group 17 — Backup & Maintenance

Variable	Default	Description
backup_schedule	0 2 * * *	Automated backup cron (UTC).
backup_retention_days	7	Retention; raise to 30–90 for production/compliance.
enable_backup_import / backup_source / backup_file / backup_format	restore options	Restore from a backup on deploy. Set false after a successful import.

Group 18 — Custom SQL Scripts

enable_custom_sql_scripts, custom_sql_scripts_bucket, custom_sql_scripts_path, custom_sql_scripts_use_root — run SQL from a GCS bucket after provisioning. See App_GKE.

Group 19 — Custom Domain, Static IP & Networking

Variable	Default	Description
enable_custom_domain	true	Provision Ingress for custom hostnames + managed certificate.
application_domains	[]	Hostnames to serve.
reserve_static_ip	true	Stable external IP across redeploys.

Group 20 — Identity-Aware Proxy (IAP)

Variable	Default	Description
enable_iap	false	Require Google sign-in in front of Cyclos.
iap_authorized_users / iap_authorized_groups	[]	Who may access.
iap_oauth_client_id / iap_oauth_client_secret	""	Required when IAP is enabled (sensitive).
iap_support_email	""	Shown on the OAuth consent screen.

Group 21 — Cloud Armor

Variable	Default	Description
enable_cloud_armor	false	Attach a Cloud Armor (WAF) policy to the Ingress backend.
admin_ip_ranges	[]	CIDRs allowed privileged access.
cloud_armor_policy_name	default-waf-policy	Policy name.
enable_cdn	false	Enable Cloud CDN on the GKE Ingress backend.

Group 22 — VPC Service Controls & Audit Logging

Variable	Default	Description
enable_vpc_sc	false	Enforce a VPC-SC perimeter (requires organization_id).
vpc_cidr_ranges / vpc_sc_dry_run	(set)	Access level CIDRs / dry-run mode.
enable_audit_logging	false	Detailed Cloud Audit Logs.

---

5. Outputs

These values are returned on a successful deployment and are the quickest way to locate and explore the running resources.

Output	Description
service_name	Kubernetes Service name.
namespace	Namespace the workload runs in.
service_cluster_ip	In-cluster ClusterIP.
stage_service_cluster_ips	Map of ClusterIPs for stage-specific services.
service_external_ip	External LoadBalancer IP (when a static IP is reserved).
service_url	URL to reach Cyclos.
database_instance_name	Cloud SQL instance name.
database_name	Application database name.
database_user	Application database user.
database_password_secret	Secret Manager secret holding the DB password.
database_host / database_port	DB endpoint / port.
storage_buckets	Created Cloud Storage buckets.
network_name / network_exists / regions	VPC network, presence, available regions.
container_image / container_registry	Deployed image and Artifact Registry repo.
monitoring_enabled / monitoring_notification_channels	Monitoring status and channels.
initialization_jobs / db_import_job	Names of the setup and (optional) import jobs.
deployment_id / tenant_id / resource_prefix	Naming identifiers.
project_id / project_number	Project identifiers.
cicd_enabled / cicd_configuration	CI/CD status and details (repo, trigger, registry).
github_repository_url / github_repository_owner / github_repository_name	GitHub repo details.
artifact_registry_repository / cloudbuild_trigger_name / cloudbuild_trigger_id	Registry and build trigger.
kubernetes_ready	Whether the cluster/workload is ready.
vpc_sc_enabled / vpc_sc_perimeter_name / vpc_sc_dry_run_mode	VPC-SC status.
audit_logging_enabled / artifact_registry_cmek_enabled	Audit logging and CMEK status.

---

6. Configuration Pitfalls & Sensible Defaults

Risk: Critical (data loss / outage / security) — High (service degraded) — Medium (cost or partial degradation) — Low (minor).

Setting	Sensible value	Risk	Consequence if wrong
database_type	POSTGRES or POSTGRES_15	Critical	Cyclos requires PostgreSQL. MySQL or NONE breaks startup entirely.
db_name / db_user	set once (cyclos / cyclos)	Critical	Immutable after first deploy; renaming recreates the DB/user and orphans all financial data.
max_instance_count	1 (default)	Critical	More than 1 without Hazelcast clustering causes non-atomic transactions and potential data corruption.
application_name	cyclos (do not change)	Critical	Embedded in GKE namespace, Artifact Registry repo, Secret Manager secrets, and GCS bucket name. Changing orphans all resources.
cyclos.storedFileContentManager env var	gcs (hardcoded)	Critical	Overriding to local writes files to ephemeral pod storage; all uploads are lost on restart.
memory_limit (in container_resources)	≥ 2Gi (4Gi recommended)	Critical	JVM throws OutOfMemoryError; pod is OOMKilled (exit code 137).
CYCLOS_OPTIONS env var	-Xmx3g for 4 GiB limit	Critical	No -Xmx: JVM grows to consume all container memory; pod OOMKilled under load.
startup_probe.path	/api	Critical	Wrong path means the probe never sees HTTP 200; GKE kills the pod before it accepts traffic.
quota_memory_requests / _limits	binary units (4Gi, 8192Mi)	Critical	Bare integers are bytes and block all pod scheduling.
enable_backup_import	false after restore	High	Leaving true re-runs the restore on every apply, overwriting live financial data.
container_resources cpu	≥ 2000m	High	Java GC and Cyclos startup are CPU-bound; too little CPU causes startup probe failures.
startup_probe.failure_threshold	≥ 5 (increase to 10 for first deploy)	High	Too low: db-init extension creation takes 1–3 min; pod killed before schema is ready.
min_instance_count	1	High	0 causes 45–120 s JVM cold starts; banking transactions time out waiting for warmup.
enable_pod_disruption_budget	false unless min_instance_count > 1	High	PDB with 1/1 blocks node drains; Autopilot upgrades stall permanently.
enable_iap / enable_cloud_armor	enable for admin-facing	Medium	The Cyclos admin interface is otherwise publicly reachable.
backup_retention_days	7 (raise for prod)	Medium	Too short for compliance retention of financial records.

---

For the foundation behaviour referenced throughout — IAM and Workload Identity, autoscaling, ingress and certificates, CI/CD, Cloud Armor, IAP, Binary Authorization, VPC-SC, backups, and image mirroring — see App_GKE. Cyclos-specific application configuration shared with the Cloud Run variant is described in Cyclos_Common.