cozystack/docs/operations/backup-classes.md

Backup Classes

Cozystack ships a single platform-managed BackupClass named cozy-default. It is provisioned automatically when the backupstrategy-controller package is installed and references the system-managed S3 bucket cozy-backups in the tenant-root namespace.

Tenants reference cozy-default from BackupJob, Plan, and RestoreJob resources — they do not supply S3 credentials, endpoints, or paths. The platform projects the system-managed credentials Secret into the tenant namespace per BackupJob (or, for long-lived references like Velero's BackupStorageLocation, into a fixed list of system namespaces on a periodic tick), and the default strategy templates encode <namespace>/<application> into every S3 path so two tenants with the same application name never collide.

Supported applications

Bound by cozy-default (work out-of-the-box)

Application Kind	Driver	Strategy CR
apps.cozystack.io/Postgres	CloudNativePG (barman)	strategy.backups.cozystack.io/CNPG cozy-default-cnpg
apps.cozystack.io/MariaDB	mariadb-operator dump	strategy.backups.cozystack.io/MariaDB cozy-default-mariadb
apps.cozystack.io/ClickHouse	Altinity clickhouse-backup sidecar	strategy.backups.cozystack.io/Altinity cozy-default-altinity
apps.cozystack.io/Etcd	etcd-operator snapshot	strategy.backups.cozystack.io/Etcd cozy-default-etcd
apps.cozystack.io/VMInstance	Velero + kubevirt-velero-plugin	strategy.backups.cozystack.io/Velero cozy-default-velero-vminstance
apps.cozystack.io/VMDisk	Velero	strategy.backups.cozystack.io/Velero cozy-default-velero-vmdisk

Shipped but NOT bound (admin opt-in required)

Application Kind	Driver	Strategy CR
apps.cozystack.io/FoundationDB	FoundationDB operator backup_agent	strategy.backups.cozystack.io/FoundationDB cozy-default-foundationdb

The FoundationDB strategy CR is rendered by the chart so admins can reference it from a custom BackupClass once the operator-side plumbing (mounting cozy-backups-creds into the cozy-foundationdb-operator Deployment) is wired manually. See "FoundationDB caveat" below.

Endpoint format per driver

Different operators expect different endpoint shapes; the strategy templates rendered by backupstrategy-controller resolve one S3 endpoint (via the backupstrategy-controller.endpoint helper) and adapt it to each consumer's contract. For a provisioned bucket (provisionBucket: true, the default) the endpoint is derived from the COSI bucket's system-credentials Secret (backupStorage.systemSecretName) and forced to https:// — the external S3 ingress with an ACME cert, the only endpoint the backup operators can verify. SeaweedFS's in-cluster S3 serves TLS on :8333 behind the self-signed "SeaweedFS CA", and the Etcd Strategy S3 schema has no caCert field, so the in-cluster endpoint cannot be targeted directly. The backupStorage.endpoint chart value (a full URL like http://seaweedfs-s3.tenant-root.svc:8333) is the fallback, used for external S3 (provisionBucket: false) and for offline helm template/pre-reconcile renders where the Secret lookup returns nothing. The resolved endpoint is adapted per consumer:

Driver	Strategy template field	Form
CNPG (Postgres)	barmanObjectStore.endpointURL	full URL (scheme preserved)
Etcd	destination.s3.endpoint	full URL (scheme preserved)
MariaDB	storage.s3.endpoint	bare host:port (scheme stripped); tls.enabled derived from the scheme
FoundationDB	blobStoreConfiguration.accountName + urlParameters.secure_connection	bare host:port + derived secure flag
Velero	BackupStorageLocation.spec.config.s3Url	full URL (scheme preserved)
ClickHouse sidecar	S3_ENDPOINT env	bare host:port (from projected Secret)

The projected cozy-backups-creds.endpoint key is stripped of scheme so chart-emitted sidecars (ClickHouse) consume it directly. Drivers that need the full URL receive the resolved endpoint described above — derived from the COSI system Secret (forced https://) for a provisioned bucket, or the backupStorage.endpoint fallback for external S3.

VM-driven (Velero) backups land in the same cozy-backups bucket under the velero/ prefix. A BackupStorageLocation named cozy-default is shipped by the backupstrategy-controller chart (packages/system/backupstrategy-controller/templates/velero-bsl.yaml) so endpoint/bucket/region come from the same backupStorage values block used by Strategy CRs and the projector.

FoundationDB caveat

The strategy CR cozy-default-foundationdb is shipped, but it is not bound by cozy-default yet. Restore runs fdbrestore from inside the cozy-foundationdb-operator Deployment, which does not yet mount cozy-backups-creds. Until the operator deployment is updated to mount the projected Secret, FDB platform-default restore silently fails — admins who need it today should keep using a per-app Bucket plus a custom BackupClass, or wire the credentials file into the operator deployment themselves.

Cleanup gotcha (zombie backup_agent). Unlike CNPG/MariaDB/Altinity (one-shot operator-side Backup CRs), the FoundationDB driver creates a foundationdb.org/FoundationDBBackup CR that drives a long-lived backup_agent Deployment streaming continuously to S3. Deleting a Cozystack Backup (e.g. via retention sweeping) does NOT stop that Deployment — the agent keeps writing until the next BackupJob's stopOtherFoundationDBBackups call swaps it out, until an admin invokes examples/backups/foundationdb/cleanup.sh, or until the operator-side CR is deleted by hand. If a tenant deletes their last Cozystack Backup and never submits another BackupJob, the agent pods will continue running indefinitely and accumulate S3 PUTs. This is intentional today (the driver has no RBAC verb to stop the operator-side CR on Cozystack-Backup deletion) but admins should be aware of it.

ClickHouse: opt-in to the system bucket

The clickhouse-backup sidecar runs inside the ClickHouse Pod itself, so the Helm chart is what wires its S3 credentials. Existing tenants on the legacy backup.s3* values continue to work unchanged. To switch a release onto the platform bucket, set:

backup:
  enabled: true
  useSystemBucket: true

When useSystemBucket: true:

• The chart-emitted <release>-backup-s3 Secret is no longer rendered.
• The sidecar consumes cozy-backups-creds (projected by the platform).
• S3_PATH is set to <namespace>/<release> so two tenants with the same ClickHouse release name never share a prefix.

s3Region, s3Bucket, endpoint, s3AccessKey, s3SecretKey, and s3CredentialsSecret are ignored in this mode.

Inspecting the defaults

kubectl get backupclasses
kubectl get backupclass cozy-default -o yaml
kubectl -n tenant-root get bucket cozy-backups
kubectl -n tenant-root get secret bucket-cozy-backups-system-credentials
kubectl -n cozy-velero get backupstoragelocation cozy-default

The bucket lives in tenant-root and is provisioned through the apps.cozystack.io/Bucket CR. The system-managed credentials Secret never leaves that namespace. The backupstrategy-controller projects a copy under the name cozy-backups-creds into a tenant namespace right before each BackupJob runs, and refreshes the same Secret in cozy-velero (and any other namespace listed in backupStorage.systemNamespaces) on a 1-minute tick. The projected Secret carries multiple key formats so each driver finds what it needs in one place:

Key	Consumer
AWS_ACCESS_KEY_ID / AWS_SECRET_ACCESS_KEY	CNPG, MariaDB, Etcd
accessKey / secretKey (plus bucketName, endpoint, region)	ClickHouse sidecar
cloud	Velero (AWS credentials file format)
blob_credentials.json	FoundationDB backup_agent

Bootstrap window

On a fresh-cluster install, the Velero BackupStorageLocation cozy-default is rendered before the credentials projector has had a chance to copy cozy-backups-creds into cozy-velero. The BSL reports Unavailable until the projector's first synchronous round completes (which happens immediately when the backupstrategy-controller Pod becomes Ready — typically tens of seconds after helm install returns, not minutes). Velero rejects new Backup AND Restore requests against storageLocation: cozy-default during that window. Plan VM backup automation accordingly, or wait for kubectl -n cozy-velero get bsl cozy-default -o jsonpath='{.status.phase}' = Available before submitting backups.

Note on controller restarts. The BSL flickers Unavailable on every backupstrategy-controller pod restart while the projector replays its first synchronous round. The window is short (single-digit seconds) but operators who alert on BSL availability should suppress alerts during the controller's kube_pod_container_status_restarts_total{container=backupstrategy-controller} events or use a longer evaluation window than the projector tick (60s).

Cozy-default Bucket bootstrap

cozy-default ships an apps.cozystack.io/Bucket cozy-backups CR in tenant-root, which the bucket-application chart turns into a BucketClaim; the COSI driver then assigns the real S3 bucket name and writes it to the BucketClaim's .status.bucketName. The strategy templates and the Velero BSL all read that real bucket name (Helm lookup against the BucketClaim). On a fresh install the BucketClaim takes a short reconcile cycle to populate its status — until it does, the strategy templates render empty and only the Bucket CR + BackupClass are present in the cluster. Flux re-renders the HelmRelease on its standard interval (default 10 minutes), at which point the populated BucketClaim status causes the missing strategy templates to materialise.

If you need the BackupClass functional immediately (e.g. an e2e), trigger a Flux reconcile (flux reconcile helmrelease backupstrategy-controller) once you see kubectl get bucketclaim -n tenant-root bucket-cozy-backups -o jsonpath='{.status.bucketName}' non-empty.

Observability

The credentials projector emits two Prometheus counters labelled by namespace (and reason for failures):

• cozystack_backup_credentials_projection_successes_total
• cozystack_backup_credentials_projection_failures_total

Alert on rate(failures_total) > 0 or absent_over_time(successes_total[10m]) to catch a stale BSL credential or a malformed source Secret without log scraping.

Admin overrides for cozy-default

cozy-default is rendered by the backupstrategy-controller chart and owned by Flux's helm-controller. Direct kubectl edit backupclass cozy-default is overwritten on the next helm reconcile — the same applies to its companion strategy.backups.cozystack.io/* CRs (cozy-default-cnpg, cozy-default-etcd, cozy-default-mariadb, cozy-default-altinity, cozy-default-foundationdb, the two cozy-default-velero-*). The supported override path is the cozystack Package CR, which lets admins inject Helm values into platform components:

apiVersion: cozystack.io/v1alpha1
kind: Package
metadata:
  name: cozystack.cozystack-platform
spec:
  components:
    backupstrategy-controller:
      values:
        backupStorage:
          provisionBucket: true                    # default; set false for external S3
          bucketName: cozy-backups                  # apps.cozystack.io/Bucket release name
          endpoint: http://seaweedfs-s3.tenant-root.svc.cozy.local:8333
          region: us-east-1
          forcePathStyle: true
          systemSecretName: bucket-cozy-backups-system-credentials
          systemNamespaces:
            - cozy-velero

Knob	Effect
provisionBucket	Toggle creation of the in-cluster apps.cozystack.io/Bucket CR. Set false for external S3 (see Disabling the platform-managed bucket).
bucketName	K8s name of the Bucket CR + lookup key for the COSI BucketClaim. The actual S3 bucket name is the COSI-assigned UUID, surfaced through BucketClaim.status.bucketName.
bucketNameOverride	Escape hatch for offline helm template renders — bypasses the live-cluster BucketClaim lookup. Leave empty in production.
endpoint	Fallback S3 endpoint. For a provisioned bucket the strategy CRs + Velero BSL derive the endpoint from the COSI system Secret (external ACME ingress, forced https://) instead; this value is used only for external S3 (provisionBucket: false) and offline renders. For external S3, switching it to https:// enables TLS in the MariaDB/FoundationDB strategies — ensure the CA bundle is reachable to the relevant operator/driver Pods first.
region	Re-projected into cozy-backups-creds on the next reconcile. Pod-restart required for chart-emitted clients consuming the region via env (ClickHouse sidecar today).
forcePathStyle	Path-style addressing; SeaweedFS S3 requires it, AWS S3 typically doesn't.
systemSecretName	Name of the human-friendly Secret produced by the Bucket app (or pre-created manually for external S3). The projector also accepts the raw COSI Secret format.
systemNamespaces	Namespaces where the controller eagerly projects cozy-backups-creds (Velero BSL, FDB operator). Tenants are projected lazily during BackupJob reconcile.

When the override needs to go beyond storage coordinates — different retention, different driver→Kind binding, multi-region split — create a sibling BackupClass with a unique name (anything but cozy-default). Sibling BackupClasses live outside the chart, are admin-owned, and Flux will not touch them. Tenants opt in by setting backupClassName: <your-class> on their BackupJobs.

Tuning via a custom BackupClass

The defaults aim at a reasonable middle (30-day retention, gzip compression where applicable). To override for a specific tenant or workload, create your own BackupClass pointing at the same strategy CRs but with tweaked parameters, or a fresh strategy CR. Common knobs:

• CNPG strategy: barmanObjectStore.retentionPolicy, data.compression, wal.compression.
• MariaDB strategy: compression, maxRetention, databases[].
• Altinity strategy: tune the clickhouse-backup sidecar via backup.* values on the ClickHouse release; the strategy Pod is a thin HTTP client.
• FoundationDB strategy: snapshotPeriodSeconds, agentCount, urlParameters[].
• Velero strategy (VMInstance / VMDisk): ttl, includedResources[], excludedResources[].
• Etcd strategy: today the strategy is path-only; combine with Plan.spec.retentionPolicy for trim cadence.

The system-managed credentials Secret is the only way for in-cluster strategies to reach cozy-backups. Do not embed access keys in BackupClass.parameters — the security model relies on Secret references, and parameters end up in Backup.status.underlyingResources, which tenants can read.

Disabling the platform-managed bucket

If a deployment runs against an external S3 (no SeaweedFS), set backupStorage.provisionBucket: false in the backupstrategy-controller values and create the source credentials Secret in tenant-root manually (flat-key format: accessKey / secretKey / endpoint / bucketName; or the raw COSI BucketInfo JSON). Update backupStorage.endpoint, backupStorage.region, and (for VM backups) the chart's Velero BSL settings to point at the external S3.

Upgrade notes from chart-managed backups

Postgres backups now use the CloudNativePG Barman Cloud plugin, not native spec.backup.barmanObjectStore.

Postgres backups were migrated off the deprecated native barmanObjectStore (removed in CNPG 1.29) onto the Barman Cloud plugin. The barman-cloud-* binaries the native path needs are absent from the standard image variant keycloak-db pins; apps/postgres pins bare (system-flavor) tags that still ship them — its breakage was the operator/CRD skew below, not missing binaries — but the system flavor is deprecated upstream, so both move to the plugin. The chart now renders spec.plugins on the cnpg.io/Cluster plus a barmancloud.cnpg.io/ObjectStore CR that carries the S3 configuration, and the CNPG backup driver SSA-applies an ObjectStore and patches spec.plugins (instead of spec.backup.barmanObjectStore) for the platform flow; Backup/ScheduledBackup use method: plugin. On helm upgrade a legacy chart-managed Cluster's spec.backup.barmanObjectStore is replaced by spec.plugins + an ObjectStore. This only works once the plugin-barman-cloud operator is installed and co-located with the CNPG operator in cozy-postgres-operator (shipped by the postgres-operator chart) and its cert-manager dependency is present — otherwise the Cluster references a plugin that is not registered and backups / WAL archiving stall.

Mixed-version window: BackupJobs fail until the app re-renders with the new chart. A BackupJob that fires while a Cluster still carries the pre-upgrade chart's native spec.backup.barmanObjectStore is rejected by the CNPG admission webhook (Cannot enable a WAL archiver plugin when barmanObjectStore is configured) — the driver cannot attach spec.plugins alongside the native config. This resolves itself once Flux re-renders the Postgres app with the new chart (which replaces barmanObjectStore with spec.plugins); re-run the BackupJob afterward. Upgrading only the operators/driver without the app charts leaves every backup.enabled: true Postgres in this state permanently.

Postgres backup.enabled: true with placeholder credentials no longer wires backups on upgrade.

The pre-PR defaults for backup.s3AccessKey / backup.s3SecretKey in packages/apps/postgres/values.yaml were the literal "<your-access-key>" / "<your-secret-key>" placeholders, so the Postgres chart still rendered a backup block on the cnpg.io/Cluster (with junk credentials, WAL archiving failing at runtime). After this PR those defaults are empty strings and the chart NO LONGER renders any backup wiring when the placeholders are unmodified. Tenants on the legacy chart-managed flow who relied on those placeholders see spec.plugins and the ObjectStore disappear from the live Cluster on helm upgrade. Action — pick one:

• Move to the platform flow (recommended). Set backup.useSystemBucket: true; the chart leaves spec.plugins unset and the CNPG backup driver SSA-applies the ObjectStore and patches spec.plugins onto the live Cluster at first BackupJob time. No tenant-side keys required.
• Stay on the legacy chart-managed flow. Supply real backup.s3AccessKey / backup.s3SecretKey (or a pre-existing backup.s3CredentialsSecret.name); the chart renders spec.plugins + the ObjectStore from those coordinates.

Two platform-level changes ride along with this migration (they are required for the plugin to run):

• CloudNativePG operator bumped to 1.28.1 (postgres-operator chart). A minor operator upgrade for the whole fleet; the CNPG CRDs move with it. This also fixes a latent bug where the operator image was newer than its bundled CRDs (status.instanceID.sessionID pruned), which made the operator believe the instance manager restarted and fail every backup cluster-wide with instance manager was restarted during backup. The vendored chart ships the CNPG CRDs as ordinary release manifests (gated by crds.create), so a normal helm upgrade updates them together with the operator — the helm.sh/resource-policy: keep annotation only prevents their deletion, not updates. The historical skew came from the image.tag pin outrunning the vendored chart's CRDs, which this PR removes; no out-of-band CRD apply is needed unless the HelmRelease itself is held back.
• LINSTOR scheduler admission webhook must not strip native-sidecar fields. Older linstor-scheduler extender builds (≤ v0.3.5's predecessors) decoded every pod through a stale vendored Kubernetes API and re-encoded it, stripping initContainers[].restartPolicy cluster-wide — which breaks the plugin's restartable barman sidecar ("startupProbe forbidden without restartPolicy=Always"). The platform already ships the fixed webhook (linstor-scheduler re-vendored to upstream chart 0.3.1 / extender v0.3.6, which stopped stripping unknown pod fields), so no action is needed on an up-to-date platform; just do not hold the linstor-scheduler package back on an older version when rolling out the plugin.

The same useSystemBucket opt-in applies to ClickHouse — see ClickHouse: opt-in to the system bucket. When useSystemBucket: true is set on ClickHouse, the legacy <release>-backup CronJob, credential Secret, and backup script are no longer rendered (they are mutually exclusive with the platform flow); migrate scheduled backups to a backups.cozystack.io/Plan against cozy-default.

Tenant workflow

Tenants only ever see the BackupClass name. Typical apply:

apiVersion: backups.cozystack.io/v1alpha1
kind: BackupJob
metadata:
  name: ad-hoc
  namespace: tenant-acme
spec:
  backupClassName: cozy-default
  applicationRef:
    apiGroup: apps.cozystack.io
    kind: Postgres
    name: orders-db