Skip to content
Open
Show file tree
Hide file tree
Changes from all commits
Commits
File filter

Filter by extension

Filter by extension

Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
206 changes: 206 additions & 0 deletions etcd/README.md
Original file line number Diff line number Diff line change
@@ -0,0 +1,206 @@
# etcd.openshift.io API Group

This API group contains CRDs related to etcd cluster management in Two Node OpenShift with Fencing deployments.

## API Versions

### v1alpha1

Contains the `PacemakerCluster` custom resource for monitoring Pacemaker cluster health in Two Node OpenShift with Fencing deployments.

#### PacemakerCluster

- **Feature Gate**: `DualReplica`
- **Component**: `two-node-fencing`
- **Scope**: Cluster-scoped singleton resource (must be named "cluster")
- **Resource Path**: `pacemakerclusters.etcd.openshift.io`

The `PacemakerCluster` resource provides visibility into the health and status of a Pacemaker-managed cluster.
It is periodically updated by the cluster-etcd-operator's status collector.

### Status Subresource Design

This resource uses the standard Kubernetes status subresource pattern (`+kubebuilder:subresource:status`).
The status collector creates the resource without status, then immediately populates it via the `/status` endpoint.

**Why not atomic create-with-status?**

We initially explored removing the status subresource to allow creating the resource with status in a single
atomic operation. This would ensure the resource is never observed in an incomplete state. However:

1. The Kubernetes API server strips the `status` field from create requests when a status subresource is enabled
2. Without the subresource, we cannot use separate RBAC for spec vs status updates
3. The OpenShift API test framework assumes status subresource exists for status update tests

The status collector performs a two-step operation: create resource, then immediately update status.
The brief window where status is empty is acceptable since the healthcheck controller handles missing status gracefully.

### Pacemaker Resources

A **pacemaker resource** is a unit of work managed by pacemaker. In pacemaker terminology, resources are services
or applications that pacemaker monitors, starts, stops, and moves between nodes to maintain high availability.

For Two Node OpenShift with Fencing, we manage three resource types:
- **Kubelet**: The Kubernetes node agent and a prerequisite for etcd
- **Etcd**: The distributed key-value store
- **FencingAgent**: Used to isolate failed nodes during a quorum loss event (tracked separately)

### Status Structure

```yaml
status: # Optional on creation, populated via status subresource
conditions: # Required when status present (min 3 items)
- type: Healthy
- type: InService
- type: NodeCountAsExpected
lastUpdated: <timestamp> # Required when status present, cannot decrease
nodes: # Control-plane nodes (0-5, expects 2 for TNF)
- name: <hostname> # RFC 1123 subdomain name
addresses: # Required: List of node addresses (1-8 items)
- type: InternalIP # Currently only InternalIP is supported
address: <ip> # First address used for etcd peer URLs
conditions: # Required: Node-level conditions (min 9 items)
- type: Healthy
- type: Online
- type: InService
- type: Active
- type: Ready
- type: Clean
- type: Member
- type: FencingAvailable
- type: FencingHealthy
resources: # Required: Pacemaker resources on this node (min 2)
- name: Kubelet # Both Kubelet and Etcd must be present
conditions: # Required: Resource-level conditions (min 8 items)
- type: Healthy
- type: InService
- type: Managed
- type: Enabled
- type: Operational
- type: Active
- type: Started
- type: Schedulable
- name: Etcd
conditions: [...] # Same 8 conditions as Kubelet (abbreviated)
fencingAgents: # Required: Fencing agents for THIS node (1-8)
- name: <nodename>_<method> # e.g., "master-0_redfish"
method: <method> # Fencing method: redfish, ipmi, fence_aws, etc.
conditions: [...] # Same 8 conditions as resources (abbreviated)
Comment on lines +86 to +88
Copy link

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

⚠️ Potential issue | 🟡 Minor

Align fencing method example with current validation (redfish-only).

The README lists multiple methods, but the CRD validation currently enforces _redfish naming. Either update the example to “redfish only” or relax the validation if multiple methods are intended.

📝 Suggested doc tweak
-          method: <method>           # Fencing method: redfish, ipmi, fence_aws, etc.
+          method: redfish            # Currently only redfish is supported (aligns with CRD validation)
📝 Committable suggestion

‼️ IMPORTANT
Carefully review the code before committing. Ensure that it accurately replaces the highlighted code, contains no missing lines, and has no issues with indentation. Thoroughly test & benchmark the code to ensure it meets the requirements.

Suggested change
- name: <nodename>_<method> # e.g., "master-0_redfish"
method: <method> # Fencing method: redfish, ipmi, fence_aws, etc.
conditions: [...] # Same 8 conditions as resources (abbreviated)
- name: <nodename>_<method> # e.g., "master-0_redfish"
method: redfish # Currently only redfish is supported (aligns with CRD validation)
conditions: [...] # Same 8 conditions as resources (abbreviated)
🤖 Prompt for AI Agents
In `@etcd/README.md` around lines 86 - 88, Update the fencing example in the
README to match the current CRD validation by showing redfish-only naming and
method: change the example name pattern to use the `_redfish` suffix (e.g.,
"master-0_redfish") and set method to "redfish" (remove other method examples
like ipmi or fence_aws); reference the example keys `name` and `method` so
reviewers can find and align the README with the CRD's `_redfish` naming
constraint.

```

### Fencing Agents

Fencing agents are STONITH (Shoot The Other Node In The Head) devices used to isolate failed nodes.
Unlike regular pacemaker resources (Kubelet, Etcd), fencing agents are tracked separately because:

1. **Mapping by target, not schedule**: Resources are mapped to the node where they are scheduled to run.
Fencing agents are mapped to the node they can *fence* (their target), regardless of which node
their monitoring operations are scheduled on.

2. **Multiple agents per node**: A node can have multiple fencing agents for redundancy
(e.g., both Redfish and IPMI). Expected: 1 per node, supported: up to 8.

3. **Health tracking via two node-level conditions**:
- **FencingAvailable**: True if at least one agent is healthy (fencing works), False if all agents unhealthy (degrades operator)
- **FencingHealthy**: True if all agents are healthy (ideal state), False if any agent is unhealthy (emits warning events)

### Cluster-Level Conditions

| Condition | True | False |
|-----------|------|-------|
| `Healthy` | Cluster is healthy (`ClusterHealthy`) | Cluster has issues (`ClusterUnhealthy`) |
| `InService` | In service (`InService`) | In maintenance (`InMaintenance`) |
| `NodeCountAsExpected` | Node count is as expected (`AsExpected`) | Wrong count (`InsufficientNodes`, `ExcessiveNodes`) |

### Node-Level Conditions

| Condition | True | False |
|-----------|------|-------|
| `Healthy` | Node is healthy (`NodeHealthy`) | Node has issues (`NodeUnhealthy`) |
| `Online` | Node is online (`Online`) | Node is offline (`Offline`) |
| `InService` | In service (`InService`) | In maintenance (`InMaintenance`) |
| `Active` | Node is active (`Active`) | Node is in standby (`Standby`) |
| `Ready` | Node is ready (`Ready`) | Node is pending (`Pending`) |
| `Clean` | Node is clean (`Clean`) | Node is unclean (`Unclean`) |
| `Member` | Node is a member (`Member`) | Not a member (`NotMember`) |
| `FencingAvailable` | At least one agent healthy (`FencingAvailable`) | All agents unhealthy (`FencingUnavailable`) - degrades operator |
| `FencingHealthy` | All agents healthy (`FencingHealthy`) | Some agents unhealthy (`FencingUnhealthy`) - emits warnings |

### Resource-Level Conditions

Each resource in the `resources` array and each fencing agent in the `fencingAgents` array has its own conditions.

| Condition | True | False |
|-----------|------|-------|
| `Healthy` | Resource is healthy (`ResourceHealthy`) | Resource has issues (`ResourceUnhealthy`) |
| `InService` | In service (`InService`) | In maintenance (`InMaintenance`) |
| `Managed` | Managed by pacemaker (`Managed`) | Not managed (`Unmanaged`) |
| `Enabled` | Resource is enabled (`Enabled`) | Resource is disabled (`Disabled`) |
| `Operational` | Resource is operational (`Operational`) | Resource has failed (`Failed`) |
| `Active` | Resource is active (`Active`) | Resource is not active (`Inactive`) |
| `Started` | Resource is started (`Started`) | Resource is stopped (`Stopped`) |
| `Schedulable` | Resource is schedulable (`Schedulable`) | Resource is not schedulable (`Unschedulable`) |

### Validation Rules

**Resource naming:**
- Resource name must be "cluster" (singleton)

**Node name validation:**
- Must be a lowercase RFC 1123 subdomain name
- Consists of lowercase alphanumeric characters, '-' or '.'
- Must start and end with an alphanumeric character
- Maximum 253 characters

**Node addresses:**
- Uses `PacemakerNodeAddress` type (similar to `corev1.NodeAddress` but with IP validation)
- Currently only `InternalIP` type is supported
- Pacemaker allows multiple addresses for Corosync communication between nodes (1-8 addresses)
- The first address in the list is used for IP-based peer URLs for etcd membership
- IP validation:
- Must be a valid global unicast IPv4 or IPv6 address
- Must be in canonical form (e.g., `192.168.1.1` not `192.168.001.001`, or `2001:db8::1` not `2001:0db8::1`)
- Excludes loopback, link-local, and multicast addresses
- Maximum length is 39 characters (full IPv6 address)

**Timestamp validation:**
- `lastUpdated` is required when status is present
- Once set, cannot be set to an earlier timestamp (validation uses `!has(oldSelf.lastUpdated)` to handle initial creation)
- Timestamps must always increase (prevents stale updates from overwriting newer data)

**Status fields:**
- `status` - Optional on creation (pointer type), populated via status subresource
- When status is present, all fields within are required:
- `conditions` - Required array of cluster conditions (min 3 items)
- `lastUpdated` - Required timestamp for staleness detection
- `nodes` - Required array of control-plane node statuses (min 0, max 5; empty allowed for catastrophic failures)

**Node fields (when node present):**
- `name` - Required, RFC 1123 subdomain
- `addresses` - Required (min 1, max 8 items)
- `conditions` - Required (min 9 items with specific types enforced via XValidation)
- `resources` - Required (min 2 items: Kubelet and Etcd)
- `fencingAgents` - Required (min 1, max 8 items)

**Conditions validation:**
- Cluster-level: MinItems=3 (Healthy, InService, NodeCountAsExpected)
- Node-level: MinItems=9 (Healthy, Online, InService, Active, Ready, Clean, Member, FencingAvailable, FencingHealthy)
- Resource-level: MinItems=8 (Healthy, InService, Managed, Enabled, Operational, Active, Started, Schedulable)
- Fencing agent-level: MinItems=8 (same conditions as resources)

All condition arrays have XValidation rules to ensure specific condition types are present.

**Resource names:**
- Valid values are: `Kubelet`, `Etcd`
- Both resources must be present in each node's `resources` array

**Fencing agent fields:**
- `name`: The pacemaker resource name (e.g., "master-0_redfish"), max 253 characters
- `method`: The fencing method (e.g., "redfish", "ipmi", "fence_aws"), max 63 characters
- `conditions`: Required, same 8 conditions as resources

### Usage

The cluster-etcd-operator healthcheck controller watches this resource and updates operator conditions based on
the cluster state. The aggregate `Healthy` conditions at each level (cluster, node, resource) provide a quick
way to determine overall health.
26 changes: 26 additions & 0 deletions etcd/install.go
Original file line number Diff line number Diff line change
@@ -0,0 +1,26 @@
package etcd

import (
"k8s.io/apimachinery/pkg/runtime"
"k8s.io/apimachinery/pkg/runtime/schema"

v1alpha1 "github.com/openshift/api/etcd/v1alpha1"
)

const (
GroupName = "etcd.openshift.io"
)

var (
schemeBuilder = runtime.NewSchemeBuilder(v1alpha1.Install)
// Install is a function which adds every version of this group to a scheme
Install = schemeBuilder.AddToScheme
)

func Resource(resource string) schema.GroupResource {
return schema.GroupResource{Group: GroupName, Resource: resource}
}

func Kind(kind string) schema.GroupKind {
return schema.GroupKind{Group: GroupName, Kind: kind}
}
3 changes: 3 additions & 0 deletions etcd/v1alpha1/Makefile
Original file line number Diff line number Diff line change
@@ -0,0 +1,3 @@
.PHONY: test
test:
make -C ../../tests test GINKGO_EXTRA_ARGS=--focus="etcd.openshift.io/v1alpha1"
Comment on lines +1 to +3
Copy link

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

⚠️ Potential issue | 🟡 Minor

Add minimal all/clean targets to satisfy checkmake.

Static analysis flags missing required phony targets; this can break linting if enforced.

🧹 Suggested Makefile tweaks
-.PHONY: test
+.PHONY: all clean test
+all: test
+clean:
+	`@true`
 test:
 	make -C ../../tests test GINKGO_EXTRA_ARGS=--focus="etcd.openshift.io/v1alpha1"
📝 Committable suggestion

‼️ IMPORTANT
Carefully review the code before committing. Ensure that it accurately replaces the highlighted code, contains no missing lines, and has no issues with indentation. Thoroughly test & benchmark the code to ensure it meets the requirements.

Suggested change
.PHONY: test
test:
make -C ../../tests test GINKGO_EXTRA_ARGS=--focus="etcd.openshift.io/v1alpha1"
.PHONY: all clean test
all: test
clean:
`@true`
test:
make -C ../../tests test GINKGO_EXTRA_ARGS=--focus="etcd.openshift.io/v1alpha1"
🧰 Tools
🪛 checkmake (0.2.2)

[warning] 1-1: Missing required phony target "all"

(minphony)


[warning] 1-1: Missing required phony target "clean"

(minphony)

🤖 Prompt for AI Agents
In `@etcd/v1alpha1/Makefile` around lines 1 - 3, The Makefile only defines a test
target and is missing minimal all and clean targets required by checkmake;
update the Makefile to add an all target (e.g., make all depends on test) and a
clean target (no-op or removing generated artifacts), and include both "all" and
"clean" in the .PHONY declaration alongside "test" so .PHONY lists all three
targets and the new targets are implemented (referencing the Makefile's existing
"test" target when wiring "all").

6 changes: 6 additions & 0 deletions etcd/v1alpha1/doc.go
Original file line number Diff line number Diff line change
@@ -0,0 +1,6 @@
// +k8s:deepcopy-gen=package,register
// +k8s:defaulter-gen=TypeMeta
// +k8s:openapi-gen=true
// +openshift:featuregated-schema-gen=true
// +groupName=etcd.openshift.io
package v1alpha1
39 changes: 39 additions & 0 deletions etcd/v1alpha1/register.go
Original file line number Diff line number Diff line change
@@ -0,0 +1,39 @@
package v1alpha1

import (
metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
"k8s.io/apimachinery/pkg/runtime"
"k8s.io/apimachinery/pkg/runtime/schema"
)

var (
GroupName = "etcd.openshift.io"
GroupVersion = schema.GroupVersion{Group: GroupName, Version: "v1alpha1"}
schemeBuilder = runtime.NewSchemeBuilder(addKnownTypes)
// Install is a function which adds this version to a scheme
Install = schemeBuilder.AddToScheme

// SchemeGroupVersion generated code relies on this name
// Deprecated
SchemeGroupVersion = GroupVersion
// AddToScheme exists solely to keep the old generators creating valid code
// DEPRECATED
AddToScheme = schemeBuilder.AddToScheme
)

// Resource generated code relies on this being here, but it logically belongs to the group
// DEPRECATED
func Resource(resource string) schema.GroupResource {
return schema.GroupResource{Group: GroupName, Resource: resource}
}

func addKnownTypes(scheme *runtime.Scheme) error {
metav1.AddToGroupVersion(scheme, GroupVersion)

scheme.AddKnownTypes(GroupVersion,
&PacemakerCluster{},
&PacemakerClusterList{},
)

return nil
}
Loading