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Add health-based connection routing for Kubernetes#60083

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Oct 14, 2025
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Add health-based connection routing for Kubernetes#60083
rana merged 1 commit intomasterfrom
rana/kube-healthchecks-9

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@rana rana commented Oct 9, 2025

Kubernetes servers are grouped by health, and dialed in order of healthy, unknown, then unhealthy, with random shuffling within each group for load distribution.

The grouping and shuffling is implemented generically in a separate iterator function OrderByTargetHealthStatus for reuse and testability.

In this PR:

  • Added function OrderByTargetHealthStatus to the healthcheck package
  • Added units tests
  • Kubernetes forwarder calls OrderByTargetHealthStatus when dialing servers

Implementation details:

OrderByTargetHealthStatus was originally placed in the existing file api/types/target_health.go, but encountered a cyclic import for using lib/utils.ShuffleVisit. The cyclic import is resolved by moving it into the healthcheck package.

Relates to:

@rana rana force-pushed the rana/kube-healthchecks-9 branch 2 times, most recently from 631d1ee to 36aa44d Compare October 9, 2025 16:50
@rana rana added kubernetes-access no-changelog Indicates that a PR does not require a changelog entry health-check Resource health check related labels Oct 9, 2025
@rana rana force-pushed the rana/kube-healthchecks-9 branch from 36aa44d to 4f6b2b0 Compare October 9, 2025 17:55
@rana rana marked this pull request as ready for review October 9, 2025 18:24
@github-actions github-actions bot added database-access Database access related issues and PRs size/md labels Oct 9, 2025
@rana rana requested review from GavinFrazar and espadolini October 9, 2025 18:27
Comment thread api/types/target_health.go
Comment thread lib/healthcheck/order_by.go
@rana rana force-pushed the rana/kube-healthchecks-9 branch from 4f6b2b0 to 53ce9cb Compare October 9, 2025 21:18
Comment thread lib/healthcheck/order_by.go Outdated
Comment thread lib/healthcheck/order_by_test.go Outdated
Comment thread lib/healthcheck/order_by.go Outdated
Comment thread lib/kube/proxy/transport.go Outdated
Comment thread lib/kube/proxy/transport.go
@rana rana force-pushed the rana/kube-healthchecks-9 branch 3 times, most recently from 1b0ad96 to d09b2d3 Compare October 10, 2025 22:30
@rana rana requested a review from rosstimothy October 11, 2025 20:28
Comment thread lib/healthcheck/order_by_test.go Outdated
Comment thread lib/kube/proxy/transport_test.go Outdated
Comment thread lib/kube/proxy/transport_test.go Outdated
@rana rana force-pushed the rana/kube-healthchecks-9 branch from d09b2d3 to 7f7fe27 Compare October 14, 2025 17:46
Kubernetes servers are grouped by health, and dialed in order of healthy, unknown, then unhealthy, with random shuffling within each group for load distribution.

The grouping and shuffling is implemented generically in a separate iterator function `OrderByTargetHealthStatus()` for reuse and testability.

Changes:
- Added `healthcheck.OrderByTargetHealthStatus()` function with tests

Part of #58413

Co-authored-by: rosstimothy <39066650+rosstimothy@users.noreply.github.com>
@rana rana force-pushed the rana/kube-healthchecks-9 branch from 7f7fe27 to 91feaa5 Compare October 14, 2025 22:24
@rana rana added this pull request to the merge queue Oct 14, 2025
Merged via the queue into master with commit 9b1e4fa Oct 14, 2025
40 checks passed
@rana rana deleted the rana/kube-healthchecks-9 branch October 14, 2025 23:13
rana added a commit that referenced this pull request Oct 23, 2025
Kubernetes servers are grouped by health, and dialed in order of healthy, unknown, then unhealthy, with random shuffling within each group for load distribution.

The grouping and shuffling is implemented generically in a separate iterator function `OrderByTargetHealthStatus()` for reuse and testability.

Changes:
- Added `healthcheck.OrderByTargetHealthStatus()` function with tests

Part of #58413

Co-authored-by: rosstimothy <39066650+rosstimothy@users.noreply.github.com>
@rana rana mentioned this pull request Oct 23, 2025
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rana added a commit that referenced this pull request Oct 27, 2025
Kubernetes servers are grouped by health, and dialed in order of healthy, unknown, then unhealthy, with random shuffling within each group for load distribution.

The grouping and shuffling is implemented generically in a separate iterator function `OrderByTargetHealthStatus()` for reuse and testability.

Changes:
- Added `healthcheck.OrderByTargetHealthStatus()` function with tests

Part of #58413

Co-authored-by: rosstimothy <39066650+rosstimothy@users.noreply.github.com>
rana added a commit that referenced this pull request Oct 29, 2025
Kubernetes servers are grouped by health, and dialed in order of healthy, unknown, then unhealthy, with random shuffling within each group for load distribution.

The grouping and shuffling is implemented generically in a separate iterator function `OrderByTargetHealthStatus()` for reuse and testability.

Changes:
- Added `healthcheck.OrderByTargetHealthStatus()` function with tests

Part of #58413

Co-authored-by: rosstimothy <39066650+rosstimothy@users.noreply.github.com>
rana added a commit that referenced this pull request Oct 29, 2025
Kubernetes servers are grouped by health, and dialed in order of healthy, unknown, then unhealthy, with random shuffling within each group for load distribution.

The grouping and shuffling is implemented generically in a separate iterator function `OrderByTargetHealthStatus()` for reuse and testability.

Changes:
- Added `healthcheck.OrderByTargetHealthStatus()` function with tests

Part of #58413

Co-authored-by: rosstimothy <39066650+rosstimothy@users.noreply.github.com>
rana added a commit that referenced this pull request Oct 29, 2025
Kubernetes servers are grouped by health, and dialed in order of healthy, unknown, then unhealthy, with random shuffling within each group for load distribution.

The grouping and shuffling is implemented generically in a separate iterator function `OrderByTargetHealthStatus()` for reuse and testability.

Changes:
- Added `healthcheck.OrderByTargetHealthStatus()` function with tests

Part of #58413

Co-authored-by: rosstimothy <39066650+rosstimothy@users.noreply.github.com>
github-merge-queue bot pushed a commit that referenced this pull request Oct 29, 2025
* Add protobufs for Kubernetes health checks (#58415)

- Add Kubernetes label matchers to `Matcher` for `HealthCheckConfig`
- Add message `KubernetesServerStatusV3`
- Add `status` field to `KubernetesServerV3`
- Add `target_health` field to `Kube` for UI
- Regenerate Terraform schema and docs for `HealthCheckConfig`
- Add Kubernetes label matchers to Terraform test `TestImportHealthCheckConfig`

Relates to #58413

Co-authored-by: Edoardo Spadolini <edoardo.spadolini@goteleport.com>

* Refactor `healthcheck` for Kubernetes extensibility with `HealthChecker` interface (#59396)

The main intent of refactoring is to provide health check extensibility for Kubernetes while supporting the existing DB health checks. A `HealthChecker` interface is added to support the different health check approaches of DBs and Kubernetes. Existing DB TCP health check logic is moved to a new `TargetDialer` struct.

Changes:
- Added `HealthChecker` interface with two functions:
    - `CheckHealth(ctx context.Context) ([]string, error)`
    - `GetProtocol() types.TargetHealthProtocol`
- Added `TargetDialer` struct which encapsulates existing TCP health check logic
- Changed `Target` struct to use the `HealthChecker` interface
- Changed `worker.checkHealth` to call the new `CheckHealth` function
- Removed a `protocol` field from `healthCheckConfig`
- Added `TargetHealthProtocolHTTP` for use with Kubernetes health checks
- Moved and renamed test `Test_dialEndpoints` to `TestTargetDialer_dialEndpoints`
- Added files `net.go` and `net_test.go` for `TargetDialer`

Part of #58413

* Add health checks to Kubernetes agent and proxy (#59565)

Implements core health check logic for Kubernetes.

- Added functions `CheckHealth` and `GetProtocol` to `kubeDetails`
- Added a `HealthCheckManager` field to the Kubernetes `TLSServerConfig`
- Kube agent and proxy now instantiate a `HealthCheckManager`
- Added a `HealthCheckConfigReader` to interfaces `ReadKubernetesAccessPoint` and `ReadProxyAccessPoint`
- Added `HealthCheckConfig` read-only permissions for proxy and kube
- Added `HealthCheckConfig` watching for proxy and kube
- Added functions to `KubeServer` interface and `KubernetesServerV3` struct:
    - `GetTargetHealth() TargetHealth`
    - `SetTargetHealth(h TargetHealth)`
    - `GetTargetHealthStatus() TargetHealthStatus`
    - `SetTargetHealthStatus(status TargetHealthStatus)`

- Health check supports dynamic discovery of Kubernetes clusters. Calls to `startHealthCheck()` and `stopHealthCheck()` were rearranged.
    - Added functions `startHeartbeatAndHealthCheck()` and `stopHeartbeatAndHealthCheck()`
- Moved call to `HealthCheckManager.Start()` outside of the Kubernetes proxy server providing a future option to reuse `HealthCheckManager` in multiple proxy services
- Removed `Status` initialization in KubernetesServerV3 `CheckAndSetDefaults()`
- Added `kubernetesLabelMatchers` to `healthCheckConfig` struct. Default presets are omitted until the entire kube health check is complete.
- Added Kubernetes matcher checking to `ValidateHealthCheckConfig()`
- Changed `ValidateHealthCheckConfig()` to allow zero total DB matchers and Kubernetes matchers.
- Changed KubernetesServerV3 `GetTargetHealthStatus()` to return `TargetHealthStatusUnknown` instead of an empty string
- Changed health check worker `getTargetHealthTimeout` default timeout to `4s` from `10s`. This potentially reduces the response time of the initial heartbeat polling call to `GetServerInfo()`.

Part of #58413

Co-authored-by: rosstimothy <39066650+rosstimothy@users.noreply.github.com>
Co-authored-by: Edoardo Spadolini <edoardo.spadolini@goteleport.com>

* Add UI for Kubernetes health checks (#59929)

Adds health status indicators for Kubernetes clusters on the Resources
page. Unhealthy clusters are highlighted, and clicking them opens a side
panel displaying server information.

Changes include:
- New `KubeServer` protobuf message and `ListKubernetesServers` RPC
- Web and Connect API endpoints for fetching Kubernetes server data
- Health status filtering in `matchAndFilterKubeClusters`
- `TargetHealth` fields added to frontend/backend types
- Updated `StatusInfo.tsx` to display `kube_cluster` data

Part of #58413

Co-authored-by: rosstimothy <39066650+rosstimothy@users.noreply.github.com>

* Add health-based connection routing for Kubernetes (#60083)

Kubernetes servers are grouped by health, and dialed in order of healthy, unknown, then unhealthy, with random shuffling within each group for load distribution.

The grouping and shuffling is implemented generically in a separate iterator function `OrderByTargetHealthStatus()` for reuse and testability.

Changes:
- Added `healthcheck.OrderByTargetHealthStatus()` function with tests

Part of #58413

Co-authored-by: rosstimothy <39066650+rosstimothy@users.noreply.github.com>

* Allow disabling health check configs (#60447)

Health check configuration can be disabled and enabled through the matcher. Disabling the matcher disables health checks for this configuration's resources including databases, Kubernetes clusters, and any future resources.

Changes:
- Added `disabled` field to health check matcher proto
- Updated matcher selection logic
- Updated unit tests

Part of #58413

* Add documentation for Kubernetes health checks (#60201)

A new Kubernetes-specific health check page is added. The existing Kubernetes troubleshooting documentation page is updated with health check specific error resolutions.

Part of #58413

Co-authored-by: rosstimothy <39066650+rosstimothy@users.noreply.github.com>
Co-authored-by: Gavin Frazar <gavin.frazar@goteleport.com>
Co-authored-by: Paul Gottschling <paul.gottschling@goteleport.com>

* Enable health checks for Kubernetes with virtual defaults (#60544)

Health checks are enabled for all Kubernetes clusters by default.

A design of creating one health check config default per resource is implemented. The choice eases adoption of health checks, supports existing clusters that already have database health checks, and avoids migrating the backend database. A new Kubernetes-specific `default-kube` health check config is added. And a database-specific `default` health check config already exists, and is preserved.

A virtual default design is implemented by returning health check configs from memory if they don't exist in the backend database. The approach has the benefit of not re-inserting default values to the backend after they're deleted, which a prior approach had.

Virtual defaults are added at the local health check service level, and returned from functions `GetHealthCheckConfig` and `ListHealthCheckConfigs`. Virtual defaults may be written, updated, and deleted to and from the backend. While virtual defaults may be deleted, it has the net effect of resetting the config to default settings, and matching all resources of that type (db, kube). Virtual defaults are always returned from health check `get` and `list` functions.

Changes:
- Added `default-kube` health check config specific to Kubernetes only
- Updated local service functions `GetHealthCheckConfig` and `ListHealthCheckConfigs` to return virtual defaults
- Added unit tests
- Updated health check documentation with `default-kube` and info about virtual defaults

Part of #58413

Co-authored-by: Edoardo Spadolini <edoardo.spadolini@goteleport.com>

* Add `Resources` function for v18 backport

The generic `Resources` function is backported to the generic `Service` type.
`Resources` is used in a related commit enabling health checks for Kubernetes (#60544).

Part of #58413

* Fix test for terraform health check config (#60640)

Filters virtual defaults to allow explicit config references.

Part of #58413

---------

Co-authored-by: Edoardo Spadolini <edoardo.spadolini@goteleport.com>
Co-authored-by: rosstimothy <39066650+rosstimothy@users.noreply.github.com>
Co-authored-by: Gavin Frazar <gavin.frazar@goteleport.com>
Co-authored-by: Paul Gottschling <paul.gottschling@goteleport.com>
mmcallister pushed a commit that referenced this pull request Nov 6, 2025
Kubernetes servers are grouped by health, and dialed in order of healthy, unknown, then unhealthy, with random shuffling within each group for load distribution.

The grouping and shuffling is implemented generically in a separate iterator function `OrderByTargetHealthStatus()` for reuse and testability.

Changes:
- Added `healthcheck.OrderByTargetHealthStatus()` function with tests

Part of #58413

Co-authored-by: rosstimothy <39066650+rosstimothy@users.noreply.github.com>
mmcallister pushed a commit that referenced this pull request Nov 19, 2025
Kubernetes servers are grouped by health, and dialed in order of healthy, unknown, then unhealthy, with random shuffling within each group for load distribution.

The grouping and shuffling is implemented generically in a separate iterator function `OrderByTargetHealthStatus()` for reuse and testability.

Changes:
- Added `healthcheck.OrderByTargetHealthStatus()` function with tests

Part of #58413

Co-authored-by: rosstimothy <39066650+rosstimothy@users.noreply.github.com>
mmcallister pushed a commit that referenced this pull request Nov 20, 2025
Kubernetes servers are grouped by health, and dialed in order of healthy, unknown, then unhealthy, with random shuffling within each group for load distribution.

The grouping and shuffling is implemented generically in a separate iterator function `OrderByTargetHealthStatus()` for reuse and testability.

Changes:
- Added `healthcheck.OrderByTargetHealthStatus()` function with tests

Part of #58413

Co-authored-by: rosstimothy <39066650+rosstimothy@users.noreply.github.com>
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