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Usage

CLI flags, environment variables, and runtime tuning options for lfk.

Command-line flags

# Use default kubeconfig (~/.kube/config + ~/.kube/config.d/*)
lfk

# Start in a specific context
lfk --context my-cluster

# Start in a specific namespace (disables all-namespaces mode)
lfk -n kube-system

# Start with multiple namespaces selected
lfk -n default -n kube-system

# Combine context and namespace
lfk --context production -n monitoring

# Merge resources from multiple clusters into a single view ("union" mode).
# Requires --namespace; mutually exclusive with --context. Each row shows a
# "Context" column identifying the source. Read-only at the merged level
# except for Pod Delete / Force Delete / Force Finalize and workload
# Restart — drill into a resource to act on a specific cluster for
# anything else.
lfk --union-context blue --union-context green -n cloud-cd

# Recall a named union view from the config file (see "Union Sets" below
# in this doc, or config-reference.md). The set's namespace fills in if
# unset on the CLI; --namespace overrides whatever the set declared.
# Mutually exclusive with --context and --union-context.
lfk --union-set ski-staging-west
lfk --union-set ski-staging-west -n other-namespace

# Use a specific config file (overrides ~/.config/lfk/config.yaml)
lfk -c /path/to/config.yaml
lfk --config /path/to/config.yaml

# Use a specific kubeconfig file (overrides default discovery)
lfk --kubeconfig /path/to/kubeconfig

# Use a specific directory instead of ~/.kube/config.d/
lfk --kubeconfig-dir /path/to/configs/

# Merge multiple custom directories (repeat the flag)
lfk --kubeconfig-dir /team-a/configs/ --kubeconfig-dir /team-b/configs/

# Disable mouse capture (enables native terminal text selection)
lfk --no-mouse

# Disable all colors (selection stays visible via bold/reverse video)
lfk --no-color
# Equivalent environment variable (https://no-color.org):
NO_COLOR=1 lfk

# Disable all mutating actions (delete, edit, scale, restart, exec, etc.)
lfk --read-only

# Override the watch-mode polling interval (default 2s; clamped to [500ms, 10m])
lfk --watch-interval 5s

# Use a specific kubeconfig via environment variable
KUBECONFIG=/path/to/config lfk

# Use multiple kubeconfigs via environment variable
KUBECONFIG=/path/to/config1:/path/to/config2 lfk

# Use a custom kubeconfig directory via environment variable
KUBECONFIG_DIR=/path/to/configs/ lfk

# Merge multiple custom directories via env var (colon-separated, like KUBECONFIG)
KUBECONFIG_DIR=/team-a/configs:/team-b/configs lfk

When --context or --namespace flags are provided, the saved session state is ignored and the app opens directly in the specified context/namespace. The user can still change the namespace during the session.

Mouse Support

By default, lfk captures mouse input for click navigation, scroll, and tab switching. If you need native terminal text selection (e.g., shift+click to select text), you can disable mouse capture:

  • CLI flag: lfk --no-mouse
  • Config file: Add mouse: false to ~/.config/lfk/config.yaml

Explorer click semantics

The three-pane explorer maps mouse clicks to navigation actions:

Click Action
Left pane Drill out one level (same as h / Left arrow)
Middle pane (different row) Select that row and load its preview in the right pane
Middle pane (cursored row) Drill into it (same as Enter / Right arrow)
Right pane Drill into the selected item
Table header row Sort by that column; click again toggles direction
Right-click on middle pane Move cursor to the clicked row and open the action menu
Right-click on right pane Open the action menu for the currently selected item
Right-click on left pane No-op
Wheel up / down Scroll the focused pane

The two-step "select then click again to drill" flow lets you scan items and preview them in the right pane without committing — equivalent to using j / k followed by Enter on the keyboard.

Overlay click semantics

While an overlay is open (action menu, namespace selector, confirm dialog, etc.) the mouse interacts with the overlay rather than the explorer underneath:

Click Action
Click outside the overlay box Dismiss the overlay (same as Esc)
Click on a row in the action menu Run that action (same as Enter)
Click on a row in the namespace selector Apply that namespace and close
Click on the namespace badge in the title bar Open the namespace selector
Wheel up / down inside an overlay Scroll the list cursor — three rows per tick (same as pressing j / k)
Click inside the box on padding/title/border No-op (use Esc or click outside to dismiss)

Other list overlays (color scheme picker, bookmarks, templates, container / pod / log selectors, column toggle, etc.) accept wheel scroll; row-click activation is being added incrementally — for now use Enter after wheel scrolling to the desired row.

Fullscreen overlays (the secret / config-map / label editors, rollback / helm-history pickers, the auto-sync dialog, the Can-I browser, and the NetworkPolicy viewer) cover the entire screen, so there is no "outside" to click; press Esc to close them.

macOS Terminal.app does not support shift+click text selection while mouse capture is active. Use --no-mouse or switch to a terminal that handles this correctly (iTerm2, Kitty, Alacritty, WezTerm, Ghostty).

No-Color Mode

Disable all foreground and background colors while keeping selection and other highlights visible via bold, underline, and reverse-video SGR codes. Useful for monochrome terminals, piped output, or lower CPU usage.

  • CLI flag: lfk --no-color
  • Environment variable: NO_COLOR=1 lfk (any non-empty value; see no-color.org)
  • Config file: Add no_color: true to ~/.config/lfk/config.yaml

Precedence: --no-color flag > NO_COLOR env var > config file.

Kubeconfig Directory

By default, lfk discovers additional kubeconfig files from ~/.kube/config.d/ (recursively). This can be overridden — and multiple directories can be merged — via CLI, environment variable, or config:

  • CLI flag: lfk --kubeconfig-dir /path/to/configs/ (repeatable: pass --kubeconfig-dir multiple times to merge several directories).

  • Environment variable: KUBECONFIG_DIR=/path/to/configs/ lfk. Colon-separated for multiple directories on Unix (KUBECONFIG_DIR=/dir/a:/dir/b), matching the convention KUBECONFIG uses.

  • Config file: Add kubeconfig_dir: /path/to/configs/ to ~/.config/lfk/config.yaml. The value may be either a single string or a list:

    kubeconfig_dir:
  - /team-a/configs
  - /team-b/configs

Precedence (replacement, not merge): --kubeconfig-dir flag > KUBECONFIG_DIR env var > config file > default ~/.kube/config.d/. Each entry's tilde (~/) is expanded against $HOME. lfk validates every directory exists at startup and errors out loudly on a typo. The --kubeconfig flag bypasses all directory discovery entirely.

Read-Only Mode

Read-only mode disables every action that changes cluster state — delete, edit, scale, restart, rollback, exec, attach, port-forward, drain, cordon, taint, label/annotation edits, secret/configmap edits, paste-apply, and template create. Listing, describing, viewing logs, viewing YAML, diff, and other read paths still work.

Read-only is per-context (and per-tab). The UI surfaces it in two places:

  • Inside a context (any level deeper than the cluster picker): the title bar shows a [RO] badge for the current tab, and mutating shortcuts are filtered out of the action menu and hint bar.
  • At the cluster picker: each context row shows a [RO] suffix when it is configured read-only (per-context config, global config, or the --read-only CLI flag). The title-bar badge is suppressed here — it has no specific context to refer to. The per-row marker is the declarative view of which clusters are locked.

Read-only is opt-in at four levels (precedence highest first):

  1. CLI flag (sticky): lfk --read-only. Once set, the flag stays on for the life of the process — context switches cannot drop it, and the picker row toggle is rejected with a status hint.
  2. Session row toggle (Ctrl+R at the cluster picker): highlights a context and presses Ctrl+R to flip its [RO] marker. The toggle is recorded for the session, persists across re-navigation to the picker, and is honored when entering that context.
  3. Per-context config: lock specific clusters by name. 
    clusters:
  prod:
    read_only: true
  audit-cluster:
    read_only: true
  4. Global config: read_only: true at the top level applies to every context.

Read-only state is per-tab. New tabs inherit the setting from the active tab when created and re-evaluate on context switch.

In-app toggle

Ctrl+R behavior depends on where you are:

  • At the cluster picker: flips the [RO] marker on the highlighted context row. The toggle is stored as a session override that wins over per-context and global config when entering that context. Persists across back-and-forth navigation to the picker; cleared on process exit. Blocked when --read-only is set.
  • Inside a context: flips read-only for the current tab and records the choice as a session override for that context, so it survives navigating back to the picker and re-entering, and keeps the picker's [RO] marker in sync. Session-scoped — does not write to the config file. Keyed by context, so unlocking one context never leaks read-write state into another. Blocked when --read-only is set; the CLI flag is the strongest precedence level and cannot be defeated within the running process.

CLI flag

lfk --read-only            # all contexts read-only for the session
lfk --context prod --read-only

--read-only is process-wide. --context only selects the starting context; it does not scope the read-only flag.

Discovery

The cluster picker hint bar advertises Ctrl+R toggle RO so users can find the row toggle without reading docs.

Node Shell

From the Node action menu (x → s), lfk launches a privileged debug pod that nsenters into PID 1 on the selected node, giving an interactive shell with the host's mount, network, PID, and IPC namespaces.

The pod runs in kube-system with priorityClassName: system-node-critical so it can land on nodes reporting DiskPressure / MemoryPressure / PIDPressure, and tolerates all taints. It is created with --rm --restart=Never, so it is removed when the shell exits.

Node shell is a mutating action and is gated by the read-only check.

Cluster Color Coding

Tag any cluster with a background color so the title bar tints the moment you enter it — useful for "I am unmistakably in prod" feedback when a stray D would do real damage.

  • Open the picker: at the cluster picker, highlight a row and press L (Shift+L). Same overlay opens from the action menu (x → "Set color…").
  • Pick a color: 8 named choices (red, yellow, green, blue, magenta, cyan, white, gray) plus None to clear. The cursor pre-seeds on the cluster's current color, or on None if it has none.
  • Visual treatment: the picker row gets a ██ swatch in the chosen color so all your clusters are recognizable at a glance, and entering the context tints the entire title-bar background with the same color while the existing badges ([RO], watch indicator, namespace, etc.) stay legible on top.
  • Persistence: the assignment is saved to $XDG_STATE_HOME/lfk/cluster-colors.yaml (defaults to ~/.local/state/lfk/cluster-colors.yaml) so colors survive restarts. The file is lfk-managed — don't hand-edit; use the in-app picker. Unknown color names in the file are ignored on load (with a warning written to the lfk log) so a typo doesn't poison neighbouring entries.

Four of the colors follow lfk's active theme so they re-skin when you switch colorschemes:

Picker name Theme token
red theme.Error
yellow theme.Warning
green theme.Secondary
blue theme.Primary

The remaining four (magenta, cyan, white, gray) stay on ANSI bright codes so they look the same regardless of which lfk theme is active — useful when none of the theme accent colors fit a particular cluster's identity.

Watch-Mode Interval

Watch mode (toggle with w) polls the current resource list on an interval. The default 2-second interval is a good balance between freshness and API load. Tune it with:

  • CLI flag: lfk --watch-interval 5s (accepts Go durations: 500ms, 2s, 1m, ...)
  • Config file: Add watch_interval: 5s to ~/.config/lfk/config.yaml

Values outside [500ms, 10m] are clamped to the bounds; invalid values fall back to 2s.

Discovery Cache

API discovery (the list of resource types and CRDs the server exposes) is cached on disk under ~/.kube/cache/discovery/<host>/ with a 5-minute TTL. Layout matches kubectl and k9s so the same cache is shared across all three tools — a cold start hits zero discovery round-trips when the cache is warm. On busy clusters with many CRDs this eliminates redundant discovery round-trips on the API server and reduces startup time.

  • Override location: Set KUBECACHEDIR (same env var kubectl honors) to relocate <KUBECACHEDIR>/discovery/... and <KUBECACHEDIR>/http/....
  • Force refresh: Press R (Shift+r) at the resource types level to invalidate the cache and re-run discovery — newly installed or removed CRDs show up immediately without restarting lfk.
  • TTL: 5 minutes. Stale entries are refetched automatically on the next discovery request.

Endpoint Visibility

The right-pane preview for the Endpoints and EndpointSlices kinds shows every endpoint individually, with target pod, node, and ready state:

READY      3
NOT READY  1
PORTS      http:80/TCP

ENDPOINTS
  192.168.1.5  → pod/foo-7d9         on node-a
  192.168.1.6  → pod/foo-7d9-9fr     on node-b
  192.168.1.7  → pod/foo-7d9-2qx     on node-a
  192.168.1.8  → pod/foo-7d9-broken  on node-c   (NotReady)

Ready endpoints render with no status suffix; only (NotReady) is shown inline so the eye is drawn to the broken ones. A row degrades gracefully when targetRef (no target pod) or nodeName (host-network endpoints) is absent. Multiple addresses on a single EndpointSlice entry (dual-stack IPv4/IPv6 setups) each get their own line.

The Service preview includes its own rollup, fetched lazily on hover from the matching EndpointSlice resources (label kubernetes.io/service-name=<svc>):

BACKING ENDPOINTS  3 ready / 1 not ready

ENDPOINTS
  10.0.0.1  → pod/foo-7d9         on node-a
  10.0.0.2  → pod/foo-7d9-9fr     on node-b
  10.0.0.3  → pod/foo-7d9-2qx     on node-a
  10.0.0.4  → pod/foo-7d9-broken  on node-c   (NotReady)

The fetch is stale-while-revalidate: the cached rollup paints instantly and a fresh fetch fires in parallel, so pod churn is reflected within one watch tick without blanking the row mid-rebuild.

Headless Services (clusterIP: None) and ExternalName Services are skipped — they have no backing EndpointSlices to roll up.

For a fuller kubectl describe-style view of a Service (events, session affinity, etc.), press v (Describe).

Orphan detection

lfk flags Kubernetes resources that have no live consumer or controller, across 11 kinds:

  • Pods without owners — typically debug / one-off pods that escaped a controller. Static pods (kubelet-managed) are excluded; terminal pods older than an hour are tagged separately.
  • Secrets / ConfigMaps not mounted — anything not referenced by a Pod (volumes, env, envFrom, imagePullSecrets), an Ingress (spec.tls.secretName), or a ServiceAccount.
  • Services with no endpoints — non-Headless, non-ExternalName Services with zero backing addresses.
  • PersistentVolumeClaims not mounted — bound but no Pod or workload template references them.
  • HorizontalPodAutoscalers with a missing target — scaleTargetRef doesn't resolve.
  • PodDisruptionBudgets / NetworkPolicies that match nothing — selector resolves to zero live or templated pods.
  • Roles / ClusterRoles with no binding — no RoleBinding or ClusterRoleBinding refers to them.
  • RoleBindings / ClusterRoleBindings with a missing role or empty subjects.

Cluster-wide overview

Press Shift+O anywhere in the explorer (or type :orphans in the command bar) to open the orphan overview overlay. It scans the cluster and lists every orphan in one table grouped by kind:

  • Tab / Shift+Tab cycle through every kind filter chip (All plus all supported orphan kinds rendered in the strip)
  • s toggles strict / lenient — strict (default) hides items referenced by workload templates (e.g. CronJob between firings, scaled-to-zero Deployment); lenient surfaces them
  • / filters by namespace + name
  • Enter jumps straight to the highlighted resource (the namespace switches automatically)
  • R re-scans the cluster
  • Esc, q, or Shift+O close the overlay

Partial-RBAC denials surface as a warning banner at the top of the overlay; whatever could be listed is still shown.

Per-kind filter presets

Inside a list for any supported kind, press . to open the filter-preset overlay and pick the orphan preset. :orphans <kind> (e.g. :orphans secrets, :orphans pvcs, :orphans rolebindings) jumps to the kind's list with the preset already applied.

Auto-exclusions

To avoid false positives, the detector excludes these system-managed resources:

Resource Excluded When
Pod Static pod (kubernetes.io/config.mirror annotation)
Secret type=helm.sh/release.v1 (Helm release storage)
Secret type=kubernetes.io/service-account-token (auto-generated)
Secret/CM Has any ownerReference (managed by another controller)
ConfigMap Named kube-root-ca.crt (auto-injected per namespace)
Service Headless (clusterIP=None) or type=ExternalName

Traffic capture

Press c on a Pod or Service to open the capture overlay. Backends auto-detected:

Backend Mechanism Requirements
kubectl debug Ephemeral container streaming tcpdump kubectl 1.30+, ephemeral containers enabled, target pod can grant NET_ADMIN / NET_RAW
kubeshark Hand-off (port-forward + browser) kubeshark-hub Service in kubeshark namespace (override via kubeshark.namespace)

Hardened non-root pods can't grant NET_ADMIN / NET_RAW; capture fails with a message pointing at kubeshark. Install with helm install kubeshark kubeshark/kubeshark -n kubeshark --create-namespace.

pcap output: $XDG_STATE_HOME/lfk/captures/ (default ~/.local/state/lfk/captures/). The full per-phase keymap lives in docs/keybindings.md; the load-bearing keys:

  • s — stop, stay in overlay
  • Esc — stop and stay; second Esc dismisses + deletes the pcap unless Y was pressed
  • Y — copy pcap path to system clipboard, marks the capture as saved
  • e (from stopped phase) — re-open config to tweak the filter, then Enter to restart
  • __captures__ (Networking sidebar group) — cluster-wide list of running and stopped captures

Read-only mode (--read-only, or Ctrl+R) blocks the kubectl-debug backend (which creates an ephemeral container). The kubeshark hand-off stays available even though it uses port-forward internally — the listed Read-Only port-forward block applies to the user-triggered Port Forward action, not to the kubeshark backend's read-only tunnel to its in-cluster hub.

Secret Lazy Loading

On clusters with many Helm releases or large TLS secrets, listing the Secrets resource type can transfer tens of megabytes. Enable lazy loading to fetch only metadata for the list and defer decoded values to hover:

  • Config file: Add secret_lazy_loading: true to ~/.config/lfk/config.yaml

Trade-off: the Type column is dropped from the list (metadata-only fetch doesn't include it) and there's a small per-hover fetch for decoded values (cached thereafter). See Configuration Reference for details.

Diagnostics

Two opt-in environment variables help diagnose performance and memory issues. Both are off by default.

Variable Effect
LFK_PPROF_ADDR Serves Go pprof on the given loopback address (e.g. 127.0.0.1:6060). Non-loopback addresses are refused.
LFK_MEMSTATS_INTERVAL Logs heap and goroutine counts to the app log on each interval (Go duration, e.g. 30s; clamped to a 1s floor). 
# Periodic memory snapshots in the app log (heap_objects, goroutines, ...)
LFK_MEMSTATS_INTERVAL=30s lfk

# Capture a heap profile while lfk runs
LFK_PPROF_ADDR=127.0.0.1:6060 lfk
go tool pprof http://127.0.0.1:6060/debug/pprof/heap

Reading a suspected leak: rising heap_objects with a flat goroutines count points at an unbounded cache or buffer; a steadily climbing goroutines count points at a watch or stream that is never stopped.