Stop reporting process cache evictions and misses as errors

Stop reporting tetragon_errors_total metric with "type" label values: process_cache_miss_on_get process_cache_evicted process_cache_miss_on_remove Evictions and misses are not errors, this is just cache's life, sometimes you hit, sometimes you miss, and sometimes you gotta evict a process. They are now reported by more intuitive metrics: tetragon_process_cache_evictions_total tetragon_process_cache_misses_total{operation=~"get|remove"} Signed-off-by: Anna Kapuscinska <[email protected]>
cilium · Sep 1, 2024 · c7354b0 · c7354b0
1 parent 4077c53
commit c7354b0
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Showing 4 changed files with 5 additions and 15 deletions.
diff --git a/contrib/upgrade-notes/latest.md b/contrib/upgrade-notes/latest.md
@@ -53,3 +53,6 @@ tetragon:
   * `tetragon_ringbuf_perf_event_lost_total` -> `tetragon_observer_ringbuf_events_lost_total`
   * `tetragon_ringbuf_queue_received_total` -> `tetragon_observer_ringbuf_queue_events_received_total`
   * `tetragon_ringbuf_queue_lost_total` -> `tetragon_observer_ringbuf_queue_events_lost_total`
+* `tetragon_errors_total{type="process_cache_evicted"}` metric is replaced by `tetragon_process_cache_evicted_total`.
+* `tetragon_errors_total{type=~"process_cache_miss_on_get|process_cache_miss_on_remove"}` metrics are replaced by
+  `tetragon_process_cache_misses_total{operation=~"get|remove"}`.
diff --git a/docs/content/en/docs/reference/metrics.md b/docs/content/en/docs/reference/metrics.md
diff --git a/pkg/metrics/errormetrics/errormetrics.go b/pkg/metrics/errormetrics/errormetrics.go
@@ -15,14 +15,8 @@ import (
 type ErrorType int
 
 const (
-	// Process not found on get() call.
-	ProcessCacheMissOnGet ErrorType = iota
-	// Process evicted from the cache.
-	ProcessCacheEvicted
-	// Process not found on remove() call.
-	ProcessCacheMissOnRemove
 	// Tid and Pid mismatch that could affect BPF and user space caching logic
-	ProcessPidTidMismatch
+	ProcessPidTidMismatch ErrorType = iota
 	// An event is missing process info.
 	EventMissingProcessInfo
 	// An error occurred in an event handler.
@@ -37,9 +31,6 @@ const (
 )
 
 var errorTypeLabelValues = map[ErrorType]string{
-	ProcessCacheMissOnGet:                   "process_cache_miss_on_get",
-	ProcessCacheEvicted:                     "process_cache_evicted",
-	ProcessCacheMissOnRemove:                "process_cache_miss_on_remove",
 	ProcessPidTidMismatch:                   "process_pid_tid_mismatch",
 	EventMissingProcessInfo:                 "event_missing_process_info",
 	HandlerError:                            "handler_error",

diff --git a/pkg/process/cache.go b/pkg/process/cache.go
@@ -10,7 +10,6 @@ import (
 
 	"github.com/cilium/tetragon/api/v1/tetragon"
 	"github.com/cilium/tetragon/pkg/logger"
-	"github.com/cilium/tetragon/pkg/metrics/errormetrics"
 	lru "github.com/hashicorp/golang-lru/v2"
 )
 
@@ -132,7 +131,6 @@ func NewCache(
 	lruCache, err := lru.NewWithEvict(
 		processCacheSize,
 		func(_ string, _ *ProcessInternal) {
-			errormetrics.ErrorTotalInc(errormetrics.ProcessCacheEvicted)
 			processCacheEvictions.Inc()
 		},
 	)
@@ -151,7 +149,6 @@ func (pc *Cache) get(processID string) (*ProcessInternal, error) {
 	process, ok := pc.cache.Get(processID)
 	if !ok {
 		logger.GetLogger().WithField("id in event", processID).Debug("process not found in cache")
-		errormetrics.ErrorTotalInc(errormetrics.ProcessCacheMissOnGet)
 		processCacheMisses.WithLabelValues("get").Inc()
 		return nil, fmt.Errorf("invalid entry for process ID: %s", processID)
 	}
@@ -173,7 +170,6 @@ func (pc *Cache) remove(process *tetragon.Process) bool {
 	if present {
 		processCacheTotal.Dec()
 	} else {
-		errormetrics.ErrorTotalInc(errormetrics.ProcessCacheMissOnRemove)
 		processCacheMisses.WithLabelValues("remove").Inc()
 	}
 	return present