Tekton Controllers flags

The different controllers tektoncd/pipeline ships come with a set of flags that can be changed (in the yaml payloads) for advanced use cases. This page documents them.

Flag availability overview

Not all flags are available on every controller. The table below shows which flags and environment variables are supported by each controller binary.

Flags from `knative/pkg` (available on all controllers)

These flags are registered by injection.ParseAndGetRESTConfigOrDie() and klog, and are available on all controllers (controller, webhook, events, resolvers):

Flag	Description
`-cluster`	Defaults to the current cluster in kubeconfig.
`-server`	The address of the Kubernetes API server. Overrides any value in kubeconfig. Only required if out-of-cluster.
`-kubeconfig`	Path to a kubeconfig. Only required if out-of-cluster.
`-kube-api-burst`	Maximum burst for throttle.
`-kube-api-qps`	Maximum QPS to the server from the client.
`-v`	Number for the log level verbosity.
`-vmodule`	Comma-separated list of `pattern=N` settings for file-filtered logging.
`-add_dir_header`	If true, adds the file directory to the header of the log messages.
`-alsologtostderr`	Log to standard error as well as files (no effect when `-logtostderr=true`).
`-log_backtrace_at`	When logging hits line `file:N`, emit a stack trace.
`-log_dir`	If non-empty, write log files in this directory (no effect when `-logtostderr=true`).
`-log_file`	If non-empty, use this log file (no effect when `-logtostderr=true`).
`-log_file_max_size`	Maximum size a log file can grow to in megabytes (default 1800, 0 = unlimited; no effect when `-logtostderr=true`).
`-logtostderr`	Log to standard error instead of files (default true).
`-one_output`	If true, only write logs to their native severity level (no effect when `-logtostderr=true`).
`-skip_headers`	If true, avoid header prefixes in the log messages.
`-skip_log_headers`	If true, avoid headers when opening log files (no effect when `-logtostderr=true`).
`-stderrthreshold`	Logs at or above this threshold go to stderr (default 2; no effect when `-logtostderr=true` or `-alsologtostderr=false`).

Flags and environment variables that vary by controller

The following flags and environment variables are not available on all controllers. Their availability depends on whether the controller calls sharedmain.MainWithContext() (which registers --disable-ha and reads K_THREADS_PER_CONTROLLER) or registers flags directly in its own main().

Flag / Environment Variable	Source	`controller`	`webhook`	`events`	`resolvers`
`--disable-ha`	`sharedmain` / Tekton	Yes	Yes	Yes	No
`--threads-per-controller`	Tekton	Yes	No	No	Yes
`--namespace`	Tekton	Yes	No	No	No
`--resync-period`	Tekton	Yes	No	No	No
`THREADS_PER_CONTROLLER` env var	Tekton	Yes	No	No	Yes
`K_THREADS_PER_CONTROLLER` env var	`sharedmain`	No	Yes	Yes	No

Note: controller and resolvers read the THREADS_PER_CONTROLLER environment variable (without the K_ prefix) in their own code before parsing flags, while webhook and events read K_THREADS_PER_CONTROLLER (with the K_ prefix) via sharedmain.MainWithContext(). Both environment variables set the same underlying controller.DefaultThreadsPerController value; the difference is only in the variable name.

`controller`

The main controller binary (cmd/controller/main.go) has additional flags to configure its behavior.

  -disable-ha
        Whether to disable high-availability functionality for this component.
        This flag will be deprecated and removed when we have promoted this
        feature to stable, so do not pass it without filing an issue upstream!
  -entrypoint-image string
        The container image containing our entrypoint binary.
  -namespace string
        Namespace to restrict informer to. Optional, defaults to all namespaces.
  -nop-image string
        The container image used to stop sidecars
  -resync-period duration
        The period between two resync run (going through all objects) (default 10h0m0s)
  -shell-image string
        The container image containing a shell
  -shell-image-win string
        The container image containing a windows shell
  -sidecarlogresults-image string
        The container image containing the binary for accessing results.
  -threads-per-controller int
        Threads (goroutines) to create per controller (default 2)
  -workingdirinit-image string
        The container image containing our working dir init binary.

Environment variables: THREADS_PER_CONTROLLER

`webhook`

The webhook binary (cmd/webhook/main.go) calls sharedmain.MainWithContext(), which provides:

  -disable-ha
        Whether to disable high-availability functionality for this component.
        This flag will be deprecated and removed when we have promoted this
        feature to stable, so do not pass it without filing an issue upstream!

Environment variables: K_THREADS_PER_CONTROLLER

`events`

The events controller binary (cmd/events/main.go) calls sharedmain.Main(), which provides:

  -disable-ha
        Whether to disable high-availability functionality for this component.
        This flag will be deprecated and removed when we have promoted this
        feature to stable, so do not pass it without filing an issue upstream!

Environment variables: K_THREADS_PER_CONTROLLER

`resolvers`

The resolvers binary (cmd/resolvers/main.go) has the following additional flag:

  -threads-per-controller int
        Threads (goroutines) to create per controller (default 2)

Environment variables: THREADS_PER_CONTROLLER

Note: The resolvers binary does not support --disable-ha. It calls injection.ParseAndGetRESTConfigOrDie() followed by sharedmain.MainWithConfig(), which does not register the --disable-ha flag.

Tekton Controllers flags

Tekton Controllers flags

Flag availability overview

Flags from knative/pkg (available on all controllers)

Flags and environment variables that vary by controller

controller

webhook

events

resolvers

Flags from `knative/pkg` (available on all controllers)

`controller`

`webhook`

`events`

`resolvers`