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Parameters

Every command-line parameter corresponds to an environment variable which you can set instead. For example, for --param-name there is the SB_PARAM_NAME environment variable. Environment variable names are created by adding the SB_ prefix to the capitalized parameter name, with all dashes (-) replaced by underscores (_).

Common parameters​

listen​

String, defaults to 0.0.0.0:4444 when Selebrow is started in Kubernetes or Docker container and 127.0.0.1:4444 otherwise.

(Optional) IP and port for Selebrow to listen on. Below are few valid examples

  • 0.0.0.0:4444 - bind to all interfaces, listen on port 4444
  • :4444 - same as above
  • 127.0.0.1:4444 - bind to 127.0.0.1 (loopback interface) only, listen on port 4444

backend​

String, defaults to auto

Backend to use, allowed values are:

  • auto (default)
  • kubernetes (see Kubernetes)
  • docker (see Docker)

When this parameter is set to auto or not specified, the Kubernetes backend will be selected if Selebrow was started inside a Kubernetes pod. Otherwise the Docker backend will be used.

create-timeout​

String, defaults to 3m

Time to wait for a browser container to start. The client will get an HTTP 504 Gateway Timeout response if this timeout has occurred. Can be increased in case browser Pods/Containers take a longer time to start (image pool is slow for example) The value must be in the Go Duration format.

connect-timeout​

String, defaults to 200ms

Timeout set on connections made to browser containers. Used in browser readiness checks as well as in forwarded Webdriver/Playwright requests. Consider increasing it if your network environment has lag issues. The value must be in the Go Duration format.

Browsers catalog parameters​

browsers-uri​

String, defaults to config/browsers.yaml

Browser catalog source to load at startup. Can be either local path ot http(s) URL

fallback-browsers-uri​

String, defaults to https://selebrow.dev/browsers.yaml

Used when Browser catalog couldn't be loaded using source specified in browsers-uri

Kubernetes parameters​

create-retries​

Integer, defaults to 5

Number of retries for failed Kubernetes Pod create requests before returning HTTP 504 Internal server error. A retry is made whenever the Reason field has one of following values in the Kubernetes API response metadata:

  • Conflict
  • TooManyRequests
  • InternalError
  • ServerTimeout
  • Timeout

kube-cluster-mode-out​

Boolean, defaults to false

Selebrow is expected to run inside a Kubernetes pod, so the Kubernetes client is created using InClusterConfig by default. However, this is not ideal for development, as you may want to run Selebrow under a debugger. In that case you can set kube-cluster-mode-out to true.

See also kube-config

kube-config​

String, defaults to $HOME/.kube/config

Kubernetes client config file to use when kube-cluster-mode-out is set to true.

kube-templates-path​

String, defaults to config/

Path to Kubernetes Pod template files. See templates reference for details.

namespace​

String, defaults to default

Kubernetes namespace to create browser Pods in.

Docker parameters​

docker-platform​

String, not set by default

Docker platform for browser images.

By default, when looking for browser image, Docker will try to get the native image for the current platform and if that doesn't exist it will fall back to amd64

You can override this behaviour by explicitly setting the required platform for browser images. Below are valid examples for the docker-platform parameter:

  • arm64 - Only look for linux/arm64 images (no fallback to amd64 will be made)
  • linux/arm64 same as above

docker-network​

String, not set by default

Docker network to use for browser containers.

When this parameter is not set (default), the following algorithm is used:

If running in port mapping mode, Docker default bridge will be used. Otherwise Selebrow will try to detect the current Docker network (assuming Selebrow itself has been started inside a Docker container)

docker-port-mapping​

String, defaults to auto

Container port mapping mode

  • auto (default)
  • enabled - explicitly enabled
  • disabled - explicitly disabled

When this parameter is set to auto, port mapping mode is set to disabled if Selebrow is running inside Docker container itself and to enabled otherwise.

docker-privileged​

Boolean, defaults to false

Enables privileged mode when running browser Containers. It's not generally recommended to enable this flag. The Selebrow images are built to work in unprivileged mode.

docker-pull-images​

Boolean, defaults to false

By default, Selebrow pulls the browser image upon first request for browser/version. This way only the required images are pulled locally to save storage space at the exchange of a longer first browser request.

When this parameter is set to true, Selebrow will pull all images configured in the Browser catalog at startup. This is useful for a server installation where you expect low browser startup time.

Browser limit and queue parameters​

quota-limit​

Integer, defaults to 0

The maximum number of simultaneously running browsers.

Some values of this parameter are treated specially:

  • 0 (default) automatically calculate limit based on available resources. Currently implemented only for the Docker backend.
  • -1 unlimited quota

The client will get an HTTP 429 Too Many Requests response if quota is exceeded, unless queue-size is set.

queue-size​

Integer, defaults to 25

The size of the internal queue of browsers waiting for available quota.

When quota-limit is set to a non negative value and the quota is full, any new browser request will be put into an internal queue until either quota is available or queue-timeout is reached. The client will get an HTTP 429 Too Many Requests response if the queue is full.

queue-timeout​

String, defaults to 1m

The time a browser can wait for available quota in the browsers queue. The client will get an HTTP 429 Too Many Requests response if this timeout occurred.

The value must be in the Go Duration format

Pool parameters​

pool-max-idle​

Integer, defaults to 5

Pool size for idle browser containers. When set to 0 the pooling feature is disabled.

pool-idle-timeout​

String, defaults to 1m

The maximum time a browser container can be idle in the pool before eviction.

The value must be in the Go Duration format

pool-max-age​

String, defaults to 15m

If a browser is older than the value specified in this parameter it's unconditionally evicted from the pool (recycled).

The value must be in the Go Duration format

UI parameters​

ui​

Boolean, defaults to true

The UI is enabled by default unless Selebrow was started in a CI environment.

vnc-password​

String

The VNC password to be used for connecting to browsers via the UI. The default value matches the default password in Selebrow images, which is selebrow.

Logging parameters​

Since logging is inititalized very early at startup, it can only be configured with environment variables, there are no corresponding command line parameters.

SB_LOG_LEVEL​

String

Log level to use. Allowed values are:

  • debug
  • info (default)
  • warn
  • error

SB_LOG_FORMAT​

String

Log format:

  • json - structured logging in json format (automatically enabled when Selebrow is run in Kubernetes).
  • console - human-readable console logs (default). Color output is enabled when running in terminal.

SB_LOG_OUTPUT​

String

Log output file/stream. Default is stdout.