FAQ & troubleshooting

Kubernetes

Can WebSummoner run in Kubernetes? Possible, but not recommended:

• WebSummoner talks directly to the Docker API and is designed for a workstation or VM with Docker installed; Kubernetes has a completely different API and may not even use Docker as its runtime.
• Even when it works, all browser containers start on the same node as the WebSummoner pod — invisible to Kubernetes scheduling, which can overload the node.
• Only one WebSummoner replica is possible: the session list lives in memory.

For Kubernetes-native Selenium, see the alternatives discussed in the comparison page.

Logs and directories

Where are WebSummoner logs? On stdout. For the container:

docker logs -f websummoner

Where are recorded videos stored? When installed with cm: ~/.websummoner/websummoner/video (or C:\Users\<user>\.websummoner\websummoner\video on Windows).

Limits and timeouts

What HTTP status do I get when the queue is full? If you send the X-WebSummoner-No-Wait header, WebSummoner replies with 429 Too Many Requests immediately. Without the header, the request blocks in the queue until a slot is free (or the client disconnects).

Limit overall browser consumption? The -limit flag — total parallel sessions, default 5. See Recommended Docker settings for sizing.

Limit per-version consumption? Not supported — by design, the only sensible limit is overall consumption.

Adjust timeouts? The main one is -timeout (max time between WebDriver requests before a session is closed). The subtle ones: -service-startup-timeout, -session-attempt-timeout, -session-delete-timeout — see the CLI flags reference.

Resources

How much do browser containers consume? Depends on tests; start with 1 CPU + 1 GB per container and raise -limit while watching stability.

Are there separate VNC images? No. Every image embeds x11vnc, and the server only runs when the session asks for it with enableVNC (or ENABLE_VNC=true standalone). Idle cost when it does run is about 20 MB — negligible next to the browser.

VNC eats all CPU? On RedHat-based distributions set LimitNOFILE=1048576 for containerd.service.

Fixes for common errors

open config/browsers.json: no such file or directory — you overrode the container command and dropped the config path. Add it back:

docker run <args> websummoner/websummoner:latest-release \
  -limit 10 -conf /etc/websummoner/browsers.json

create container: ... client version 1.36 is too new — pin the Docker API version to your daemon (docker version | grep API):

DOCKER_API_VERSION=1.32 ./websummoner <args>          # binary
docker run -e DOCKER_API_VERSION=1.32 <args> websummoner/websummoner:latest-release

Video files keep random names and VIDEO_ERROR in logs — the recorder container cannot rename the temp file. Check that:

1. OVERRIDE_VIDEO_OUTPUT_DIR points to the host directory where videos are stored.
2. When passing custom args to the container you also pass -video-output-dir /opt/websummoner/video and mount the host video directory at /opt/websummoner/video.

VNC shows “Disconnected” — the session lacks the enableVNC: true capability.

VNC shows a black screen with a cross — the test called driver.close() (closes the last tab) instead of driver.quit() (ends the session).

Miscellaneous

Can WebSummoner pull browser images automatically? No — intentional. Automatic pulls under load would make startup times and failures unpredictable. Use cm or the jq snippet in Browsers configuration.

Does it work in a Docker macvlan network? Yes — background on the driver itself: macvlan network driver; see aerokube/selenoid#795 for working setups (the thread predates the fork).