General Server Issues

• Compatible Docker Version

  Ensure the system is running compatible versions of docker and docker compose. See System Requirements for more details.

• Cloud Security Groups

  If the security group rule in the AWS / Azure / OCI console that allows https into the Web App restricts connections by IP address (the source IP is not "0.0.0.0/0"), then an additional rule must be added to allow the server to connect to itself.

  This is done by creating an additional rule to the security group allowing https connections from the same security group.

Security Group Example

Linux Server Workspaces

• No audio in Linux (xrdp) sessions

  No sound is heard in a session, and pactl list sinks short shows only a dummy auto_null sink. On Ubuntu 24.04 and later, the pulseaudio-module-xrdp package no longer exists, and xrdp audio support has moved to PipeWire (pipewire-module-xrdp). If the session is still running the legacy PulseAudio daemon, the PipeWire xrdp sink never loads and audio falls back to auto_null. Switch the session to PipeWire:

  sudo apt-get install -y pipewire pipewire-pulse wireplumber pipewire-audio alsa-utils
  sudo apt-get remove -y pulseaudio
  sudo systemctl --global enable pipewire.socket pipewire-pulse.socket wireplumber.service

  Disconnect and reconnect the session so that a fresh user session starts under PipeWire, then verify with pactl info (which should report PulseAudio (on PipeWire ...)) and pactl list sinks short (which should show an xrdp sink rather than auto_null). Apply this fix in the golden image, or in a session-start or autoscale provisioning script, so that it persists across newly provisioned sessions.

• Web browser missing or "Input/output error" in a session

  Clicking the browser icon does nothing, or it returns an Input/output error; in some images the browser is not installed by default. Do not rely on the browser being present in the base image. Install it from the autoscale provisioning script or a session-start script instead. On Ubuntu 24.04, the snap-packaged Firefox frequently fails under xrdp, so prefer a .deb browser such as Chromium, Chrome, or Firefox from the Mozilla PPA. A stale ~/thinclient_drives FUSE mount left over from a previous xrdp session can also cause an Input/output error; clear it with fusermount -u ~/thinclient_drives, or disable drive redirection in /etc/xrdp/sesman.ini or xrdp.ini if it is not needed.

• Active Directory domain-join failures on auto-scaled VMs

  Newly auto-scaled VMs fail to join the domain. SSH into the affected VM that was created by autoscale and review the provisioning log at /var/log/kasm_install.log (for example, sudo less /var/log/kasm_install.log). The most common cause is that the required ports are not open between the VM and the domain controllers, such as DNS (53), Kerberos (88, 464), LDAP (389, 636), SMB (445), and the Global Catalog (3268). Verify your cloud security lists or NSGs (for example, OCI security lists) and any host firewall rules. When using autoscale to join VMs to Active Directory, also review the Linux VM startup script README for the required configuration.