Debugging

Contents

• 1   Runtime
  • 1.1   Specify an output directory
  • 1.2   Add debug options to configuration file
  • 1.3   Update docker service file to use helper script
• 2   Clear Linux
• 3   Other distributions
  • 3.1   Apply changes
• 4   Generate debug output
• 5   Further information

1   Runtime

To enable full debug for cc-oci-runtime when running under docker, follow the instructions below.

Note that enabling debug is slightly awkward in this scenario due to the fact that docker does not currently provide a way to pass extra command-line options to the runtime. To get around this restriction, the runtime provides a helper script called cc-oci-runtime.sh which reads extra arguments to pass to the runtime from /etc/cc-oci-runtime/cc-oci-runtime.sh.cfg on a normal system.

1.1   Specify an output directory

# Adjust directory as required
$ logdir=/tmp/cc-oci-runtime
$ sudo mkdir -p "$logdir"

1.2   Add debug options to configuration file

# Create the configuration directory
$ sudo mkdir -p /etc/cc-oci-runtime/

# Create the config file containing the extra command-line arguments to be
# passed to the real runtime.
$ cat << EOT | sudo tee -a /etc/cc-oci-runtime/cc-oci-runtime.sh.cfg
--debug
--global-log
$logdir/cc-oci-runtime.log
--hypervisor-log-dir
$logdir
EOT

1.3   Update docker service file to use helper script

2   Clear Linux

# Tell docker to run the helper script as the runtime.
# This script will launch the real runtime with the correct arguments.
$ sudo sed -i -e 's!/usr/bin/cc-oci-runtime!/usr/bin/cc-oci-runtime.sh!g' /lib/systemd/system/docker-cor.service

3   Other distributions

# Tell docker to run the helper script as the runtime.
# This script will launch the real runtime with the correct arguments.
$ sudo sed -i -e 's!/usr/bin/cc-oci-runtime!/usr/bin/cc-oci-runtime.sh!g' /etc/systemd/system/docker.service.d/clr-containers.conf

3.1   Apply changes

$ sudo systemctl daemon-reload
$ sudo systemctl restart docker-cor

4   Generate debug output

With debug enabled, if you run, say:

$ docker run -ti busybox

... you should find the following files in /tmp/cc-oci-runtime/:

• cc-oci-runtime.log
• ${container}-hypervisor.stdout
• ${container}-hypervisor.stderr

Note that the global log file is always appended to, so if you run docker run twice, you'll end up with output for both containers in the same file.

5   Further information

Full instructions on how to use the helper script are at the top of the script itself:

$ more /usr/bin/cc-oci-runtime.sh