Provided by: charliecloud-runtime_0.38-3_amd64 
NAME
ch-run-oci - OCI wrapper for "ch-run"
SYNOPSIS
$ ch-run-oci OPERATION [ARG ...]
DESCRIPTION
NOTE:
This command is experimental. Features may be incomplete and/or buggy. The quality of code is not yet
up to the usual Charliecloud standards, and error handling is poor. Please report any issues you find,
so we can fix them!
Open Containers Initiative (OCI) wrapper for ch-run(1). You probably don’t want to run this command
directly; it is intended to interface with other software that expects an OCI runtime. The current goal
is to support completely unprivileged image building (e.g. buildah --runtime=ch-run-oci) rather than
general OCI container running.
Support of the OCI runtime specification is only partial. This is for two reasons. First, it’s an
experimental and incomplete feature. More importantly, the philosophy and goals of OCI differ
significantly from those of Charliecloud. Key differences include:
• OCI is designed to run services, while Charliecloud is designed to run scientific applications.
• OCI containers are persistent things with a complex lifecycle, while Charliecloud containers are
simply UNIX processes.
• OCI expects support for a variety of namespaces, while Charliecloud supports user and mount, no more
and no less.
• OCI expects runtimes to maintain a supervisor process in addition to user processes; Charliecloud
has no need for this.
• OCI expects runtimes to maintain state throughout the container lifecycle in a location independent
from the caller.
For these reasons, ch-run-oci is a bit of a kludge, and much of what it does is provide scaffolding to
satisfy OCI requirements.
Which OCI features are and are not supported is provided in the rest of this man page, and technical
analysis and discussion are in the Contributor’s Guide.
This command supports OCI version 1.0.0 only and fails with an error if other versions are offered.
OPERATIONS
All OCI operations are accepted, but some are no-ops or merely scaffolding to satisfy the caller. For
comparison, see also:
• OCI runtime and lifecycle spec
• The runc man pages
create
$ ch-run-oci create --bundle DIR --pid-file FILE [--no-new-keyring] CONTAINER_ID
Create a container. Charliecloud does not have separate create and start phases, so this operation only
sets up OCI-related scaffolding.
Arguments:
--bundle DIR
Directory containing the OCI bundle. This must be /tmp/buildahYYY, where YYY matches
CONTAINER_ID below.
--pid-file FILE
Filename to write the “container” process PID to. Note that for Charliecloud, the process given
is fake; see above. This must be DIR/pid, where DIR is given by --bundle.
--no-new-keyring
Ignored. (Charliecloud does not implement session keyrings.)
CONTAINER_ID
String to use as the container ID. This must be buildah-buildahYYY, where YYY matches DIR
above.
Unsupported arguments:
--console-socket PATH
UNIX socket to pass pseudoterminal file descriptor. Charliecloud does not support
pseudoterminals; fail with an error if this argument is given. For Buildah, redirect its input
from /dev/null to prevent it from requesting a pseudoterminal.
delete
$ ch-run-oci delete CONTAINER_ID
Clean up the OCI-related scaffolding for specified container.
kill
$ ch-run-oci kill CONTAINER_ID
No-op.
start
$ ch-run-oci start CONTAINER_ID
Eexecute the user command specified at create time in a Charliecloud container.
state
$ ch-run-oci state CONTAINER_ID
Print the state of the given container on standard output as an OCI compliant JSON document.
UNSUPPORTED OCI FEATURES
As noted above, various OCI features are not supported by Charliecloud. We have tried to guess which
features would be essential to callers; ch-run-oci fails with an error if these are requested. Otherwise,
the request is simply ignored.
We are interested in hearing about scientific-computing use cases for unsupported features, so we can add
support for things that are needed.
Our goal is for this man page to be comprehensive: every OCI runtime feature should either work or be
listed as unsupported.
Unsupported features that are an error:
• Pseudoterminals
• Hooks (prestart, poststart, and prestop)
• Annotations
• Joining existing namespaces
• Intel Resource Director Technology (RDT)
Unsupported features that are ignored:
• Mounts other than the root filesystem
• User/group mappings beyond one user mapped to EUID and one group mapped to EGID
• Disabling prctl(PR_SET_NO_NEW_PRIVS)
• Root filesystem propagation mode
• sysctl directives
• masked and read-only paths (remaining unprivileged protects you)
• Capabilities
• rlimits
• Devices (all devices are inherited from the host)
• cgroups
• seccomp
• SELinux
• AppArmor
• Container hostname setting
ENVIRONMENT VARIABLES
CH_LOG_FILE
If set, append log chatter to this file, rather than standard error. This is useful for debugging
situations where standard error is consumed or lost.
Also sets verbose mode if not already set (equivalent to --verbose).
CH_LOG_FESTOON
If set, prepend PID and timestamp to logged chatter.
CH_XATTRS
If set, save xattrs in the build cache and restore them when rebuilding from the cache (equivalent
to --xattrs).
CH_RUN_OCI_HANG
If set to the name of a command (e.g., create), sleep indefinitely when that command is invoked. The
purpose here is to halt a build so it can be examined and debugged.
REPORTING BUGS
If Charliecloud was obtained from your Linux distribution, use your distribution’s bug reporting
procedures.
Otherwise, report bugs to: https://github.com/hpc/charliecloud/issues
SEE ALSO
charliecloud(7)
Full documentation at: <https://hpc.github.io/charliecloud>
COPYRIGHT
2014–2023, Triad National Security, LLC and others
0.38 2025-04-06 08:24 UTC CH-RUN-OCI(1)