97c9115c02
Don't sort OCI hooks using the locale collation order; it does not make sense for the same system-wide directory to be interpreted differently depending on the user's LC_COLLATE setting, and the language-specific collation order can even change over time. Besides, the current collation order determination code has never worked with the most common LC_COLLATE values like en_US.UTF-8. Ideally, we would like to just order based on Unicode code points to be reliably stable, but the existing implementation is case-insensitive, so we are forced to rely on the unicode case mapping tables at least. (This gives up on canonicalization and width-insensitivity, potentially breaking users who rely on these previously documented properties.) Signed-off-by: Miloslav Trmač <mitr@redhat.com>
OCI Hooks Configuration
For POSIX platforms, the OCI runtime configuration supports hooks for configuring custom actions related to the life cycle of the container.
The way you enable the hooks above is by editing the OCI runtime configuration before running the OCI runtime (e.g. runc).
CRI-O and podman create create the OCI configuration for you, and this documentation allows developers to configure them to set their intended hooks.
One problem with hooks is that the runtime actually stalls execution of the container before running the hooks and stalls completion of the container, until all hooks complete.
This can cause some performance issues.
Also a lot of hooks just check if certain configuration is set and then exit early, without doing anything.
For example the oci-systemd-hook only executes if the command is init or systemd, otherwise it just exits.
This means if we automatically enabled all hooks, every container would have to execute oci-systemd-hook, even if they don't run systemd inside of the container.
Performance would also suffer if we exectuted each hook at each stage (pre-start, post-start, and post-stop).
The hooks configuration is documented in oci-hooks.5.