From 5c87cc6469f41fdbb5f0d22cdc16f9d585232fbc Mon Sep 17 00:00:00 2001 From: "W. Trevor King" Date: Wed, 8 Feb 2017 16:02:01 -0800 Subject: [PATCH] runtime: Add a 'kill' command Similar to the 'signal' command removed in b9227323 (Drop exec, pause, resume, and signal, 2015-12-02, wking/oci-command-line-api#3). The runtime-spec gained a kill operation as part of opencontainers/runtime-spec@be594153 (Split create and start, 2016-04-01, opencontainers/runtime-spec#384). The interface is based on POSIX [1], util-linux [2], and GNU coreutils [3]. The TERM/KILL requirement is a minimum portability requirement for soft/hard stops. Windows lacks POSIX signals [4], and currently supports soft stops in Docker with whatever is behind hcsshim.ShutdownComputeSystem [5]. The docs we're landing here explicitly allow that sort of substitution, because we need to have soft/hard stop on those platforms but *can't* use POSIX signals. They borrow wording from opencontainers/runtime-spec@35b0e9ee (config: Clarify MUST for platform.os and .arch, 2016-05-19, opencontainers/runtime-spec#441) to recommend runtime authors document the alternative technology so bundle-authors can prepare (e.g. by installing the equivalent to a SIGTERM signal handler). [1]: http://pubs.opengroup.org/onlinepubs/9699919799/utilities/kill.html [2]: http://man7.org/linux/man-pages/man1/kill.1.html [3]: http://www.gnu.org/software/coreutils/manual/html_node/kill-invocation.html [4]: https://groups.google.com/a/opencontainers.org/forum/#!topic/dev/PlGKu7QUwLE Subject: Fwd: Windows support for OCI stop/signal/kill (runtime-spec#356) Date: Thu, 26 May 2016 11:03:29 -0700 Message-ID: <20160526180329.GL17496@odin.tremily.us> [5]: https://github.com/docker/docker/pull/16997/files#diff-5d0b72cccc4809455d52aadc62329817R230 docker/docker@bc503ca8 (Windows: [TP4] docker kill handling, 2015-10-12, docker/docker#16997) Signed-off-by: W. Trevor King --- runtime.md | 36 ++++++++++++++++++++++++++++++++++++ 1 file changed, 36 insertions(+) diff --git a/runtime.md b/runtime.md index 83dea6d..380ca92 100644 --- a/runtime.md +++ b/runtime.md @@ -90,9 +90,45 @@ $ echo $? 0 ``` +### kill + +[Send a signal][kill] to the container process. + +* *Arguments* + * *``* The container being signaled. +* *Options* + * *`--signal `* The signal to send (defaults to `TERM`). + The runtime MUST support `TERM` and `KILL` signals with [the POSIX semantics][posix-signals]. + The runtime MAY support additional signal names. + On platforms that support [POSIX signals][posix-signals], the runtime MUST implement this command using POSIX signals. + On platforms that do not support POSIX signals, the runtime MAY implement this command with alternative technology as long as `TERM` and `KILL` retain their POSIX semantics. + Runtime authors on non-POSIX platforms SHOULD submit documentation for their TERM implementation to this specificiation, so runtime callers can configure the container process to gracefully handle the signals. +* *Standard streams:* + * *stdin:* The runtime MUST NOT attempt to read from its stdin. + * *stdout:* The handling of stdout is unspecified. + * *stderr:* The runtime MAY print diagnostic messages to stderr, and the format for those lines is not specified in this document. +* *Exit code:* Zero if the signal was successfully sent to the container process and non-zero on errors. + Successfully sent does not mean that the signal was successfully received or handled by the container process. + +#### Example + +``` +# in a bundle directory with a process ignores TERM +$ funC start --id sleeper-1 & +$ funC kill sleeper-1 +$ echo $? +0 +$ funC kill --signal KILL sleeper-1 +$ echo $? +0 +``` + +[kill]: https://github.com/opencontainers/runtime-spec/blob/v1.0.0-rc4/runtime.md#kill +[kill.2]: http://man7.org/linux/man-pages/man2/kill.2.html [posix-encoding]: http://pubs.opengroup.org/onlinepubs/9699919799/basedefs/V1_chap06.html#tag_06_02 [posix-lang]: http://pubs.opengroup.org/onlinepubs/9699919799/basedefs/V1_chap08.html#tag_08_02 [posix-locale-encoding]: http://www.unicode.org/reports/tr35/#Bundle_vs_Item_Lookup +[posix-signals]: http://pubs.opengroup.org/onlinepubs/9699919799/basedefs/signal.h.html#tag_13_42_03 [semver]: http://semver.org/spec/v2.0.0.html [standard-streams]: https://github.com/opencontainers/specs/blob/v0.1.1/runtime-linux.md#file-descriptors [systemd-listen-fds]: http://www.freedesktop.org/software/systemd/man/sd_listen_fds.html