cephadm: add command to send signals to daemons

This command figures out the container id for the
daemon based on the given name and then uses
a docker/podman to send that signal to the container

Signed-off-by: Adam King <[email protected]>
(cherry picked from commit 16b16d1)

Conflicts:
	src/cephadm/cephadm.py

Resolves: rhbz#2373703

Author: adk3798

src/cephadm/cephadm.py

@@ -143,6 +143,7 @@
 )
 from cephadmlib.systemd import check_unit, check_units, terminate_service, enable_service
 from cephadmlib import systemd_unit
+from cephadmlib.signals import send_signal_to_container_entrypoint
 from cephadmlib import runscripts
 from cephadmlib.container_types import (
     CephContainer,
@@ -759,6 +760,24 @@ def get_legacy_daemon_fsid(ctx, cluster,
         fsid = get_legacy_config_fsid(cluster, legacy_dir=legacy_dir)
     return fsid
 
+def lookup_container_id_by_daemon_name(ctx: CephadmContext, fsid: str, name: str) -> str:
+    updater = CombinedStatusUpdater([CoreStatusUpdater()])
+    daemon_entries = daemons_matching(
+        ctx,
+        daemon_name=name,
+    )
+    daemons = [updater.expand(ctx, entry) for entry in daemon_entries]
+    if not daemons:
+        raise Error('Failed to find daemon {}'.format(name))
+    if len(daemons) > 1:
+        raise Error('Found multiple daemons matching name {}: {}'.format(name, daemons))
+
+    daemon = daemons[0]
+    try:
+        return daemon['container_id']
+    except KeyError:
+        raise Error('Failed to get container id for {}'.format(daemon))
+
 
 def create_daemon_dirs(
     ctx: CephadmContext,
@@ -3565,6 +3584,18 @@ def command_unit(ctx):
     )
     return code
 
+
+@infer_fsid
+def command_signal(ctx):
+    # type: (CephadmContext) -> int
+    if not ctx.fsid:
+        raise Error('must pass --fsid to specify cluster')
+
+    container_id = lookup_container_id_by_daemon_name(ctx, ctx.fsid, ctx.name)
+
+    return send_signal_to_container_entrypoint(ctx, container_id, ctx.signal_name, ctx.signal_number)
+
+
 ##################################
 
 
@@ -5623,6 +5654,24 @@ def _get_parser():
         help='Set LimitCORE=infinity in ceph unit files'
     )
 
+    parser_signal = subparsers.add_parser(
+        'signal', help='Send signal to entrypoint of containerized daemon')
+    parser_signal.set_defaults(func=command_signal)
+    signal_group = parser_signal.add_mutually_exclusive_group(required=True)
+    signal_group.add_argument(
+        '--signal-number',
+        help='Signal number to send',)
+    signal_group.add_argument(
+        '--signal-name',
+        help='Signal to send')
+    parser_signal.add_argument(
+        '--fsid',
+        help='cluster FSID')
+    parser_signal.add_argument(
+        '--name', '-n',
+        required=True,
+        help='daemon name (type.id)')
+
     parser_logs = subparsers.add_parser(
         'logs', help='print journald logs for a daemon container')
     parser_logs.set_defaults(func=command_logs)

src/cephadm/cephadmlib/signals.py

@@ -0,0 +1,54 @@
+# functions related to sending signals
+
+import logging
+import signal
+
+from typing import Optional
+
+from .call_wrappers import call, CallVerbosity
+from .context import CephadmContext
+from .exceptions import Error
+
+logger = logging.getLogger()
+
+
+def send_signal_to_container_entrypoint(
+    ctx: CephadmContext,
+    container_id: str,
+    signal_name: Optional[str],
+    signal_number: Optional[int],
+) -> int:
+    if not signal_name and not signal_number:
+        raise Error(
+            f'Got request to send signal to entrypoint of container with id {container_id} but no signal specified'
+        )
+
+    if signal_number and signal_name:
+        raise Error(
+            'signal_name and signal_number params to send_signal_to_container_entrypoint are mutually exclusive'
+        )
+
+    if signal_number:
+        signal_name = signal.Signals(signal_number).name
+    elif signal_name:
+        signal_name = signal_name.upper()
+        signal_number = signal.Signals[signal_name].value
+    assert signal_name is not None and signal_number is not None
+
+    logger.info(
+        f'Sending signal {signal_name} ({signal_number}) to entrypoint of container with id {container_id}'
+    )
+
+    _, _, code = call(
+        ctx,
+        [
+            ctx.container_engine.path,
+            'kill',
+            container_id,
+            '--signal',
+            signal_name,
+        ],
+        verbosity=CallVerbosity.VERBOSE,
+        desc='',
+    )
+    return code