cephadm: run tcmu-runner through script to do restart on failure

Currently, cephadm runs tcmu-runner as a background
process inside the unit file deployed for iscsi
(rbd-target-api is the primary process). This means
if tcmu-runner crashes for whatever reason, systemd
will not attempt to restart it. This commits sets
up a script to serve as the container entrypoint
for the tcmu-runner container that will run
tcmu-runner and also restart it on failure
(unless there are too many failures in a short
period, at which point it gives up).

The hope is to eventually drop use of this script
for a better solution in squid onward, but this
should be helpful on older releases (quincy and
pacific at least) where we won't be able to
bring that better solution

Fixes: https://tracker.ceph.com/issues/61667
Signed-off-by: Adam King <adking@redhat.com>
(cherry picked from commit 47eb6b3f62afe993073429b02051ae0343d7aea3)

Conflicts:
	src/cephadm/tests/test_cephadm.py

diff --git a/src/cephadm/cephadm b/src/cephadm/cephadm
index 85232507e6b916ad588cafdba397ed85e923221e..96a28449c3e58b402828e0f62e2c9b81e814fc09 100755 (executable)
--- a/src/cephadm/cephadm
+++ b/src/cephadm/cephadm
@@ -845,6 +845,7 @@ class CephIscsi(object):
         mounts[os.path.join(data_dir, 'keyring')] = '/etc/ceph/keyring:z'
         mounts[os.path.join(data_dir, 'iscsi-gateway.cfg')] = '/etc/ceph/iscsi-gateway.cfg:z'
         mounts[os.path.join(data_dir, 'configfs')] = '/sys/kernel/config'
+        mounts[os.path.join(data_dir, 'tcmu-runner-entrypoint.sh')] = '/usr/local/scripts/tcmu-runner-entrypoint.sh'
         mounts[log_dir] = '/var/log:z'
         mounts['/dev'] = '/dev'
         return mounts
@@ -908,9 +909,19 @@ class CephIscsi(object):
         configfs_dir = os.path.join(data_dir, 'configfs')
         makedirs(configfs_dir, uid, gid, 0o755)
 
+        # set up the tcmu-runner entrypoint script
+        # to be mounted into the container. For more info
+        # on why we need this script, see the
+        # tcmu_runner_entrypoint_script function
+        self.files['tcmu-runner-entrypoint.sh'] = self.tcmu_runner_entrypoint_script()
+
         # populate files from the config-json
         populate_files(data_dir, self.files, uid, gid)
 
+        # we want the tcmu runner entrypoint script to be executable
+        # populate_files will give it 0o600 by default
+        os.chmod(os.path.join(data_dir, 'tcmu-runner-entrypoint.sh'), 0o700)
+
     @staticmethod
     def configfs_mount_umount(data_dir, mount=True):
         # type: (str, bool) -> List[str]
@@ -923,13 +934,53 @@ class CephIscsi(object):
                   'umount {0}; fi'.format(mount_path)
         return cmd.split()
 
+    @staticmethod
+    def tcmu_runner_entrypoint_script() -> str:
+        # since we are having tcmu-runner be a background
+        # process in its systemd unit (rbd-target-api being
+        # the main process) systemd will not restart it when
+        # it fails. in order to try and get around that for now
+        # we can have a script mounted in the container that
+        # that attempts to do the restarting for us. This script
+        # can then become the entrypoint for the tcmu-runner
+        # container
+
+        # This is intended to be dropped for a better solution
+        # for at least the squid release onward
+        return """#!/bin/bash
+RUN_DIR=/var/run/tcmu-runner
+
+if [ ! -d "${RUN_DIR}" ] ; then
+    mkdir -p "${RUN_DIR}"
+fi
+
+rm -rf "${RUN_DIR}"/*
+
+while true
+do
+    touch "${RUN_DIR}"/start-up-$(date -Ins)
+    /usr/bin/tcmu-runner
+
+    # If we got around 3 kills/segfaults in the last minute,
+    # don't start anymore
+    if [ $(find "${RUN_DIR}" -type f -cmin -1 | wc -l) -ge 3 ] ; then
+        exit 0
+    fi
+
+    sleep 1
+done
+"""
+
     def get_tcmu_runner_container(self):
         # type: () -> CephContainer
         # daemon_id, is used to generated the cid and pid files used by podman but as both tcmu-runner
         # and rbd-target-api have the same daemon_id, it conflits and prevent the second container from
         # starting. .tcmu runner is appended to the daemon_id to fix that.
         tcmu_container = get_deployment_container(self.ctx, self.fsid, self.daemon_type, str(self.daemon_id) + '.tcmu')
-        tcmu_container.entrypoint = '/usr/bin/tcmu-runner'
+        # TODO: Eventually we don't want to run tcmu-runner through this script.
+        # This is intended to be a workaround backported to older releases
+        # and should eventually be removed in at least squid onward
+        tcmu_container.entrypoint = '/usr/local/scripts/tcmu-runner-entrypoint.sh'
         tcmu_container.cname = self.get_container_name(desc='tcmu')
         return tcmu_container
 

diff --git a/src/cephadm/tests/test_cephadm.py b/src/cephadm/tests/test_cephadm.py
index 7559402d3983b6b4a9f9565d2ba8ac0d32006709..641483d8504f2a6485dedfbdded8a9025861209f 100644 (file)
--- a/src/cephadm/tests/test_cephadm.py
+++ b/src/cephadm/tests/test_cephadm.py
@@ -1751,11 +1751,11 @@ if ! grep -qs /var/lib/ceph/9b9d7609-f4d5-4aba-94c8-effa764d96c9/iscsi.daemon_id
 # iscsi tcmu-runner container
 ! /usr/bin/podman rm -f ceph-9b9d7609-f4d5-4aba-94c8-effa764d96c9-iscsi.daemon_id-tcmu 2> /dev/null
 ! /usr/bin/podman rm -f ceph-9b9d7609-f4d5-4aba-94c8-effa764d96c9-iscsi-daemon_id-tcmu 2> /dev/null
-/usr/bin/podman run --rm --ipc=host --stop-signal=SIGTERM --net=host --entrypoint /usr/bin/tcmu-runner --privileged --group-add=disk --init --name ceph-9b9d7609-f4d5-4aba-94c8-effa764d96c9-iscsi-daemon_id-tcmu --pids-limit=0 -e CONTAINER_IMAGE=ceph/ceph -e NODE_NAME=host1 -e CEPH_USE_RANDOM_NONCE=1 -v /var/lib/ceph/9b9d7609-f4d5-4aba-94c8-effa764d96c9/iscsi.daemon_id/config:/etc/ceph/ceph.conf:z -v /var/lib/ceph/9b9d7609-f4d5-4aba-94c8-effa764d96c9/iscsi.daemon_id/keyring:/etc/ceph/keyring:z -v /var/lib/ceph/9b9d7609-f4d5-4aba-94c8-effa764d96c9/iscsi.daemon_id/iscsi-gateway.cfg:/etc/ceph/iscsi-gateway.cfg:z -v /var/lib/ceph/9b9d7609-f4d5-4aba-94c8-effa764d96c9/iscsi.daemon_id/configfs:/sys/kernel/config -v /var/log/ceph/9b9d7609-f4d5-4aba-94c8-effa764d96c9:/var/log:z -v /dev:/dev --mount type=bind,source=/lib/modules,destination=/lib/modules,ro=true ceph/ceph &
+/usr/bin/podman run --rm --ipc=host --stop-signal=SIGTERM --net=host --entrypoint /usr/local/scripts/tcmu-runner-entrypoint.sh --privileged --group-add=disk --init --name ceph-9b9d7609-f4d5-4aba-94c8-effa764d96c9-iscsi-daemon_id-tcmu --pids-limit=0 -e CONTAINER_IMAGE=ceph/ceph -e NODE_NAME=host1 -e CEPH_USE_RANDOM_NONCE=1 -v /var/lib/ceph/9b9d7609-f4d5-4aba-94c8-effa764d96c9/iscsi.daemon_id/config:/etc/ceph/ceph.conf:z -v /var/lib/ceph/9b9d7609-f4d5-4aba-94c8-effa764d96c9/iscsi.daemon_id/keyring:/etc/ceph/keyring:z -v /var/lib/ceph/9b9d7609-f4d5-4aba-94c8-effa764d96c9/iscsi.daemon_id/iscsi-gateway.cfg:/etc/ceph/iscsi-gateway.cfg:z -v /var/lib/ceph/9b9d7609-f4d5-4aba-94c8-effa764d96c9/iscsi.daemon_id/configfs:/sys/kernel/config -v /var/lib/ceph/9b9d7609-f4d5-4aba-94c8-effa764d96c9/iscsi.daemon_id/tcmu-runner-entrypoint.sh:/usr/local/scripts/tcmu-runner-entrypoint.sh -v /var/log/ceph/9b9d7609-f4d5-4aba-94c8-effa764d96c9:/var/log:z -v /dev:/dev --mount type=bind,source=/lib/modules,destination=/lib/modules,ro=true ceph/ceph &
 # iscsi.daemon_id
 ! /usr/bin/podman rm -f ceph-9b9d7609-f4d5-4aba-94c8-effa764d96c9-iscsi.daemon_id 2> /dev/null
 ! /usr/bin/podman rm -f ceph-9b9d7609-f4d5-4aba-94c8-effa764d96c9-iscsi-daemon_id 2> /dev/null
-/usr/bin/podman run --rm --ipc=host --stop-signal=SIGTERM --net=host --entrypoint /usr/bin/rbd-target-api --privileged --group-add=disk --init --name ceph-9b9d7609-f4d5-4aba-94c8-effa764d96c9-iscsi-daemon_id --pids-limit=0 -e CONTAINER_IMAGE=ceph/ceph -e NODE_NAME=host1 -e CEPH_USE_RANDOM_NONCE=1 -v /var/lib/ceph/9b9d7609-f4d5-4aba-94c8-effa764d96c9/iscsi.daemon_id/config:/etc/ceph/ceph.conf:z -v /var/lib/ceph/9b9d7609-f4d5-4aba-94c8-effa764d96c9/iscsi.daemon_id/keyring:/etc/ceph/keyring:z -v /var/lib/ceph/9b9d7609-f4d5-4aba-94c8-effa764d96c9/iscsi.daemon_id/iscsi-gateway.cfg:/etc/ceph/iscsi-gateway.cfg:z -v /var/lib/ceph/9b9d7609-f4d5-4aba-94c8-effa764d96c9/iscsi.daemon_id/configfs:/sys/kernel/config -v /var/log/ceph/9b9d7609-f4d5-4aba-94c8-effa764d96c9:/var/log:z -v /dev:/dev --mount type=bind,source=/lib/modules,destination=/lib/modules,ro=true ceph/ceph
+/usr/bin/podman run --rm --ipc=host --stop-signal=SIGTERM --net=host --entrypoint /usr/bin/rbd-target-api --privileged --group-add=disk --init --name ceph-9b9d7609-f4d5-4aba-94c8-effa764d96c9-iscsi-daemon_id --pids-limit=0 -e CONTAINER_IMAGE=ceph/ceph -e NODE_NAME=host1 -e CEPH_USE_RANDOM_NONCE=1 -v /var/lib/ceph/9b9d7609-f4d5-4aba-94c8-effa764d96c9/iscsi.daemon_id/config:/etc/ceph/ceph.conf:z -v /var/lib/ceph/9b9d7609-f4d5-4aba-94c8-effa764d96c9/iscsi.daemon_id/keyring:/etc/ceph/keyring:z -v /var/lib/ceph/9b9d7609-f4d5-4aba-94c8-effa764d96c9/iscsi.daemon_id/iscsi-gateway.cfg:/etc/ceph/iscsi-gateway.cfg:z -v /var/lib/ceph/9b9d7609-f4d5-4aba-94c8-effa764d96c9/iscsi.daemon_id/configfs:/sys/kernel/config -v /var/lib/ceph/9b9d7609-f4d5-4aba-94c8-effa764d96c9/iscsi.daemon_id/tcmu-runner-entrypoint.sh:/usr/local/scripts/tcmu-runner-entrypoint.sh -v /var/log/ceph/9b9d7609-f4d5-4aba-94c8-effa764d96c9:/var/log:z -v /dev:/dev --mount type=bind,source=/lib/modules,destination=/lib/modules,ro=true ceph/ceph
 """
 
     def test_get_container(self):