[jira] [Commented] (MESOS-9334) Container stuck at ISOLATING state due to libevent poll never returns
[
https://issues.apache.org/jira/browse/MESOS-9334?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel=16669327#comment-16669327
]
Qian Zhang commented on MESOS-9334:
---
commit 610064942d4a75f16f045480ca9e3414d37f1ecc
Author: Benjamin Mahler
Date: Fri Oct 26 10:50:54 2018 +0800
Fixed an early fd close in the cgroups event notifier.
The cgroups event notifier was closing the eventfd while an
`io::read()` operation may be in progress. This can lead to
bugs where the fd gets re-used and read from a stale io::read.
Review: https://reviews.apache.org/r/69123/
commit 9bd3a32b68b165d9a1a45548cebe3b22069cecc0
Author: Qian Zhang
Date: Fri Oct 26 10:57:20 2018 +0800
Ensured failed / discarded cgroups OOM notification is logged.
Failed or discarded OOM notificaitions in the cgroups memory
subsystem were not being logged, due to the continuation being
accidentally set up using `onReady` rather than `onAny`.
Review: https://reviews.apache.org/r/69188
> Container stuck at ISOLATING state due to libevent poll never returns
> -
>
> Key: MESOS-9334
> URL: https://issues.apache.org/jira/browse/MESOS-9334
> Project: Mesos
> Issue Type: Bug
> Components: containerization
>Reporter: Qian Zhang
>Assignee: Qian Zhang
>Priority: Critical
>
> We found UCR container may be stuck at `ISOLATING` state:
> {code:java}
> 2018-10-03 09:13:23: I1003 09:13:23.274561 2355 containerizer.cpp:3122]
> Transitioning the state of container 1e5b8fc3-5c9e-4159-a0b9-3d46595a5b54
> from PREPARING to ISOLATING
> 2018-10-03 09:13:23: I1003 09:13:23.279223 2354 cni.cpp:962] Bind mounted
> '/proc/5244/ns/net' to
> '/run/mesos/isolators/network/cni/1e5b8fc3-5c9e-4159-a0b9-3d46595a5b54/ns'
> for container 1e5b8fc3-5c9e-4159-a0b9-3d46595a5b54
> 2018-10-03 09:23:22: I1003 09:23:22.879868 2354 containerizer.cpp:2459]
> Destroying container 1e5b8fc3-5c9e-4159-a0b9-3d46595a5b54 in ISOLATING state
> {code}
> In the above logs, the state of container
> `1e5b8fc3-5c9e-4159-a0b9-3d46595a5b54` was transitioned to `ISOLATING` at
> 09:13:23, but did not transitioned to any other states until it was destroyed
> due to the executor registration timeout (10 mins). And the destroy can never
> complete since it needs to wait for the container to finish isolating.
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[jira] [Commented] (MESOS-9334) Container stuck at ISOLATING state due to libevent poll never returns
[
https://issues.apache.org/jira/browse/MESOS-9334?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel=16664603#comment-16664603
]
Qian Zhang commented on MESOS-9334:
---
RR: https://reviews.apache.org/r/69123/
> Container stuck at ISOLATING state due to libevent poll never returns
> -
>
> Key: MESOS-9334
> URL: https://issues.apache.org/jira/browse/MESOS-9334
> Project: Mesos
> Issue Type: Bug
> Components: containerization
>Reporter: Qian Zhang
>Assignee: Qian Zhang
>Priority: Critical
>
> We found UCR container may be stuck at `ISOLATING` state:
> {code:java}
> 2018-10-03 09:13:23: I1003 09:13:23.274561 2355 containerizer.cpp:3122]
> Transitioning the state of container 1e5b8fc3-5c9e-4159-a0b9-3d46595a5b54
> from PREPARING to ISOLATING
> 2018-10-03 09:13:23: I1003 09:13:23.279223 2354 cni.cpp:962] Bind mounted
> '/proc/5244/ns/net' to
> '/run/mesos/isolators/network/cni/1e5b8fc3-5c9e-4159-a0b9-3d46595a5b54/ns'
> for container 1e5b8fc3-5c9e-4159-a0b9-3d46595a5b54
> 2018-10-03 09:23:22: I1003 09:23:22.879868 2354 containerizer.cpp:2459]
> Destroying container 1e5b8fc3-5c9e-4159-a0b9-3d46595a5b54 in ISOLATING state
> {code}
> In the above logs, the state of container
> `1e5b8fc3-5c9e-4159-a0b9-3d46595a5b54` was transitioned to `ISOLATING` at
> 09:13:23, but did not transitioned to any other states until it was destroyed
> due to the executor registration timeout (10 mins). And the destroy can never
> complete since it needs to wait for the container to finish isolating.
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[jira] [Commented] (MESOS-9334) Container stuck at ISOLATING state due to libevent poll never returns
[
https://issues.apache.org/jira/browse/MESOS-9334?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel=16661975#comment-16661975
]
Qian Zhang commented on MESOS-9334:
---
After reading some libevent code and our code to call libevent, I think the
root cause of this issue is, after we call libevent to poll an fd, that fd is
disabled inside libevent due to a race. Here is the flow:
# Container1 is launched and cgroups memory subsystem calls the function
`cgroups::memory::oom::listen()` to listen OOM event for this container, and
that function will internally open an fd, call libevent to poll it, and return
a future to cgroups memory subsystem.
# Container1 exits and when we destroy it, the cleanup method of cgroups
memory subsystem will discard the future got in #1. As the result,
`Listener::finalize()` will be called (see [this
code|https://github.com/apache/mesos/blob/1.7.0/src/linux/cgroups.cpp#L1069:L1087]
for details), and it will
** Discard the future returned by libevent poll which will cause
`pollDiscard()` called and that will trigger `pollCallback` to be executed
*asynchronously* (see [this
code|https://github.com/apache/mesos/blob/1.7.0/3rdparty/libprocess/src/posix/libevent/libevent_poll.cpp#L66:L70]
for details).
** Close the fd opened in #1 *immediately* which means the fd can be reused
now.
# Container2 is launched, and CNI isolator calls `io::read` to read the
stdout/stderr of CNI plugin for this container. Internally `io::read` *reuses*
the fd closed in #2 and call libevent to poll it.
# Now the function `pollCallback` for container1 is executed, and it will
delete the poll object which will trigger `event_free` to deallocate the event
for this container (see [this
code|https://github.com/apache/mesos/blob/1.7.0/3rdparty/libprocess/src/posix/libevent/libevent_poll.cpp#L50:L52]
for details). Internally `event_free` will call `event_del` ->
`event_del_internal` -> `evmap_io_del` -> `evsel->del` to *disable* the fd (see
[this
code|https://github.com/libevent/libevent/blob/release-2.0.22-stable/event-internal.h#L78:L79]
for details), but that fd is now used to read stdout/stderr for container2 in
#3. Since the fd is disabled inside libevent, the `io::read` we do in #3 will
never return so the container2 will be stuck at `ISOLATING` state.
> Container stuck at ISOLATING state due to libevent poll never returns
> -
>
> Key: MESOS-9334
> URL: https://issues.apache.org/jira/browse/MESOS-9334
> Project: Mesos
> Issue Type: Bug
> Components: containerization
>Reporter: Qian Zhang
>Assignee: Qian Zhang
>Priority: Critical
>
> We found UCR container may be stuck at `ISOLATING` state:
> {code:java}
> 2018-10-03 09:13:23: I1003 09:13:23.274561 2355 containerizer.cpp:3122]
> Transitioning the state of container 1e5b8fc3-5c9e-4159-a0b9-3d46595a5b54
> from PREPARING to ISOLATING
> 2018-10-03 09:13:23: I1003 09:13:23.279223 2354 cni.cpp:962] Bind mounted
> '/proc/5244/ns/net' to
> '/run/mesos/isolators/network/cni/1e5b8fc3-5c9e-4159-a0b9-3d46595a5b54/ns'
> for container 1e5b8fc3-5c9e-4159-a0b9-3d46595a5b54
> 2018-10-03 09:23:22: I1003 09:23:22.879868 2354 containerizer.cpp:2459]
> Destroying container 1e5b8fc3-5c9e-4159-a0b9-3d46595a5b54 in ISOLATING state
> {code}
> In the above logs, the state of container
> `1e5b8fc3-5c9e-4159-a0b9-3d46595a5b54` was transitioned to `ISOLATING` at
> 09:13:23, but did not transitioned to any other states until it was destroyed
> due to the executor registration timeout (10 mins). And the destroy can never
> complete since it needs to wait for the container to finish isolating.
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[jira] [Commented] (MESOS-9334) Container stuck at ISOLATING state due to libevent poll never returns
[
https://issues.apache.org/jira/browse/MESOS-9334?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel=16658795#comment-16658795
]
Qian Zhang commented on MESOS-9334:
---
I added some logs into `libevent_poll.cpp` (see the diff below for details) and
reproduced this issue a couple of times.
{code:java}
--- a/3rdparty/libprocess/src/posix/libevent/libevent_poll.cpp
+++ b/3rdparty/libprocess/src/posix/libevent/libevent_poll.cpp
@@ -32,11 +34,17 @@ struct Poll
};
-void pollCallback(evutil_socket_t, short what, void* arg)
+void pollCallback(evutil_socket_t fd, short what, void* arg)
{
Poll* poll = reinterpret_cast(arg);
+ LOG(INFO) << "==pollCallback starts with fd " << fd
+<< " and with poll " << poll << "==";
+
if (poll->promise.future().hasDiscard()) {
+LOG(INFO) << "==pollCallback discards with fd "
+ << fd << "==";
+
poll->promise.discard();
} else {
// Convert libevent specific EV_READ / EV_WRITE to io::* specific
@@ -44,17 +52,24 @@ void pollCallback(evutil_socket_t, short what, void* arg)
short events =
((what & EV_READ) ? io::READ : 0) | ((what & EV_WRITE) ? io::WRITE : 0);
+LOG(INFO) << "==pollCallback sets promise with fd " << fd
+ << " and with events " << events << "==";
+
poll->promise.set(events);
}
// Deleting the `poll` also destructs `ev` and hence triggers `event_free`,
// which makes the event non-pending.
delete poll;
+
+ LOG(INFO) << "==pollCallback ends with fd " << fd << "==";
}
void pollDiscard(const std::weak_ptr& ev, short events)
{
+ LOG(INFO) << "==pollDiscard is called==";
+
// Discarding inside the event loop prevents `pollCallback()` from being
// called twice if the future is discarded.
run_in_event_loop([=]() {
@@ -78,6 +93,9 @@ Future poll(int_fd fd, short events)
internal::Poll* poll = new internal::Poll();
+ LOG(INFO) << "==libevent starts polling with fd " << fd
+<< " and with poll " << poll << "==";
+
Future future = poll->promise.future();
// Convert io::READ / io::WRITE to libevent specific values of these
{code}
Here is what I found in the agent log when this issue occurred (fd 48 is the
stderr file descriptor of `NetworkCniIsolatorSetup`):
{code:java}
I1021 15:57:45.00 2116 libevent_poll.cpp:96] ==libevent starts
polling with fd 48 and with poll 0x7f60df029eb0==
I1021 15:57:45.00 2117 libevent_poll.cpp:41] ==pollCallback starts
with fd 48 and with poll 0x7f60e6e56c70==
I1021 15:57:45.00 2117 libevent_poll.cpp:45] ==pollCallback
discards with fd 48==
I1021 15:57:45.00 2117 libevent_poll.cpp:65] ==pollCallback ends
with fd 48==
{code}
We can see libevent started to poll fd 48 with the poll object whose address is
0x7f60df029eb0, but when `pollCallback` was called for fd 48, the address of
poll object is different (0x7f60e6e56c70) which has been discarded (see the
third log line) !!!
And when I searched 0x7f60e6e56c70 in the agent log, I found:
{code:java}
I1021 15:57:22.00 2115 memory.cpp:478] Started listening for OOM events for
container 4753a5ef-eccd-4373-b8f0-a4b40abf0fb5
I1021 15:57:22.00 2115 libevent_poll.cpp:96] ==libevent starts
polling with fd 48 and with poll 0x7f60e6e56c70==
{code}
So the poll object 0x7f60e6e56c70 was created 23 seconds ago with the same file
descriptor (fd 48) which is used to listen OOM events for another container
(4753a5ef-eccd-4373-b8f0-a4b40abf0fb5), and that container was destroyed at
15:57:44 right before agent started to wait the stderr of
`NetworkCniIsolatorSetup` (15:57:45).
{code:java}
I1021 15:57:44.00 2114 containerizer.cpp:2459] Destroying container
4753a5ef-eccd-4373-b8f0-a4b40abf0fb5 in RUNNING state
{code}
I reproduced this issue a couple of times, the observations I had from agent
log are same as the above.
> Container stuck at ISOLATING state due to libevent poll never returns
> -
>
> Key: MESOS-9334
> URL: https://issues.apache.org/jira/browse/MESOS-9334
> Project: Mesos
> Issue Type: Bug
> Components: containerization
>Reporter: Qian Zhang
>Priority: Critical
>
> We found UCR container may be stuck at `ISOLATING` state:
> {code:java}
> 2018-10-03 09:13:23: I1003 09:13:23.274561 2355 containerizer.cpp:3122]
> Transitioning the state of container 1e5b8fc3-5c9e-4159-a0b9-3d46595a5b54
> from PREPARING to ISOLATING
> 2018-10-03 09:13:23: I1003 09:13:23.279223 2354 cni.cpp:962] Bind mounted
> '/proc/5244/ns/net' to
> '/run/mesos/isolators/network/cni/1e5b8fc3-5c9e-4159-a0b9-3d46595a5b54/ns'
> for container
[jira] [Commented] (MESOS-9334) Container stuck at ISOLATING state due to libevent poll never returns
[
https://issues.apache.org/jira/browse/MESOS-9334?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel=16656592#comment-16656592
]
Qian Zhang commented on MESOS-9334:
---
I added some logs into Mesos agent and libprocess, and then found the CNI
isolator may hang at two places when isolating a container:
# Wait for a CNI plugin (see [this
code|https://github.com/apache/mesos/blob/1.7.0/src/slave/containerizer/mesos/isolators/network/cni/cni.cpp#L1327]
for details). When this issue occurred, I found actually the CNI plugin has
finished its job and exited, but the CNI isolator hung at reading the CNI
plugin's stdout/stderr.
# Wait for `NetworkCniIsolatorSetup` (see [this
code|https://github.com/apache/mesos/blob/1.7.0/src/slave/containerizer/mesos/isolators/network/cni/cni.cpp#L1154]
for details). Similarly when this issue occurred, I found actually
`NetworkCniIsolatorSetup` has finished its job and exited, but CNI isolator
hung at reading its stderr.
For both of the above two cases, I found it was [libevent
poll|https://github.com/apache/mesos/blob/1.7.0/3rdparty/libprocess/src/posix/libevent/libevent_poll.cpp#L75]
never return for the fd to read stdout/stderr, and it seems there was no fd
leak when this issue occurred.
> Container stuck at ISOLATING state due to libevent poll never returns
> -
>
> Key: MESOS-9334
> URL: https://issues.apache.org/jira/browse/MESOS-9334
> Project: Mesos
> Issue Type: Bug
> Components: containerization
>Reporter: Qian Zhang
>Priority: Critical
>
> We found UCR container may be stuck at `ISOLATING` state:
>
> {code:java}
> 2018-10-03 09:13:23: I1003 09:13:23.274561 2355 containerizer.cpp:3122]
> Transitioning the state of container 1e5b8fc3-5c9e-4159-a0b9-3d46595a5b54
> from PREPARING to ISOLATING
> 2018-10-03 09:13:23: I1003 09:13:23.279223 2354 cni.cpp:962] Bind mounted
> '/proc/5244/ns/net' to
> '/run/mesos/isolators/network/cni/1e5b8fc3-5c9e-4159-a0b9-3d46595a5b54/ns'
> for container 1e5b8fc3-5c9e-4159-a0b9-3d46595a5b54
> 2018-10-03 09:23:22: I1003 09:23:22.879868 2354 containerizer.cpp:2459]
> Destroying container 1e5b8fc3-5c9e-4159-a0b9-3d46595a5b54 in ISOLATING state
> {code}
>
> In the above logs, the state of container
> `1e5b8fc3-5c9e-4159-a0b9-3d46595a5b54` was transitioned to `ISOLATING` at
> 09:13:23, but did not transitioned to any other states until it was destroyed
> due to the executor registration timeout (10 mins). And the destroy can never
> complete since it needs to wait for the container to finish isolating.
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