We have integration tests which assert the invariant that a
GET /containers/{id}/json response lists only IDs of execs which are in
the Running state, according to GET /exec/{id}/json. The invariant could
be violated if those requests were to race the handling of the exec's
task-exit event. The coarse-grained locking of the container ExecStore
when starting an exec task was accidentally synchronizing
(*Daemon).ProcessEvent and (*Daemon).ContainerExecInspect to it just
enough to make it improbable for the integration tests to catch the
invariant violation on execs which exit immediately. Removing the
unnecessary locking made the underlying race condition more likely for
the tests to hit.
Maintain the invariant by deleting the exec from its container's
ExecCommands before clearing its Running flag. Additionally, fix other
potential data races with execs by ensuring that the ExecConfig lock is
held whenever a mutable field is read from or written to.
Signed-off-by: Cory Snider <csnider@mirantis.com>
The containerd client is very chatty at the best of times. Because the
libcontained API is stateless and references containers and processes by
string ID for every method call, the implementation is essentially
forced to use the containerd client in a way which amplifies the number
of redundant RPCs invoked to perform any operation. The libcontainerd
remote implementation has to reload the containerd container, task
and/or process metadata for nearly every operation. This in turn
amplifies the number of context switches between dockerd and containerd
to perform any container operation or handle a containerd event,
increasing the load on the system which could otherwise be allocated to
workloads.
Overhaul the libcontainerd interface to reduce the impedance mismatch
with the containerd client so that the containerd client can be used
more efficiently. Split the API out into container, task and process
interfaces which the consumer is expected to retain so that
libcontainerd can retain state---especially the analogous containerd
client objects---without having to manage any state-store inside the
libcontainerd client.
Signed-off-by: Cory Snider <csnider@mirantis.com>
Add an integration test to verify that health checks are killed on
timeout and that the output is captured.
Co-authored-by: Nicolas De Loof <nicolas.deloof@gmail.com>
Signed-off-by: Cory Snider <csnider@mirantis.com>
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
Terminating the exec process when the context is canceled has been
broken since Docker v17.11 so nobody has been able to depend upon that
behaviour in five years of releases. We are thus free from backwards-
compatibility constraints.
Co-authored-by: Nicolas De Loof <nicolas.deloof@gmail.com>
Co-authored-by: Sebastiaan van Stijn <github@gone.nl>
Signed-off-by: Nicolas De Loof <nicolas.deloof@gmail.com>
Signed-off-by: Cory Snider <csnider@mirantis.com>
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
Now client have the possibility to set the console size of the executed
process immediately at the creation. This makes a difference for example
when executing commands that output some kind of text user interface
which is bounded by the console dimensions.
Signed-off-by: Paweł Gronowski <pawel.gronowski@docker.com>
Starting an exec can take a significant amount of time while under heavy
container operation load. In extreme cases the time to start the process
can take upwards of a second, which is a significant fraction of the
default health probe timeout (30s). With a shorter timeout, the exec
start delay could make the difference between a successful probe and a
probe timeout! Mitigate the impact of excessive exec start latencies by
only starting the probe timeout timer after the exec'ed process has
started.
Add a metric to sample the latency of starting health-check exec probes.
Signed-off-by: Cory Snider <csnider@mirantis.com>
As reported in docker/compose#6445, when deploying a Linux
container on Windows (LCOW), the daemon made the wrong assumption
when deciding which shell to use to execute the healthcheck, looking
at the host's platform instead of the container's platform.
This patch adds a check for the container's platform when deploying
on Windows, and sets the correct shell.
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
`time.After` keeps a timer running until the specified duration is
completed. It also allocates a new timer on each call. This can wind up
leaving lots of uneccessary timers running in the background that are
not needed and consume resources.
Instead of `time.After`, use `time.NewTimer` so the timer can actually
be stopped.
In some of these cases it's not a big deal since the duraiton is really
short, but in others it is much worse.
Signed-off-by: Brian Goff <cpuguy83@gmail.com>
Since Go 1.7, context is a standard package. Since Go 1.9, everything
that is provided by "x/net/context" is a couple of type aliases to
types in "context".
Many vendored packages still use x/net/context, so vendor entry remains
for now.
Signed-off-by: Kir Kolyshkin <kolyshkin@gmail.com>
Adds a mutex to protect the status, as well. When running the race
detector with the unit test, we can see that the Status field is written
without holding this lock. Adding a mutex to read and set status
addresses the issue.
Signed-off-by: Stephen J Day <stephen.day@docker.com>
Replicate relevant mutations to the in-memory ACID store. Readers will
then be able to query container state without locking.
Signed-off-by: Fabio Kung <fabio.kung@gmail.com>
The health check process doesn't have all the environment
varialbes in the container or has them set incorrectly.
This patch should fix that problem.
Signed-off-by: Boaz Shuster <ripcurld.github@gmail.com>
This adds a metrics packages that creates additional metrics. Add the
metrics endpoint to the docker api server under `/metrics`.
Signed-off-by: Michael Crosby <crosbymichael@gmail.com>
Add metrics to daemon package
Signed-off-by: Michael Crosby <crosbymichael@gmail.com>
api: use standard way for metrics route
Also add "type" query parameter
Signed-off-by: Alexander Morozov <lk4d4@docker.com>
Convert timers to ms
Signed-off-by: Michael Crosby <crosbymichael@gmail.com>
Instead reserve exit code 2 to be future proof, document that it should
not be used. Implementation-wise, it is considered as unhealthy, but
users should not rely on this as it may change in the future.
Signed-off-by: Tibor Vass <tibor@docker.com>
This fix tries to fix logrus formatting by removing `f` from
`logrus.[Error|Warn|Debug|Fatal|Panic|Info]f` when formatting string
is not present.
This fix fixes#23459.
Signed-off-by: Yong Tang <yong.tang.github@outlook.com>
This PR adds support for user-defined health-check probes for Docker
containers. It adds a `HEALTHCHECK` instruction to the Dockerfile syntax plus
some corresponding "docker run" options. It can be used with a restart policy
to automatically restart a container if the check fails.
The `HEALTHCHECK` instruction has two forms:
* `HEALTHCHECK [OPTIONS] CMD command` (check container health by running a command inside the container)
* `HEALTHCHECK NONE` (disable any healthcheck inherited from the base image)
The `HEALTHCHECK` instruction tells Docker how to test a container to check that
it is still working. This can detect cases such as a web server that is stuck in
an infinite loop and unable to handle new connections, even though the server
process is still running.
When a container has a healthcheck specified, it has a _health status_ in
addition to its normal status. This status is initially `starting`. Whenever a
health check passes, it becomes `healthy` (whatever state it was previously in).
After a certain number of consecutive failures, it becomes `unhealthy`.
The options that can appear before `CMD` are:
* `--interval=DURATION` (default: `30s`)
* `--timeout=DURATION` (default: `30s`)
* `--retries=N` (default: `1`)
The health check will first run **interval** seconds after the container is
started, and then again **interval** seconds after each previous check completes.
If a single run of the check takes longer than **timeout** seconds then the check
is considered to have failed.
It takes **retries** consecutive failures of the health check for the container
to be considered `unhealthy`.
There can only be one `HEALTHCHECK` instruction in a Dockerfile. If you list
more than one then only the last `HEALTHCHECK` will take effect.
The command after the `CMD` keyword can be either a shell command (e.g. `HEALTHCHECK
CMD /bin/check-running`) or an _exec_ array (as with other Dockerfile commands;
see e.g. `ENTRYPOINT` for details).
The command's exit status indicates the health status of the container.
The possible values are:
- 0: success - the container is healthy and ready for use
- 1: unhealthy - the container is not working correctly
- 2: starting - the container is not ready for use yet, but is working correctly
If the probe returns 2 ("starting") when the container has already moved out of the
"starting" state then it is treated as "unhealthy" instead.
For example, to check every five minutes or so that a web-server is able to
serve the site's main page within three seconds:
HEALTHCHECK --interval=5m --timeout=3s \
CMD curl -f http://localhost/ || exit 1
To help debug failing probes, any output text (UTF-8 encoded) that the command writes
on stdout or stderr will be stored in the health status and can be queried with
`docker inspect`. Such output should be kept short (only the first 4096 bytes
are stored currently).
When the health status of a container changes, a `health_status` event is
generated with the new status. The health status is also displayed in the
`docker ps` output.
Signed-off-by: Thomas Leonard <thomas.leonard@docker.com>
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
