Since the commit d88fe447df ("Add support for sharing /dev/shm/ and
/dev/mqueue between containers") container's /dev/shm is mounted on the
host first, then bind-mounted inside the container. This is done that
way in order to be able to share this container's IPC namespace
(and the /dev/shm mount point) with another container.
Unfortunately, this functionality breaks container checkpoint/restore
(even if IPC is not shared). Since /dev/shm is an external mount, its
contents is not saved by `criu checkpoint`, and so upon restore any
application that tries to access data under /dev/shm is severily
disappointed (which usually results in a fatal crash).
This commit solves the issue by introducing new IPC modes for containers
(in addition to 'host' and 'container:ID'). The new modes are:
- 'shareable': enables sharing this container's IPC with others
(this used to be the implicit default);
- 'private': disables sharing this container's IPC.
In 'private' mode, container's /dev/shm is truly mounted inside the
container, without any bind-mounting from the host, which solves the
issue.
While at it, let's also implement 'none' mode. The motivation, as
eloquently put by Justin Cormack, is:
> I wondered a while back about having a none shm mode, as currently it is
> not possible to have a totally unwriteable container as there is always
> a /dev/shm writeable mount. It is a bit of a niche case (and clearly
> should never be allowed to be daemon default) but it would be trivial to
> add now so maybe we should...
...so here's yet yet another mode:
- 'none': no /dev/shm mount inside the container (though it still
has its own private IPC namespace).
Now, to ultimately solve the abovementioned checkpoint/restore issue, we'd
need to make 'private' the default mode, but unfortunately it breaks the
backward compatibility. So, let's make the default container IPC mode
per-daemon configurable (with the built-in default set to 'shareable'
for now). The default can be changed either via a daemon CLI option
(--default-shm-mode) or a daemon.json configuration file parameter
of the same name.
Note one can only set either 'shareable' or 'private' IPC modes as a
daemon default (i.e. in this context 'host', 'container', or 'none'
do not make much sense).
Some other changes this patch introduces are:
1. A mount for /dev/shm is added to default OCI Linux spec.
2. IpcMode.Valid() is simplified to remove duplicated code that parsed
'container:ID' form. Note the old version used to check that ID does
not contain a semicolon -- this is no longer the case (tests are
modified accordingly). The motivation is we should either do a
proper check for container ID validity, or don't check it at all
(since it is checked in other places anyway). I chose the latter.
3. IpcMode.Container() is modified to not return container ID if the
mode value does not start with "container:", unifying the check to
be the same as in IpcMode.IsContainer().
3. IPC mode unit tests (runconfig/hostconfig_test.go) are modified
to add checks for newly added values.
[v2: addressed review at https://github.com/moby/moby/pull/34087#pullrequestreview-51345997]
[v3: addressed review at https://github.com/moby/moby/pull/34087#pullrequestreview-53902833]
[v4: addressed the case of upgrading from older daemon, in this case
container.HostConfig.IpcMode is unset and this is valid]
[v5: document old and new IpcMode values in api/swagger.yaml]
[v6: add the 'none' mode, changelog entry to docs/api/version-history.md]
Signed-off-by: Kir Kolyshkin <kolyshkin@gmail.com>
containers may specify these cgroup values at runtime. This will allow
processes to change their priority to real-time within the container
when CONFIG_RT_GROUP_SCHED is enabled in the kernel. See #22380.
Also added sanity checks for the new --cpu-rt-runtime and --cpu-rt-period
flags to ensure that that the kernel supports these features and that
runtime is not greater than period.
Daemon will support a --cpu-rt-runtime flag to initialize the parent
cgroup on startup, this prevents the administrator from alotting runtime
to docker after each restart.
There are additional checks that could be added but maybe too far? Check
parent cgroups to ensure values are <= parent, inspecting rtprio ulimit
and issuing a warning.
Signed-off-by: Erik St. Martin <alakriti@gmail.com>
This commit is a follow up of the last commit:
Vendor engine-api to allow docker daemon reload event.
After vendor/engine-api has been updated, the following
unit test fails:
```
--- FAIL: TestRestartPolicy (0.00s)
hostconfig_test.go:177: RestartPolicy.IsNone for { 0} should have been false but was true
```
The reason for the above failed unit test is that pull request:
https://github.com/docker/engine-api/pull/200
updated behavior of the restart policy and makes restartpolicy.IsNone
return true if restart policy name is `""`. As a result, the above
mentioned unit test fails.
This fix fixes the inconsistency of the unit test so that `TestRestartPolicy`
could pass again.
Signed-off-by: Yong Tang <yong.tang.github@outlook.com>
Following #19995 and #17409 this PR enables skipping userns re-mapping
when creating a container (or when executing a command). Thus, enabling
privileged containers running side by side with userns remapped
containers.
The feature is enabled by specifying ```--userns:host```, which will not
remapped the user if userns are applied. If this flag is not specified,
the existing behavior (which blocks specific privileged operation)
remains.
Signed-off-by: Liron Levin <liron@twistlock.com>
- Make the API client library completely standalone.
- Move windows partition isolation detection to the client, so the
driver doesn't use external types.
Signed-off-by: David Calavera <david.calavera@gmail.com>
The LXC driver was deprecated in Docker 1.8.
Following the deprecation rules, we can remove a deprecated feature
after two major releases. LXC won't be supported anymore starting on Docker 1.10.
Signed-off-by: David Calavera <david.calavera@gmail.com>
* Moving Network Remote APIs out of experimental
* --net can now accept user created networks using network drivers/plugins
* Removed the experimental services concept and --default-network option
* Neccessary backend changes to accomodate multiple networks per container
* Integration Tests
Signed-off-by: David Calavera <david.calavera@gmail.com>
Signed-off-by: Madhu Venugopal <madhu@docker.com>
Kir Kolyshkin