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>
Add daemon config to allow the user to specify the MTU of the control plane network.
The first user of this new parameter is actually libnetwork that can seed the
gossip with the proper MTU value allowing to pack multiple messages per UDP packet sent.
If the value is not specified or is lower than 1500 the logic will set it to the default.
Signed-off-by: Flavio Crisciani <flavio.crisciani@docker.com>
Allows storing key under any directory. In the case where the
"/etc/docker" directory is not preserved, this file can be
specified to a location where it will be preserved to ensure
the ID does not change across restarts.
Note this key is currently only used today to generate the ID
used in Docker info and for manifest schema v1 pushes. The key
signature and finger on these manifests are not checked or
used any longer for security, deprecated by notary.
Removes old key migration from a pre-release of Docker which put
the key under the home directory and was used to preserve ID used
for swarm v1 after the file moved.
closes#32135
Signed-off-by: Derek McGowan <derek@mcgstyle.net>
plugins exist in a chain that composes potentially mutating requests and
responses. This simply reverts the sorting of AuthZ plugins so that the
/info API endpoint returns the internal ordering used for AuthZ composition.
Volume driver plugins are not affected because they are just a set.
Signed-off-by: David Sheets <dsheets@docker.com>
- Moved DefaultInitBinary from daemon/daemon.go to
daemon/config/config.go since it's a daemon config and is referred in
config package files.
- Added condition in GetInitPath to check for any explicitly configured
DefaultInitBinary. If not, the default value of DefaultInitBinary is
returned.
- Changed all references of DefaultInitBinary to refer to the variable
from new location.
- Added TestCommonUnixGetInitPath to test for the various values of
GetInitPath.
Fixes#32314
Signed-off-by: Sunny Gogoi <indiasuny000@gmail.com>
When the daemon is configured to run with an authorization-plugin and if
the plugin is disabled, the daemon continues to send API requests to the
plugin and expect it to respond. But the plugin has been disabled. As a
result, all API requests are blocked. Fix this behavior by removing the
disabled plugin from the authz middleware chain.
Tested using riyaz/authz-no-volume-plugin and observed that after
disabling the plugin, API request/response is functional.
Fixes#31836
Signed-off-by: Anusha Ragunathan <anusha.ragunathan@docker.com>
This also moves some cli specific in `cmd/dockerd` as it does not
really belong to the `daemon/config` package.
Signed-off-by: Vincent Demeester <vincent@sbr.pm>
