Format the source according to latest goimports.
Signed-off-by: Kir Kolyshkin <kolyshkin@gmail.com>
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
This adds both a daemon-wide flag and a container creation property:
- Set the `CgroupnsMode: "host|private"` HostConfig property at
container creation time to control what cgroup namespace the container
is created in
- Set the `--default-cgroupns-mode=host|private` daemon flag to control
what cgroup namespace containers are created in by default
- Set the default if the daemon flag is unset to "host", for backward
compatibility
- Default to CgroupnsMode: "host" for client versions < 1.40
Signed-off-by: Rob Gulewich <rgulewich@netflix.com>
This changes the default ipc mode of daemon/engine to be private,
meaning the containers will not have their /dev/shm bind-mounted
from the host by default. The benefits of doing this are:
1. No leaked mounts. Eliminate a possibility to leak mounts into
other namespaces (and therefore unfortunate errors like "Unable to
remove filesystem for <ID>: remove /var/lib/docker/containers/<ID>/shm:
device or resource busy").
2. Working checkpoint/restore. Make `docker checkpoint`
not lose the contents of `/dev/shm`, but save it to
the dump, and be restored back upon `docker start --checkpoint`
(currently it is lost -- while CRIU handles tmpfs mounts,
the "shareable" mount is seen as external to container,
and thus rightfully ignored).
3. Better security. Currently any container is opened to share
its /dev/shm with any other container.
Obviously, this change will break the following usage scenario:
$ docker run -d --name donor busybox top
$ docker run --rm -it --ipc container:donor busybox sh
Error response from daemon: linux spec namespaces: can't join IPC
of container <ID>: non-shareable IPC (hint: use IpcMode:shareable
for the donor container)
The soution, as hinted by the (amended) error message, is to
explicitly enable donor sharing by using --ipc shareable:
$ docker run -d --name donor --ipc shareable busybox top
Compatibility notes:
1. This only applies to containers created _after_ this change.
Existing containers are not affected and will work fine
as their ipc mode is stored in HostConfig.
2. Old backward compatible behavior ("shareable" containers
by default) can be enabled by either using
`--default-ipc-mode shareable` daemon command line option,
or by adding a `"default-ipc-mode": "shareable"`
line in `/etc/docker/daemon.json` configuration file.
3. If an older client (API < 1.40) is used, a "shareable" container
is created. A test to check that is added.
Signed-off-by: Kir Kolyshkin <kolyshkin@gmail.com>
Please refer to `docs/rootless.md`.
TLDR:
* Make sure `/etc/subuid` and `/etc/subgid` contain the entry for you
* `dockerd-rootless.sh --experimental`
* `docker -H unix://$XDG_RUNTIME_DIR/docker.sock run ...`
Signed-off-by: Akihiro Suda <suda.akihiro@lab.ntt.co.jp>
Handle the case of systemd-resolved, and if in place
use a different resolv.conf source.
Set appropriately the option on libnetwork.
Move unix specific code to container_operation_unix
Signed-off-by: Flavio Crisciani <flavio.crisciani@docker.com>
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>
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>
