The existing runtimes reload logic went to great lengths to replace the
directory containing runtime wrapper scripts as atomically as possible
within the limitations of the Linux filesystem ABI. Trouble is,
atomically swapping the wrapper scripts directory solves the wrong
problem! The runtime configuration is "locked in" when a container is
started, including the path to the runC binary. If a container is
started with a runtime which requires a daemon-managed wrapper script
and then the daemon is reloaded with a config which no longer requires
the wrapper script (i.e. some args -> no args, or the runtime is dropped
from the config), that container would become unmanageable. Any attempts
to stop, exec or otherwise perform lifecycle management operations on
the container are likely to fail due to the wrapper script no longer
existing at its original path.
Atomically swapping the wrapper scripts is also incompatible with the
read-copy-update paradigm for reloading configuration. A handler in the
daemon could retain a reference to the pre-reload configuration for an
indeterminate amount of time after the daemon configuration has been
reloaded and updated. It is possible for the daemon to attempt to start
a container using a deleted wrapper script if a request to run a
container races a reload.
Solve the problem of deleting referenced wrapper scripts by ensuring
that all wrapper scripts are *immutable* for the lifetime of the daemon
process. Any given runtime wrapper script must always exist with the
same contents, no matter how many times the daemon config is reloaded,
or what changes are made to the config. This is accomplished by using
everyone's favourite design pattern: content-addressable storage. Each
wrapper script file name is suffixed with the SHA-256 digest of its
contents to (probabilistically) guarantee immutability without needing
any concurrency control. Stale runtime wrapper scripts are only cleaned
up on the next daemon restart.
Split the derived runtimes configuration from the user-supplied
configuration to have a place to store derived state without mutating
the user-supplied configuration or exposing daemon internals in API
struct types. Hold the derived state and the user-supplied configuration
in a single struct value so that they can be updated as an atomic unit.
Signed-off-by: Cory Snider <csnider@mirantis.com>
Ensure data-race-free access to the daemon configuration without
locking by mutating a deep copy of the config and atomically storing
a pointer to the copy into the daemon-wide configStore value. Any
operations which need to read from the daemon config must capture the
configStore value only once and pass it around to guarantee a consistent
view of the config.
Signed-off-by: Cory Snider <csnider@mirantis.com>
- Split these options to a separate struct, so that we can handle them in isolation.
- Change some tests to use subtests, and improve coverage
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
This test runs with t.Parallel() _and_ uses subtests, but didn't capture
the `tc` variable, which potentialy (likely) makes it test the same testcase
multiple times.
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
The io/ioutil package has been deprecated in Go 1.16. This commit
replaces the existing io/ioutil functions with their new definitions in
io and os packages.
Signed-off-by: Eng Zer Jun <engzerjun@gmail.com>
Disabling the oom-killer for a container without setting a memory limit
is dangerous, as it can result in the container consuming unlimited memory,
without the kernel being able to kill it. A check for this situation is curently
done in the CLI, but other consumers of the API won't receive this warning.
This patch adds a check for this situation to the daemon, so that all consumers
of the API will receive this warning.
This patch will have one side-effect; docker cli's that also perform this check
client-side will print the warning twice; this can be addressed by disabling
the cli-side check for newer API versions, but will generate a bit of extra
noise when using an older CLI.
With this patch applied (and a cli that does not take the new warning into account);
```
docker create --oom-kill-disable busybox
WARNING: OOM killer is disabled for the container, but no memory limit is set, this can result in the system running out of resources.
669933b9b237fa27da699483b5cf15355a9027050825146587a0e5be0d848adf
docker run --rm --oom-kill-disable busybox
WARNING: Disabling the OOM killer on containers without setting a '-m/--memory' limit may be dangerous.
WARNING: OOM killer is disabled for the container, but no memory limit is set, this can result in the system running out of resources.
```
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
Migrate legacy volumes (Daemon.verifyVolumesInfo) before containers are
registered on the Daemon, so state on disk is not overwritten and legacy
fields lost during registration.
Signed-off-by: Fabio Kung <fabio.kung@gmail.com>
Reuse existing structures and rely on json serialization to deep copy
Container objects.
Also consolidate all "save" operations on container.CheckpointTo, which
now both saves a serialized json to disk, and replicates state to the
ACID in-memory store.
Signed-off-by: Fabio Kung <fabio.kung@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>
This was removed in a clean-up
(060f4ae617) but should not have been.
Fixes issues with volumes when upgrading from pre-1.7.0 daemons.
Signed-off-by: Brian Goff <cpuguy83@gmail.com>
All other options we have use `=` as separator, labels,
log configurations, graph configurations and so on.
We should be consistent and use `=` for the security
options too.
Signed-off-by: David Calavera <david.calavera@gmail.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>
