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>
Config reloading has interleaved validations and other fallible
operations with mutating the live daemon configuration. The daemon
configuration could be left in a partially-reloaded state if any of the
operations returns an error. Mutating a copy of the configuration and
atomically swapping the config struct on success is not currently an
option as config values are not copyable due to the presence of
sync.Mutex fields. Introduce a two-phase commit protocol to defer any
mutations of the daemon state until after all fallible operations have
succeeded.
Reload transactions are not yet entirely hermetic. The platform
reloading logic for custom runtimes on *nix could still leave the
directory of generated runtime wrapper scripts in an indeterminate state
if an error is encountered.
Signed-off-by: Cory Snider <csnider@mirantis.com>
daemon/network/filter_test.go:174:19: empty-lines: extra empty line at the end of a block (revive)
daemon/restart.go:17:116: empty-lines: extra empty line at the end of a block (revive)
daemon/daemon_linux_test.go:255:41: empty-lines: extra empty line at the end of a block (revive)
daemon/reload_test.go:340:58: empty-lines: extra empty line at the end of a block (revive)
daemon/oci_linux.go:495:101: empty-lines: extra empty line at the end of a block (revive)
daemon/seccomp_linux_test.go:17:36: empty-lines: extra empty line at the start of a block (revive)
daemon/container_operations.go:560:73: empty-lines: extra empty line at the end of a block (revive)
daemon/daemon_unix.go:558:76: empty-lines: extra empty line at the end of a block (revive)
daemon/daemon_unix.go:1092:64: empty-lines: extra empty line at the start of a block (revive)
daemon/container_operations.go:587:24: empty-lines: extra empty line at the end of a block (revive)
daemon/network.go:807:18: empty-lines: extra empty line at the end of a block (revive)
daemon/network.go:813:42: empty-lines: extra empty line at the end of a block (revive)
daemon/network.go:872:72: empty-lines: extra empty line at the end of a block (revive)
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
This is a method on the daemon, which itself holds the Config, so
there's no need to pass the same configuration as an argument.
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
These are used internally only, and set by daemon.NewDaemon(). If they're
used externally, we should add an accessor added (which may be something
we want to do for daemon.registryService (which should be its own backend)
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
After moving libnetwork to this repo, we need to update all the import
paths for libnetwork to point to docker/docker/libnetwork instead of
docker/libnetwork.
This change implements that.
Signed-off-by: Brian Goff <cpuguy83@gmail.com>
Some tests were using domain names that were intended to be "fake", but are
actually registered domain names (such as domain.com, registry.com, mytest.com).
Even though we were not actually making connections to these domains, it's
better to use domains that are designated for testing/examples in RFC2606:
https://tools.ietf.org/html/rfc2606
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
This prevents the following test case failures "go test" is run
as non-root in the daemon/ directory:
> --- FAIL: TestContainerInitDNS (0.02s)
> daemon_test.go:209: chown /tmp/docker-container-test-054812199/volumes: operation not permitted
>
> --- FAIL: TestDaemonReloadNetworkDiagnosticPort (0.00s)
> reload_test.go:525: mkdir /var/lib/docker/network/files/: permission denied
> --- FAIL: TestRootMountCleanup (0.00s)
> daemon_linux_test.go:240: assertion failed: error is not nil: operation not permitted
Signed-off-by: Kir Kolyshkin <kolyshkin@gmail.com>
Add a new configuration option to allow the enabling
of the networkDB debug. The option is only parsed using the
reload event. This will protect the daemon on start or restart
if the option is left behind in the config file
Signed-off-by: Flavio Crisciani <flavio.crisciani@docker.com>
The --allow-nondistributable-artifacts daemon option specifies
registries to which foreign layers should be pushed. (By default,
foreign layers are not pushed to registries.)
Additionally, to make this option effective, foreign layers are now
pulled from the registry if possible, falling back to the URLs in the
image manifest otherwise.
This option is useful when pushing images containing foreign layers to a
registry on an air-gapped network so hosts on that network can pull the
images without connecting to another server.
Signed-off-by: Noah Treuhaft <noah.treuhaft@docker.com>
