In UNIX, any zombies without parent process get re-parented to process
with PID 1 (usually running init), and PID 1 process should take care of
them (usually simply clean them up). Cleaning up zombies is important,
as they still take kerner resources, and having enormous amount of
zombie processes signifcantly degrades system performance.
For Talos, PID 1 process is machined, and machined itself forks to run
other processes in process runner and `pkg/cmd` one-time commands. Naive
solution of running `wait()` loop doesn't work as it might race with
`Process.Wait()` and clean up zombie which wasn't re-parented which
leads to process execution false failure.
After considering other solutions, we decided to go with the simple
approach: machined runs global zombie process reaper which publishes
information about reaped zombies. Any call to `Process.Wait()` (or
`Command.Wait()` which calls it) should be replaced with listening to
reaper's channel for notifications to catch info about the process which
was created in this call.
There are several changes in this PR:
1. Reaper implementation itself, started from machined.
2. Process runner and `pkg/cmd` can either use regular `Command.Wait()`
or use reaper notifications depending on reaper status (running/not
running). This allows using this code outside of machined.
3. Small bug fixes with process log which was affecting the tests.
Signed-off-by: Andrey Smirnov <smirnov.andrey@gmail.com>
We need to support eventing with associated data. This moves the event
bus to an observer design pattern that allows observers to register for
specific events, and to receive the associated data.
Signed-off-by: Andrew Rynhard <andrew@andrewrynhard.com>
This adds an interface that can be used to descibe boot, shutdown, and
upgrade events in a set of phases.
Signed-off-by: Andrew Rynhard <andrew@andrewrynhard.com>
This adds a well defined task for handling all overlay mount points that
are required by the system.
Signed-off-by: Andrew Rynhard <andrew@andrewrynhard.com>
This is a major rewrite of our network subsystem.
- This changes networkd to run as a standalone app versus internal goroutine
- This changes out the netlink package with the more idiomatic netlink/rtnetlink
packages
- This changes the initial network bootstrap/discovery from using a single
interface to attempting to bring up all interfaces
- This moves us back on to the upstream dhcp library
Signed-off-by: Brad Beam <brad.beam@talos-systems.com>
This also includes a fix for #955 which had the unintended side effect
of breaking image creation ( since it would attempt to grow the filesystem
always ).
The refactor standardizes around looking for the DATA and ESP labels to
discover any existing installations/filesystems. If none are found, an
installation will proceed -- for both image creation and bare metal.
During bootup, the DATA partition will always attempt to expand/grow.
This also introduces a new phase to verify the installation through the
existance of /boot/installed ( migrated from install stage ).
Signed-off-by: Brad Beam <brad.beam@talos-systems.com>
This re-arranges phases a bit so that shutdown actions are pushed back
to the top-level main.go of machined.
Small rudimentary event.Bus is introduce to facilitate event passing
(shutdown/restart) between various machined components and main.go. This
might be not the best implementation, just something to allow this
message passing without global variables or such.
Machined API was refactored to run as goroutine service.
ACPI & signal handlers re-built as phase tasks, and activated for
non-container, container modes respectively.
As part of the fix, now `docker stop` triggers correct shutdown of Talos
(not a big deal, but good for testing).
Signed-off-by: Andrey Smirnov <smirnov.andrey@gmail.com>
This change aims to make installations more unified and reliable. It
introduces the concept of a mountpoint manager that is capable of
mounting, unmounting, and moving a set of mountpoints in the correct
order.
Signed-off-by: Andrew Rynhard <andrew@andrewrynhard.com>
Without running the install task first, /var is read-only. This causes
the overlay phase to fail as it tries to create /var/system.
Signed-off-by: Andrew Rynhard <andrew@andrewrynhard.com>
Phases should run sequentially, while tasks concurrently in a phase.
There are two potential issues fixed:
1. `result` multierror was updated inside goroutine without any
synchronization, so this is a data race
2. panic inside task/phase runner might happen and as unhandled panic in a
goroutine aborts whole process, this might lead to a system halt as
as the 'machined' exits
Signed-off-by: Andrey Smirnov <smirnov.andrey@gmail.com>
This change aims to standardize the boot process. It introduces the
concept of a phase, which is comprised of tasks. Phases are ran in serial and
the tasks that make up a phase are ran concurrently.
Signed-off-by: Andrew Rynhard <andrew@andrewrynhard.com>
The responsibility of init should only be to mount the rootfs. This
change moves Talos specific logic into machined. This will allow us to
define a version of Talos in a single binary instead of split across
two. This will enable cleaner upgrades and helps make the codebase
easier to reason about.
Signed-off-by: Andrew Rynhard <andrew@andrewrynhard.com>
We need /etc/resolv.conf to be writable so that networkd can update it.
This change achieves this by creating a symlink at /etc/resolv.conf that
points to /var/resolv.conf.
Signed-off-by: Andrew Rynhard <andrew@andrewrynhard.com>
