Docker expects containers to be created before they are restored.
However, gVisor restoring requires specificactions regarding the kernel
and the file system. These actions were originally in booting the sandbox.
Now setting up the file system is deferred until a call to a call to
runsc start. In the restore case, the kernel is destroyed and a new kernel
is created in the same process, as we need the same process for Docker.
These changes required careful execution of concurrent processes which
required the use of a channel.
Full docker integration still needs the ability to restore into the same
container.
PiperOrigin-RevId: 205161441
Change-Id: Ie1d2304ead7e06855319d5dc310678f701bd099f
This is another step towards multi-container support.
Previously, we delivered signals directly to the sandbox process (which then
forwarded the signal to PID 1 inside the sandbox). Similarly, we waited on a
container by waiting on the sandbox process itself. This approach will not work
when there are multiple containers inside the sandbox, and we need to
signal/wait on individual containers.
This CL adds two new messages, ContainerSignal and ContainerWait. These
messages include the id of the container to signal/wait. The controller inside
the sandbox receives these messages and signals/waits on the appropriate
process inside the sandbox.
The container id is plumbed into the sandbox, but it currently is not used. We
still end up signaling/waiting on PID 1 in all cases. Once we actually have
multiple containers inside the sandbox, we will need to keep some sort of map
of container id -> pid (or possibly pid namespace), and signal/kill the
appropriate process for the container.
PiperOrigin-RevId: 197028366
Change-Id: I07b4d5dc91ecd2affc1447e6b4bdd6b0b7360895
Justine Olshan
Nicolas Lacasse
Googler