Container runtimes provide different levels of isolation, from kernel
namespaces to hardware virtualization. When starting a specific
container, one may want to decide which level of isolation to use
depending on how much we trust the container workload. Fully verified
and signed containers may not need the hardware isolation layer but e.g.
CI jobs pulling packages from many untrusted sources should probably not
run only on a kernel namespace isolation layer.
Here we allow CRI-O users to define a container runtime for trusted
containers and another one for untrusted containers, and also to define
a general, default trust level. This anticipates future kubelet
implementations that would be able to tag containers as trusted or
untrusted. When missing a kubelet hint, containers are trusted by
default.
A container becomes untrusted if we get a hint in that direction from
kubelet or if the default trust level is set to "untrusted" and the
container is not privileged. In both cases CRI-O will try to use the
untrusted container runtime. For any other cases, it will switch to the
trusted one.
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
We use a SOCK_SEQPACKET socket for the attach unix domain socket, which
means the kernel will ensure that the reading side only ever get the
data from one write operation. We use this for frameing, where the
first byte is the pipe that the next bytes are for. We have to make sure
that all reads from the socket are using at least the same size of buffer
as the write side, because otherwise the extra data in the message
will be dropped.
This also adds a stdin pipe for the container, similar to the ones we
use for stdout/err, because we need a way for an attached client
to write to stdin, even if not using a tty.
This fixes https://github.com/kubernetes-incubator/cri-o/issues/569
Signed-off-by: Alexander Larsson <alexl@redhat.com>
we were blindly applying RO mount options but net addons like calico
modify those files.
This patch sets RO only when container's rootfs is RO, same behavior as
docker.
Signed-off-by: Antonio Murdaca <runcom@redhat.com>
tmpfs'es can override whatever there's on the container rootfs. We just
mkdir the volume as we're confident kube manages volumes in container.
We don't need any tmpfs nor any complex volume handling for now.
Signed-off-by: Antonio Murdaca <runcom@redhat.com>
Vendor and use docker/pkg/pools.
pools are used to lower the number of memory allocations and reuse buffers when
processing large streams operations..
The use of pools.Copy avoids io.Copy's internal buffer allocation.
This commit replaces io.Copy with pools.Copy to avoid the allocation of
buffers in io.Copy.
Signed-off-by: Antonio Murdaca <runcom@redhat.com>
This was cluttering the logs on my clusters. The log should be just in
debug mode as we do for every request/response flow.
Signed-off-by: Antonio Murdaca <runcom@redhat.com>
By only handling create events, we are breaking plugins that don't
create and write atomically, like weave for example.
The Weave plugin creates the file first and later write to it. We are
missing the second part and never see the final CNI config file.
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
We don't want to block on accepting the terminal fd, because then
we can't detect if runc died before calling out to pass the terminal
fd. To handle this we spin the glib mainloop listening to both the
terminal accept fd and a child pid watch.
Signed-off-by: Alexander Larsson <alexl@redhat.com>
This is an optimization of our image pull code path. It's basically
how docker handles pulls as well. Let's be smart and check the image in
pull code path as well.
This also matches docker behavior which first checks whether we're
allowed to actually pull an image before looking into local storage.
Signed-off-by: Antonio Murdaca <runcom@redhat.com>
This patch fixes the following command:
kubectl run -i --tty centos --image=centos -- sh
The command above use to fail with:
/usr/bin/sh: /usr/bin/sh: cannot execute binary file
That's because we were wrongly assembling the OCI processArgs.
Thanks @alexlarsson for spotting this.
This patch basically replicates what docker does when merging container
config and image config. It also replicates how docker sets processArgs
for the OCI runtime.
Signed-off-by: Antonio Murdaca <runcom@redhat.com>
