This PR replaces use of time.After with a safe helper function
that creates a time.Timer to use instead. The new function returns
both a time.Timer and a Stop function that the caller must handle.
Unlike time.NewTimer, the helper function does not panic if the duration
set is <= 0.
Add a new hostname string parameter to the network block which
allows operators to specify the hostname of the network namespace.
Changing this causes a destructive update to the allocation and it
is omitted if empty from API responses. This parameter also supports
interpolation.
In order to have a hostname passed as a configuration param when
creating an allocation network, the CreateNetwork func of the
DriverNetworkManager interface needs to be updated. In order to
minimize the disruption of future changes, rather than add another
string func arg, the function now accepts a request struct along with
the allocID param. The struct has the hostname as a field.
The in-tree implementations of DriverNetworkManager.CreateNetwork
have been modified to account for the function signature change.
In updating for the change, the enhancement of adding hostnames to
network namespaces has also been added to the Docker driver, whilst
the default Linux manager does not current implement it.
In Nomad 1.1.1 we generate a hosts file based on the Nomad-owned network
namespace, rather than using the default hosts file from the pause
container. This hosts file should be shared between tasks in the same
allocation so that tasks can update the file and have the results propagated
between tasks.
When `network.mode = "bridge"`, we create a pause container in Docker with no
networking so that we have a process to hold the network namespace we create
in Nomad. The default `/etc/hosts` file of that pause container is then used
for all the Docker tasks that share that network namespace. Some applications
rely on this file being populated.
This changeset generates a `/etc/hosts` file and bind-mounts it to the
container when Nomad owns the network, so that the container's hostname has an
IP in the file as expected. The hosts file will include the entries added by
the Docker driver's `extra_hosts` field.
In this changeset, only the Docker task driver will take advantage of this
option, as the `exec`/`java` drivers currently copy the host's `/etc/hosts`
file and this can't be changed without breaking backwards compatibility. But
the fields are available in the task driver protobuf for community task
drivers to use if they'd like.
The error output being checked depends on the linux caps supported
by the particular operating system. Fix these test cases to just
check that an error did occur.
This changeset does not introduce any functional change for the
docker driver, but rather cleans up the implementation around
computing configured capabilities by re-using code written for
the exec/java task drivers.
This PR enables setting allow_caps on the exec driver
plugin configuration, as well as cap_add and cap_drop in
exec task configuration. These options replicate the
functionality already present in the docker task driver.
Important: this change also reduces the default set of
capabilities enabled by the exec driver to match the
default set enabled by the docker driver. Until v1.0.5
the exec task driver would enable all capabilities supported
by the operating system. v1.0.5 removed NET_RAW from that
list of default capabilities, but left may others which
could potentially also be leveraged by compromised tasks.
Important: the "root" user is still special cased when
used with the exec driver. Older versions of Nomad enabled
enabled all capabilities supported by the operating system
for tasks set with the root user. To maintain compatibility
with existing clusters we continue supporting this "feature",
however we maintain support for the legacy set of capabilities
rather than enabling all capabilities now supported on modern
operating systems.
The default Linux Capabilities set enabled by the docker, exec, and
java task drivers includes CAP_NET_RAW (for making ping just work),
which has the side affect of opening an ARP DoS/MiTM attack between
tasks using bridge networking on the same host network.
https://docs.docker.com/engine/reference/run/#runtime-privilege-and-linux-capabilities
This PR disables CAP_NET_RAW for the docker, exec, and java task
drivers. The previous behavior can be restored for docker using the
allow_caps docker plugin configuration option.
A future version of nomad will enable similar configurability for the
exec and java task drivers.
This fixes a bug where Nomad overrides a Dockerfile's STOPSIGNAL with
the default kill_signal (SIGTERM).
This adds a check for kill_signal. If it's not set, it calls
StopContainer instead of Signal, which uses STOPSIGNAL if it's
specified. If both kill_signal and STOPSIGNAL are set, Nomad tries to
stop the container with kill_signal first, before then calling
StopContainer.
Fixes#9989
The error returned from the stdlib's `exec` package is always a message with
the exit code of the exec'd process, not any error message that process might
have given us. This results in opaque failures for the Nomad user. Cast to an
`ExitError` so that we can access the output from stderr.
If the docker engine is running on cgroup-v2 host, then RSS and Max
Usage doesn't get reported.
Using a heauristic here to avoid adding more API calls to the Docker
Engine to infer cgroups version. Also, opted to avoid coordinating stats
collection with fingerprinting, which adds concurrency complexities.
The test assertion that we don't have a delete future remaining races with the
code its testing, because the removal of the image and the removal of the
future are not atomic. Move this assertion into a `WaitForResult` to avoid
test flakes which we're seeing on CI on Windows in particular.
Introduce a new more-block friendly syntax for specifying mounts with a new `mount` block type with the target as label:
```hcl
config {
image = "..."
mount {
type = "..."
target = "target-path"
volume_options { ... }
}
}
```
The main benefit here is that by `mount` being a block, it can nest blocks and avoids the compatibility problems noted in https://github.com/hashicorp/nomad/pull/9634/files#diff-2161d829655a3a36ba2d916023e4eec125b9bd22873493c1c2e5e3f7ba92c691R128-R155 .
The intention is for us to promote this `mount` blocks and quietly deprecate the `mounts` type, while still honoring to preserve compatibility as much as we could.
This addresses the issue in https://github.com/hashicorp/nomad/issues/9604 .
When the Docker driver kills as task, we send a request via the Docker API for
dockerd to fire the signal. We send that signal and then block for the
`kill_timeout` waiting for the container to exit. But if the Docker API
blocks, we will block indefinitely because we haven't configured the API call
with the same timeout.
This changeset is a minimal intervention to add the timeout to the Docker API
call _only_ when we have the `kill_timeout` set. Future work should examine
whether we should be threading contexts through other `go-dockerclient` API
calls.
The default behavior for `docker.volumes.enabled` is intended to be `false`,
but the HCL schema defaults to `true` if the value is unset. Set the default
literal value to `true`.
Additionally, Docker driver mounts of type "volume" (but not "bind") are not
being properly sandboxed with that setting. Disable Docker mounts with type
"volume" entirely whenever the `docker.volumes.enabled` flag is set to
false. Note this is unrelated to the `volume_mount` feature, which is
constrained to preconfigured host volumes or whatever is mounted by a CSI
plugin.
This changeset includes updates to unit tests that should have been failing
under the documented behavior but were not.
Dockerhub is going to rate limit unauthenticated pulls.
Use our HashiCorp internal mirror for builds run through CircleCI.
Co-authored-by: Mahmood Ali <mahmood@hashicorp.com>
In the Docker driver plugin config for garbage collection, the `image_delay`
field was missing from the default we set if the entire `gc` stanza is
missing. This results in a default of 0s and immediate GC of Docker images.
Expanded docker gc config test fields.
