When an allocation runs for a task driver that can't support volume mounts,
the mounting will fail in a way that can be hard to understand. With host
volumes this usually means failing silently, whereas with CSI the operator
gets inscrutable internals exposed in the `nomad alloc status`.
This changeset adds a MountConfig field to the task driver Capabilities
response. We validate this when the `csi_hook` or `volume_hook` fires and
return a user-friendly error.
Note that we don't currently have a way to get driver capabilities up to the
server, except through attributes. Validating this when the user initially
submits the jobspec would be even better than what we're doing here (and could
be useful for all our other capabilities), but that's out of scope for this
changeset.
Also note that the MountConfig enum starts with "supports all" in order to
support community plugins in a backwards compatible way, rather than cutting
them off from volume mounting unexpectedly.
Some CSI plugins don't return much for errors over the gRPC socket
above and beyond the bare minimum error codes. This changeset improves
the operator experience by unpacking the error codes when available
and wrapping the error with some user-friendly direction.
Improving these errors also revealed a bad comparison with
`require.Error` when `require.EqualError` should be used in the test
code for plugin errors. This defect in turn was hiding a bug in volume
validation where we're being overly permissive in allowing mount
flags, which is now fixed.
The plugin supervisor lazily connects to plugins, but this means we
only get "Unavailable" back from the gRPC call in cases where the
plugin can never be reached (for example, if the Nomad client has the
wrong permissions for the socket).
This changeset improves the operator experience by switching to a
blocking `DialWithContext`. It eagerly connects so that we can
validate the connection is real and get a "failed to open" error in
case where Nomad can't establish the initial connection.
The MVP for CSI in the 0.11.0 release of Nomad did not include support
for opaque volume parameters or volume context. This changeset adds
support for both.
This also moves args for ControllerValidateCapabilities into a struct.
The CSI plugin `ControllerValidateCapabilities` struct that we turn
into a CSI RPC is accumulating arguments, so moving it into a request
struct will reduce the churn of this internal API, make the plugin
code more readable, and make this method consistent with the other
plugin methods in that package.
The plugin supervisor lazily connects to plugins, but this means we
only get "Unavailable" back from the gRPC call in cases where the
plugin can never be reached (for example, if the Nomad client has the
wrong permissions for the socket).
This changeset improves the operator experience by switching to a
blocking `DialWithContext`. It eagerly connects so that we can
validate the connection is real and get a "failed to open" error in
case where Nomad can't establish the initial connection.
The CSI plugins RPCs require the use of the storage provider's volume
ID, rather than the user-defined volume ID. Although changing the RPCs
to use the field name `ExternalID` risks breaking backwards
compatibility, we can use the `ExternalID` name internally for the
client and only use `VolumeID` at the RPC boundaries.
CSI plugins can require credentials for some publishing and
unpublishing workflow RPCs. Secrets are configured at the time of
volume registration, stored in the volume struct, and then passed
around as an opaque map by Nomad to the plugins.
When serializing structs with msgpack, only consider type tags of
`codec`.
Hashicorp/go-msgpack (based on ugorji/go) defaults to interpretting
`codec` tag if it's available, but falls to using `json` if `codec`
isn't present.
This behavior is surprising in cases where we want to serialize json
differently from msgpack, e.g. serializing `ConsulExposeConfig`.
Several of the CSI `VolumeCapability` methods return pointers, which
we were then comparing to pointers in the request rather than
dereferencing them and comparing their contents.
This changeset does a more fine-grained comparison of the request vs
the capabilities, and adds better error messaging.
This changeset corrects handling of the `ValidationVolumeCapabilities`
response:
* The CSI spec for the `ValidationVolumeCapabilities` requires that
plugins only set the `Confirmed` field if they've validated all
capabilities. The Nomad client improperly assumes that the lack of a
`Confirmed` field should be treated as a failure. This breaks the
Azure and Linode block storage plugins, which don't set this
optional field.
* The CSI spec also requires that the orchestrator check the validation
responses to guard against older versions of a plugin reporting
"valid" for newer fields it doesn't understand.
The CSI Specification defines various gRPC Errors and how they may be retried. After auditing all our CSI RPC calls in #6863, this changeset:
* adds retries and backoffs to the where they were needed but not implemented
* annotates those CSI RPCs that do not need retries so that we don't wonder whether it's been left off accidentally
* added a timeout and cancellation context to the `Probe` call, which didn't have one.
Add mount_options to both the volume definition on registration and to the volume block in the group where the volume is requested. If both are specified, the options provided in the request replace the options defined in the volume. They get passed to the NodePublishVolume, which causes the node plugin to actually mount the volume on the host.
Individual tasks just mount bind into the host mounted volume (unchanged behavior). An operator can mount the same volume with different options by specifying it twice in the group context.
closes#7007
* nomad/structs/volumes: add MountOptions to volume request
* jobspec/test-fixtures/basic.hcl: add mount_options to volume block
* jobspec/parse_test: add expected MountOptions
* api/tasks: add mount_options
* jobspec/parse_group: use hcl decode not mapstructure, mount_options
* client/allocrunner/csi_hook: pass MountOptions through
client/allocrunner/csi_hook: add a VolumeMountOptions
client/allocrunner/csi_hook: drop Options
client/allocrunner/csi_hook: use the structs options
* client/pluginmanager/csimanager/interface: UsageOptions.MountOptions
* client/pluginmanager/csimanager/volume: pass MountOptions in capabilities
* plugins/csi/plugin: remove todo 7007 comment
* nomad/structs/csi: MountOptions
* api/csi: add options to the api for parsing, match structs
* plugins/csi/plugin: move VolumeMountOptions to structs
* api/csi: use specific type for mount_options
* client/allocrunner/csi_hook: merge MountOptions here
* rename CSIOptions to CSIMountOptions
* client/allocrunner/csi_hook
* client/pluginmanager/csimanager/volume
* nomad/structs/csi
* plugins/csi/fake/client: add PrevVolumeCapability
* plugins/csi/plugin
* client/pluginmanager/csimanager/volume_test: remove debugging
* client/pluginmanager/csimanager/volume: fix odd merging logic
* api: rename CSIOptions -> CSIMountOptions
* nomad/csi_endpoint: remove a 7007 comment
* command/alloc_status: show mount options in the volume list
* nomad/structs/csi: include MountOptions in the volume stub
* api/csi: add MountOptions to stub
* command/volume_status_csi: clean up csiVolMountOption, add it
* command/alloc_status: csiVolMountOption lives in volume_csi_status
* command/node_status: display mount flags
* nomad/structs/volumes: npe
* plugins/csi/plugin: npe in ToCSIRepresentation
* jobspec/parse_test: expand volume parse test cases
* command/agent/job_endpoint: ApiTgToStructsTG needs MountOptions
* command/volume_status_csi: copy paste error
* jobspec/test-fixtures/basic: hclfmt
* command/volume_status_csi: clean up csiVolMountOption
Run the plugin fingerprint one last time with a closed client during
instance manager shutdown. This will return quickly and will give us a
correctly-populated `PluginInfo` marked as unhealthy so the Nomad
client can update the server about plugin health.
Derive a provider name and version for plugins (and the volumes that
use them) from the CSI identity API `GetPluginInfo`. Expose the vendor
name as `Provider` in the API and CLI commands.
This changeset implements the minimal structs on the client-side we
need to compile the work-in-progress implementation of the
server-to-controller RPCs. It doesn't include implementing the
`ClientCSI.DettachVolume` RPC on the client.
This commit introduces a nomad model for interacting with CSI
VolumeCapabilities as a pre-requisite for implementing NodeStageVolume
and NodeMountVolume correctly.
These fields have a few special characteristics that I've tried to model
here - specificially, we make a basic attempt to avoid printing data
that should be redacted during debug logs (additional mount flags), and
also attempt to make debuggability of other integer fields easier by
implementing the fmt.Stringer and fmt.GoStringer interfaces as
necessary.
We do not currnetly implement a CSI Protobuf -> Nomad implementation
transformation as this is currently not needed by any used RPCs.
This changeset implements the initial registration and fingerprinting
of CSI Plugins as part of #5378. At a high level, it introduces the
following:
* A `csi_plugin` stanza as part of a Nomad task configuration, to
allow a task to expose that it is a plugin.
* A new task runner hook: `csi_plugin_supervisor`. This hook does two
things. When the `csi_plugin` stanza is detected, it will
automatically configure the plugin task to receive bidirectional
mounts to the CSI intermediary directory. At runtime, it will then
perform an initial heartbeat of the plugin and handle submitting it to
the new `dynamicplugins.Registry` for further use by the client, and
then run a lightweight heartbeat loop that will emit task events
when health changes.
* The `dynamicplugins.Registry` for handling plugins that run
as Nomad tasks, in contrast to the existing catalog that requires
`go-plugin` type plugins and to know the plugin configuration in
advance.
* The `csimanager` which fingerprints CSI plugins, in a similar way to
`drivermanager` and `devicemanager`. It currently only fingerprints
the NodeID from the plugin, and assumes that all plugins are
monolithic.
Missing features
* We do not use the live updates of the `dynamicplugin` registry in
the `csimanager` yet.
* We do not deregister the plugins from the client when they shutdown
yet, they just become indefinitely marked as unhealthy. This is
deliberate until we figure out how we should manage deploying new
versions of plugins/transitioning them.
Operators commonly have docker logs aggregated using various tools and
don't need nomad to manage their docker logs. Worse, Nomad uses a
somewhat heavy docker api call to collect them and it seems to cause
problems when a client runs hundreds of log collections.
Here we add a knob to disable log aggregation completely for nomad.
When log collection is disabled, we avoid running logmon and
docker_logger for the docker tasks in this implementation.
The downside here is once disabled, `nomad logs ...` commands and API
no longer return logs and operators must corrolate alloc-ids with their
aggregated log info.
This is meant as a stop gap measure. Ideally, we'd follow up with at
least two changes:
First, we should optimize behavior when we can such that operators don't
need to disable docker log collection. Potentially by reverting to
using pre-0.9 syslog aggregation in linux environments, though with
different trade-offs.
Second, when/if logs are disabled, nomad logs endpoints should lookup
docker logs api on demand. This ensures that the cost of log collection
is paid sparingly.
* fix plugin launcher SetConfig msgpack params
The plugin launcher tool was passing the wrong byte array into
`SetConfig`, resulting in msgpack decoding errors. This was fixed in
a949050 (#6725) but accidentally reverted in 6aff18d (#6590).
Co-Authored-By: Chris Baker <1675087+cgbaker@users.noreply.github.com>
This commit introduces support for configuring mount propagation when
mounting volumes with the `volume_mount` stanza on Linux targets.
Similar to Kubernetes, we expose 3 options for configuring mount
propagation:
- private, which is equivalent to `rprivate` on Linux, which does not allow the
container to see any new nested mounts after the chroot was created.
- host-to-task, which is equivalent to `rslave` on Linux, which allows new mounts
that have been created _outside of the container_ to be visible
inside the container after the chroot is created.
- bidirectional, which is equivalent to `rshared` on Linux, which allows both
the container to see new mounts created on the host, but
importantly _allows the container to create mounts that are
visible in other containers an don the host_
private and host-to-task are safe, but bidirectional mounts can be
dangerous, as if the code inside a container creates a mount, and does
not clean it up before tearing down the container, it can cause bad
things to happen inside the kernel.
To add a layer of safety here, we require that the user has ReadWrite
permissions on the volume before allowing bidirectional mounts, as a
defense in depth / validation case, although creating mounts should also require
a priviliged execution environment inside the container.
Tim Gross