The mkdir plugin creates the directory and then chowns it. In the
event the chown command fails, we should attempt to remove the
directory. Without this, we leave directories on the client in
partial failure situations.
Errors from `volume create` or `volume delete` only get logged by the client
agent, which may make it harder for volume authors to debug these tasks if they
are not also the cluster administrator with access to host logs.
Allow plugins to include an optional error message in their response. Because we
can't count on receiving this response (the error could come before the plugin
executes), we parse this message optimistically and include it only if
available.
Ref: https://hashicorp.atlassian.net/browse/NET-12087
The output of `GetDynamicHostVolumes` is a slice but that slice is constructed
from iterating over a map and isn't sorted. Sort the output in the test to
eliminate a test flake.
When we register a volume without a plugin, we need to send a client RPC so that
the node fingerprint can be updated. The registered volume also needs to be
written to client state so that we can restore the fingerprint after a restart.
Co-authored-by: Daniel Bennett <dbennett@hashicorp.com>
a node can have only one volume with a given name.
the scheduler prevents duplicates, but can only
do so after the server knows about the volume.
this prevents multiple concurrent creates being
called faster than the fingerprint/heartbeat interval.
users may still modify an existing volume only
if they set the `id` in the volume spec and
re-issue `nomad volume create`
if a *static* vol is added to config with a name
already being used by a dynamic volume, the
dynamic takes precedence, but log a warning.
Instead of a plugin `version` subcommand that responds with a string
(established in #24497), respond to a `fingerprint` command with a data
structure that we may extend in the future (such as plugin capabilities,
like size constraint support?). In the immediate term, it's still just the
version: `{"version": "0.0.1"}`
In addition to leaving the door open for future expansion, I think it will
also avoid false positives detecting executables that just happen to
respond to a `version` command.
This also reverses the ordering of the fingerprint string parts
from `plugins.host_volume.version.mkdir` (which aligned with CNI)
to `plugins.host_volume.mkdir.version` (makes more sense to me)
store dynamic host volume creations in client state,
so they can be "restored" on agent restart. restore works
by repeating the same Create operation as initial creation,
and expecting the plugin to be idempotent.
this is (potentially) especially important after host restarts,
which may have dropped mount points or such.
also ensure that volume ID is uuid-shaped so user-provided input
like `id = "../../../"` which is used as part of the target directory
can not find its way very far into the volume submission process
* mkdir: HostVolumePluginMkdir: just creates a directory
* example-host-volume: HostVolumePluginExternal:
plugin script that does mkfs and mount loopback
Co-authored-by: Tim Gross <tgross@hashicorp.com>
