Request: Propagate Firecracker Task Driver errors to Nomad UI

[wimax-grapl]

So I have a task start failing with the following, not-very-useful info:

rpc error: code = Unknown desc = task with ID "8ee3098b-7420-cb04-2892-fedaa3c730ba/tenant-plugin/339ec6bd" failed

However, going to the Nomad Agent logs I get the following, much more intelligible errors:
failure when invoking CNI: failed to load CNI configuration from dir "/etc/cni/conf.d" for network "default": no net configurations found in /etc/cni/conf.d"

    2022-04-04T13:23:32.274-0400 [INFO]  client.driver_mgr.firecracker-task-driver: starting firecracker task: driver=firecracker-task-driver driver_cfg="{KernelImage: BootOptions: BootDis
k: Disks:[] Network:default Nic:{Ip: Gateway: Interface: Nameservers:[]} Vcpus:1 Cputype: Mem:128 Firecracker:/usr/bin/firecracker Log: DisableHt:false}" @module=firecracker-task-driver ti
mestamp=2022-04-04T13:23:32.274-0400
    2022-04-04T13:23:32.274-0400 [INFO]  client.driver_mgr.firecracker-task-driver: Starting firecracker: driver=firecracker-task-driver driver_initialize_container="&{/usr/bin/firecracker
 /tmp/NomadClient1700322499/3aee425c-e789-5c1c-e029-d552efbf942c/tenant-plugin/vmlinux  console=ttyS0 reboot=k panic=1 pci=off nomodules /tmp/NomadClient1700322499/3aee425c-e789-5c1c-e029-
d552efbf942c/tenant-plugin/rootfs.ext4  [] default {   []} []    false 1  300    false false [] <nil> 0xc384c0}+" @module=firecracker-task-driver timestamp=2022-04-04T13:23:32.274-0400
    2022-04-04T13:23:32.275-0400 [INFO]  client.driver_mgr.firecracker-task-driver: Error starting firecracker vm: driver=firecracker-task-driver @module=firecracker-task-driver driver_cfg
="Failed to start machine: failure when invoking CNI: failed to load CNI configuration from dir \"/etc/cni/conf.d\" for network \"default\": no net configurations found in /etc/cni/conf.d"
 timestamp=2022-04-04T13:23:32.275-0400
    2022-04-04T13:23:32.275-0400 [ERROR] client.alloc_runner.task_runner: running driver failed: alloc_id=3aee425c-e789-5c1c-e029-d552efbf942c task=tenant-plugin error="rpc error: code = U
nknown desc = task with ID \"3aee425c-e789-5c1c-e029-d552efbf942c/tenant-plugin/0e1713e6\" failed"
    2022-04-04T13:23:32.275-0400 [INFO]  client.alloc_runner.task_runner: not restarting task: alloc_id=3aee425c-e789-5c1c-e029-d552efbf942c task=tenant-plugin reason="Error was unrecovera
ble"

I was wondering if it'd be possible to propagate that error up to the UI? Thanks!

[wimax-grapl]

(you'll note that the alloc_id is different, I accidentally captured a retry, but the same shows up for 8ee3098b.)

[ValentaTomas]

I would also appreciate this. I'm doing some custom changes to the task driver and even just letting the errors propagate as they are was really helpful.

Do you think just propagating the error here:
https://github.com/cneira/firecracker-task-driver/blob/master/driver/driver.go#L297
https://github.com/cneira/firecracker-task-driver/blob/master/driver/driver.go#L258
would be alright?

[wimax-grapl]

I'm not the author of this plugin, but I think based on how other official supported Nomad drivers work, it'd be totally reasonable.

The vast majority of the StartTask return statements include the err in, say, the Docker driver:
https://github.com/hashicorp/nomad/blob/52faa167dd0e18685440de5b6613f397b5fa0aa8/drivers/docker/driver.go#L300

[ValentaTomas]

I made these changed in #21

[ValentaTomas]

@cneira I think we can close this issue.