nomad does not reevaluate system jobs after 'node-drain -disable'

[bastiaanb]

Nomad version

Nomad v0.3.2-rc1 ('36fa82654df4e9c487da6af419dd4530f5af9d8e+CHANGES')

Operating system and Environment details

Linux localhost.localdomain 4.4.6-201.fc22.x86_64 #1 SMP Wed Mar 30 18:30:16 UTC 2016 x86_64 x86_64 x86_64 GNU/Linux

Issue

Upon a nomad node-drain -enable -self comand Nomad terminates all system tasks on that node.
After a subsequent nomad node-drain -disable -self Nomad does not reevaluate system jobs, so they will not be restarted automatically.
I would expect an automatic restart of system tasks, as the may be necessary for proper functioning of service and batch tasks that might be scheduled on the reenabled node.

Reproduction steps

1 start Nomad agent:

nomad agent -dev

2 generate example system job:

nomad init
perl -pi -e 's/# type = "service"/type = "system"/' example2.nomad

3 submit job:

nomad run example.nomad 
==> Monitoring evaluation "8d7876db"
    Evaluation triggered by job "example"
    Allocation "23dcc9ba" created: node "55321c75", group "cache"
    Evaluation status changed: "pending" -> "complete"
==> Evaluation "8d7876db" finished with status "complete"

4 drain node:

nomad node-drain -enable -self

5 check that job has been stopped:

nomad node-status -verbose -allocs
ID                                    DC   Name                   Class   Drain  Status  Running Allocs
55321c75-d319-5e76-3c26-3d116783c4ef  dc1  localhost.localdomain  <none>  true   ready   0

6 disable node drain:

nomad node-drain -disable -self

7 check that system job is not restarted:

nomad node-status -verbose -allocs
ID                                    DC   Name                   Class   Drain  Status  Running Allocs
55321c75-d319-5e76-3c26-3d116783c4ef  dc1  localhost.localdomain  <none>  false  ready   0

Nomad Server logs (if appropriate)

...
    2016/04/18 21:53:42 [DEBUG] http: Request /v1/node/55321c75-d319-5e76-3c26-3d116783c4ef/drain?enable=false (91.903µs)
    2016/04/18 21:53:56 [DEBUG] http: Request /v1/nodes (82.369µs)
    2016/04/18 21:53:56 [DEBUG] http: Request /v1/node/55321c75-d319-5e76-3c26-3d116783c4ef/allocations (162.484µs)

Nomad Client logs (if appropriate)

see above

Job file (if appropriate)

see above

[github-actions]

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