Nomad tutorial sample job file not working

[mly32]

Nomad version

Nomad v1.3.1

Operating system and Environment details

macOS 12.4 arm64 (MacBookPro18)

Issue

The tutorial's sample job file generated by nomad job init has a stanza that requires Consul; however, the tutorial has no mention of Consul.

The job fails to place allocations because Constraint "${attr.consul.version} semver >= 1.7.0": 1 nodes excluded by filter.

I found two methods to resolve this:

1. Comment out part of the generated example.nomad file. Interestingly, generating the file with nomad job init -short does not include the stanza below, so the job runs fine if the shortened version is used.

    # comment this out
    service {
      name = "redis-cache"
      tags = ["global", "cache"]
      port = "db"
    }

2. Run Consul on the side (consul agent -dev) and restart the Nomad agent and job.

Reproduction steps

Follow the tutorial (without running on a VM generated by the provided Vagrantfile because the VM does not work on M1 Macs).

# start the agent
sudo nomad agent -dev -bind 0.0.0.0 -log-level INFO

# generate the sample job
nomad job init
# run the job
nomad job run example.nomad

Expected Result

==> 2022-05-31T11:12:50-07:00: Monitoring evaluation "0890a4fe"
    2022-05-31T11:12:50-07:00: Evaluation triggered by job "example"
    2022-05-31T11:12:50-07:00: Evaluation within deployment: "6eadb641"
    2022-05-31T11:12:50-07:00: Allocation "218ee9a1" created: node "212cb895", group "cache"
    2022-05-31T11:12:50-07:00: Evaluation status changed: "pending" -> "complete"
==> 2022-05-31T11:12:50-07:00: Evaluation "0890a4fe" finished with status "complete"
==> 2022-05-31T11:12:50-07:00: Monitoring deployment "6eadb641"

Actual Result

==> 2022-05-31T11:03:44-07:00: Monitoring evaluation "9f103bd6"
    2022-05-31T11:03:44-07:00: Evaluation triggered by job "example"
    2022-05-31T11:03:44-07:00: Evaluation within deployment: "0b39702a"
    2022-05-31T11:03:44-07:00: Evaluation status changed: "pending" -> "complete"
==> 2022-05-31T11:03:44-07:00: Evaluation "9f103bd6" finished with status "complete" but failed to place all allocations:
    2022-05-31T11:03:44-07:00: Task Group "cache" (failed to place 1 allocation):
      * Constraint "${attr.consul.version} semver >= 1.7.0": 1 nodes excluded by filter
    2022-05-31T11:03:44-07:00: Evaluation "5a3da30c" waiting for additional capacity to place remainder
==> 2022-05-31T11:03:44-07:00: Monitoring deployment "0b39702a"

Job file (if appropriate)

Nomad Server logs (if appropriate)

Nomad Client logs (if appropriate)

[lgfa29]

Hi @mly32, thanks for the detailed report.

This is a known issue that was fixed in #13044. The root cause is an additional validation that was added in Nomad 1.3.0 for Consul-based service discovery where Consul is not actually present. We unfortunately missed updating the long example.nomad job then.

For now you have a few options:

• as you noticed, you can remove the service block if that doesn't impact your work
• start a Consul dev agent (consul agent -dev)
• use Nomad native service discovery by adding this line to the job:

  service {
    # ...
    provider = "nomad"
  }

I'm going to close this issue since we already have a fix, but let me know if you have any other concerns 🙂

[github-actions]

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