Panic running nomad operator snapshot agent from docs

[notnoop]

Issue

panic: runtime error: invalid memory address running nomad operator snapshot agent config.hcl

Reproduction Steps

1 - Create the following configuration file, change the token, access_key_id, secret_access_key and S3 bucket values accordingly and save it as snap.hcl:

nomad {
	address = "http://127.0.0.1:4646"
	token = "management_token"
}

snapshot {
	interval = 0
	retain = 180
	stale = false
	service = "nomad-snapshot"
	deregister_after = "72h"
	lock_key = "nomad-snapshot/lock"
	max_failures = 3
	prefix = "nomad"
}

log {
	level = "DEBUG"
	enable_syslog = true
	syslog_facility = "LOCAL0"
}

aws_storage {
	access_key_id = "access_key_id"
	secret_access_key = "secret_access_key"
	s3_region = "us-east-1"
	s3_bucket = "s3_bucket_name"
	s3_key_prefix = "nomad-snapshot"
}

2 - Run nomad operator snapshot agent snap.hcl:

It fails with a runtime error.

ubuntu@ip-172-31-27-173:~$ nomad operator snapshot agent snap.hcl
Nomad snapshot agent running!
        Interval: "0s"
          Retain: 824635564512
           Stale: false
   Local Scratch: /tmp
            Mode: one-shot
Snapshot Storage: Amazon S3 -> Region: "us-east-1" Bucket: "rolt-s3-hc" Key Prefix: "nomad-snapshot" Snapshot Name: ""

Log data will now stream in as it occurs:

2020-08-24T21:42:12.908Z [INFO]  snapshotagent.license: automatic snapshot is licensed
panic: runtime error: invalid memory address or nil pointer dereference
[signal SIGSEGV: segmentation violation code=0x1 addr=0x0 pc=0x272d836]

goroutine 1 [running]:
github.com/hashicorp/raft-snapshotagent.(*Agent).snapshotAndRotate(0xc000587040, 0x0, 0x0)
	github.com/hashicorp/raft-snapshotagent@v0.0.0-20200722144111-4f9a8b6ca39e/agent.go:409 +0x176
github.com/hashicorp/raft-snapshotagent.(*Agent).Run(0xc000587040, 0x3b556c0, 0xc00057a880, 0x3b97740, 0xc00058e090)
	github.com/hashicorp/raft-snapshotagent@v0.0.0-20200722144111-4f9a8b6ca39e/agent.go:144 +0x45d
github.com/hashicorp/nomad/command.(*OperatorSnapshotAgentCommand).Run(0xc00053a4d0, 0xc00004e0e0, 0x1, 0x1, 0x0)
	github.com/hashicorp/nomad/command/operator_snapshot_agent_ent.go:225 +0xe28
github.com/mitchellh/cli.(*CLI).Run(0xc0005c48c0, 0xc0005c48c0, 0xc0005c1180, 0x3c)
	github.com/mitchellh/cli@v1.1.0/cli.go:260 +0x1da
main.RunCustom(0xc00004e0b0, 0x4, 0x4, 0xc0000a2058)
	github.com/hashicorp/nomad/main.go:139 +0x48f
main.Run(...)
	github.com/hashicorp/nomad/main.go:84
main.main()
	github.com/hashicorp/nomad/main.go:80 +0x64
ubuntu@ip-172-31-27-173:~$

3 - Add local_storage block to the config file and run nomad operator snapshot agent snap.hcl again:

local_storage {
  path = "/tmp"
}

It works as expected:

ubuntu@ip-172-31-27-173:~$ nomad operator snapshot agent snap.hcl
Nomad snapshot agent running!
        Interval: "0s"
          Retain: 824635825624
           Stale: false
   Local Scratch: /tmp
            Mode: one-shot
Snapshot Storage: Amazon S3 -> Region: "us-east-1" Bucket: "rolt-s3-hc" Key Prefix: "nomad-snapshot" Snapshot Name: ""

Log data will now stream in as it occurs:

2020-08-24T21:43:18.347Z [INFO]  snapshotagent.license: automatic snapshot is licensed
2020-08-24T21:43:18.731Z [INFO]  snapshotagent.snapshot: Saved snapshot: id=1598305398362362752
2020-08-24T21:43:18.826Z [DEBUG] snapshotagent.snapshot: Rotated snapshots: number_deleted=0
ubuntu@ip-172-31-27-173:~$

Expected behavior


It should not panic and, as per the documentation, only one storage block should be required.

Workaround: Add local_storage block to the config or pass -local-path argument to the CLI command.

Environment

ubuntu@ip-172-31-27-173:~$ nomad version
Nomad v0.12.2+ent (4dcbc0741092b7955f77768a796ef088f18b9196)
ubuntu@ip-172-31-27-173:~$

ubuntu@ip-172-31-27-173:~$ lsb_release -a
No LSB modules are available.
Distributor ID:	Ubuntu
Description:	Ubuntu 16.04.6 LTS
Release:	16.04
Codename:	xenial
ubuntu@ip-172-31-27-173:~$

ubuntu@ip-172-31-27-173:~$ nomad license get
Product        = nomad
License Status = valid
License ID     = temporary-license
Customer ID    = temporary license customer
Expires At     = 2020-08-25 03:37:36.831789619 +0000 UTC
Terminates At  = 2020-08-25 03:37:36.831789619 +0000 UTC
Datacenter     = *
Modules:
	governance-policy
	multicluster-and-efficiency
Licensed Features:
	Automated Upgrades
	Enhanced Read Scalability
	Redundancy Zones
	Namespaces
	Resource Quotas
	Audit Logging
	Sentinel Policies
	Multiregion Deployments
	Automated Backups
	Multi-Vault Namespaces
ubuntu@ip-172-31-27-173:~$

[notnoop]

Fixed in 0.12.4

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