Proposal

Use case. Why is this important?

centos7 + docker-ce + prometheus

Bug Report

no change docker default: Docker Root Dir
i can docker run prometheus right

when i change Docker Root Dir eg:Docker Root Dir: /data/docker

I do cp -R /var/lib/docker /data/

then i also start prometheus is failed

error:
level=info ts=2019-08-30T05:14:43.159Z caller=main.go:293 msg="no time or size retention was set so using the default time retention" duration=15d
level=info ts=2019-08-30T05:14:43.159Z caller=main.go:329 msg="Starting Prometheus" version="(version=2.12.0, branch=HEAD, revision=43acd0e2e93f9f70c49b2267efa0124f1e759e86)"
level=info ts=2019-08-30T05:14:43.159Z caller=main.go:330 build_context="(go=go1.12.8, user=root@7a9dbdbe0cc7, date=20190818-13:53:16)"
level=info ts=2019-08-30T05:14:43.159Z caller=main.go:331 host_details="(Linux 3.10.0-957.el7.x86_64 #1 SMP Thu Oct 4 20:48:51 UTC 2018 x86_64 4d7bb264eb92 (none))"
level=info ts=2019-08-30T05:14:43.160Z caller=main.go:332 fd_limits="(soft=1048576, hard=1048576)"
level=info ts=2019-08-30T05:14:43.160Z caller=main.go:333 vm_limits="(soft=unlimited, hard=unlimited)"
level=error ts=2019-08-30T05:14:43.160Z caller=query_logger.go:82 component=activeQueryTracker msg="Error opening query log file" file=/prometheus/queries.active err="open /prometheus/queries.active: permission denied"
panic: Unable to create mmap-ed active query log

goroutine 1 [running]:
github.com/prometheus/prometheus/promql.NewActiveQueryTracker(0x7ffef5ed3f02, 0xb, 0x14, 0x2a6b7c0, 0xc000596cf0, 0x2a6b7c0)
/app/promql/query_logger.go:112 +0x4d2
main.main()
/app/cmd/prometheus/main.go:361 +0x52bd
[root@devops-monitoring ~]#