Error connecting to the data source

Hi , i had similar issue , it appears to be the latest image tag , i.e image: master — always seems to break Loki datasource .

Image:
tag: master-ffe1093
Last update: 3 days ago and it works

Have a same issue, nothing help for me. Pulled last images loki and promtail.
In the last messages of Promtail there is not a word about the established connection or failure

promtail_1 | level=info ts=2019-02-09T17:27:45.378030372Z caller=main.go:47 msg=»Starting Promtail» version=»(version=master-58d2d21, branch=master, revision=58d2d21)»
promtail_1 | level=info ts=2019-02-09T17:27:50.37733498Z caller=filetargetmanager.go:165 msg=»Adding target» key=»{job=»varlogs»}»
promtail_1 | level=info ts=2019-02-09T17:27:50.377931998Z caller=filetarget.go:269 msg=»start tailing file» path=/var/log/backupninja.log
promtail_1 | level=info ts=2019-02-09T17:27:50.3782893Z caller=filetarget.go:269 msg=»start tailing file» path=/var/log/boot.log
promtail_1 | level=info ts=2019-02-09T17:27:50.378583606Z caller=filetarget.go:269 msg=»start tailing file» path=/var/log/maillog
promtail_1 | 2019/02/09 17:27:50 Seeked /var/log/backupninja.log — &{Offset:18304 Whence:0}
promtail_1 | 2019/02/09 17:27:50 Seeked /var/log/lastlog — &{Offset:0 Whence:0}
promtail_1 | 2019/02/09 17:27:50 Seeked /var/log/boot.log — &{Offset:95 Whence:0}
promtail_1 | 2019/02/09 17:27:50 Seeked /var/log/tallylog — &{Offset:0 Whence:0}
promtail_1 | 2019/02/09 17:27:50 Seeked /var/log/maillog — &{Offset:0 Whence:0}
promtail_1 | level=info ts=2019-02-09T17:27:50.379321674Z caller=filetarget.go:269 msg=»start tailing file» path=/var/log/tallylog
promtail_1 | level=info ts=2019-02-09T17:27:50.381192173Z caller=filetarget.go:269 msg=»start tailing file» path=/var/log/lastlog
promtail_1 | level=info ts=2019-02-09T17:27:50.381746355Z caller=filetarget.go:269 msg=»start tailing file» path=/var/log/test.log
promtail_1 | level=info ts=2019-02-09T17:27:50.381849633Z caller=filetarget.go:269 msg=»start tailing file» path=/var/log/yum.log
promtail_1 | 2019/02/09 17:27:50 Seeked /var/log/yum.log — &{Offset:22494 Whence:0}
promtail_1 | 2019/02/09 17:27:50 Seeked /var/log/test.log — &{Offset:5 Whence:0}

@wilful share the log of loki please. seems that promail part is normal.

No message is displayed on the Loki side when Promtail starts.

loki_1      | level=info ts=2019-02-11T06:03:35.982717042Z caller=loki.go:122 msg=initialising module=server
loki_1      | level=info ts=2019-02-11T06:03:35.983179243Z caller=gokit.go:36 http=[::]:3100 grpc=[::]:9095 msg="server listening on addresses"
loki_1      | level=info ts=2019-02-11T06:03:35.983718039Z caller=loki.go:122 msg=initialising module=overrides
loki_1      | level=info ts=2019-02-11T06:03:35.983750208Z caller=override.go:33 msg="per-tenant overides disabled"
loki_1      | level=info ts=2019-02-11T06:03:35.983787937Z caller=loki.go:122 msg=initialising module=store
loki_1      | level=info ts=2019-02-11T06:03:35.985754972Z caller=loki.go:122 msg=initialising module=ingester
loki_1      | level=info ts=2019-02-11T06:03:35.987309309Z caller=lifecycler.go:358 msg="entry not found in ring, adding with no tokens"
loki_1      | level=info ts=2019-02-11T06:03:35.987747435Z caller=lifecycler.go:288 msg="auto-joining cluster after timeout"
loki_1      | level=info ts=2019-02-11T06:03:36.004831721Z caller=loki.go:122 msg=initialising module=ring
loki_1      | level=info ts=2019-02-11T06:03:36.005003778Z caller=loki.go:122 msg=initialising module=querier
loki_1      | level=info ts=2019-02-11T06:03:36.005738165Z caller=loki.go:122 msg=initialising module=distributor
loki_1      | level=info ts=2019-02-11T06:03:36.005817828Z caller=loki.go:122 msg=initialising module=all
loki_1      | level=info ts=2019-02-11T06:03:36.005849317Z caller=main.go:45 msg="Starting Loki" version="(version=master-58d2d21, branch=master, revision=58d2d21)"

docker-compose exec promtail sh -c 'cat /etc/promtail/docker-config.yaml'
server:
  http_listen_port: 9080
  grpc_listen_port: 0

positions:
  filename: /tmp/positions.yaml

client:
  url: http://loki:3100/api/prom/push

scrape_configs:
- job_name: system
  entry_parser: raw
  static_configs:
  - targets:
      - localhost
    labels:
      job: varlogs
      __path__: /var/log/*log

docker-compose exec promtail sh -c 'ping loki'
PING loki (172.18.0.2): 56 data bytes
64 bytes from 172.18.0.2: seq=0 ttl=64 time=0.129 ms

I’m having same issue.
here is my complete setup: https://github.com/zajca/docker-server-explore
loki ip is resolved fine docker-compose -f ... exec grafana sh -c 'getent hosts loki' same with loki ip from promtail. Yet I’m getting error Data source connected, but no labels received. Verify that Loki and Promtail is configured properly.

If I access loki ip on port 3100 and url /metrics data are there.

Hello,
I have this problem too
Iam started my prom + loki + grafana stack and some time all is fine (about 15-20 minutes)
After that my «log line» — stop to refresh and make a double events
After 20-30 min — i have this Error:

Error connecting to datasource: Data source connected, but no labels received. Verify that Loki and Promtail is configured properly.

After that iam restarted prom container and all is fine

After 2 weeks of work, the problem returned. Have no idea what happened. UP. Nothing in logs.

Hi all.

You must mount the volume with logs describe in /etc/promtail/docker-config.yaml:

  job: varlogs
  __path__: /var/log/*log

like this:

  promtail:
   image: grafana/promtail:master
   container_name: promtail
   volumes:
     - /var/log:/var/log:ro

Check it!

I seem to be hitting the same problem, to me the problems seems to be that if nothing has been logged for some time (maybe about 20 minutes) then all the logs disappear: Grafana shows the «no label received» error, and trying some API calls such as GET /api/prom/label return nothing when there where some data a few minutes earlier.
I am sending logs to Loki using both Promtail (installed directly as a binary in virtual machines), and direct push (POST /api/prom/push) from some applications.
Edit: I think I should add that if new log lines get pushed, all the logs reappear including what was sent previously, so the data isn’t actually lost.

Ref to #430

Look like only label data was lost

This error also happened with Loki Cloud. (UserID: 2315)

Your first stop when you see this issue is the troubleshooting guide.

If you’re testing things on your laptop, and restart loki or promtail often, you’ll face the problem that your low volume logs are already consumed before loki was ready to receive (start promtail a bit after loki), or promtail already pushed all logs (delete positions file to force a new push), or loki did not have time to flush what if indexed before you restarted it (need to push it again, probably by deleting positions file). We’re still working on making this single-binary use case a bit smoother.

It’s worth noting that these issues wont affect production use of Loki: once it’s running and replicated it can handle restarts without data loss. And if your apps keep producing logs, there will be labels.

Closing this issue, seems to be related to some instability in the earlier versions of promtail/loki (which should hopefully be gone now) and miss-config (which there should hopefully be better docs and support for now)

I’m still seeing this type of issue on a fresh install (using loki-stack chart v0.16.5). Sometimes the labels disappear, sometimes the logs disappear as well. Seems sporadic, didn’t see anything in the logs to explain it.

still seeing the same issue with loki/promtail v0.3.0

same issue here #1173

Is there any config can last loki labels for long time?

Seeing issue also in loki/promtail v0.4.0
On Friday I got this:

curl -G -s  "http://someserver:3100/loki/api/v1/query" --data-urlencode 'query=sum(rate({job="varlogs"}[10m])) by (level)'
{"status":"success","data":{"resultType":"vector","result":[{"metric":{},"value":[1572013966.797,"48.016666666666666"]}]}}

On Monday I got this:

curl -G -s  "http://someserver:3100/loki/api/v1/query" --data-urlencode 'query=sum(rate({job="varlogs"}[10m])) by (level)'
{"status":"success","data":{"resultType":"vector","result":[]}}

Grafana says: «Error connecting to datasource: Data source connected, but no labels received. Verify that Loki and Promtail is configured properly.»
No restarts happened.

Service config from compose file:

  loki:
    image: grafana/loki:v0.4.0
    volumes:
      - ./config/loki/local-config.yaml:/etc/loki/local-config.yaml
      - ./data/loki:/tmp/loki/
    ports:
      - "3100:3100"
    command: -config.file=/etc/loki/local-config.yaml

  promtail:
    image: grafana/promtail:v0.4.0
    volumes:
      - /var/log:/var/log
    command: -config.file=/etc/promtail/docker-config.yaml

loki local-config.yaml:

auth_enabled: false

server:
  http_listen_port: 3100

ingester:
  lifecycler:
    address: 127.0.0.1
    ring:
      kvstore:
        store: inmemory
      replication_factor: 1
    final_sleep: 0s
  chunk_idle_period: 5m
  chunk_retain_period: 30s
  max_transfer_retries: 1

schema_config:
  configs:
  - from: 2018-04-15
    store: boltdb
    object_store: filesystem
    schema: v9
    index:
      prefix: index_
      period: 168h

storage_config:
  boltdb:
    directory: /tmp/loki/index

  filesystem:
    directory: /tmp/loki/chunks

limits_config:
  enforce_metric_name: false
  reject_old_samples: true
  reject_old_samples_max_age: 168h

chunk_store_config:
  max_look_back_period: 0

table_manager:
  chunk_tables_provisioning:
    inactive_read_throughput: 0
    inactive_write_throughput: 0
    provisioned_read_throughput: 0
    provisioned_write_throughput: 0
  index_tables_provisioning:
    inactive_read_throughput: 0
    inactive_write_throughput: 0
    provisioned_read_throughput: 0
    provisioned_write_throughput: 0
  retention_deletes_enabled: false
  retention_period: 0

When that happens can you use logcli and query for recent logs ? It looks like a problem with docker compose or the local config, let’s move the discussion to the other issue #1173 Please give as much details, logs, config , how you send logs, etc…

I seem to be hitting the same problem, to me the problems seems to be that if nothing has been logged for some time (maybe about 20 minutes) then all the logs disappear: Grafana shows the «no label received» error, and trying some API calls such as GET /api/prom/label return nothing when there where some data a few minutes earlier.

@leops I have the same problem with the latest docker images of loki and promtail on a swarm.

curl -G -s "http://<host>:3100/loki/api/v1/label" | jq .

Returns {} when there have not been any new logs for some time and the correct labels if there are new logs (for 5 minutes or so).

I m hitting the same problem in loki+promtail v1.6.1, After replacing with loki+promtail v1.6.0 ,it disappeared
I use Grafana v7.2.1 (72a6c64532)

For the posteriority: What fixed it for me was to make sure I had tenant_id set as tenant1 in the promtail config file:

clients:
  - url: http://REDACTED:3100/loki/api/v1/push
    tenant_id: tenant1